| // Graphite-specific fragment shader code |
| |
| const int $kTileModeClamp = 0; |
| const int $kTileModeRepeat = 1; |
| const int $kTileModeMirror = 2; |
| const int $kTileModeDecal = 3; |
| |
| const int $kFilterModeNearest = 0; |
| const int $kFilterModeLinear = 1; |
| |
| const int $kTFTypeSRGB = 1; |
| const int $kTFTypePQ = 2; |
| const int $kTFTypeHLG = 3; |
| const int $kTFTypeHLGinv = 4; |
| |
| const int $kColorSpaceXformFlagUnpremul = 0x1; |
| const int $kColorSpaceXformFlagLinearize = 0x2; |
| const int $kColorSpaceXformFlagGamutTransform = 0x4; |
| const int $kColorSpaceXformFlagEncode = 0x8; |
| const int $kColorSpaceXformFlagPremul = 0x10; |
| const int $kColorSpaceXformFlagAlphaSwizzle = 0x20; |
| |
| const int $kMaskFormatA8 = 0; |
| const int $kMaskFormatA565 = 1; |
| const int $kMaskFormatARGB = 2; |
| |
| const int $kShapeTypeRect = 0; |
| const int $kShapeTypeRRect = 1; |
| const int $kShapeTypeCircle = 2; |
| |
| // Matches GrTextureEffect::kLinearInset, to make sure we don't touch an outer |
| // row or column with a weight of 0 when linear filtering. |
| const float $kLinearInset = 0.5 + 0.00001; |
| |
| $pure half4 sk_error() { |
| return half4(1.0, 0.0, 0.0, 1.0); |
| } |
| |
| $pure half4 sk_passthrough(half4 color) { |
| return color; |
| } |
| |
| $pure half4 sk_solid_shader(float4 colorParam) { |
| return half4(colorParam); |
| } |
| |
| $pure half4 sk_rgb_opaque(float4 colorParam) { |
| return half4(colorParam.rgb, 1.0); |
| } |
| |
| $pure half4 sk_alpha_only(float4 colorParam) { |
| return half4(0.0, 0.0, 0.0, colorParam.a); |
| } |
| |
| $pure float $apply_xfer_fn(int kind, float x, half4 cs[2]) { |
| float G = cs[0][0], A = cs[0][1], B = cs[0][2], C = cs[0][3], |
| D = cs[1][0], E = cs[1][1], F = cs[1][2]; |
| float s = sign(x); |
| x = abs(x); |
| switch (kind) { |
| case $kTFTypeSRGB: |
| x = (x < D) ? (C * x) + F |
| : pow(A * x + B, G) + E; |
| break; |
| case $kTFTypePQ: |
| float x_C = pow(x, C); |
| x = pow(max(A + B * x_C, 0) / (D + E * x_C), F); |
| break; |
| case $kTFTypeHLG: |
| x = (x * A <= 1) ? pow(x * A, B) |
| : exp((x - E) * C) + D; |
| x *= (F + 1); |
| break; |
| case $kTFTypeHLGinv: |
| x /= (F + 1); |
| x = (x <= 1) ? A * pow(x, B) |
| : C * log(x - D) + E; |
| break; |
| } |
| return s * x; |
| } |
| |
| $pure half4 sk_color_space_transform(half4 halfColor, |
| int flags, |
| int srcKind, |
| half3x3 gamutTransform, |
| int dstKind, |
| half4x4 coeffs) { |
| float4 color = float4(halfColor); |
| |
| if (bool(flags & $kColorSpaceXformFlagUnpremul)) { |
| color = unpremul(color); |
| } |
| |
| if (bool(flags & $kColorSpaceXformFlagLinearize)) { |
| half4 srcCoeffs[2]; |
| srcCoeffs[0] = coeffs[0]; |
| srcCoeffs[1] = coeffs[1]; |
| color.r = $apply_xfer_fn(srcKind, color.r, srcCoeffs); |
| color.g = $apply_xfer_fn(srcKind, color.g, srcCoeffs); |
| color.b = $apply_xfer_fn(srcKind, color.b, srcCoeffs); |
| } |
| if (bool(flags & $kColorSpaceXformFlagGamutTransform)) { |
| color.rgb = gamutTransform * color.rgb; |
| } |
| if (bool(flags & $kColorSpaceXformFlagEncode)) { |
| half4 dstCoeffs[2]; |
| dstCoeffs[0] = coeffs[2]; |
| dstCoeffs[1] = coeffs[3]; |
| color.r = $apply_xfer_fn(dstKind, color.r, dstCoeffs); |
| color.g = $apply_xfer_fn(dstKind, color.g, dstCoeffs); |
| color.b = $apply_xfer_fn(dstKind, color.b, dstCoeffs); |
| } |
| |
| if (bool(flags & $kColorSpaceXformFlagPremul)) { |
| color.rgb *= color.a; |
| } |
| return half4(color); |
| } |
| |
| $pure half4 $color_space_transform_swizzle(half4 halfColor, |
| int flags, |
| int srcKind, |
| half3x3 gamutTransform, |
| int dstKind, |
| half4x4 coeffs) { |
| if (flags == 0) { |
| return halfColor; |
| } else { |
| if (bool(flags & $kColorSpaceXformFlagAlphaSwizzle)) { |
| halfColor.a = dot(halfColor.r1, half2(coeffs[1][3], coeffs[3][3])); |
| } |
| return sk_color_space_transform(halfColor, flags, srcKind, gamutTransform, dstKind, coeffs); |
| } |
| } |
| |
| $pure float $tile(int tileMode, float f, float low, float high) { |
| switch (tileMode) { |
| case $kTileModeClamp: |
| return clamp(f, low, high); |
| |
| case $kTileModeRepeat: { |
| float length = high - low; |
| return (mod(f - low, length) + low); |
| } |
| case $kTileModeMirror: { |
| float length = high - low; |
| float length2 = 2 * length; |
| float tmp = mod(f - low, length2); |
| return (mix(tmp, length2 - tmp, step(length, tmp)) + low); |
| } |
| default: // $kTileModeDecal |
| // Decal is handled later. |
| return f; |
| } |
| } |
| |
| $pure half4 $sample_image(float2 pos, float2 invImgSize, sampler2D s) { |
| return sample(s, pos * invImgSize); |
| } |
| |
| $pure half4 $sample_image_subset(float2 pos, |
| float2 invImgSize, |
| float4 subset, |
| int tileModeX, |
| int tileModeY, |
| int filterMode, |
| float2 linearFilterInset, |
| sampler2D s) { |
| // Do hard-edge shader transitions to the border color for nearest-neighbor decal tiling at the |
| // subset boundaries. Snap the input coordinates to nearest neighbor before comparing to the |
| // subset rect, to avoid GPU interpolation errors. See https://crbug.com/skia/10403. |
| if (tileModeX == $kTileModeDecal && filterMode == $kFilterModeNearest) { |
| float snappedX = floor(pos.x) + 0.5; |
| if (snappedX < subset.x || snappedX > subset.z) { |
| return half4(0); |
| } |
| } |
| if (tileModeY == $kTileModeDecal && filterMode == $kFilterModeNearest) { |
| float snappedY = floor(pos.y) + 0.5; |
| if (snappedY < subset.y || snappedY > subset.w) { |
| return half4(0); |
| } |
| } |
| |
| pos.x = $tile(tileModeX, pos.x, subset.x, subset.z); |
| pos.y = $tile(tileModeY, pos.y, subset.y, subset.w); |
| |
| // Clamp to an inset subset to prevent sampling neighboring texels when coords fall exactly at |
| // texel boundaries. |
| float4 insetClamp; |
| if (filterMode == $kFilterModeNearest) { |
| insetClamp = float4(floor(subset.xy) + $kLinearInset, ceil(subset.zw) - $kLinearInset); |
| } else { |
| insetClamp = float4(subset.xy + linearFilterInset.x, subset.zw - linearFilterInset.y); |
| } |
| float2 clampedPos = clamp(pos, insetClamp.xy, insetClamp.zw); |
| half4 color = $sample_image(clampedPos, invImgSize, s); |
| |
| if (filterMode == $kFilterModeLinear) { |
| // Remember the amount the coord moved for clamping. This is used to implement shader-based |
| // filtering for repeat and decal tiling. |
| half2 error = half2(pos - clampedPos); |
| half2 absError = abs(error); |
| |
| // Do 1 or 3 more texture reads depending on whether both x and y tiling modes are repeat |
| // and whether we're near a single subset edge or a corner. Then blend the multiple reads |
| // using the error values calculated above. |
| bool sampleExtraX = tileModeX == $kTileModeRepeat; |
| bool sampleExtraY = tileModeY == $kTileModeRepeat; |
| if (sampleExtraX || sampleExtraY) { |
| float extraCoordX; |
| float extraCoordY; |
| half4 extraColorX; |
| half4 extraColorY; |
| if (sampleExtraX) { |
| extraCoordX = error.x > 0 ? insetClamp.x : insetClamp.z; |
| extraColorX = $sample_image(float2(extraCoordX, clampedPos.y), |
| invImgSize, s); |
| } |
| if (sampleExtraY) { |
| extraCoordY = error.y > 0 ? insetClamp.y : insetClamp.w; |
| extraColorY = $sample_image(float2(clampedPos.x, extraCoordY), |
| invImgSize, s); |
| } |
| if (sampleExtraX && sampleExtraY) { |
| half4 extraColorXY = $sample_image(float2(extraCoordX, extraCoordY), |
| invImgSize, s); |
| color = mix(mix(color, extraColorX, absError.x), |
| mix(extraColorY, extraColorXY, absError.x), |
| absError.y); |
| } else if (sampleExtraX) { |
| color = mix(color, extraColorX, absError.x); |
| } else if (sampleExtraY) { |
| color = mix(color, extraColorY, absError.y); |
| } |
| } |
| |
| // Do soft edge shader filtering for decal tiling and linear filtering using the error |
| // values calculated above. |
| if (tileModeX == $kTileModeDecal) { |
| color *= max(1 - absError.x, 0); |
| } |
| if (tileModeY == $kTileModeDecal) { |
| color *= max(1 - absError.y, 0); |
| } |
| } |
| |
| return color; |
| } |
| |
| $pure half4 $cubic_filter_image(float2 pos, |
| float2 invImgSize, |
| float4 subset, |
| int tileModeX, |
| int tileModeY, |
| half4x4 coeffs, |
| sampler2D s) { |
| // Determine pos's fractional offset f between texel centers. |
| float2 f = fract(pos - 0.5); |
| // Sample 16 points at 1-pixel intervals from [p - 1.5 ... p + 1.5]. |
| pos -= 1.5; |
| // Snap to texel centers to prevent sampling neighboring texels. |
| pos = floor(pos) + 0.5; |
| |
| half4 wx = coeffs * half4(1.0, f.x, f.x * f.x, f.x * f.x * f.x); |
| half4 wy = coeffs * half4(1.0, f.y, f.y * f.y, f.y * f.y * f.y); |
| half4 color = half4(0); |
| for (int y = 0; y < 4; ++y) { |
| half4 rowColor = half4(0); |
| for (int x = 0; x < 4; ++x) { |
| rowColor += wx[x] * $sample_image_subset(pos + float2(x, y), invImgSize, subset, |
| tileModeX, tileModeY, $kFilterModeNearest, |
| float2($kLinearInset), s); |
| } |
| color += wy[y] * rowColor; |
| } |
| // Bicubic can send colors out of range, so clamp to get them back in gamut, assuming premul. |
| color.a = saturate(color.a); |
| color.rgb = clamp(color.rgb, half3(0.0), color.aaa); |
| return color; |
| } |
| |
| $pure half4 sk_image_shader(float2 coords, |
| float2 invImgSize, |
| float4 subset, |
| int tileModeX, |
| int tileModeY, |
| int filterMode, |
| int csXformFlags, |
| int csXformSrcKind, |
| half3x3 csXformGamutTransform, |
| int csXformDstKind, |
| half4x4 csXformCoeffs, |
| sampler2D s) { |
| half4 sampleColor = $sample_image_subset(coords, invImgSize, subset, tileModeX, tileModeY, |
| filterMode, float2($kLinearInset), s); |
| return $color_space_transform_swizzle(sampleColor, csXformFlags, csXformSrcKind, |
| csXformGamutTransform, csXformDstKind, csXformCoeffs); |
| } |
| |
| $pure half4 sk_cubic_image_shader(float2 coords, |
| float2 invImgSize, |
| float4 subset, |
| int tileModeX, |
| int tileModeY, |
| half4x4 cubicCoeffs, |
| int csXformFlags, |
| int csXformSrcKind, |
| half3x3 csXformGamutTransform, |
| int csXformDstKind, |
| half4x4 csXformCoeffs, |
| sampler2D s) { |
| half4 sampleColor = $cubic_filter_image(coords, invImgSize, subset, tileModeX, tileModeY, |
| cubicCoeffs, s); |
| return $color_space_transform_swizzle(sampleColor, csXformFlags, csXformSrcKind, |
| csXformGamutTransform, csXformDstKind, csXformCoeffs); |
| } |
| |
| $pure half4 sk_hw_image_shader(float2 coords, |
| float2 invImgSize, |
| int csXformFlags, |
| int csXformSrcKind, |
| half3x3 csXformGamutTransform, |
| int csXformDstKind, |
| half4x4 csXformCoeffs, |
| sampler2D s) { |
| half4 sampleColor = $sample_image(coords, invImgSize, s); |
| return $color_space_transform_swizzle(sampleColor, csXformFlags, csXformSrcKind, |
| csXformGamutTransform, csXformDstKind, csXformCoeffs); |
| } |
| |
| $pure half4 $yuv_to_rgb(half4 sampleColorY, |
| half4 sampleColorU, |
| half4 sampleColorV, |
| half4 sampleColorA, |
| half4 channelSelectY, |
| half4 channelSelectU, |
| half4 channelSelectV, |
| half4 channelSelectA, |
| half3x3 yuvToRGBMatrix, |
| float3 yuvToRGBTranslate) { |
| float Y = dot(channelSelectY, sampleColorY); |
| float U = dot(channelSelectU, sampleColorU); |
| float V = dot(channelSelectV, sampleColorV); |
| half3 preColor = half3(Y, U, V); |
| half4 sampleColor; |
| sampleColor.rgb = saturate(yuvToRGBMatrix * preColor.rgb + half3(yuvToRGBTranslate)); |
| sampleColor.a = dot(channelSelectA, sampleColorA); |
| // premul alpha |
| sampleColor.rgb *= sampleColor.a; |
| |
| return sampleColor; |
| } |
| |
| $pure half4 sk_yuv_image_shader(float2 coords, |
| float2 invImgSizeY, |
| float2 invImgSizeUV, // Relative to Y's coordinate space |
| float4 subset, |
| float2 linearFilterUVInset, |
| int tileModeX, |
| int tileModeY, |
| int filterModeY, |
| int filterModeUV, |
| half4 channelSelectY, |
| half4 channelSelectU, |
| half4 channelSelectV, |
| half4 channelSelectA, |
| half3x3 yuvToRGBMatrix, |
| float3 yuvToRGBTranslate, |
| sampler2D sY, |
| sampler2D sU, |
| sampler2D sV, |
| sampler2D sA) { |
| // If the filter modes are different between Y and UV, this means that |
| // the base filtermode is nearest and we have to snap the coords to Y's |
| // texel centers to get the correct positions for UV. |
| if (filterModeY != filterModeUV) { |
| coords = floor(coords) + 0.5; |
| } |
| |
| int tileModeX_UV = tileModeX == $kTileModeDecal ? $kTileModeClamp : tileModeX; |
| int tileModeY_UV = tileModeY == $kTileModeDecal ? $kTileModeClamp : tileModeY; |
| |
| half4 sampleColorY, sampleColorU, sampleColorV, sampleColorA; |
| sampleColorY = $sample_image_subset(coords, invImgSizeY, subset, tileModeX, tileModeY, |
| filterModeY, float2($kLinearInset), sY); |
| sampleColorU = $sample_image_subset(coords, invImgSizeUV, subset, tileModeX_UV, tileModeY_UV, |
| filterModeUV, linearFilterUVInset, sU); |
| sampleColorV = $sample_image_subset(coords, invImgSizeUV, subset, tileModeX_UV, tileModeY_UV, |
| filterModeUV, linearFilterUVInset, sV); |
| if (channelSelectA == half4(1)) { |
| sampleColorA = half4(0, 0, 0, 1); |
| } else { |
| sampleColorA = $sample_image_subset(coords, invImgSizeY, subset, tileModeX, tileModeY, |
| filterModeY, float2($kLinearInset), sA); |
| } |
| |
| return $yuv_to_rgb(sampleColorY, sampleColorU, sampleColorV, sampleColorA, |
| channelSelectY, channelSelectU, channelSelectV, channelSelectA, |
| yuvToRGBMatrix, yuvToRGBTranslate); |
| } |
| |
| $pure half4 sk_cubic_yuv_image_shader(float2 coords, |
| float2 invImgSizeY, |
| float2 invImgSizeUV, // Relative to Y's coordinate space |
| float4 subset, |
| int tileModeX, |
| int tileModeY, |
| half4x4 cubicCoeffs, |
| half4 channelSelectY, |
| half4 channelSelectU, |
| half4 channelSelectV, |
| half4 channelSelectA, |
| half3x3 yuvToRGBMatrix, |
| float3 yuvToRGBTranslate, |
| sampler2D sY, |
| sampler2D sU, |
| sampler2D sV, |
| sampler2D sA) { |
| int tileModeX_UV = tileModeX == $kTileModeDecal ? $kTileModeClamp : tileModeX; |
| int tileModeY_UV = tileModeY == $kTileModeDecal ? $kTileModeClamp : tileModeY; |
| |
| half4 sampleColorY, sampleColorU, sampleColorV, sampleColorA; |
| sampleColorY = $cubic_filter_image(coords, invImgSizeY, subset, tileModeX, tileModeY, |
| cubicCoeffs, sY); |
| sampleColorU = $cubic_filter_image(coords, invImgSizeUV, subset, tileModeX_UV, tileModeY_UV, |
| cubicCoeffs, sU); |
| sampleColorV = $cubic_filter_image(coords, invImgSizeUV, subset, tileModeX_UV, tileModeY_UV, |
| cubicCoeffs, sV); |
| if (channelSelectA == half4(1)) { |
| sampleColorA = half4(0, 0, 0, 1); |
| } else { |
| sampleColorA = $cubic_filter_image(coords, invImgSizeY, subset, tileModeX, tileModeY, |
| cubicCoeffs, sA); |
| } |
| |
| return $yuv_to_rgb(sampleColorY, sampleColorU, sampleColorV, sampleColorA, |
| channelSelectY, channelSelectU, channelSelectV, channelSelectA, |
| yuvToRGBMatrix, yuvToRGBTranslate); |
| } |
| |
| $pure half4 sk_dither_shader(half4 colorIn, |
| float2 coords, |
| half range, |
| sampler2D lut) { |
| const float kImgSize = 8; |
| |
| half value = sample(lut, coords / kImgSize).r - 0.5; // undo the bias in the table |
| // For each color channel, add the random offset to the channel value and then clamp |
| // between 0 and alpha to keep the color premultiplied. |
| return half4(clamp(colorIn.rgb + value * range, 0.0, colorIn.a), colorIn.a); |
| } |
| |
| $pure float2 $tile_grad(int tileMode, float2 t) { |
| switch (tileMode) { |
| case $kTileModeClamp: |
| t.x = saturate(t.x); |
| break; |
| |
| case $kTileModeRepeat: |
| t.x = fract(t.x); |
| break; |
| |
| case $kTileModeMirror: { |
| float t_1 = t.x - 1; |
| t.x = t_1 - 2 * floor(t_1 * 0.5) - 1; |
| if (sk_Caps.mustDoOpBetweenFloorAndAbs) { |
| // At this point the expected value of tiled_t should between -1 and 1, so this |
| // clamp has no effect other than to break up the floor and abs calls and make sure |
| // the compiler doesn't merge them back together. |
| t.x = clamp(t.x, -1, 1); |
| } |
| t.x = abs(t.x); |
| break; |
| } |
| |
| case $kTileModeDecal: |
| if (t.x < 0 || t.x > 1) { |
| return float2(0, -1); |
| } |
| break; |
| } |
| |
| return t; |
| } |
| |
| $pure half4 $colorize_grad_4(float4 colorsParam[4], float4 offsetsParam, float2 t) { |
| if (t.y < 0) { |
| return half4(0); |
| |
| } else if (t.x <= offsetsParam[0]) { |
| return half4(colorsParam[0]); |
| } else if (t.x < offsetsParam[1]) { |
| return half4(mix(colorsParam[0], colorsParam[1], (t.x - offsetsParam[0]) / |
| (offsetsParam[1] - offsetsParam[0]))); |
| } else if (t.x < offsetsParam[2]) { |
| return half4(mix(colorsParam[1], colorsParam[2], (t.x - offsetsParam[1]) / |
| (offsetsParam[2] - offsetsParam[1]))); |
| } else if (t.x < offsetsParam[3]) { |
| return half4(mix(colorsParam[2], colorsParam[3], (t.x - offsetsParam[2]) / |
| (offsetsParam[3] - offsetsParam[2]))); |
| } else { |
| return half4(colorsParam[3]); |
| } |
| } |
| |
| $pure half4 $colorize_grad_8(float4 colorsParam[8], float4 offsetsParam[2], float2 t) { |
| if (t.y < 0) { |
| return half4(0); |
| |
| // Unrolled binary search through intervals |
| // ( .. 0), (0 .. 1), (1 .. 2), (2 .. 3), (3 .. 4), (4 .. 5), (5 .. 6), (6 .. 7), (7 .. ). |
| } else if (t.x < offsetsParam[1][0]) { |
| if (t.x < offsetsParam[0][2]) { |
| if (t.x <= offsetsParam[0][0]) { |
| return half4(colorsParam[0]); |
| } else if (t.x < offsetsParam[0][1]) { |
| return half4(mix(colorsParam[0], colorsParam[1], |
| (t.x - offsetsParam[0][0]) / |
| (offsetsParam[0][1] - offsetsParam[0][0]))); |
| } else { |
| return half4(mix(colorsParam[1], colorsParam[2], |
| (t.x - offsetsParam[0][1]) / |
| (offsetsParam[0][2] - offsetsParam[0][1]))); |
| } |
| } else { |
| if (t.x < offsetsParam[0][3]) { |
| return half4(mix(colorsParam[2], colorsParam[3], |
| (t.x - offsetsParam[0][2]) / |
| (offsetsParam[0][3] - offsetsParam[0][2]))); |
| } else { |
| return half4(mix(colorsParam[3], colorsParam[4], |
| (t.x - offsetsParam[0][3]) / |
| (offsetsParam[1][0] - offsetsParam[0][3]))); |
| } |
| } |
| } else { |
| if (t.x < offsetsParam[1][2]) { |
| if (t.x < offsetsParam[1][1]) { |
| return half4(mix(colorsParam[4], colorsParam[5], |
| (t.x - offsetsParam[1][0]) / |
| (offsetsParam[1][1] - offsetsParam[1][0]))); |
| } else { |
| return half4(mix(colorsParam[5], colorsParam[6], |
| (t.x - offsetsParam[1][1]) / |
| (offsetsParam[1][2] - offsetsParam[1][1]))); |
| } |
| } else { |
| if (t.x < offsetsParam[1][3]) { |
| return half4(mix(colorsParam[6], colorsParam[7], |
| (t.x - offsetsParam[1][2]) / |
| (offsetsParam[1][3] - offsetsParam[1][2]))); |
| } else { |
| return half4(colorsParam[7]); |
| } |
| } |
| } |
| } |
| |
| half4 $colorize_grad_tex(sampler2D colorsAndOffsetsSampler, int numStops, float2 t) { |
| const float kColorCoord = 0.25; |
| const float kOffsetCoord = 0.75; |
| |
| if (t.y < 0) { |
| return half4(0); |
| } else if (t.x == 0) { |
| return sampleLod(colorsAndOffsetsSampler, float2(0, kColorCoord), 0); |
| } else if (t.x == 1) { |
| return sampleLod(colorsAndOffsetsSampler, float2(1, kColorCoord), 0); |
| } else { |
| float low = 0; |
| float high = float(numStops); |
| float invNumStops = 1.0 / high; |
| for (int loop = 1; loop < numStops; loop += loop) { |
| float mid = floor((low + high) * 0.5); |
| float samplePos = (mid + 0.5) * invNumStops; |
| |
| float2 tmp = sampleLod(colorsAndOffsetsSampler, float2(samplePos, kOffsetCoord), 0).xy; |
| float offset = ldexp(tmp.x, int(tmp.y)); |
| |
| if (t.x < offset) { |
| high = mid; |
| } else { |
| low = mid; |
| } |
| } |
| |
| high = (low + 1.5) * invNumStops; |
| low = (low + 0.5) * invNumStops; |
| half4 color0 = sampleLod(colorsAndOffsetsSampler, float2(low, kColorCoord), 0); |
| half4 color1 = sampleLod(colorsAndOffsetsSampler, float2(high, kColorCoord), 0); |
| |
| float2 tmp = sampleLod(colorsAndOffsetsSampler, float2(low, kOffsetCoord), 0).xy; |
| float offset0 = ldexp(tmp.x, int(tmp.y)); |
| |
| tmp = sampleLod(colorsAndOffsetsSampler, float2(high, kOffsetCoord), 0).xy; |
| float offset1 = ldexp(tmp.x, int(tmp.y)); |
| |
| return half4(mix(color0, color1, |
| (t.x - offset0) / |
| (offset1 - offset0))); |
| } |
| } |
| |
| $pure float2 $linear_grad_layout(float2 pos) { |
| return float2(pos.x, 1); |
| } |
| |
| $pure float2 $radial_grad_layout(float2 pos) { |
| float t = length(pos); |
| return float2(t, 1); |
| } |
| |
| $pure float2 $sweep_grad_layout(float biasParam, float scaleParam, float2 pos) { |
| // Some devices incorrectly implement atan2(y,x) as atan(y/x). In actuality it is |
| // atan2(y,x) = 2 * atan(y / (sqrt(x^2 + y^2) + x)). To work around this we pass in |
| // (sqrt(x^2 + y^2) + x) as the second parameter to atan2 in these cases. We let the device |
| // handle the undefined behavior if the second parameter is 0, instead of doing the divide |
| // ourselves and calling atan with the quotient. |
| float angle; |
| if (sk_Caps.atan2ImplementedAsAtanYOverX) { |
| angle = 2 * atan(-pos.y, length(pos) - pos.x); |
| } else { |
| // Hardcode pi/2 for the angle when x == 0, to avoid undefined behavior in this |
| // case. This hasn't proven to be necessary in the atan workaround case. |
| angle = pos.x != 0.0 ? atan(-pos.y, -pos.x) : sign(pos.y) * -1.5707963267949; |
| } |
| |
| // 0.1591549430918 is 1/(2*pi), used since atan returns values [-pi, pi] |
| float t = (angle * 0.1591549430918 + 0.5 + biasParam) * scaleParam; |
| return float2(t, 1); |
| } |
| |
| $pure float2 $conical_grad_layout(float radius0, |
| float dRadius, |
| float a, |
| float invA, |
| float2 pos) { |
| // When writing uniform values, if the gradient is radial, we encode a == 0 and since |
| // the linear edge case is when a == 0, we differentiate the radial case with invA == 1. |
| if (a == 0 && invA == 1) { |
| // Radial case |
| float t = length(pos) * dRadius - radius0; |
| |
| return float2(t, 1); |
| } else { |
| // Focal/strip case. |
| float c = dot(pos, pos) - radius0 * radius0; |
| float negB = 2 * (dRadius * radius0 + pos.x); |
| |
| float t; |
| if (a == 0) { |
| // Linear case, both circles intersect as exactly one point |
| // with the focal point sitting on that point. |
| |
| // It is highly unlikely that b and c would be 0 resulting in NaN, if b == 0 due to |
| // a specific translation, it would result is +/-Inf which propogates the sign to |
| // isValid resulting in how the pixel is expected to look. |
| t = c / negB; |
| } else { |
| // Quadratic case |
| float d = negB*negB - 4*a*c; |
| if (d < 0) { |
| return float2(0, -1); |
| } |
| |
| // T should be as large as possible, so when one circle fully encloses the other, |
| // the sign will be positive or negative depending on the sign of dRadius. |
| // When this isn't the case and they form a cone, the sign will always be positive. |
| float quadSign = sign(1 - dRadius); |
| t = invA * (negB + quadSign * sqrt(d)); |
| } |
| |
| // Interpolated radius must be positive. |
| float isValid = sign(t * dRadius + radius0); |
| return float2(t, isValid); |
| } |
| } |
| |
| $pure half4 sk_linear_grad_4_shader(float2 coords, |
| float4 colorsParam[4], |
| float4 offsetsParam, |
| int tileMode, |
| int colorSpace, |
| int doUnpremul) { |
| float2 t = $linear_grad_layout(coords); |
| t = $tile_grad(tileMode, t); |
| half4 color = $colorize_grad_4(colorsParam, offsetsParam, t); |
| return $interpolated_to_rgb_unpremul(color, colorSpace, doUnpremul); |
| } |
| |
| $pure half4 sk_linear_grad_8_shader(float2 coords, |
| float4 colorsParam[8], |
| float4 offsetsParam[2], |
| int tileMode, |
| int colorSpace, |
| int doUnpremul) { |
| float2 t = $linear_grad_layout(coords); |
| t = $tile_grad(tileMode, t); |
| half4 color = $colorize_grad_8(colorsParam, offsetsParam, t); |
| return $interpolated_to_rgb_unpremul(color, colorSpace, doUnpremul); |
| } |
| |
| $pure half4 sk_linear_grad_tex_shader(float2 coords, |
| int numStops, |
| int tileMode, |
| int colorSpace, |
| int doUnpremul, |
| sampler2D colorAndOffsetSampler) { |
| float2 t = $linear_grad_layout(coords); |
| t = $tile_grad(tileMode, t); |
| half4 color = $colorize_grad_tex(colorAndOffsetSampler, numStops, t); |
| return $interpolated_to_rgb_unpremul(color, colorSpace, doUnpremul); |
| } |
| |
| $pure half4 sk_radial_grad_4_shader(float2 coords, |
| float4 colorsParam[4], |
| float4 offsetsParam, |
| int tileMode, |
| int colorSpace, |
| int doUnpremul) { |
| float2 t = $radial_grad_layout(coords); |
| t = $tile_grad(tileMode, t); |
| half4 color = $colorize_grad_4(colorsParam, offsetsParam, t); |
| return $interpolated_to_rgb_unpremul(color, colorSpace, doUnpremul); |
| } |
| |
| $pure half4 sk_radial_grad_8_shader(float2 coords, |
| float4 colorsParam[8], |
| float4 offsetsParam[2], |
| int tileMode, |
| int colorSpace, |
| int doUnpremul) { |
| float2 t = $radial_grad_layout(coords); |
| t = $tile_grad(tileMode, t); |
| half4 color = $colorize_grad_8(colorsParam, offsetsParam, t); |
| return $interpolated_to_rgb_unpremul(color, colorSpace, doUnpremul); |
| } |
| |
| $pure half4 sk_radial_grad_tex_shader(float2 coords, |
| int numStops, |
| int tileMode, |
| int colorSpace, |
| int doUnpremul, |
| sampler2D colorAndOffsetSampler) { |
| float2 t = $radial_grad_layout(coords); |
| t = $tile_grad(tileMode, t); |
| half4 color = $colorize_grad_tex(colorAndOffsetSampler, numStops, t); |
| return $interpolated_to_rgb_unpremul(color, colorSpace, doUnpremul); |
| } |
| |
| $pure half4 sk_sweep_grad_4_shader(float2 coords, |
| float4 colorsParam[4], |
| float4 offsetsParam, |
| float biasParam, |
| float scaleParam, |
| int tileMode, |
| int colorSpace, |
| int doUnpremul) { |
| float2 t = $sweep_grad_layout(biasParam, scaleParam, coords); |
| t = $tile_grad(tileMode, t); |
| half4 color = $colorize_grad_4(colorsParam, offsetsParam, t); |
| return $interpolated_to_rgb_unpremul(color, colorSpace, doUnpremul); |
| } |
| |
| $pure half4 sk_sweep_grad_8_shader(float2 coords, |
| float4 colorsParam[8], |
| float4 offsetsParam[2], |
| float biasParam, |
| float scaleParam, |
| int tileMode, |
| int colorSpace, |
| int doUnpremul) { |
| float2 t = $sweep_grad_layout(biasParam, scaleParam, coords); |
| t = $tile_grad(tileMode, t); |
| half4 color = $colorize_grad_8(colorsParam, offsetsParam, t); |
| return $interpolated_to_rgb_unpremul(color, colorSpace, doUnpremul); |
| } |
| |
| $pure half4 sk_sweep_grad_tex_shader(float2 coords, |
| float biasParam, |
| float scaleParam, |
| int numStops, |
| int tileMode, |
| int colorSpace, |
| int doUnpremul, |
| sampler2D colorAndOffsetSampler) { |
| float2 t = $sweep_grad_layout(biasParam, scaleParam, coords); |
| t = $tile_grad(tileMode, t); |
| half4 color = $colorize_grad_tex(colorAndOffsetSampler, numStops, t); |
| return $interpolated_to_rgb_unpremul(color, colorSpace, doUnpremul); |
| } |
| |
| $pure half4 sk_conical_grad_4_shader(float2 coords, |
| float4 colorsParam[4], |
| float4 offsetsParam, |
| float radius0Param, |
| float dRadiusParam, |
| float aParam, |
| float invAParam, |
| int tileMode, |
| int colorSpace, |
| int doUnpremul) { |
| float2 t = $conical_grad_layout(radius0Param, dRadiusParam, aParam, invAParam, coords); |
| t = $tile_grad(tileMode, t); |
| half4 color = $colorize_grad_4(colorsParam, offsetsParam, t); |
| return $interpolated_to_rgb_unpremul(color, colorSpace, doUnpremul); |
| } |
| |
| $pure half4 sk_conical_grad_8_shader(float2 coords, |
| float4 colorsParam[8], |
| float4 offsetsParam[2], |
| float radius0Param, |
| float dRadiusParam, |
| float aParam, |
| float invAParam, |
| int tileMode, |
| int colorSpace, |
| int doUnpremul) { |
| float2 t = $conical_grad_layout(radius0Param, dRadiusParam, aParam, invAParam, coords); |
| t = $tile_grad(tileMode, t); |
| half4 color = $colorize_grad_8(colorsParam, offsetsParam, t); |
| return $interpolated_to_rgb_unpremul(color, colorSpace, doUnpremul); |
| } |
| |
| $pure half4 sk_conical_grad_tex_shader(float2 coords, |
| float radius0Param, |
| float dRadiusParam, |
| float aParam, |
| float invAParam, |
| int numStops, |
| int tileMode, |
| int colorSpace, |
| int doUnpremul, |
| sampler2D colorAndOffsetSampler) { |
| float2 t = $conical_grad_layout(radius0Param, dRadiusParam, aParam, invAParam, coords); |
| t = $tile_grad(tileMode, t); |
| half4 color = $colorize_grad_tex(colorAndOffsetSampler, numStops, t); |
| return $interpolated_to_rgb_unpremul(color, colorSpace, doUnpremul); |
| } |
| |
| $pure half4 sk_matrix_colorfilter(half4 colorIn, float4x4 m, float4 v, int inHSLA) { |
| if (bool(inHSLA)) { |
| colorIn = $rgb_to_hsl(colorIn.rgb, colorIn.a); // includes unpremul |
| } else { |
| colorIn = unpremul(colorIn); |
| } |
| |
| half4 colorOut = half4((m * colorIn) + v); |
| |
| if (bool(inHSLA)) { |
| colorOut = $hsl_to_rgb(colorOut.rgb, colorOut.a); // includes clamp and premul |
| } else { |
| colorOut = saturate(colorOut); |
| colorOut.rgb *= colorOut.a; |
| } |
| |
| return colorOut; |
| } |
| |
| // This method computes the 4 x-coodinates ([0..1]) that should be used to look |
| // up in the Perlin noise shader's noise table. |
| $pure half4 $noise_helper(half2 noiseVec, |
| half2 stitchData, |
| int stitching, |
| sampler2D permutationSampler) { |
| const half kBlockSize = 256.0; |
| |
| half4 floorVal; |
| floorVal.xy = floor(noiseVec); |
| floorVal.zw = floorVal.xy + half2(1); |
| |
| // Adjust frequencies if we're stitching tiles |
| if (bool(stitching)) { |
| floorVal -= step(stitchData.xyxy, floorVal) * stitchData.xyxy; |
| } |
| |
| half sampleX = sample(permutationSampler, half2((floorVal.x + 0.5) / kBlockSize, 0.5)).r; |
| half sampleY = sample(permutationSampler, half2((floorVal.z + 0.5) / kBlockSize, 0.5)).r; |
| |
| half2 latticeIdx = half2(sampleX, sampleY); |
| |
| if (sk_Caps.PerlinNoiseRoundingFix) { |
| // Aggressively round to the nearest exact (N / 255) floating point values. |
| // This prevents rounding errors on some platforms (e.g., Tegras) |
| const half kInv255 = 1.0 / 255.0; |
| |
| latticeIdx = floor(latticeIdx * half2(255.0) + half2(0.5)) * half2(kInv255); |
| } |
| |
| // Get (x,y) coordinates with the permuted x |
| half4 noiseXCoords = kBlockSize*latticeIdx.xyxy + floorVal.yyww; |
| |
| noiseXCoords /= half4(kBlockSize); |
| return noiseXCoords; |
| } |
| |
| $pure half4 $noise_function(half2 noiseVec, |
| half4 noiseXCoords, |
| sampler2D noiseSampler) { |
| half2 fractVal = fract(noiseVec); |
| |
| // Hermite interpolation : t^2*(3 - 2*t) |
| half2 noiseSmooth = smoothstep(0, 1, fractVal); |
| |
| // This is used to convert the two 16bit integers packed into rgba 8 bit input into |
| // a [-1,1] vector |
| const half kInv256 = 0.00390625; // 1.0 / 256.0 |
| |
| half4 result; |
| |
| for (int channel = 0; channel < 4; channel++) { |
| |
| // There are 4 lines in the noise texture, put y coords at center of each. |
| half chanCoord = (half(channel) + 0.5) / 4.0; |
| |
| half4 sampleA = sample(noiseSampler, float2(noiseXCoords.x, chanCoord)); |
| half4 sampleB = sample(noiseSampler, float2(noiseXCoords.y, chanCoord)); |
| half4 sampleC = sample(noiseSampler, float2(noiseXCoords.w, chanCoord)); |
| half4 sampleD = sample(noiseSampler, float2(noiseXCoords.z, chanCoord)); |
| |
| half2 tmpFractVal = fractVal; |
| |
| // Compute u, at offset (0,0) |
| half u = dot((sampleA.ga + sampleA.rb*kInv256)*2 - 1, tmpFractVal); |
| |
| // Compute v, at offset (-1,0) |
| tmpFractVal.x -= 1.0; |
| half v = dot((sampleB.ga + sampleB.rb*kInv256)*2 - 1, tmpFractVal); |
| |
| // Compute 'a' as a linear interpolation of 'u' and 'v' |
| half a = mix(u, v, noiseSmooth.x); |
| |
| // Compute v, at offset (-1,-1) |
| tmpFractVal.y -= 1.0; |
| v = dot((sampleC.ga + sampleC.rb*kInv256)*2 - 1, tmpFractVal); |
| |
| // Compute u, at offset (0,-1) |
| tmpFractVal.x += 1.0; |
| u = dot((sampleD.ga + sampleD.rb*kInv256)*2 - 1, tmpFractVal); |
| |
| // Compute 'b' as a linear interpolation of 'u' and 'v' |
| half b = mix(u, v, noiseSmooth.x); |
| |
| // Compute the noise as a linear interpolation of 'a' and 'b' |
| result[channel] = mix(a, b, noiseSmooth.y); |
| } |
| |
| return result; |
| } |
| |
| // permutationSampler is [kBlockSize x 1] A8 |
| // noiseSampler is [kBlockSize x 4] RGBA8 premul |
| $pure half4 perlin_noise_shader(float2 coords, |
| float2 baseFrequency, |
| float2 stitchDataIn, |
| int noiseType, |
| int numOctaves, |
| int stitching, |
| sampler2D permutationSampler, |
| sampler2D noiseSampler) { |
| const int kFractalNoise = 0; |
| const int kTurbulence = 1; |
| |
| // In the past, Perlin noise handled coordinates a bit differently than most shaders. |
| // It operated in device space, floored; it also had a one-pixel transform matrix applied to |
| // both the X and Y coordinates. This is roughly equivalent to adding 0.5 to the coordinates. |
| // This was originally done in order to better match preexisting golden images from WebKit. |
| // Perlin noise now operates in local space, which allows rotation to work correctly. To better |
| // approximate past behavior, we add 0.5 to the coordinates here. This is _not_ exactly the same |
| // because this adjustment is occurring in local space, not device space. |
| half2 noiseVec = half2((coords + 0.5) * baseFrequency); |
| |
| // Clear the color accumulator |
| half4 color = half4(0); |
| |
| half2 stitchData = half2(stitchDataIn); |
| |
| half ratio = 1.0; |
| |
| // Loop over all octaves |
| for (int octave = 0; octave < numOctaves; ++octave) { |
| half4 noiseXCoords = $noise_helper(noiseVec, stitchData, stitching, permutationSampler); |
| |
| half4 tmp = $noise_function(noiseVec, noiseXCoords, noiseSampler); |
| |
| if (noiseType != kFractalNoise) { |
| // For kTurbulence the result is: abs(noise[-1,1]) |
| tmp = abs(tmp); |
| } |
| |
| color += tmp * ratio; |
| |
| noiseVec *= half2(2.0); |
| ratio *= 0.5; |
| stitchData *= half2(2.0); |
| } |
| |
| if (noiseType == kFractalNoise) { |
| // For kFractalNoise the result is: noise[-1,1] * 0.5 + 0.5 |
| color = color * half4(0.5) + half4(0.5); |
| } |
| |
| // Clamp values |
| color = saturate(color); |
| |
| // Pre-multiply the result |
| return half4(color.rgb * color.aaa, color.a); |
| } |
| |
| $pure half4 sk_blend(half4 src, half4 dst, int blendMode) { |
| const int kClear = 0; |
| const int kSrc = 1; |
| const int kDst = 2; |
| const int kSrcOver = 3; |
| const int kDstOver = 4; |
| const int kSrcIn = 5; |
| const int kDstIn = 6; |
| const int kSrcOut = 7; |
| const int kDstOut = 8; |
| const int kSrcATop = 9; |
| const int kDstATop = 10; |
| const int kXor = 11; |
| const int kPlus = 12; |
| const int kModulate = 13; |
| const int kScreen = 14; |
| const int kOverlay = 15; |
| const int kDarken = 16; |
| const int kLighten = 17; |
| const int kColorDodge = 18; |
| const int kColorBurn = 19; |
| const int kHardLight = 20; |
| const int kSoftLight = 21; |
| const int kDifference = 22; |
| const int kExclusion = 23; |
| const int kMultiply = 24; |
| const int kHue = 25; |
| const int kSaturation = 26; |
| const int kColor = 27; |
| const int kLuminosity = 28; |
| |
| switch (blendMode) { |
| case kClear: return blend_clear(src, dst); |
| case kSrc: return blend_src(src, dst); |
| case kDst: return blend_dst(src, dst); |
| case kSrcOver: return blend_porter_duff(half4(1, 0, 0, -1), src, dst); |
| case kDstOver: return blend_porter_duff(half4(0, 1, -1, 0), src, dst); |
| case kSrcIn: return blend_porter_duff(half4(0, 0, 1, 0), src, dst); |
| case kDstIn: return blend_porter_duff(half4(0, 0, 0, 1), src, dst); |
| case kSrcOut: return blend_porter_duff(half4(0, 0, -1, 0), src, dst); |
| case kDstOut: return blend_porter_duff(half4(0, 0, 0, -1), src, dst); |
| case kSrcATop: return blend_porter_duff(half4(0, 0, 1, -1), src, dst); |
| case kDstATop: return blend_porter_duff(half4(0, 0, -1, 1), src, dst); |
| case kXor: return blend_porter_duff(half4(0, 0, -1, -1), src, dst); |
| case kPlus: return blend_porter_duff(half4(1, 1, 0, 0), src, dst); |
| case kModulate: return blend_modulate(src, dst); |
| case kScreen: return blend_screen(src, dst); |
| case kOverlay: return blend_overlay(/*flip=*/0, src, dst); |
| case kDarken: return blend_darken(/*mode=*/1, src, dst); |
| case kLighten: return blend_darken(/*mode=*/-1, src, dst); |
| case kColorDodge: return blend_color_dodge(src, dst); |
| case kColorBurn: return blend_color_burn(src, dst); |
| case kHardLight: return blend_overlay(/*flip=*/1, src, dst); |
| case kSoftLight: return blend_soft_light(src, dst); |
| case kDifference: return blend_difference(src, dst); |
| case kExclusion: return blend_exclusion(src, dst); |
| case kMultiply: return blend_multiply(src, dst); |
| case kHue: return blend_hslc(/*flipSat=*/half2(0, 1), src, dst); |
| case kSaturation: return blend_hslc(/*flipSat=*/half2(1), src, dst); |
| case kColor: return blend_hslc(/*flipSat=*/half2(0), src, dst); |
| case kLuminosity: return blend_hslc(/*flipSat=*/half2(1, 0), src, dst); |
| default: return half4(0); // avoid 'blend can exit without returning a value' error |
| } |
| } |
| |
| $pure half4 sk_coeff_blend(half4 src, half4 dst, half4 coeffs) { |
| return blend_porter_duff(coeffs, src, dst); |
| } |
| |
| $pure half4 sk_table_colorfilter(half4 inColor, sampler2D s) { |
| half4 coords = unpremul(inColor) * (255.0/256.0) + (0.5/256.0); |
| half4 color = half4(sample(s, half2(coords.r, 3.0/8.0)).r, |
| sample(s, half2(coords.g, 5.0/8.0)).r, |
| sample(s, half2(coords.b, 7.0/8.0)).r, |
| 1); |
| return color * sample(s, half2(coords.a, 1.0/8.0)).r; |
| } |
| |
| $pure half4 sk_gaussian_colorfilter(half4 inColor) { |
| half factor = 1 - inColor.a; |
| factor = exp(-factor * factor * 4) - 0.018; |
| return half4(factor); |
| } |
| |
| $pure half4 sample_indexed_atlas(float2 textureCoords, |
| int atlasIndex, |
| sampler2D atlas0, |
| sampler2D atlas1, |
| sampler2D atlas2, |
| sampler2D atlas3) { |
| switch (atlasIndex) { |
| case 1: |
| return sample(atlas1, textureCoords); |
| case 2: |
| return sample(atlas2, textureCoords); |
| case 3: |
| return sample(atlas3, textureCoords); |
| default: |
| return sample(atlas0, textureCoords); |
| } |
| } |
| |
| $pure half3 $sample_indexed_atlas_lcd(float2 textureCoords, |
| int atlasIndex, |
| half2 offset, |
| sampler2D atlas0, |
| sampler2D atlas1, |
| sampler2D atlas2, |
| sampler2D atlas3) { |
| half3 distance = half3(1); |
| switch (atlasIndex) { |
| case 1: |
| distance.x = sample(atlas1, half2(textureCoords) - offset).r; |
| distance.y = sample(atlas1, textureCoords).r; |
| distance.z = sample(atlas1, half2(textureCoords) + offset).r; |
| case 2: |
| distance.x = sample(atlas2, half2(textureCoords) - offset).r; |
| distance.y = sample(atlas2, textureCoords).r; |
| distance.z = sample(atlas2, half2(textureCoords) + offset).r; |
| case 3: |
| distance.x = sample(atlas3, half2(textureCoords) - offset).r; |
| distance.y = sample(atlas3, textureCoords).r; |
| distance.z = sample(atlas3, half2(textureCoords) + offset).r; |
| default: |
| distance.x = sample(atlas0, half2(textureCoords) - offset).r; |
| distance.y = sample(atlas0, textureCoords).r; |
| distance.z = sample(atlas0, half2(textureCoords) + offset).r; |
| } |
| return distance; |
| } |
| |
| $pure half4 bitmap_text_coverage_fn(half4 texColor, int maskFormat) { |
| return (maskFormat == $kMaskFormatA8) ? texColor.rrrr |
| : texColor; |
| } |
| |
| $pure half4 sdf_text_coverage_fn(half texColor, |
| half2 gammaParams, |
| float2 unormTexCoords) { |
| // TODO: To minimize the number of shaders generated this is the full affine shader. |
| // For best performance it may be worth creating the uniform scale shader as well, |
| // as that's the most common case. |
| // TODO: Need to add 565 support. |
| |
| // The distance field is constructed as uchar8_t values, so that the zero value is at 128, |
| // and the supported range of distances is [-4 * 127/128, 4]. |
| // Hence to convert to floats our multiplier (width of the range) is 4 * 255/128 = 7.96875 |
| // and zero threshold is 128/255 = 0.50196078431. |
| half dist = 7.96875 * (texColor - 0.50196078431); |
| |
| // We may further adjust the distance for gamma correction. |
| dist -= gammaParams.x; |
| |
| // After the distance is unpacked, we need to correct it by a factor dependent on the |
| // current transformation. For general transforms, to determine the amount of correction |
| // we multiply a unit vector pointing along the SDF gradient direction by the Jacobian of |
| // unormTexCoords (which is the inverse transform for this fragment) and take the length of |
| // the result. |
| half2 dist_grad = half2(dFdx(dist), dFdy(dist)); |
| half dg_len2 = dot(dist_grad, dist_grad); |
| |
| // The length of the gradient may be near 0, so we need to check for that. This also |
| // compensates for the Adreno, which likes to drop tiles on division by 0. |
| dist_grad = (dg_len2 >= 0.0001) ? dist_grad * inversesqrt(dg_len2) |
| : half2(0.7071); |
| |
| // Computing the Jacobian and multiplying by the gradient. |
| float2x2 jacobian = float2x2(dFdx(unormTexCoords), dFdy(unormTexCoords)); |
| half2 grad = half2(jacobian * dist_grad); |
| |
| // This gives us a smooth step across approximately one fragment. |
| half approxFragWidth = 0.65 * length(grad); |
| |
| // TODO: handle aliased rendering |
| if (gammaParams.y > 0) { |
| // The smoothstep falloff compensates for the non-linear sRGB response curve. If we are |
| // doing gamma-correct rendering (to an sRGB or F16 buffer), then we actually want |
| // distance mapped linearly to coverage, so use a linear step: |
| return half4(saturate((dist + approxFragWidth) / (2.0 * approxFragWidth))); |
| } else { |
| return half4(smoothstep(-approxFragWidth, approxFragWidth, dist)); |
| } |
| } |
| |
| $pure half4 sdf_text_lcd_coverage_fn(float2 textureCoords, |
| half2 pixelGeometryDelta, |
| half4 gammaParams, |
| float2 unormTexCoords, |
| float texIndex, |
| sampler2D atlas0, |
| sampler2D atlas1, |
| sampler2D atlas2, |
| sampler2D atlas3) { |
| // TODO: To minimize the number of shaders generated this is the full affine shader. |
| // For best performance it may be worth creating the uniform scale shader as well, |
| // as that's the most common case. |
| |
| float2x2 jacobian = float2x2(dFdx(unormTexCoords), dFdy(unormTexCoords)); |
| half2 offset = half2(jacobian * pixelGeometryDelta); |
| |
| half3 distance = $sample_indexed_atlas_lcd(textureCoords, |
| int(texIndex), |
| offset, |
| atlas0, |
| atlas1, |
| atlas2, |
| atlas3); |
| // The distance field is constructed as uchar8_t values, so that the zero value is at 128, |
| // and the supported range of distances is [-4 * 127/128, 4]. |
| // Hence to convert to floats our multiplier (width of the range) is 4 * 255/128 = 7.96875 |
| // and zero threshold is 128/255 = 0.50196078431. |
| half3 dist = half3(7.96875) * (distance - half3(0.50196078431)); |
| |
| // We may further adjust the distance for gamma correction. |
| dist -= gammaParams.xyz; |
| |
| // After the distance is unpacked, we need to correct it by a factor dependent on the |
| // current transformation. For general transforms, to determine the amount of correction |
| // we multiply a unit vector pointing along the SDF gradient direction by the Jacobian of |
| // unormTexCoords (which is the inverse transform for this fragment) and take the length of |
| // the result. |
| half2 dist_grad = half2(dFdx(dist.g), dFdy(dist.g)); |
| half dg_len2 = dot(dist_grad, dist_grad); |
| |
| // The length of the gradient may be near 0, so we need to check for that. This also |
| // compensates for the Adreno, which likes to drop tiles on division by 0. |
| dist_grad = (dg_len2 >= 0.0001) ? dist_grad * inversesqrt(dg_len2) |
| : half2(0.7071); |
| |
| // Multiplying the Jacobian by the gradient. |
| half2 grad = half2(jacobian * dist_grad); |
| |
| // This gives us a smooth step across approximately one fragment. |
| half3 approxFragWidth = half3(0.65 * length(grad)); |
| |
| // TODO: handle aliased rendering |
| if (gammaParams.w > 0) { |
| // The smoothstep falloff compensates for the non-linear sRGB response curve. If we are |
| // doing gamma-correct rendering (to an sRGB or F16 buffer), then we actually want |
| // distance mapped linearly to coverage, so use a linear step: |
| return half4(saturate((dist + approxFragWidth / (2.0 * approxFragWidth))), 1); |
| } else { |
| return half4(smoothstep(half3(-approxFragWidth), half3(approxFragWidth), dist), 1); |
| } |
| } |
| |
| /////////////////////////////////////////////////////////////////////////////////////////////////// |
| // Support functions for analytic round rectangles |
| |
| // Calculates 1/|∇| in device space by applying the chain rule to a local gradient vector and the |
| // 2x2 Jacobian describing the transform from local-to-device space. For non-perspective, this is |
| // equivalent to the "normal matrix", or the inverse transpose. For perspective, J should be |
| // W(u,v) [m00' - m20'u m01' - m21'u] derived from the first two columns of the 3x3 inverse. |
| // [m10' - m20'v m11' - m21'v] |
| $pure float $inverse_grad_len(float2 localGrad, float2x2 jacobian) { |
| // NOTE: By chain rule, the local gradient is on the left side of the Jacobian matrix |
| float2 devGrad = localGrad * jacobian; |
| // NOTE: This uses the L2 norm, which is more accurate than the L1 norm used by fwidth(). |
| // TODO: Switch to L1 since it is a 2x perf improvement according to Xcode with little visual |
| // impact, but start with L2 to measure the change separately from the algorithmic update. |
| // return 1.0 / (abs(devGrad.x) + abs(devGrad.y)); |
| return inversesqrt(dot(devGrad, devGrad)); |
| } |
| |
| // Returns distance from both sides of a stroked circle or ellipse. Elliptical coverage is |
| // only accurate if strokeRadius = 0. A positive value represents the interior of the stroke. |
| $pure float2 $elliptical_distance(float2 uv, float2 radii, float strokeRadius, float2x2 jacobian) { |
| // We do need to evaluate up to two circle equations: one with |
| // R = cornerRadius(r)+strokeRadius(s), and another with R = r-s. |
| // This can be consolidated into a common evaluation against a circle of radius sqrt(r^2+s^2): |
| // (x/(r+/-s))^2 + (y/(r+/-s))^2 = 1 |
| // x^2 + y^2 = (r+/-s)^2 |
| // x^2 + y^2 = r^2 + s^2 +/- 2rs |
| // (x/sqrt(r^2+s^2))^2 + (y/sqrt(r^2+s^2)) = 1 +/- 2rs/(r^2+s^2) |
| // The 2rs/(r^2+s^2) is the "width" that adjusts the implicit function to the outer or inner |
| // edge of the stroke. For fills and hairlines, s = 0, which means these operations remain valid |
| // for elliptical corners where radii holds the different X and Y corner radii. |
| float2 invR2 = 1.0 / (radii * radii + strokeRadius*strokeRadius); |
| float2 normUV = invR2 * uv; |
| float invGradLength = $inverse_grad_len(normUV, jacobian); |
| |
| // Since normUV already includes 1/r^2 in the denominator, dot with just 'uv' instead. |
| float f = 0.5 * invGradLength * (dot(uv, normUV) - 1.0); |
| |
| // This is 0 for fills/hairlines, which are the only types that allow |
| // elliptical corners (strokeRadius == 0). For regular strokes just use X. |
| float width = radii.x * strokeRadius * invR2.x * invGradLength; |
| return float2(width - f, width + f); |
| } |
| |
| // Accumulates the minimum (and negative maximum) of the outer and inner corner distances in 'dist' |
| // for a possibly elliptical corner with 'radii' and relative pixel location specified by |
| // 'cornerEdgeDist'. The corner's basis relative to the jacobian is defined in 'xyFlip'. |
| void $corner_distance(inout float2 dist, |
| float2x2 jacobian, |
| float2 strokeParams, |
| float2 cornerEdgeDist, |
| float2 xyFlip, |
| float2 radii) { |
| float2 uv = radii - cornerEdgeDist; |
| // NOTE: For mitered corners uv > 0 only if it's stroked, and in that case the |
| // subsequent conditions skip calculating anything. |
| if (all(greaterThan(uv, float2(0.0)))) { |
| if (all(greaterThan(radii, float2(0.0))) || |
| (strokeParams.x > 0.0 && strokeParams.y < 0.0 /* round-join */)) { |
| // A rounded corner so incorporate outer elliptical distance if we're within the |
| // quarter circle. |
| float2 d = $elliptical_distance(uv * xyFlip, radii, strokeParams.x, jacobian); |
| d.y = (radii.x - strokeParams.x <= 0.0) |
| ? 1.0 // Disregard inner curve since it's collapsed into an inner miter. |
| : -d.y; // Negate so that "min" accumulates the maximum value instead. |
| dist = min(dist, d); |
| } else if (strokeParams.y == 0.0 /* bevel-join */) { |
| // Bevels are--by construction--interior mitered, so inner distance is based |
| // purely on the edge distance calculations, but the outer distance is to a 45-degree |
| // line and not the vertical/horizontal lines of the other edges. |
| float bevelDist = (strokeParams.x - uv.x - uv.y) * $inverse_grad_len(xyFlip, jacobian); |
| dist.x = min(dist.x, bevelDist); |
| } // Else it's a miter so both inner and outer distances are unmodified |
| } // Else we're not affected by the corner so leave distances unmodified |
| } |
| |
| // Accumulates the minimum (and negative maximum) of the outer and inner corner distances into 'd', |
| // for all four corners of a [round] rectangle. 'edgeDists' should be ordered LTRB with positive |
| // distance representing the interior of the edge. 'xRadii' and 'yRadii' should hold the per-corner |
| // elliptical radii, ordered TL, TR, BR, BL. |
| void $corner_distances(inout float2 d, |
| float2x2 J, |
| float2 stroke, // {radii, joinStyle}, see StrokeStyle struct definition |
| float4 edgeDists, |
| float4 xRadii, |
| float4 yRadii) { |
| $corner_distance(d, J, stroke, edgeDists.xy, float2(-1.0, -1.0), float2(xRadii[0], yRadii[0])); |
| $corner_distance(d, J, stroke, edgeDists.zy, float2( 1.0, -1.0), float2(xRadii[1], yRadii[1])); |
| $corner_distance(d, J, stroke, edgeDists.zw, float2( 1.0, 1.0), float2(xRadii[2], yRadii[2])); |
| $corner_distance(d, J, stroke, edgeDists.xw, float2(-1.0, 1.0), float2(xRadii[3], yRadii[3])); |
| } |
| |
| $pure half4 analytic_rrect_coverage_fn(float4 coords, |
| float4 jacobian, |
| float4 edgeDistances, |
| float4 xRadii, |
| float4 yRadii, |
| float2 strokeParams, |
| float2 perPixelControl) { |
| if (perPixelControl.x > 0.0) { |
| // A trivially solid interior pixel, either from a filled rect or round rect, or a |
| // stroke with sufficiently large width that the interior completely overlaps itself. |
| return half4(1.0); |
| } else if (perPixelControl.y > 1.0) { |
| // This represents a filled rectangle or quadrilateral, where the distances have already |
| // been converted to device space. Mitered strokes cannot use this optimization because |
| // their scale and bias is not uniform over the shape; Rounded shapes cannot use this |
| // because they rely on the edge distances being in local space to reconstruct the |
| // per-corner positions for the elliptical implicit functions. |
| float2 outerDist = min(edgeDistances.xy, edgeDistances.zw); |
| float c = min(outerDist.x, outerDist.y) * coords.w; |
| float scale = (perPixelControl.y - 1.0) * coords.w; |
| float bias = coverage_bias(scale); |
| return half4(saturate(scale * (c + bias))); |
| } else { |
| // Compute per-pixel coverage, mixing four outer edge distances, possibly four inner |
| // edge distances, and per-corner elliptical distances into a final coverage value. |
| // The Jacobian needs to be multiplied by W, but coords.w stores 1/w. |
| float2x2 J = float2x2(jacobian) / coords.w; |
| |
| float2 invGradLen = float2($inverse_grad_len(float2(1.0, 0.0), J), |
| $inverse_grad_len(float2(0.0, 1.0), J)); |
| float2 outerDist = invGradLen * (strokeParams.x + min(edgeDistances.xy, |
| edgeDistances.zw)); |
| |
| // d.x tracks minimum outer distance (pre scale-and-biasing to a coverage value). |
| // d.y tracks negative maximum inner distance (so min() over c accumulates min and outer |
| // and max inner simultaneously).) |
| float2 d = float2(min(outerDist.x, outerDist.y), -1.0); |
| float scale, bias; |
| |
| // Check for bidirectional coverage, which is is marked as a -1 from the vertex shader. |
| // We don't just check for < 0 since extrapolated fill triangle samples can have small |
| // negative values. |
| if (perPixelControl.x > -0.95) { |
| // A solid interior, so update scale and bias based on full width and height |
| float2 dim = invGradLen * (edgeDistances.xy + edgeDistances.zw + 2*strokeParams.xx); |
| scale = min(min(dim.x, dim.y), 1.0); |
| bias = coverage_bias(scale); |
| // Since we leave d.y = -1.0, no inner curve coverage will adjust it closer to 0, |
| // so 'finalCoverage' is based solely on outer edges and curves. |
| } else { |
| // Bidirectional coverage, so we modify c.y to hold the negative of the maximum |
| // interior coverage, and update scale and bias based on stroke width. |
| float2 strokeWidth = 2.0 * strokeParams.x * invGradLen; |
| float2 innerDist = strokeWidth - outerDist; |
| |
| d.y = -max(innerDist.x, innerDist.y); |
| if (strokeParams.x > 0.0) { |
| float narrowStroke = min(strokeWidth.x, strokeWidth.y); |
| // On an axis where innerDist >= -0.5, allow strokeWidth.x/y to be preserved as-is. |
| // On an axis where innerDist < -0.5, use the smaller of strokeWidth.x/y. |
| float2 strokeDim = mix(float2(narrowStroke), strokeWidth, |
| greaterThanEqual(innerDist, float2(-0.5))); |
| // Preserve the wider axis from the above calculation. |
| scale = saturate(max(strokeDim.x, strokeDim.y)); |
| bias = coverage_bias(scale); |
| } else { |
| // A hairline, so scale and bias should both be 1 |
| scale = bias = 1.0; |
| } |
| } |
| |
| // Check all corners, although most pixels should only be influenced by 1. |
| $corner_distances(d, J, strokeParams, edgeDistances, xRadii, yRadii); |
| |
| float outsetDist = min(perPixelControl.y, 0.0) * coords.w; |
| float finalCoverage = scale * (min(d.x + outsetDist, -d.y) + bias); |
| |
| return half4(saturate(finalCoverage)); |
| } |
| } |
| |
| $pure half4 per_edge_aa_quad_coverage_fn(float4 coords, |
| float4 edgeDistances) { |
| // This represents a filled rectangle or quadrilateral, where the distances have already |
| // been converted to device space. |
| float2 outerDist = min(edgeDistances.xy, edgeDistances.zw); |
| float c = min(outerDist.x, outerDist.y) * coords.w; |
| return half4(saturate(c)); |
| } |
| |
| $pure half4 $rect_blur_coverage_fn(float2 coords, |
| float4 rect, |
| half isFast, |
| half invSixSigma, |
| sampler2D integral) { |
| half xCoverage; |
| half yCoverage; |
| |
| if (isFast != 0.0) { |
| // Get the smaller of the signed distance from the frag coord to the left and right |
| // edges and similar for y. |
| // The integral texture goes "backwards" (from 3*sigma to -3*sigma), So, the below |
| // computations align the left edge of the integral texture with the inset rect's |
| // edge extending outward 6 * sigma from the inset rect. |
| half2 pos = max(half2(rect.LT - coords), half2(coords - rect.RB)); |
| xCoverage = sample(integral, float2(invSixSigma * pos.x, 0.5)).r; |
| yCoverage = sample(integral, float2(invSixSigma * pos.y, 0.5)).r; |
| |
| } else { |
| // We just consider just the x direction here. In practice we compute x and y |
| // separately and multiply them together. |
| // We define our coord system so that the point at which we're evaluating a kernel |
| // defined by the normal distribution (K) at 0. In this coord system let L be left |
| // edge and R be the right edge of the rectangle. |
| // We can calculate C by integrating K with the half infinite ranges outside the |
| // L to R range and subtracting from 1: |
| // C = 1 - <integral of K from from -inf to L> - <integral of K from R to inf> |
| // K is symmetric about x=0 so: |
| // C = 1 - <integral of K from from -inf to L> - <integral of K from -inf to -R> |
| |
| // The integral texture goes "backwards" (from 3*sigma to -3*sigma) which is |
| // factored in to the below calculations. |
| // Also, our rect uniform was pre-inset by 3 sigma from the actual rect being |
| // blurred, also factored in. |
| half4 rect = half4(half2(rect.LT - coords), half2(coords - rect.RB)); |
| xCoverage = 1 - sample(integral, float2(invSixSigma * rect.L, 0.5)).r |
| - sample(integral, float2(invSixSigma * rect.R, 0.5)).r; |
| yCoverage = 1 - sample(integral, float2(invSixSigma * rect.T, 0.5)).r |
| - sample(integral, float2(invSixSigma * rect.B, 0.5)).r; |
| } |
| |
| return half4(xCoverage * yCoverage); |
| } |
| |
| $pure half4 $circle_blur_coverage_fn(float2 coords, float4 circle, sampler2D blurProfile) { |
| // We just want to compute "(length(vec) - solidRadius + 0.5) / textureRadius" but need to |
| // rearrange to avoid passing large values to length() that would overflow. We've precalculated |
| // "1 / textureRadius" and "(solidRadius - 0.5) / textureRadius" on the CPU as circle.z and |
| // circle.w, respectively. |
| float invTextureRadius = circle.z; |
| float normSolidRadius = circle.w; |
| |
| half2 vec = half2((coords - circle.xy) * invTextureRadius); |
| float dist = length(vec) - normSolidRadius; |
| return sample(blurProfile, float2(dist, 0.5)).rrrr; |
| } |
| |
| $pure half4 $rrect_blur_coverage_fn(float2 coords, |
| float4 proxyRect, |
| half edgeSize, |
| sampler2D ninePatch) { |
| // Warp the fragment position to the appropriate part of the 9-patch blur texture by |
| // snipping out the middle section of the proxy rect. |
| float2 translatedFragPosFloat = coords - proxyRect.LT; |
| float2 proxyCenter = (proxyRect.RB - proxyRect.LT) * 0.5; |
| |
| // Position the fragment so that (0, 0) marks the center of the proxy rectangle. |
| // Negative coordinates are on the left/top side and positive numbers are on the |
| // right/bottom. |
| translatedFragPosFloat -= proxyCenter; |
| |
| // Temporarily strip off the fragment's sign. x/y are now strictly increasing as we |
| // move away from the center. |
| half2 fragDirection = half2(sign(translatedFragPosFloat)); |
| translatedFragPosFloat = abs(translatedFragPosFloat); |
| |
| // Our goal is to snip out the "middle section" of the proxy rect (everything but the |
| // edge). We've repositioned our fragment position so that (0, 0) is the centerpoint |
| // and x/y are always positive, so we can subtract here and interpret negative results |
| // as being within the middle section. |
| half2 translatedFragPosHalf = half2(translatedFragPosFloat - (proxyCenter - edgeSize)); |
| |
| // Remove the middle section by clamping to zero. |
| translatedFragPosHalf = max(translatedFragPosHalf, 0); |
| |
| // Reapply the fragment's sign, so that negative coordinates once again mean left/top |
| // side and positive means bottom/right side. |
| translatedFragPosHalf *= fragDirection; |
| |
| // Offset the fragment so that (0, 0) marks the upper-left again, instead of the center |
| // point. |
| translatedFragPosHalf += half2(edgeSize); |
| |
| half2 proxyDims = half2(2.0 * edgeSize); |
| half2 texCoord = translatedFragPosHalf / proxyDims; |
| |
| return sample(ninePatch, texCoord).rrrr; |
| } |
| |
| $pure half4 blur_coverage_fn(float2 coords, |
| float4 shapeData, |
| half2 blurData, |
| int shapeType, |
| sampler2D s) { |
| switch (shapeType) { |
| case $kShapeTypeRect: { |
| return $rect_blur_coverage_fn(coords, shapeData, blurData.x, blurData.y, s); |
| } |
| case $kShapeTypeCircle: { |
| return $circle_blur_coverage_fn(coords, shapeData, s); |
| } |
| case $kShapeTypeRRect: { |
| return $rrect_blur_coverage_fn(coords, shapeData, blurData.x, s); |
| } |
| } |
| return half4(0); |
| } |
