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/*
* Copyright 2019 Google LLC
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#include "gm/gm.h"
#include "include/core/SkCanvas.h"
#include "include/core/SkColorFilter.h"
#include "include/core/SkColorSpace.h"
#include "include/core/SkData.h"
#include "include/core/SkImage.h"
#include "include/core/SkPaint.h"
#include "include/core/SkRSXform.h"
#include "include/core/SkRefCnt.h"
#include "include/core/SkSize.h"
#include "include/core/SkString.h"
#include "include/core/SkSurface.h"
#include "include/core/SkVertices.h"
#include "include/effects/SkRuntimeEffect.h"
#include "tools/Resources.h"
#include <stddef.h>
#include <utility>
const char* gNoop = R"(
half4 main(half4 color) {
return color;
}
)";
const char* gLumaSrc = R"(
half4 main(half4 color) {
return dot(color.rgb, half3(0.3, 0.6, 0.1)).000r;
}
)";
// Build up the same effect with increasingly complex control flow syntax.
// All of these are semantically equivalent and can be reduced in principle to one basic block.
// Simplest to run; hardest to write?
const char* gTernary = R"(
half4 main(half4 color) {
half luma = dot(color.rgb, half3(0.3, 0.6, 0.1));
half scale = luma < 0.33333 ? 0.5
: luma < 0.66666 ? (0.166666 + 2.0 * (luma - 0.33333)) / luma
: /* else */ (0.833333 + 0.5 * (luma - 0.66666)) / luma;
return half4(color.rgb * scale, color.a);
}
)";
// Uses conditional if statements but no early return.
const char* gIfs = R"(
half4 main(half4 color) {
half luma = dot(color.rgb, half3(0.3, 0.6, 0.1));
half scale = 0;
if (luma < 0.33333) {
scale = 0.5;
} else if (luma < 0.66666) {
scale = (0.166666 + 2.0 * (luma - 0.33333)) / luma;
} else {
scale = (0.833333 + 0.5 * (luma - 0.66666)) / luma;
}
return half4(color.rgb * scale, color.a);
}
)";
// Distilled from AOSP tone mapping shaders, more like what people tend to write.
const char* gEarlyReturn = R"(
half4 main(half4 color) {
half luma = dot(color.rgb, half3(0.3, 0.6, 0.1));
half scale = 0;
if (luma < 0.33333) {
return half4(color.rgb * 0.5, color.a);
} else if (luma < 0.66666) {
scale = 0.166666 + 2.0 * (luma - 0.33333);
} else {
scale = 0.833333 + 0.5 * (luma - 0.66666);
}
return half4(color.rgb * (scale/luma), color.a);
}
)";
DEF_SIMPLE_GM(runtimecolorfilter, canvas, 256 * 3, 256 * 2) {
sk_sp<SkImage> img = GetResourceAsImage("images/mandrill_256.png");
auto draw_filter = [&](const char* src) {
auto [effect, err] = SkRuntimeEffect::MakeForColorFilter(SkString(src));
if (!effect) {
SkDebugf("%s\n%s\n", src, err.c_str());
}
SkASSERT(effect);
SkPaint p;
p.setColorFilter(effect->makeColorFilter(nullptr));
canvas->drawImage(img, 0, 0, SkSamplingOptions(), &p);
canvas->translate(256, 0);
};
for (const char* src : { gNoop, gLumaSrc }) {
draw_filter(src);
}
canvas->translate(-256*2, 256);
for (const char* src : { gTernary, gIfs, gEarlyReturn}) {
draw_filter(src);
}
}
DEF_SIMPLE_GM(runtimecolorfilter_vertices_atlas_and_patch, canvas, 404, 404) {
constexpr SkRect r = SkRect::MakeWH(128, 128);
// Make a vertices that draws the same as SkRect 'r'.
SkPoint pos[4];
r.toQuad(pos);
constexpr SkColor kColors[] = {SK_ColorBLUE, SK_ColorGREEN, SK_ColorCYAN, SK_ColorYELLOW};
auto verts = SkVertices::MakeCopy(SkVertices::kTriangleFan_VertexMode, 4, pos, pos, kColors);
// Make an image from the vertices to do equivalent drawAtlas, drawPatch using an image shader.
auto info = SkImageInfo::Make({128, 128},
kRGBA_8888_SkColorType,
kPremul_SkAlphaType,
canvas->imageInfo().refColorSpace());
auto surf = SkSurface::MakeRaster(info);
surf->getCanvas()->drawVertices(verts, SkBlendMode::kDst, SkPaint());
auto atlas = surf->makeImageSnapshot();
auto xform = SkRSXform::Make(1, 0, 0, 0);
// Make a patch that draws the same as the SkRect 'r'
SkVector vx = pos[1] - pos[0];
SkVector vy = pos[3] - pos[0];
vx.setLength(vx.length()/3.f);
vy.setLength(vy.length()/3.f);
const SkPoint cubics[12] = {
pos[0], pos[0] + vx, pos[1] - vx,
pos[1], pos[1] + vy, pos[2] - vy,
pos[2], pos[2] - vx, pos[3] + vx,
pos[3], pos[3] - vy, pos[0] + vy
};
auto [effect, err] = SkRuntimeEffect::MakeForColorFilter(SkString(gLumaSrc));
if (!effect) {
SkDebugf("%s\n%s\n", gLumaSrc, err.c_str());
}
SkASSERT(effect);
sk_sp<SkColorFilter> colorfilter = effect->makeColorFilter(nullptr);
auto makePaint = [&](bool useCF, bool useShader) {
SkPaint paint;
paint.setColorFilter(useCF ? colorfilter : nullptr);
paint.setShader(useShader ? atlas->makeShader(SkSamplingOptions{}) : nullptr);
return paint;
};
auto drawVertices = [&](float x, bool useCF, bool useShader) {
SkAutoCanvasRestore acr(canvas, /*doSave=*/true);
canvas->translate(x, 0);
// Use just the shader or just the vertex colors.
auto mode = useShader ? SkBlendMode::kSrc : SkBlendMode::kDst;
canvas->drawVertices(verts, mode, makePaint(useCF, useShader));
};
auto drawAtlas = [&](float x, bool useCF) {
SkAutoCanvasRestore acr(canvas, /*doSave=*/true);
canvas->translate(x, 0);
SkPaint paint = makePaint(useCF, /*useShader=*/false);
constexpr SkColor kColor = SK_ColorWHITE;
canvas->drawAtlas(atlas.get(),
&xform,
&r,
&kColor,
1,
SkBlendMode::kModulate,
SkSamplingOptions{},
nullptr,
&paint);
};
auto drawPatch = [&](float x, bool useCF) {
SkAutoCanvasRestore acr(canvas, true);
canvas->translate(x, 0);
SkPaint paint = makePaint(useCF, /*useShader=*/true);
canvas->drawPatch(cubics, nullptr, pos, SkBlendMode::kModulate, paint);
};
drawVertices( 0, /*useCF=*/false, /*useShader=*/false);
drawVertices( r.width() + 10, /*useCF=*/ true, /*useShader=*/false);
drawVertices(2*(r.width() + 10), /*useCF=*/ true, /*useShader=*/ true);
canvas->translate(0, r.height() + 10);
drawAtlas( 0, /*useCF=*/false);
drawAtlas(r.width() + 10, /*useCF=*/ true);
canvas->translate(0, r.height() + 10);
drawPatch( 0, /*useCF=*/false);
drawPatch(r.width() + 10, /*useCF=*/ true);
}