Google Git
Sign in
skia/external/github.com/rive-app/rive-cpp/c5e2a9fdbeb528b0526c35c4d38743483929e5e5/./renderer/include/rive/renderer/gpu.hpp
blob: 88a9ec92d78da470de4267a7a88431644a5da59b [file] [log] [blame]
/*
* Copyright 2022 Rive
*/
#pragma once
#include "rive/enum_bitset.hpp"
#include "rive/math/aabb.hpp"
#include "rive/math/mat2d.hpp"
#include "rive/math/vec2d.hpp"
#include "rive/math/simd.hpp"
#include "rive/shapes/paint/blend_mode.hpp"
#include "rive/shapes/paint/color.hpp"
#include "rive/renderer/trivial_block_allocator.hpp"
#include "rive/shapes/paint/image_sampler.hpp"
namespace rive
{
class GrInnerFanTriangulator;
class RenderBuffer;
} // namespace rive
// This header defines constants and data structures for Rive's pixel local
// storage path rendering algorithm.
//
// Main algorithm:
// https://docs.google.com/document/d/19Uk9eyFxav6dNSYsI2ZyiX9zHU1YOaJsMB2sdDFVz6s/edit
//
// Batching multiple unique paths:
// https://docs.google.com/document/d/1DLrQimS5pbNaJJ2sAW5oSOsH6_glwDPo73-mtG5_zns/edit
//
// Batching strokes as well:
// https://docs.google.com/document/d/1CRKihkFjbd1bwT08ErMCP4fwSR7D4gnHvgdw_esY9GM/edit
namespace rive::gpu
{
class Draw;
class Gradient;
class RenderContextImpl;
class RenderTarget;
class Texture;
// Tessellate in parametric space until each segment is within 1/4 pixel of the
// true curve.
constexpr static int kParametricPrecision = 4;
// Tessellate in polar space until the outset edge is within 1/8 pixel of the
// true stroke.
constexpr static int kPolarPrecision = 8;
// Maximum supported numbers of tessellated segments in a single curve.
constexpr static uint32_t kMaxParametricSegments = 1023;
constexpr static uint32_t kMaxPolarSegments = 1023;
// The Gaussian distribution is very blurry on the outer edges. Regardless of
// how wide a feather is, the polar segments never need to have a finer angle
// than this value.
constexpr static float FEATHER_POLAR_SEGMENT_MIN_ANGLE = math::PI / 16;
// cos(FEATHER_MIN_POLAR_SEGMENT_ANGLE / 2)
constexpr static float COS_FEATHER_POLAR_SEGMENT_MIN_ANGLE_OVER_2 =
0.99518472667f;
// We allocate all our GPU buffers in rings. This ensures the CPU can prepare
// frames in parallel while the GPU renders them.
constexpr static int kBufferRingSize = 3;
// Every coverage value in pixel local storage has an associated 16-bit path ID.
// This ID enables us to batch multiple paths together without having to clear
// the coverage buffer in between. This ID is implemented as an fp16, so the
// maximum path ID therefore cannot be NaN (or conservatively, all 5 exponent
// bits cannot be 1's). We also skip denormalized values (exp == 0) because they
// have been empirically unreliable on Android as ID values.
constexpr static int kLargestFP16BeforeExponentAll1s = (0x1f << 10) - 1;
constexpr static int kLargestDenormalizedFP16 = 1023;
constexpr static int MaxPathID(int granularity)
{
// Floating point equality gets funky when the exponent bits are all 1's, so
// the largest pathID we can support is kLargestFP16BeforeExponentAll1s.
//
// The shader converts an integer path ID to fp16 as:
//
// (id + kLargestDenormalizedFP16) * granularity
//
// So the largest path ID we can support is as follows.
return kLargestFP16BeforeExponentAll1s / granularity -
kLargestDenormalizedFP16;
}
// Each contour has its own unique ID, which it uses to index a data record
// containing per-contour information. This value is currently 16 bit.
constexpr static size_t kMaxContourID = 65535;
constexpr static uint32_t kContourIDMask = 0xffff;
static_assert((kMaxContourID & kContourIDMask) == kMaxContourID);
// Tessellation is performed by rendering vertices into a data texture. These
// values define the dimensions of the tessellation data texture.
constexpr static size_t kTessTextureWidth =
2048; // GL_MAX_TEXTURE_SIZE spec minimum on ES3/WebGL2.
constexpr static size_t kTessTextureWidthLog2 = 11;
static_assert(1 << kTessTextureWidthLog2 == kTessTextureWidth);
// Gradients are implemented by sampling a horizontal ramp of pixels allocated
// in a global gradient texture.
constexpr static uint32_t kGradTextureWidth = 512;
constexpr static uint32_t kGradTextureWidthInSimpleRamps =
kGradTextureWidth / 2;
// Depth/stencil parameters
constexpr static float DEPTH_MIN = 0.0f;
constexpr static float DEPTH_MAX = 1.0f;
constexpr static uint8_t STENCIL_CLEAR = 0u;
// Backend-specific capabilities/workarounds and fine tunin// g.
struct PlatformFeatures
{
// InterlockMode::rasterOrdering.
bool supportsRasterOrdering = false;
// InterlockMode::atomics.
bool supportsFragmentShaderAtomics = false;
// Experimental rendering mode selected by InterlockMode::clockwiseAtomic.
bool supportsClockwiseAtomicRendering = false;
// Use KHR_blend_equation_advanced in msaa mode?
bool supportsBlendAdvancedKHR = false;
bool supportsBlendAdvancedCoherentKHR = false;
// Required for @ENABLE_CLIP_RECT in msaa mode.
bool supportsClipPlanes = false;
bool avoidFlatVaryings = false;
// Vivo Y21 (PowerVR Rogue GE8320; OpenGL ES 3.2 build 1.13@5776728a) seems
// to hit some sort of reset condition that corrupts pixel local storage
// when rendering a complex feather. Provide a workaround that allows the
// implementation to opt in to always feathering to the atlas instead of
// rendering directly to the screen.
bool alwaysFeatherToAtlas = false;
// clipSpaceBottomUp specifies whether the top of the viewport, in clip
// coordinates, is at Y=+1 (OpenGL, Metal, D3D, WebGPU) or Y=-1 (Vulkan).
//
// framebufferBottomUp specifies whether "row 0" of the framebuffer is the
// bottom of the image (OpenGL) or the top (Metal, D3D, WebGPU, Vulkan).
//
//
// OpenGL
// (clipSpaceBottomUp=true, framebufferBottomUp=true)
//
// Rive Pixel Space Clip Space Framebuffer
//
// 0 -----------> ^ +1 ^ height
// | width | |
// | -1 | +1 |
// | ===> <------|------> ===> |
// | | |
// | | | width
// v height v -1 0 ----------->
//
//
//
// Metal/D3D/WebGPU
// (clipSpaceBottomUp=true, framebufferBottomUp=false)
//
// Rive Pixel Space Clip Space Framebuffer
//
// 0 -----------> ^ +1 0 ----------->
// | width | | width
// | -1 | +1 |
// | ===> <------|------> ===> |
// | | |
// | | |
// v height v -1 v height
//
//
//
// Vulkan
// (clipSpaceBottomUp=false, framebufferBottomUp=false)
//
// Rive Pixel Space Clip Space Framebuffer
//
// 0 -----------> ^ -1 0 ----------->
// | width | | width
// | -1 | +1 |
// | ===> <------|------> ===> |
// | | |
// | | |
// v height v +1 v height
//
bool clipSpaceBottomUp = false;
bool framebufferBottomUp = false;
// Backend cannot initialize PLS with typical clear/load APIs in atomic
// mode. Issue a "DrawType::renderPassInitialize" draw instead.
bool atomicPLSInitNeedsDraw = false;
// Backend API does not support initializing our (transient) MSAA color
// buffer with the existing (non-MSAA) target texture at the beginning of a
// render pass. Draw the previous renderTarget contents into it manually via
// DrawType::renderPassInitialize when LoadAction::preserveRenderTarget is
// specified.
bool msaaColorPreserveNeedsDraw = false;
// Workaround for precision issues. Determines how far apart we space unique
// path IDs when they will be bit-casted to fp16.
uint8_t pathIDGranularity = 1;
// Maximum size (width or height) of a texture.
uint32_t maxTextureSize = 2048;
// Maximum length (in 32-bit uints) of the coverage buffer used for paths in
// clockwiseFill/atomic mode. 2^27 bytes is the minimum storage buffer size
// requirement in the Vulkan, GL, and D3D11 specs. Metal guarantees 256 MB.
size_t maxCoverageBufferLength = (1 << 27) / sizeof(uint32_t);
};
// Gradient color stops are implemented as a horizontal span of pixels in a
// global gradient texture. They are rendered by "GradientSpan" instances.
struct GradientSpan
{
// x0Fixed and x1Fixed are normalized texel x coordinates, in the
// fixed-point range 0..65535.
RIVE_ALWAYS_INLINE void set(uint32_t x0Fixed,
uint32_t x1Fixed,
uint32_t y,
uint32_t flags,
ColorInt color0_,
ColorInt color1_)
{
assert(x0Fixed < 65536);
assert(x1Fixed < 65536);
horizontalSpan = (x1Fixed << 16) | x0Fixed;
yWithFlags = flags | y;
color0 = color0_;
color1 = color1_;
}
uint32_t horizontalSpan;
uint32_t yWithFlags;
uint32_t color0;
uint32_t color1;
};
static_assert(sizeof(GradientSpan) == sizeof(uint32_t) * 4);
static_assert(256 % sizeof(GradientSpan) == 0);
// Metal requires vertex buffers to be 256-byte aligned.
constexpr static size_t kGradSpanBufferAlignmentInElements =
256 / sizeof(GradientSpan);
// Gradient spans are drawn as 1px-tall triangle strips with 3 sub-rectangles.
constexpr uint32_t GRAD_SPAN_TRI_STRIP_VERTEX_COUNT = 8;
// Each curve gets tessellated into vertices. This is performed by rendering a
// horizontal span of positions and normals into the tessellation data texture,
// GP-GPU style. TessVertexSpan defines one instance of a horizontal
// tessellation span for rendering.
//
// Each span has an optional reflection, rendered right to left, with the same
// vertices in reverse order. These are used to draw mirrored patches with
// negative coverage when we have back-face culling enabled. This emits every
// triangle twice, once clockwise and once counterclockwise, and back-face
// culling naturally selects the triangle with the appropriately signed coverage
// (discarding the other).
struct TessVertexSpan
{
RIVE_ALWAYS_INLINE void set(const Vec2D pts_[4],
Vec2D joinTangent_,
float y_,
int32_t x0,
int32_t x1,
uint32_t parametricSegmentCount,
uint32_t polarSegmentCount,
uint32_t joinSegmentCount,
uint32_t contourIDWithFlags_)
{
set(pts_,
joinTangent_,
y_,
x0,
x1,
std::numeric_limits<float>::quiet_NaN(), // Discard the reflection.
-1,
-1,
parametricSegmentCount,
polarSegmentCount,
joinSegmentCount,
contourIDWithFlags_);
}
RIVE_ALWAYS_INLINE void set(const Vec2D pts_[4],
Vec2D joinTangent_,
float y_,
int32_t x0,
int32_t x1,
float reflectionY_,
int32_t reflectionX0,
int32_t reflectionX1,
uint32_t parametricSegmentCount,
uint32_t polarSegmentCount,
uint32_t joinSegmentCount,
uint32_t contourIDWithFlags_)
{
#ifndef NDEBUG
// Write to an intermediate local object in debug mode, so we can check
// its values. (Otherwise we can't read it because mapped memory is
// write-only.)
TessVertexSpan localCopy;
#define LOCAL(VAR) localCopy.VAR
#else
#define LOCAL(VAR) VAR
#endif
RIVE_INLINE_MEMCPY(LOCAL(pts), pts_, sizeof(LOCAL(pts)));
LOCAL(joinTangent) = joinTangent_;
LOCAL(y) = y_;
LOCAL(reflectionY) = reflectionY_;
LOCAL(x0x1) = (x1 << 16 | (x0 & 0xffff));
LOCAL(reflectionX0X1) = (reflectionX1 << 16 | (reflectionX0 & 0xffff));
LOCAL(segmentCounts) = (joinSegmentCount << 20) |
(polarSegmentCount << 10) |
parametricSegmentCount;
LOCAL(contourIDWithFlags) = contourIDWithFlags_;
#undef LOCAL
// Ensure we didn't lose any data from packing.
assert(localCopy.x0x1 << 16 >> 16 == x0);
assert(localCopy.x0x1 >> 16 == x1);
assert(localCopy.reflectionX0X1 << 16 >> 16 == reflectionX0);
assert(localCopy.reflectionX0X1 >> 16 == reflectionX1);
assert((localCopy.segmentCounts & 0x3ff) == parametricSegmentCount);
assert(((localCopy.segmentCounts >> 10) & 0x3ff) == polarSegmentCount);
assert(localCopy.segmentCounts >> 20 == joinSegmentCount);
#ifndef NDEBUG
memcpy(this, &localCopy, sizeof(*this));
#endif
}
Vec2D pts[4]; // Cubic bezier curve.
Vec2D joinTangent; // Ending tangent of the join that follows the cubic.
float y;
float reflectionY;
int32_t x0x1;
int32_t reflectionX0X1;
uint32_t segmentCounts; // [joinSegmentCount, polarSegmentCount,
// parametricSegmentCount]
uint32_t contourIDWithFlags; // flags | contourID
};
static_assert(sizeof(TessVertexSpan) == sizeof(float) * 16);
static_assert(256 % sizeof(TessVertexSpan) == 0);
// Metal requires vertex buffers to be 256-byte aligned.
constexpr static size_t kTessVertexBufferAlignmentInElements =
256 / sizeof(TessVertexSpan);
// Tessellation spans are drawn as two distinct, 1px-tall rectangles: the span
// and its reflection.
constexpr uint16_t kTessSpanIndices[4 * 3] =
{0, 1, 2, 2, 1, 3, 4, 5, 6, 6, 5, 7};
// ImageRects are a special type of non-overlapping antialiased draw that we
// only have to use in atomic mode. They allow us to bind a texture and draw it
// in its entirety in a single pass.
struct ImageRectVertex
{
float x;
float y;
float aaOffsetX;
float aaOffsetY;
};
constexpr ImageRectVertex kImageRectVertices[12] = {
{0, 0, .0, -1},
{1, 0, .0, -1},
{1, 0, +1, .0},
{1, 1, +1, .0},
{1, 1, .0, +1},
{0, 1, .0, +1},
{0, 1, -1, .0},
{0, 0, -1, .0},
{0, 0, +1, +1},
{1, 0, -1, +1},
{1, 1, -1, -1},
{0, 1, +1, -1},
};
constexpr uint16_t kImageRectIndices[14 * 3] = {
8, 0, 9, 9, 0, 1, 1, 2, 9, 9, 2, 10, 10, 2, 3, 3, 4, 10, 10, 4, 11,
11, 4, 5, 5, 6, 11, 11, 6, 8, 8, 6, 7, 7, 0, 8, 9, 10, 8, 10, 8, 11,
};
enum class PaintType : uint32_t
{
clipUpdate, // Update the clip buffer instead of drawing to the framebuffer.
solidColor,
linearGradient,
radialGradient,
image,
};
// Specifies the location of a simple or complex horizontal color ramp within
// the gradient texture. A simple color ramp is two texels wide, beginning at
// the specified row and column. A complex color ramp spans the entire width of
// the gradient texture, on the row:
// "GradTextureLayout::complexOffsetY + ColorRampLocation::row".
struct ColorRampLocation
{
constexpr static uint16_t kComplexGradientMarker = 0xffff;
bool isComplex() const { return col == kComplexGradientMarker; }
uint16_t row;
uint16_t col;
};
// Most of a paint's information can be described in a single value. Gradients
// and images reference an additional Gradient* and Texture* respectively.
union SimplePaintValue
{
ColorInt color = 0xff000000; // PaintType::solidColor
ColorRampLocation colorRampLocation; // Paintype::linear/radialGradient
float imageOpacity; // PaintType::image
uint32_t outerClipID; // Paintype::clipUpdate
};
static_assert(sizeof(SimplePaintValue) == 4);
// This class encapsulates a matrix that maps from _fragCoord to a space where
// the clipRect is the normalized rectangle: [-1, -1, +1, +1]
class ClipRectInverseMatrix
{
public:
// When the clipRect inverse matrix is singular (e.g., all 0 in scale and
// skew), the shader uses tx and ty as fixed clip coverage values instead of
// finding edge distances.
constexpr static ClipRectInverseMatrix WideOpen()
{
return Mat2D{0, 0, 0, 0, 1, 1};
}
constexpr static ClipRectInverseMatrix Empty()
{
return Mat2D{0, 0, 0, 0, 0, 0};
}
ClipRectInverseMatrix() = default;
ClipRectInverseMatrix(const Mat2D& clipMatrix, const AABB& clipRect)
{
reset(clipMatrix, clipRect);
}
void reset(const Mat2D& clipMatrix, const AABB& clipRect);
const Mat2D& inverseMatrix() const { return m_inverseMatrix; }
private:
constexpr ClipRectInverseMatrix(const Mat2D& inverseMatrix) :
m_inverseMatrix(inverseMatrix)
{}
Mat2D m_inverseMatrix;
};
// Specifies the height of the gradient texture, and the row at which we
// transition from simple color ramps to complex.
//
// This information is computed at flush time, once we know exactly how many
// color ramps of each type will be in the gradient texture.
struct GradTextureLayout
{
uint32_t complexOffsetY; // Row of the first complex gradient.
float inverseHeight; // 1 / textureHeight
};
// Once all curves in a contour have been tessellated, we render the tessellated
// vertices in "patches" (aka specific instanced geometry).
//
// See:
// https://docs.google.com/document/d/19Uk9eyFxav6dNSYsI2ZyiX9zHU1YOaJsMB2sdDFVz6s/edit#heading=h.fa4kubk3vimk
//
// With strokes:
// https://docs.google.com/document/d/1CRKihkFjbd1bwT08ErMCP4fwSR7D4gnHvgdw_esY9GM/edit#heading=h.dcd0c58pxfs5
//
// A single patch spans N tessellation segments, connecting N + 1 tessellation
// vertices. It is composed of a an AA border and fan triangles. The specifics
// of the fan triangles depend on the PatchType.
enum class PatchType
{
// Patches fan around the contour midpoint. Outer edges are inset by ~1px,
// followed by a ~1px AA ramp.
midpointFan,
// Similar to midpointFan, except AA ramps are split down the center and
// drawn with a ~1/2px outset AA ramp and a ~1/2px inset AA ramp that
// overlaps the inner tessellation and has negative coverage.
midpointFanCenterAA,
// Patches only cover the AA ramps and interiors of bezier curves. The
// interior path triangles that connect the outer curves are triangulated on
// the CPU to eliminate overlap, and are drawn in a separate call. AA ramps
// are split down the center (on the same lines as the interior
// triangulation), and drawn with a ~1/2px outset AA ramp and a ~1/2px inset
// AA ramp that overlaps the inner tessellation and has negative coverage. A
// lone bowtie join is emitted at the end of the patch to tie the outer
// curves together.
outerCurves,
};
// When tessellating path vertices, we have the ability to generate the
// triangles wound in forward or reverse order. Depending on the path and the
// rendering algorithm, we will either want the triangles wound forward,
// reverse, or BOTH.
enum class ContourDirections
{
forward,
reverse,
// Generate two tessellations of the contour: reverse first, then forward.
reverseThenForward,
// Generate two tessellations of the contour: forward first, then reverse.
forwardThenReverse,
};
constexpr static bool ContourDirectionsAreDoubleSided(
ContourDirections contourDirections)
{
return contourDirections >= ContourDirections::reverseThenForward;
}
struct PatchVertex
{
void set(float localVertexID_,
float outset_,
float fillCoverage_,
float params_)
{
localVertexID = localVertexID_;
outset = outset_;
fillCoverage = fillCoverage_;
params = params_;
setMirroredPosition(localVertexID_, outset_, fillCoverage_);
}
// Patch vertices can have an optional, alternate position when mirrored.
// This is so we can ensure the diagonals inside the stroke line up on both
// versions of the patch (mirrored and not).
void setMirroredPosition(float localVertexID_,
float outset_,
float fillCoverage_)
{
mirroredVertexID = localVertexID_;
mirroredOutset = outset_;
mirroredFillCoverage = fillCoverage_;
}
float localVertexID; // 0 or 1 -- which tessellated vertex of the two that
// we are connecting?
float outset; // Outset from the tessellated position, in the direction of
// the normal.
float fillCoverage; // 0..1 for the stroke. 1 all around for the triangles.
// (Coverage will be negated later for counterclockwise
// triangles.)
int32_t params; // "(patchSize << 2) | [flags::kStrokeVertex,
// flags::kFanVertex,
// flags::kFanMidpointVertex]"
float mirroredVertexID;
float mirroredOutset;
float mirroredFillCoverage;
int32_t padding = 0;
};
static_assert(sizeof(PatchVertex) == sizeof(float) * 8);
// # of tessellation segments spanned by the midpoint fan patch.
constexpr static uint32_t kMidpointFanPatchSegmentSpan = 8;
// # of tessellation segments spanned by the outer curve patch. (In this
// particular instance, the final segment is a bowtie join with zero length and
// no fan triangle.)
constexpr static uint32_t kOuterCurvePatchSegmentSpan = 17;
// Define vertex and index buffers that contain all the triangles in every
// PatchType.
constexpr static uint32_t kMidpointFanPatchVertexCount =
kMidpointFanPatchSegmentSpan * 4 /*Stroke and/or AA outer ramp*/ +
(kMidpointFanPatchSegmentSpan + 1) /*Curve fan*/ +
1 /*Triangle from path midpoint*/;
constexpr static uint32_t kMidpointFanPatchBorderIndexCount =
kMidpointFanPatchSegmentSpan * 6 /*Stroke and/or AA outer ramp*/;
constexpr static uint32_t kMidpointFanPatchIndexCount =
kMidpointFanPatchBorderIndexCount /*Stroke and/or AA outer ramp*/ +
(kMidpointFanPatchSegmentSpan - 1) * 3 /*Curve fan*/ +
3 /*Triangle from path midpoint*/;
constexpr static uint32_t kMidpointFanPatchBaseIndex = 0;
static_assert((kMidpointFanPatchBaseIndex * sizeof(uint16_t)) % 4 == 0);
constexpr static uint32_t kMidpointFanCenterAAPatchVertexCount =
kMidpointFanPatchSegmentSpan * 4 * 2 /*Stroke and/or AA outer ramp*/ +
(kMidpointFanPatchSegmentSpan + 1) /*Curve fan*/ +
1 /*Triangle from path midpoint*/;
constexpr static uint32_t kMidpointFanCenterAAPatchBorderIndexCount =
kMidpointFanPatchSegmentSpan * 12 /*Stroke and/or AA outer ramp*/;
constexpr static uint32_t kMidpointFanCenterAAPatchIndexCount =
kMidpointFanCenterAAPatchBorderIndexCount /*Stroke and/or AA outer ramp*/ +
(kMidpointFanPatchSegmentSpan - 1) * 3 /*Curve fan*/ +
3 /*Triangle from path midpoint*/;
constexpr static uint32_t kMidpointFanCenterAAPatchBaseIndex =
kMidpointFanPatchBaseIndex + kMidpointFanPatchIndexCount;
static_assert((kMidpointFanCenterAAPatchBaseIndex * sizeof(uint16_t)) % 4 == 0);
constexpr static uint32_t kOuterCurvePatchVertexCount =
kOuterCurvePatchSegmentSpan * 8 /*AA center ramp with bowtie*/ +
kOuterCurvePatchSegmentSpan /*Curve fan*/;
constexpr static uint32_t kOuterCurvePatchBorderIndexCount =
kOuterCurvePatchSegmentSpan * 12 /*AA center ramp with bowtie*/;
constexpr static uint32_t kOuterCurvePatchIndexCount =
kOuterCurvePatchBorderIndexCount /*AA center ramp with bowtie*/ +
(kOuterCurvePatchSegmentSpan - 2) * 3 /*Curve fan*/;
constexpr static uint32_t kOuterCurvePatchBaseIndex =
kMidpointFanCenterAAPatchBaseIndex + kMidpointFanCenterAAPatchIndexCount;
static_assert((kOuterCurvePatchBaseIndex * sizeof(uint16_t)) % 4 == 0);
constexpr static uint32_t kPatchVertexBufferCount =
kMidpointFanPatchVertexCount + kMidpointFanCenterAAPatchVertexCount +
kOuterCurvePatchVertexCount;
constexpr static uint32_t kPatchIndexBufferCount =
kMidpointFanPatchIndexCount + kMidpointFanCenterAAPatchIndexCount +
kOuterCurvePatchIndexCount;
void GeneratePatchBufferData(PatchVertex[kPatchVertexBufferCount],
uint16_t indices[kPatchIndexBufferCount]);
enum class DrawType : uint8_t
{
// Fills, strokes, feathered strokes.
midpointFanPatches,
// Feathered fills.
midpointFanCenterAAPatches,
// Just the outer curves of a path; the interior will be triangulated.
outerCurvePatches,
interiorTriangulation,
atlasBlit,
imageRect,
imageMesh,
// MSAA strokes can't be merged with fills because they require their own
// dedicated stencil settings.
msaaStrokes,
// MSAA "fast" path: (effectively) single pass rendering.
msaaMidpointFanBorrowedCoverage,
msaaMidpointFans,
msaaMidpointFanStencilReset,
// MSAA "slow" path: stencil-then-cover.
msaaMidpointFanPathsStencil,
msaaMidpointFanPathsCover,
// MSAA interior triangulation is not currently supported, but this one draw
// type is included in order to support the "retrofittedcubictriangles" GM.
msaaOuterCubics,
// Clear or intersect (based on DrawContents) the stencil clip bit.
msaaStencilClipReset,
// Clear/init render pass data with a fullscreen draw when we can't do it
// with existing clear/load APIs. (e.g., for pixel local storage in buffers
// that don't have copy/clear commands, or preserving existing color data in
// a transient MSAA arrachment).
renderPassInitialize,
// Resolve render pass data (e.g., by applying the final deferred color in
// atomic mode, or copying an offscreen attachment to the final
// renderTarget).
renderPassResolve,
};
constexpr static bool DrawTypeIsImageDraw(DrawType drawType)
{
switch (drawType)
{
case DrawType::imageRect:
case DrawType::imageMesh:
return true;
case DrawType::midpointFanPatches:
case DrawType::midpointFanCenterAAPatches:
case DrawType::outerCurvePatches:
case DrawType::interiorTriangulation:
case DrawType::atlasBlit:
case DrawType::msaaStrokes:
case DrawType::msaaMidpointFanBorrowedCoverage:
case DrawType::msaaMidpointFans:
case DrawType::msaaMidpointFanStencilReset:
case DrawType::msaaMidpointFanPathsStencil:
case DrawType::msaaMidpointFanPathsCover:
case DrawType::msaaOuterCubics:
case DrawType::msaaStencilClipReset:
case DrawType::renderPassInitialize:
case DrawType::renderPassResolve:
return false;
}
RIVE_UNREACHABLE();
}
constexpr static uint32_t PatchIndexCount(DrawType drawType)
{
switch (drawType)
{
case DrawType::midpointFanPatches:
return kMidpointFanPatchIndexCount;
case DrawType::midpointFanCenterAAPatches:
return kMidpointFanCenterAAPatchIndexCount;
case DrawType::outerCurvePatches:
return kOuterCurvePatchIndexCount;
case DrawType::msaaStrokes:
return kMidpointFanPatchBorderIndexCount;
case DrawType::msaaMidpointFanBorrowedCoverage:
case DrawType::msaaMidpointFans:
case DrawType::msaaMidpointFanStencilReset:
case DrawType::msaaMidpointFanPathsStencil:
case DrawType::msaaMidpointFanPathsCover:
return kMidpointFanPatchIndexCount -
kMidpointFanPatchBorderIndexCount;
case DrawType::msaaOuterCubics:
return kOuterCurvePatchIndexCount -
kOuterCurvePatchBorderIndexCount;
case DrawType::interiorTriangulation:
case DrawType::atlasBlit:
case DrawType::imageRect:
case DrawType::imageMesh:
case DrawType::msaaStencilClipReset:
case DrawType::renderPassInitialize:
case DrawType::renderPassResolve:
RIVE_UNREACHABLE();
}
RIVE_UNREACHABLE();
}
constexpr static uint32_t PatchBaseIndex(DrawType drawType)
{
switch (drawType)
{
case DrawType::midpointFanPatches:
case DrawType::msaaStrokes:
return kMidpointFanPatchBaseIndex;
case DrawType::midpointFanCenterAAPatches:
return kMidpointFanCenterAAPatchBaseIndex;
case DrawType::outerCurvePatches:
return kOuterCurvePatchBaseIndex;
case DrawType::msaaMidpointFanBorrowedCoverage:
case DrawType::msaaMidpointFans:
case DrawType::msaaMidpointFanStencilReset:
case DrawType::msaaMidpointFanPathsStencil:
case DrawType::msaaMidpointFanPathsCover:
return kMidpointFanPatchBaseIndex +
kMidpointFanPatchBorderIndexCount;
case DrawType::msaaOuterCubics:
return kOuterCurvePatchBaseIndex + kOuterCurvePatchBorderIndexCount;
case DrawType::interiorTriangulation:
case DrawType::atlasBlit:
case DrawType::imageRect:
case DrawType::imageMesh:
case DrawType::msaaStencilClipReset:
case DrawType::renderPassInitialize:
case DrawType::renderPassResolve:
RIVE_UNREACHABLE();
}
RIVE_UNREACHABLE();
}
// Specifies what to do with the render target at the beginning of a flush.
enum class LoadAction
{
clear,
preserveRenderTarget,
dontCare,
};
// Synchronization method for pixel local storage with overlapping fragments.
enum class InterlockMode
{
rasterOrdering,
atomics,
// Use an experimental path rendering algorithm that utilizes atomics
// without barriers. This requires that we override all paths' fill rules
// (winding or even/odd) with a "clockwise" fill rule, where only regions
// with a positive winding number get filled.
clockwiseAtomic,
msaa,
};
constexpr static size_t kInterlockModeCount = 4;
// Low-level batch of scissored geometry for rendering to the offscreen atlas.
struct AtlasDrawBatch
{
TAABB<uint16_t> scissor;
uint32_t patchCount;
uint32_t basePatch;
};
// "Uber shader" features that can be #defined in a draw shader.
// This set is strictly limited to switches that don't *change* the behavior of
// the shader, i.e., turning them all on will enable all types Rive content, but
// simple content will still draw identically; we can turn a feature off if we
// know a batch doesn't need it for better performance.
enum class ShaderFeatures
{
NONE = 0,
// Whole program features.
ENABLE_CLIPPING = 1 << 0,
ENABLE_CLIP_RECT = 1 << 1,
ENABLE_ADVANCED_BLEND = 1 << 2,
ENABLE_FEATHER = 1 << 3,
// Fragment-only features.
ENABLE_EVEN_ODD = 1 << 4,
ENABLE_NESTED_CLIPPING = 1 << 5,
ENABLE_HSL_BLEND_MODES = 1 << 6,
};
RIVE_MAKE_ENUM_BITSET(ShaderFeatures)
constexpr static size_t kShaderFeatureCount = 7;
constexpr static ShaderFeatures kAllShaderFeatures =
static_cast<gpu::ShaderFeatures>((1 << kShaderFeatureCount) - 1);
constexpr static ShaderFeatures kVertexShaderFeaturesMask =
ShaderFeatures::ENABLE_CLIPPING | ShaderFeatures::ENABLE_CLIP_RECT |
ShaderFeatures::ENABLE_ADVANCED_BLEND | ShaderFeatures::ENABLE_FEATHER;
// These shader features change the way atomic pipelines are set up (or cause
// validation failures when enabled but not used)
constexpr static ShaderFeatures kExclusiveAtomicUbershaderFeaturesMask =
ShaderFeatures::ENABLE_ADVANCED_BLEND;
constexpr static ShaderFeatures ShaderFeaturesMaskFor(
InterlockMode interlockMode)
{
switch (interlockMode)
{
case InterlockMode::rasterOrdering:
return kAllShaderFeatures;
case InterlockMode::atomics:
return kAllShaderFeatures & ~ShaderFeatures::ENABLE_NESTED_CLIPPING;
case InterlockMode::clockwiseAtomic:
// TODO: shader features aren't fully implemented yet in
// clockwiseAtomic mode.
return ShaderFeatures::ENABLE_FEATHER;
case InterlockMode::msaa:
return ShaderFeatures::ENABLE_CLIP_RECT |
ShaderFeatures::ENABLE_ADVANCED_BLEND |
ShaderFeatures::ENABLE_HSL_BLEND_MODES;
}
RIVE_UNREACHABLE();
}
// Miscellaneous switches that *do* affect the behavior of the fragment shader.
// The renderContext may add some of these, and a backend may also add them to a
// shader key if it wants to implement the behavior.
enum class ShaderMiscFlags : uint32_t
{
none = 0,
// InterlockMode::atomics only (without advanced blend). Render color to a
// standard attachment instead of PLS. The backend implementation is
// responsible to turn on src-over blending.
fixedFunctionColorOutput = 1 << 0,
// Override all paths' fill rules (winding or even/odd) with an experimental
// "clockwise" fill rule, where only regions with a positive winding number
// get filled.
clockwiseFill = 1 << 1,
// clockwiseAtomic mode only. This shader is a prepass that only subtracts
// (counterclockwise) borrowed coverage from the coverage buffer. It doesn't
// output color or clip.
borrowedCoveragePrepass = 1 << 2,
// DrawType::renderPassInitialize only. Also store the color clear value to
// PLS when drawing a clear, in addition to clearing the other PLS planes.
storeColorClear = 1 << 3,
// DrawType::renderPassInitialize only. Swizzle the existing framebuffer
// contents from BGRA to RGBA. (For when this data had to get copied from a
// BGRA target.)
swizzleColorBGRAToRGBA = 1 << 4,
// DrawType::renderPassResolve only. Optimization for when rendering to an
// offscreen texture.
//
// It renders the final "resolve" operation directly to the renderTarget in
// a single pass, instead of (1) resolving the offscreen texture, and then
// (2) copying the offscreen texture to back the renderTarget.
coalescedResolveAndTransfer = 1 << 5,
};
RIVE_MAKE_ENUM_BITSET(ShaderMiscFlags)
constexpr static ShaderFeatures ShaderFeaturesMaskFor(
DrawType drawType,
InterlockMode interlockMode)
{
ShaderFeatures mask = ShaderFeatures::NONE;
switch (drawType)
{
case DrawType::imageRect:
case DrawType::imageMesh:
case DrawType::atlasBlit:
if (interlockMode != gpu::InterlockMode::atomics)
{
mask = ShaderFeatures::ENABLE_CLIPPING |
ShaderFeatures::ENABLE_CLIP_RECT |
ShaderFeatures::ENABLE_ADVANCED_BLEND |
ShaderFeatures::ENABLE_HSL_BLEND_MODES;
break;
}
// Since atomic mode has to resolve previous draws, images need to
// consider the same shader features for path draws.
[[fallthrough]];
case DrawType::midpointFanPatches:
case DrawType::midpointFanCenterAAPatches:
case DrawType::outerCurvePatches:
case DrawType::interiorTriangulation:
case DrawType::msaaStrokes:
case DrawType::msaaMidpointFanBorrowedCoverage:
case DrawType::msaaMidpointFans:
case DrawType::msaaMidpointFanStencilReset:
case DrawType::msaaMidpointFanPathsStencil:
case DrawType::msaaMidpointFanPathsCover:
case DrawType::msaaOuterCubics:
mask = kAllShaderFeatures;
break;
case DrawType::msaaStencilClipReset:
mask = ShaderFeatures::NONE;
break;
case DrawType::renderPassInitialize:
if (interlockMode == gpu::InterlockMode::atomics)
{
// Atomic mode initializes clipping and color (when advanced
// blend is active).
mask = ShaderFeatures::ENABLE_CLIPPING |
ShaderFeatures::ENABLE_ADVANCED_BLEND;
}
else
{
assert(interlockMode == gpu::InterlockMode::msaa);
// MSAA mode only needs to initialize color, and only when
// preserving the render target but using a transient MSAA
// attachment.
mask = ShaderFeatures::NONE;
}
break;
case DrawType::renderPassResolve:
assert(interlockMode == gpu::InterlockMode::atomics);
mask = kAllShaderFeatures;
break;
}
return mask & ShaderFeaturesMaskFor(interlockMode);
}
// Returns the flags that are valid for an ubershader version of the currently-
// requested shader feature set. There are some shader features that change
// how the render passes are set up in atomic mode that need to be accounted
// for beyond just using ShaderFeaturesMaskFor.
constexpr static ShaderFeatures UbershaderFeaturesMaskFor(
ShaderFeatures requestedFeatures,
DrawType drawType,
InterlockMode interlockMode,
const PlatformFeatures& platformFeatures)
{
ShaderFeatures outFeatures = ShaderFeaturesMaskFor(drawType, interlockMode);
if (interlockMode == InterlockMode::atomics)
{
// Turn off the exclusive atomic features unless they're set in our
// requested feature flags.
outFeatures &=
(requestedFeatures | ~kExclusiveAtomicUbershaderFeaturesMask);
}
// Ensure that we haven't dropped features we care about somehow
assert((requestedFeatures & outFeatures) == requestedFeatures);
// ENABLE_CLIP_RECT shouldn't be set if we're in MSAA mode without clip
// plane support.
if (interlockMode == InterlockMode::msaa &&
!platformFeatures.supportsClipPlanes)
{
outFeatures &= ~ShaderFeatures::ENABLE_CLIP_RECT;
}
return outFeatures;
}
// Returns a unique value that can be used to key a shader.
uint32_t ShaderUniqueKey(DrawType,
ShaderFeatures,
InterlockMode,
ShaderMiscFlags);
extern const char* GetShaderFeatureGLSLName(ShaderFeatures feature);
// Flags indicating the contents of a draw. These don't affect shaders, but in
// msaa mode they are needed to break up batching. (msaa needs different
// stencil/blend state, depending on the DrawContents.)
//
// These also affect the draw sort order, so we attempt associate more expensive
// shader branch misses with higher flags.
enum class DrawContents
{
none = 0,
opaquePaint = 1 << 0,
// Put feathered fills down low because they only need to draw different
// geometry, which isn't really a context switch at all.
featheredFill = 1 << 1,
stroke = 1 << 2,
clockwiseFill = 1 << 3,
nonZeroFill = 1 << 4,
evenOddFill = 1 << 5,
activeClip = 1 << 6,
clipUpdate = 1 << 7,
advancedBlend = 1 << 8,
};
RIVE_MAKE_ENUM_BITSET(DrawContents)
// A nestedClip draw updates the clip buffer while simultaneously clipping
// against the outerClip that is currently in the clip buffer.
constexpr static gpu::DrawContents kNestedClipUpdateMask =
(gpu::DrawContents::activeClip | gpu::DrawContents::clipUpdate);
// Types of barriers that may be required between DrawBatches.
enum class BarrierFlags : uint8_t
{
none = 0,
// Pixel-local dependency in the PLS planes. (Atomic mode only.) Ensure
// prior draws complete at each pixel before beginning new ones.
plsAtomic = 1 << 0,
plsAtomicPreResolve = 1 << 1, // Once before the final resolve.
// MSAA needs a special barrier (e.g., subpass transition) after manually
// loading the render target into the transient MSAA attachment.
msaaPostInit = 1 << 2,
// Pixel-local dependency in the coverage buffer. (clockwiseAtomic mode
// only.) All "borrowed coverage" draws have now been issued. Ensure they
// complete at each pixel before beginning the "forward coverage" draws.
clockwiseBorrowedCoverage = 1 << 3,
// The next DrawBatch needs to perform an advanced blend, but the current
// hardware requires an implementation-dependent barrier before reading the
// dstColor (pipeline barrier for input attachments, KHR blend barrier, or
// even a full MSAA resolve & blit into a separate texture.)
dstBlend = 1 << 4,
// Only prevent future DrawBatches from being combined with the current
// drawList. (No GPU dependencies.)
drawBatchBreak = 1 << 5,
};
RIVE_MAKE_ENUM_BITSET(BarrierFlags);
// Low-level batch of geometry to submit to the GPU.
struct DrawBatch
{
DrawBatch(DrawType drawType_,
gpu::ShaderMiscFlags shaderMiscFlags_,
uint32_t elementCount_,
uint32_t baseElement_,
rive::BlendMode blendMode_,
rive::ImageSampler imageSampler_,
BarrierFlags barrierFlags_) :
drawType(drawType_),
shaderMiscFlags(shaderMiscFlags_),
elementCount(elementCount_),
baseElement(baseElement_),
firstBlendMode(blendMode_),
barriers(barrierFlags_),
imageSampler(imageSampler_)
{}
const DrawType drawType;
const ShaderMiscFlags shaderMiscFlags;
uint32_t elementCount; // Vertex, index, or instance count.
uint32_t baseElement; // Base vertex, index, or instance.
rive::BlendMode firstBlendMode;
BarrierFlags barriers; // Barriers to execute before drawing this batch.
DrawContents drawContents = DrawContents::none;
ShaderFeatures shaderFeatures = ShaderFeatures::NONE;
// DrawType::imageRect and DrawType::imageMesh.
uint32_t imageDrawDataOffset = 0;
Texture* imageTexture = nullptr;
const ImageSampler imageSampler = ImageSampler::LinearClamp();
// DrawType::imageMesh.
RenderBuffer* vertexBuffer;
RenderBuffer* uvBuffer;
RenderBuffer* indexBuffer;
// When shaders don't have a mechanism to read the framebuffer (e.g.,
// WebGL msaa), this is a linked list of all the draws in the batch whose
// bounding boxes needs to be blitted to the "dstRead" texture before
// drawing.
const Draw* dstReadList = nullptr;
};
// Simple gradients only have 2 texels, so we write them to mapped texture
// memory from the CPU instead of rendering them.
struct TwoTexelRamp
{
ColorInt color0, color1;
};
static_assert(sizeof(TwoTexelRamp) == 8 * sizeof(uint8_t));
#ifdef WITH_RIVE_TOOLS
enum class SynthesizedFailureType
{
none,
ubershaderLoad,
shaderCompilation,
pipelineCreation,
};
#endif
// Detailed description of exactly how a RenderContextImpl should bind its
// buffers and draw a flush. A typical flush is done in 4 steps:
//
// 1. Render the complex gradients from the gradSpanBuffer to the gradient
// texture (gradSpanCount, firstComplexGradSpan, complexGradRowsTop,
// complexGradRowsHeight).
//
// 2. Transfer the simple gradient texels from the simpleColorRampsBuffer to
// the top of the gradient texture (simpleGradTexelsWidth,
// simpleGradTexelsHeight, simpleGradDataOffsetInBytes, tessDataHeight).
//
// 3. Render the tessellation texture from the tessVertexSpanBuffer
// (tessVertexSpanCount, firstTessVertexSpan).
//
// 4. Execute the drawList, reading from the newly rendered resource textures.
//
struct FlushDescriptor
{
RenderTarget* renderTarget = nullptr;
ShaderFeatures combinedShaderFeatures = ShaderFeatures::NONE;
InterlockMode interlockMode = InterlockMode::rasterOrdering;
// Atomic mode only: there a no advanced blend modes, so we can render
// directly to the main target with fixed function (src-over) blending.
bool atomicFixedFunctionColorOutput = false;
int msaaSampleCount = 0; // (0 unless interlockMode is msaa.)
LoadAction colorLoadAction = LoadAction::clear;
ColorInt colorClearValue = 0; // When loadAction == LoadAction::clear.
uint32_t coverageClearValue = 0;
float depthClearValue = DEPTH_MAX;
uint8_t stencilClearValue = STENCIL_CLEAR;
IAABB renderTargetUpdateBounds; // drawBounds, or renderTargetBounds if
// loadAction == LoadAction::clear.
// Physical size of the atlas texture.
uint16_t atlasTextureWidth;
uint16_t atlasTextureHeight;
// Boundaries of the content for this specific flush within the atlas
// texture.
uint16_t atlasContentWidth;
uint16_t atlasContentHeight;
// Monotonically increasing prefix that gets appended to the most
// significant "32 - CLOCKWISE_COVERAGE_BIT_COUNT" bits of coverage buffer
// values.
//
// The coverage buffer is used in clockwiseAtomic mode.
//
// Increasing this prefix implicitly clears the entire coverage buffer to
// zero.
uint32_t coverageBufferPrefix = 0;
// (clockwiseAtomic mode only.) We usually don't have to clear the coverage
// buffer because of coverageBufferPrefix, but when this value is true, the
// entire coverage buffer must be cleared to zero before rendering.
bool needsCoverageBufferClear = false;
size_t flushUniformDataOffsetInBytes = 0;
uint32_t pathCount = 0;
size_t firstPath = 0;
size_t firstPaint = 0;
size_t firstPaintAux = 0;
uint32_t contourCount = 0;
size_t firstContour = 0;
uint32_t gradSpanCount = 0;
size_t firstGradSpan = 0;
uint32_t tessVertexSpanCount = 0;
size_t firstTessVertexSpan = 0;
uint32_t gradDataHeight = 0;
uint32_t tessDataHeight = 0;
// Override path fill rules with "clockwise".
bool clockwiseFillOverride = false;
bool hasTriangleVertices = false;
bool wireframe = false;
#ifdef WITH_RIVE_TOOLS
// Synthesize compilation failures to make sure the device handles them
// gracefully. (e.g., by falling back on an uber shader or at least not
// crashing.) Valid compilations may fail in the real world if the device is
// pressed for resources or in a bad state.
SynthesizedFailureType synthesizedFailureType =
SynthesizedFailureType::none;
#endif
// Command buffer that rendering commands will be added to.
// - VkCommandBuffer on Vulkan.
// - id<MTLCommandBuffer> on Metal.
// - Unused otherwise.
void* externalCommandBuffer = nullptr;
// List of feathered fills (if any) that must be rendered to the atlas
// before the main render pass.
const AtlasDrawBatch* atlasFillBatches = nullptr;
size_t atlasFillBatchCount = 0;
// List of feathered strokes (if any) that must be rendered to the atlas
// before the main render pass.
const AtlasDrawBatch* atlasStrokeBatches = nullptr;
size_t atlasStrokeBatchCount = 0;
// List of draws in the main render pass. These are rendered directly to the
// renderTarget.
const BlockAllocatedLinkedList<DrawBatch>* drawList = nullptr;
};
// Returns the area of the (potentially non-rectangular) quadrilateral that
// results from transforming the given bounds by the given matrix.
float find_transformed_area(const AABB& bounds, const Mat2D&);
// Convert a BlendMode to the tightly-packed range used by PLS shaders.
uint32_t ConvertBlendModeToPLSBlendMode(BlendMode riveMode);
// Swizzles the byte order of ColorInt to litte-endian RGBA (the order expected
// by GLSL).
RIVE_ALWAYS_INLINE uint32_t SwizzleRiveColorToRGBA(ColorInt riveColor)
{
return (riveColor & 0xff00ff00) |
(math::rotateleft32(riveColor, 16) & 0x00ff00ff);
}
// Swizzles the byte order of ColorInt to litte-endian RGBA (the order expected
// by GLSL), and premultiplies alpha.
uint32_t SwizzleRiveColorToRGBAPremul(ColorInt riveColor);
// Used for fields that are used to layout write-only mapped GPU memory.
// "volatile" to discourage the compiler from generating code that reads these
// values (e.g., don't let the compiler generate "x ^= x" instead of "x = 0").
// "RIVE_MAYBE_UNUSED" to suppress -Wunused-private-field.
#define WRITEONLY RIVE_MAYBE_UNUSED volatile
// Per-flush shared uniforms used by all shaders.
struct FlushUniforms
{
public:
FlushUniforms(const FlushDescriptor&, const PlatformFeatures&);
FlushUniforms(const FlushUniforms& other) { *this = other; }
void operator=(const FlushUniforms& rhs)
{
memcpy(static_cast<void*>(this),
&rhs,
sizeof(*this) - sizeof(m_padTo256Bytes));
}
bool operator!=(const FlushUniforms& rhs) const
{
return memcmp(this, &rhs, sizeof(*this) - sizeof(m_padTo256Bytes)) != 0;
}
private:
class InverseViewports
{
public:
InverseViewports() = default;
InverseViewports(const FlushDescriptor&, const PlatformFeatures&);
private:
// [complexGradientsY, tessDataY, renderTargetX, renderTargetY]
WRITEONLY float m_vals[4];
};
WRITEONLY InverseViewports m_inverseViewports;
WRITEONLY uint32_t m_renderTargetWidth;
WRITEONLY uint32_t m_renderTargetHeight;
// Only used if clears are implemented as draws.
WRITEONLY uint32_t m_colorClearValue;
// Only used if clears are implemented as draws.
WRITEONLY uint32_t m_coverageClearValue;
// drawBounds, or renderTargetBounds if there is a clear. (Used by the
// "@RESOLVE_PLS" step in InterlockMode::atomics.)
WRITEONLY IAABB m_renderTargetUpdateBounds;
WRITEONLY Vec2D m_atlasTextureInverseSize; // 1 / [atlasWidth, atlasHeight]
WRITEONLY Vec2D m_atlasContentInverseViewport; // 2 / atlasContentBounds
// Monotonically increasing prefix that gets appended to the most
// significant "32 - CLOCKWISE_COVERAGE_BIT_COUNT" bits of coverage buffer
// values. (clockwiseAtomic mode only.)
WRITEONLY uint32_t m_coverageBufferPrefix;
// Spacing between adjacent path IDs (1 if IEEE compliant).
WRITEONLY uint32_t m_pathIDGranularity;
WRITEONLY float m_vertexDiscardValue;
WRITEONLY uint32_t m_wireframeEnabled; // Forces coverage to solid.
// Uniform blocks must be multiples of 256 bytes in size.
WRITEONLY uint8_t m_padTo256Bytes[256 - 80];
};
static_assert(sizeof(FlushUniforms) == 256);
// Storage buffers are logically layed out as arrays of structs on the CPU, but
// the GPU shaders access them as arrays of basic types. We do it this way in
// order to be able to easily polyfill them with textures.
//
// This enum defines the underlying basic type that each storage buffer struct
// is layed on top of.
enum StorageBufferStructure
{
uint32x4,
uint32x2,
float32x4,
};
constexpr static uint32_t StorageBufferElementSizeInBytes(
StorageBufferStructure bufferStructure)
{
switch (bufferStructure)
{
case StorageBufferStructure::uint32x4:
return sizeof(uint32_t) * 4;
case StorageBufferStructure::uint32x2:
return sizeof(uint32_t) * 2;
case StorageBufferStructure::float32x4:
return sizeof(float) * 4;
}
RIVE_UNREACHABLE();
}
// Defines a transform from screen space into a region of the atlas.
// The atlas may have a different scale factor than the screen.
struct AtlasTransform
{
float scaleFactor;
float translateX;
float translateY;
};
// Defines a sub-allocation for a path's coverage data within the
// renderContext's coverage buffer. (clockwiseAtomic mode only.)
struct CoverageBufferRange
{
// Index of the first pixel of this allocation within the coverage buffer.
// Must be a multiple of 32*32.
uint32_t offset;
// Line width in pixels of the image in this coverage allocation.
// Must be a multiple of 32.
uint32_t pitch;
// Offset from screen space to image coords within the coverage allocation.
float offsetX;
float offsetY;
};
// High level structure of the "path" storage buffer. Each path has a unique
// data record on the GPU that is accessed from the vertex shader.
struct PathData
{
public:
constexpr static StorageBufferStructure kBufferStructure =
StorageBufferStructure::uint32x4;
void set(const Mat2D&,
float strokeRadius,
float featherRadius,
uint32_t zIndex,
const AtlasTransform&,
const CoverageBufferRange&);
private:
WRITEONLY float m_matrix[6];
// "0" indicates that the path is filled, not stroked.
WRITEONLY float m_strokeRadius;
WRITEONLY float m_featherRadius;
// InterlockMode::msaa.
WRITEONLY uint32_t m_zIndex;
// Only used when rendering coverage via the atlas.
WRITEONLY AtlasTransform m_atlasTransform;
// InterlockMode::clockwiseAtomic.
WRITEONLY CoverageBufferRange m_coverageBufferRange;
};
static_assert(sizeof(PathData) ==
StorageBufferElementSizeInBytes(PathData::kBufferStructure) * 4);
static_assert(256 % sizeof(PathData) == 0);
constexpr static size_t kPathBufferAlignmentInElements = 256 / sizeof(PathData);
// High level structure of the "paint" storage buffer. Each path also has a data
// small record describing its paint at a high level. Complex paints (gradients,
// images, or any path with a clipRect) store additional rendering info in the
// PaintAuxData buffer.
struct PaintData
{
public:
constexpr static StorageBufferStructure kBufferStructure =
StorageBufferStructure::uint32x2;
void set(DrawContents singleDrawContents,
PaintType,
SimplePaintValue,
GradTextureLayout,
uint32_t clipID,
bool hasClipRect,
BlendMode);
private:
WRITEONLY uint32_t m_params; // [clipID, flags, paintType]
union
{
WRITEONLY uint32_t m_color; // PaintType::solidColor
WRITEONLY float m_gradTextureY; // Paintype::linearGradient,
// Paintype::radialGradient
WRITEONLY float m_opacity; // PaintType::image
WRITEONLY uint32_t m_shiftedClipReplacementID; // PaintType::clipUpdate
};
};
static_assert(sizeof(PaintData) ==
StorageBufferElementSizeInBytes(PaintData::kBufferStructure));
static_assert(256 % sizeof(PaintData) == 0);
constexpr static size_t kPaintBufferAlignmentInElements =
256 / sizeof(PaintData);
// Structure of the "paintAux" storage buffer. Gradients, images, and clipRects
// store their details here, indexed by pathID.
struct PaintAuxData
{
public:
constexpr static StorageBufferStructure kBufferStructure =
StorageBufferStructure::float32x4;
void set(const Mat2D& viewMatrix,
PaintType,
SimplePaintValue,
const Gradient*,
const Texture*,
const ClipRectInverseMatrix*,
const RenderTarget*,
const gpu::PlatformFeatures&);
private:
WRITEONLY float m_matrix[6]; // Maps _fragCoord to paint coordinates.
union
{
WRITEONLY float
m_gradTextureHorizontalSpan[2]; // Paintype::linearGradient,
// Paintype::radialGradient
WRITEONLY float m_imageTextureLOD; // PaintType::image
};
WRITEONLY float m_clipRectInverseMatrix[6]; // Maps _fragCoord to normalized
// clipRect coords.
WRITEONLY Vec2D m_inverseFwidth; // -1 / fwidth(matrix * _fragCoord) -- for
// antialiasing.
};
static_assert(sizeof(PaintAuxData) ==
StorageBufferElementSizeInBytes(PaintAuxData::kBufferStructure) *
4);
static_assert(256 % sizeof(PaintAuxData) == 0);
constexpr static size_t kPaintAuxBufferAlignmentInElements =
256 / sizeof(PaintAuxData);
// High level structure of the "contour" storage buffer. Each contour of every
// path has a data record describing its info.
struct ContourData
{
public:
constexpr static StorageBufferStructure kBufferStructure =
StorageBufferStructure::uint32x4;
ContourData(Vec2D midpoint, uint32_t pathID, uint32_t vertexIndex0) :
m_midpoint(midpoint), m_pathID(pathID), m_vertexIndex0(vertexIndex0)
{}
private:
WRITEONLY Vec2D
m_midpoint; // Midpoint of the curve endpoints in just this contour.
WRITEONLY uint32_t m_pathID; // ID of the path this contour belongs to.
WRITEONLY uint32_t m_vertexIndex0; // Index of the first tessellation vertex
// of the contour.
};
static_assert(sizeof(ContourData) ==
StorageBufferElementSizeInBytes(ContourData::kBufferStructure));
static_assert(256 % sizeof(ContourData) == 0);
constexpr static size_t kContourBufferAlignmentInElements =
256 / sizeof(ContourData);
// Per-vertex data for shaders that draw triangles.
struct TriangleVertex
{
public:
TriangleVertex() = default;
TriangleVertex(Vec2D point, int16_t weight, uint16_t pathID) :
m_point(point),
m_weight_pathID((static_cast<int32_t>(weight) << 16) | pathID)
{}
#ifdef TESTING
Vec2D testing_point() const { return {m_point.x, m_point.y}; }
int32_t testing_weight_pathID() const { return m_weight_pathID; }
#endif
private:
WRITEONLY Vec2D m_point;
WRITEONLY int32_t m_weight_pathID; // [(weight << 16 | pathID]
};
static_assert(sizeof(TriangleVertex) == sizeof(float) * 3);
// Per-draw uniforms used by image meshes.
struct ImageDrawUniforms
{
public:
ImageDrawUniforms() = default;
ImageDrawUniforms(const Mat2D&,
float opacity,
const ClipRectInverseMatrix*,
uint32_t clipID,
BlendMode,
uint32_t zIndex);
private:
WRITEONLY float m_matrix[6];
WRITEONLY float m_opacity;
WRITEONLY float m_padding = 0;
WRITEONLY float m_clipRectInverseMatrix[6];
WRITEONLY uint32_t m_clipID;
WRITEONLY uint32_t m_blendMode;
WRITEONLY uint32_t m_zIndex; // gpu::InterlockMode::msaa only.
// Uniform blocks must be multiples of 256 bytes in size.
WRITEONLY uint8_t m_padTo256Bytes[256 - 68];
constexpr void staticChecks()
{
static_assert(offsetof(ImageDrawUniforms, m_matrix) % 16 == 0);
static_assert(
offsetof(ImageDrawUniforms, m_clipRectInverseMatrix) % 16 == 0);
static_assert(sizeof(ImageDrawUniforms) == 256);
}
};
#undef WRITEONLY
// The maximum number of storage buffers we will ever use in a vertex or
// fragment shader.
constexpr static size_t kMaxStorageBuffers = 4;
// If the backend doesn't support "kMaxStorageBuffers" a shader, we polyfill
// with textures. This function returns the dimensions to use for these
// textures.
std::tuple<uint32_t, uint32_t> StorageTextureSize(size_t bufferSizeInBytes,
StorageBufferStructure);
// If the backend doesn't support "kMaxStorageBuffers" in a shader, we polyfill
// with textures. The polyfill texture needs to be updated in entire rows at a
// time, meaning, its transfer buffer might need to be larger than requested.
// This function returns a size that is large enough to service a worst-case
// texture update.
size_t StorageTextureBufferSize(size_t bufferSizeInBytes,
StorageBufferStructure);
// Should the triangulator emit triangles with negative winding, positive
// winding, or both?
enum class WindingFaces
{
negative = 1 << 0,
positive = 1 << 1,
all = negative | positive,
};
RIVE_MAKE_ENUM_BITSET(WindingFaces)
// Represents a block of mapped GPU memory. Since it can be extremely expensive
// to read mapped memory, we use this class to enforce the write-only nature of
// this memory.
template <typename T> class WriteOnlyMappedMemory
{
public:
WriteOnlyMappedMemory() { reset(); }
WriteOnlyMappedMemory(T* ptr, size_t elementCount)
{
reset(ptr, elementCount);
}
void reset() { reset(nullptr, 0); }
void reset(T* ptr, size_t elementCount)
{
m_mappedMemory = ptr;
m_nextMappedItem = ptr;
m_mappingEnd = ptr + elementCount;
}
using MapResourceBufferFn =
void* (RenderContextImpl::*)(size_t mapSizeInBytes);
void mapElements(RenderContextImpl* impl,
MapResourceBufferFn mapFn,
size_t elementCount)
{
assert(m_mappedMemory == nullptr);
void* ptr = (impl->*mapFn)(elementCount * sizeof(T));
reset(reinterpret_cast<T*>(ptr), elementCount);
}
using UnmapResourceBufferFn =
void (RenderContextImpl::*)(size_t mapSizeInBytes);
void unmapElements(RenderContextImpl* impl,
UnmapResourceBufferFn unmapFn,
size_t elementCount)
{
assert(m_mappedMemory != nullptr);
assert(m_mappingEnd - m_mappedMemory == elementCount);
(impl->*unmapFn)(elementCount * sizeof(T));
reset();
}
operator bool() const { return m_mappedMemory; }
// How many bytes have been written to the buffer?
size_t bytesWritten() const
{
return reinterpret_cast<uintptr_t>(m_nextMappedItem) -
reinterpret_cast<uintptr_t>(m_mappedMemory);
}
size_t elementsWritten() const { return bytesWritten() / sizeof(T); }
// Is there room to push() itemCount items to the buffer?
bool hasRoomFor(size_t itemCount)
{
return m_nextMappedItem + itemCount <= m_mappingEnd;
}
// Append and write a new item to the buffer. In order to enforce the
// write-only requirement of a mapped buffer, these methods do not return
// any pointers to the client.
template <typename... Args>
RIVE_ALWAYS_INLINE void emplace_back(Args&&... args)
{
new (&push()) T(std::forward<Args>(args)...);
}
template <typename... Args> RIVE_ALWAYS_INLINE void set_back(Args&&... args)
{
push().set(std::forward<Args>(args)...);
}
void push_back_n(const T* values, size_t count)
{
T* dst = push(count);
if (values != nullptr)
{
memcpy(static_cast<void*>(dst), values, count * sizeof(T));
}
}
void skip_back() { push(); }
private:
RIVE_ALWAYS_INLINE T& push()
{
assert(hasRoomFor(1));
return *m_nextMappedItem++;
}
RIVE_ALWAYS_INLINE T* push(size_t count)
{
assert(hasRoomFor(count));
T* ret = m_nextMappedItem;
m_nextMappedItem += count;
return ret;
}
T* m_mappedMemory;
T* m_nextMappedItem;
const T* m_mappingEnd;
};
// Utility for tracking booleans that may be unknown (e.g., lazily computed
// values, GL state, etc.)
enum class TriState
{
no,
yes,
unknown
};
enum class StencilOp : uint8_t
{
keep,
replace,
zero,
decrClamp,
incrWrap,
decrWrap
};
enum class StencilCompareOp : uint8_t
{
less,
equal,
lessOrEqual,
notEqual,
always,
};
struct StencilFaceOps
{
StencilOp failOp;
StencilOp passOp;
StencilOp depthFailOp;
StencilCompareOp compareOp;
};
enum class CullFace : uint8_t
{
none,
clockwise,
counterclockwise,
};
// Blend equation to select for the fixed-function GPU pipeline (not our own
// in-shader blending). For now, the backend is free to decide whether it will
// use premultiplied alpha or not.
enum class BlendEquation : uint8_t
{
// Hardware blend is disabled.
none = 0,
// Core hardware blend equations supported on all platforms.
srcOver = static_cast<int>(rive::BlendMode::srcOver),
plus = srcOver + 1,
max = plus + 1,
// "Advanced" hardware blend equations.
// PlatformFeatures::supportsKHRBlendEquations is required.
screen = static_cast<int>(rive::BlendMode::screen),
overlay = static_cast<int>(rive::BlendMode::overlay),
darken = static_cast<int>(rive::BlendMode::darken),
lighten = static_cast<int>(rive::BlendMode::lighten),
colorDodge = static_cast<int>(rive::BlendMode::colorDodge),
colorBurn = static_cast<int>(rive::BlendMode::colorBurn),
hardLight = static_cast<int>(rive::BlendMode::hardLight),
softLight = static_cast<int>(rive::BlendMode::softLight),
difference = static_cast<int>(rive::BlendMode::difference),
exclusion = static_cast<int>(rive::BlendMode::exclusion),
multiply = static_cast<int>(rive::BlendMode::multiply),
hue = static_cast<int>(rive::BlendMode::hue),
saturation = static_cast<int>(rive::BlendMode::saturation),
color = static_cast<int>(rive::BlendMode::color),
luminosity = static_cast<int>(rive::BlendMode::luminosity),
};
// Common pipeline state that applies to every Rive draw and every backend.
struct PipelineState
{
// Depth.
bool depthTestEnabled;
bool depthWriteEnabled;
// Stencil.
bool stencilTestEnabled;
uint8_t stencilCompareMask;
uint8_t stencilWriteMask;
uint8_t stencilReference;
StencilFaceOps stencilFrontOps;
StencilFaceOps stencilBackOps;
bool stencilDoubleSided; // If true, use stencilFrontOps for both faces.
CullFace cullFace;
BlendEquation blendEquation;
bool colorWriteEnabled;
// 18-bit key that uniquely identifies the pipeline state.
constexpr static int UNIQUE_KEY_BIT_COUNT = 18;
uint32_t uniqueKey;
};
void get_pipeline_state(const DrawBatch&,
const FlushDescriptor&,
const PlatformFeatures&,
PipelineState*);
constexpr static PipelineState COLOR_ONLY_PIPELINE_STATE = {
.depthTestEnabled = false,
.depthWriteEnabled = false,
.stencilTestEnabled = false,
.stencilWriteMask = 0,
.cullFace = CullFace::none,
.blendEquation = BlendEquation::none,
.colorWriteEnabled = true,
};
constexpr static PipelineState ATLAS_FILL_PIPELINE_STATE = {
.depthTestEnabled = false,
.depthWriteEnabled = false,
.stencilTestEnabled = false,
.stencilWriteMask = 0,
.cullFace = CullFace::counterclockwise,
.blendEquation = BlendEquation::plus,
.colorWriteEnabled = true,
};
constexpr static PipelineState ATLAS_STROKE_PIPELINE_STATE = {
.depthTestEnabled = false,
.depthWriteEnabled = false,
.stencilTestEnabled = false,
.stencilWriteMask = 0,
.cullFace = CullFace::counterclockwise,
.blendEquation = BlendEquation::max,
.colorWriteEnabled = true,
};
float4 cast_f16_to_f32(uint16x4 x);
uint16x4 cast_f32_to_f16(float4);
// These tables integrate the gaussian function, and its inverse, covering a
// spread of -FEATHER_TEXTURE_STDDEVS to +FEATHER_TEXTURE_STDDEVS.
constexpr static uint32_t GAUSSIAN_TABLE_SIZE = 512;
extern const uint16_t g_gaussianIntegralTableF16[GAUSSIAN_TABLE_SIZE];
extern const uint16_t g_inverseGaussianIntegralTableF16[GAUSSIAN_TABLE_SIZE];
// Code to generate g_gaussianIntegralTableF16 and
// g_inverseGaussianIntegralTableF32. This is left in the codebase but #ifdef'd
// out in case we ever want to change any parameters of the built-in tables.
#if 0
void generate_gausian_integral_table(float (&)[GAUSSIAN_TABLE_SIZE]);
void generate_inverse_gausian_integral_table(float (&)[GAUSSIAN_TABLE_SIZE]);
#endif
} // namespace rive::gpu