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/*
* Copyright 2017 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#include "GrCCPRPathProcessor.h"
#include "GrOnFlushResourceProvider.h"
#include "GrTexture.h"
#include "glsl/GrGLSLFragmentShaderBuilder.h"
#include "glsl/GrGLSLGeometryProcessor.h"
#include "glsl/GrGLSLProgramBuilder.h"
#include "glsl/GrGLSLVarying.h"
// Slightly undershoot an AA bloat radius of 0.5 so vertices that fall on integer boundaries don't
// accidentally reach into neighboring path masks within the atlas.
constexpr float kAABloatRadius = 0.491111f;
// Paths are drawn as octagons. Each point on the octagon is the intersection of two lines: one edge
// from the path's bounding box and one edge from its 45-degree bounding box. The below inputs
// define a vertex by the two edges that need to be intersected. Normals point out of the octagon,
// and the bounding boxes are sent in as instance attribs.
static constexpr float kOctoEdgeNorms[8 * 4] = {
// bbox // bbox45
-1, 0, -1,+1,
-1, 0, -1,-1,
0,-1, -1,-1,
0,-1, +1,-1,
+1, 0, +1,-1,
+1, 0, +1,+1,
0,+1, +1,+1,
0,+1, -1,+1,
};
GR_DECLARE_STATIC_UNIQUE_KEY(gVertexBufferKey);
// Index buffer for the octagon defined above.
static uint16_t kOctoIndices[GrCCPRPathProcessor::kPerInstanceIndexCount] = {
0, 4, 2,
0, 6, 4,
0, 2, 1,
2, 4, 3,
4, 6, 5,
6, 0, 7,
};
GR_DECLARE_STATIC_UNIQUE_KEY(gIndexBufferKey);
GrCCPRPathProcessor::GrCCPRPathProcessor(GrResourceProvider* rp, sk_sp<GrTextureProxy> atlas,
SkPath::FillType fillType, const GrShaderCaps& shaderCaps)
: fFillType(fillType) {
this->addInstanceAttrib("devbounds", kVec4f_GrVertexAttribType, kHigh_GrSLPrecision);
this->addInstanceAttrib("devbounds45", kVec4f_GrVertexAttribType, kHigh_GrSLPrecision);
this->addInstanceAttrib("view_matrix", kVec4f_GrVertexAttribType, kHigh_GrSLPrecision);
this->addInstanceAttrib("view_translate", kVec2f_GrVertexAttribType, kHigh_GrSLPrecision);
// FIXME: this could be a vector of two shorts if it were supported by Ganesh.
this->addInstanceAttrib("atlas_offset", kVec2i_GrVertexAttribType, kHigh_GrSLPrecision);
this->addInstanceAttrib("color", kVec4ub_GrVertexAttribType, kLow_GrSLPrecision);
SkASSERT(offsetof(Instance, fDevBounds) ==
this->getInstanceAttrib(InstanceAttribs::kDevBounds).fOffsetInRecord);
SkASSERT(offsetof(Instance, fDevBounds45) ==
this->getInstanceAttrib(InstanceAttribs::kDevBounds45).fOffsetInRecord);
SkASSERT(offsetof(Instance, fViewMatrix) ==
this->getInstanceAttrib(InstanceAttribs::kViewMatrix).fOffsetInRecord);
SkASSERT(offsetof(Instance, fViewTranslate) ==
this->getInstanceAttrib(InstanceAttribs::kViewTranslate).fOffsetInRecord);
SkASSERT(offsetof(Instance, fAtlasOffset) ==
this->getInstanceAttrib(InstanceAttribs::kAtlasOffset).fOffsetInRecord);
SkASSERT(offsetof(Instance, fColor) ==
this->getInstanceAttrib(InstanceAttribs::kColor).fOffsetInRecord);
SkASSERT(sizeof(Instance) == this->getInstanceStride());
GR_STATIC_ASSERT(6 == kNumInstanceAttribs);
this->addVertexAttrib("edge_norms", kVec4f_GrVertexAttribType, kHigh_GrSLPrecision);
fAtlasAccess.reset(std::move(atlas), GrSamplerParams::FilterMode::kNone_FilterMode,
SkShader::TileMode::kClamp_TileMode, kFragment_GrShaderFlag);
fAtlasAccess.instantiate(rp);
this->addTextureSampler(&fAtlasAccess);
this->initClassID<GrCCPRPathProcessor>();
}
void GrCCPRPathProcessor::getGLSLProcessorKey(const GrShaderCaps&, GrProcessorKeyBuilder* b) const {
b->add32((fFillType << 16) | this->atlasProxy()->origin());
}
class GLSLPathProcessor : public GrGLSLGeometryProcessor {
public:
void onEmitCode(EmitArgs& args, GrGPArgs* gpArgs) override;
private:
void setData(const GrGLSLProgramDataManager& pdman, const GrPrimitiveProcessor& primProc,
FPCoordTransformIter&& transformIter) override {
const GrCCPRPathProcessor& proc = primProc.cast<GrCCPRPathProcessor>();
pdman.set2f(fAtlasAdjustUniform, 1.0f / proc.atlas()->width(),
1.0f / proc.atlas()->height());
this->setTransformDataHelper(SkMatrix::I(), pdman, &transformIter);
}
GrGLSLUniformHandler::UniformHandle fAtlasAdjustUniform;
typedef GrGLSLGeometryProcessor INHERITED;
};
GrGLSLPrimitiveProcessor* GrCCPRPathProcessor::createGLSLInstance(const GrShaderCaps&) const {
return new GLSLPathProcessor();
}
void GLSLPathProcessor::onEmitCode(EmitArgs& args, GrGPArgs* gpArgs) {
using InstanceAttribs = GrCCPRPathProcessor::InstanceAttribs;
const GrCCPRPathProcessor& proc = args.fGP.cast<GrCCPRPathProcessor>();
GrGLSLUniformHandler* uniHandler = args.fUniformHandler;
GrGLSLVaryingHandler* varyingHandler = args.fVaryingHandler;
const char* atlasAdjust;
fAtlasAdjustUniform = uniHandler->addUniform(
kVertex_GrShaderFlag,
kVec2f_GrSLType, kHigh_GrSLPrecision, "atlas_adjust", &atlasAdjust);
varyingHandler->emitAttributes(proc);
GrGLSLVertToFrag texcoord(kVec2f_GrSLType);
GrGLSLVertToFrag color(kVec4f_GrSLType);
varyingHandler->addVarying("texcoord", &texcoord, kHigh_GrSLPrecision);
varyingHandler->addFlatPassThroughAttribute(&proc.getInstanceAttrib(InstanceAttribs::kColor),
args.fOutputColor, kLow_GrSLPrecision);
// Vertex shader.
GrGLSLVertexBuilder* v = args.fVertBuilder;
// Find the intersections of (bloated) devBounds and devBounds45 in order to come up with an
// octagon that circumscribes the (bloated) path. A vertex is the intersection of two lines:
// one edge from the path's bounding box and one edge from its 45-degree bounding box.
v->codeAppendf("highp mat2 N = mat2(%s);", proc.getEdgeNormsAttrib().fName);
// N[0] is the normal for the edge we are intersecting from the regular bounding box, pointing
// out of the octagon.
v->codeAppendf("highp vec2 refpt = (min(N[0].x, N[0].y) < 0) ? %s.xy : %s.zw;",
proc.getInstanceAttrib(InstanceAttribs::kDevBounds).fName,
proc.getInstanceAttrib(InstanceAttribs::kDevBounds).fName);
v->codeAppendf("refpt += N[0] * %f;", kAABloatRadius); // bloat for AA.
// N[1] is the normal for the edge we are intersecting from the 45-degree bounding box, pointing
// out of the octagon.
v->codeAppendf("highp vec2 refpt45 = (N[1].x < 0) ? %s.xy : %s.zw;",
proc.getInstanceAttrib(InstanceAttribs::kDevBounds45).fName,
proc.getInstanceAttrib(InstanceAttribs::kDevBounds45).fName);
v->codeAppendf("refpt45 *= mat2(.5,.5,-.5,.5);"); // transform back to device space.
v->codeAppendf("refpt45 += N[1] * %f;", kAABloatRadius); // bloat for AA.
v->codeAppend ("highp vec2 K = vec2(dot(N[0], refpt), dot(N[1], refpt45));");
v->codeAppendf("highp vec2 octocoord = K * inverse(N);");
gpArgs->fPositionVar.set(kVec2f_GrSLType, "octocoord");
// Convert to atlas coordinates in order to do our texture lookup.
v->codeAppendf("highp vec2 atlascoord = octocoord + vec2(%s);",
proc.getInstanceAttrib(InstanceAttribs::kAtlasOffset).fName);
if (kTopLeft_GrSurfaceOrigin == proc.atlasProxy()->origin()) {
v->codeAppendf("%s = atlascoord * %s;", texcoord.vsOut(), atlasAdjust);
} else {
SkASSERT(kBottomLeft_GrSurfaceOrigin == proc.atlasProxy()->origin());
v->codeAppendf("%s = vec2(atlascoord.x * %s.x, 1 - atlascoord.y * %s.y);",
texcoord.vsOut(), atlasAdjust, atlasAdjust);
}
// Convert to (local) path cordinates.
v->codeAppendf("highp vec2 pathcoord = inverse(mat2(%s)) * (octocoord - %s);",
proc.getInstanceAttrib(InstanceAttribs::kViewMatrix).fName,
proc.getInstanceAttrib(InstanceAttribs::kViewTranslate).fName);
this->emitTransforms(v, varyingHandler, uniHandler, gpArgs->fPositionVar, "pathcoord",
args.fFPCoordTransformHandler);
// Fragment shader.
GrGLSLPPFragmentBuilder* f = args.fFragBuilder;
f->codeAppend ("mediump float coverage_count = ");
f->appendTextureLookup(args.fTexSamplers[0], texcoord.fsIn(), kVec2f_GrSLType);
f->codeAppend (".a;");
if (SkPath::kWinding_FillType == proc.fillType()) {
f->codeAppendf("%s = vec4(min(abs(coverage_count), 1));", args.fOutputCoverage);
} else {
SkASSERT(SkPath::kEvenOdd_FillType == proc.fillType());
f->codeAppend ("mediump float t = mod(abs(coverage_count), 2);");
f->codeAppendf("%s = vec4(1 - abs(t - 1));", args.fOutputCoverage);
}
}
sk_sp<GrBuffer> GrCCPRPathProcessor::FindOrMakeIndexBuffer(GrOnFlushResourceProvider* onFlushRP) {
GR_DEFINE_STATIC_UNIQUE_KEY(gIndexBufferKey);
return onFlushRP->findOrMakeStaticBuffer(gIndexBufferKey, kIndex_GrBufferType,
sizeof(kOctoIndices), kOctoIndices);
}
sk_sp<GrBuffer> GrCCPRPathProcessor::FindOrMakeVertexBuffer(GrOnFlushResourceProvider* onFlushRP) {
GR_DEFINE_STATIC_UNIQUE_KEY(gVertexBufferKey);
return onFlushRP->findOrMakeStaticBuffer(gVertexBufferKey, kVertex_GrBufferType,
sizeof(kOctoEdgeNorms), kOctoEdgeNorms);
}
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