diff options
Diffstat (limited to 'src/gpu/effects/GrEdgeEffect.cpp')
| -rw-r--r-- | src/gpu/effects/GrEdgeEffect.cpp | 138 |
1 files changed, 138 insertions, 0 deletions
diff --git a/src/gpu/effects/GrEdgeEffect.cpp b/src/gpu/effects/GrEdgeEffect.cpp new file mode 100644 index 0000000000..f02fa35ae0 --- /dev/null +++ b/src/gpu/effects/GrEdgeEffect.cpp @@ -0,0 +1,138 @@ +/* + * Copyright 2013 Google Inc. + * + * Use of this source code is governed by a BSD-style license that can be + * found in the LICENSE file. + */ + +#include "GrEdgeEffect.h" +#include "gl/GrGLEffect.h" +#include "gl/GrGLSL.h" +#include "GrTBackendEffectFactory.h" + +class GrGLEdgeEffect : public GrGLEffect { +public: + GrGLEdgeEffect(const GrBackendEffectFactory& factory, const GrDrawEffect&) + : INHERITED (factory) {} + + virtual void emitCode(GrGLShaderBuilder* builder, + const GrDrawEffect& drawEffect, + EffectKey key, + const char* outputColor, + const char* inputColor, + const TextureSamplerArray& samplers) SK_OVERRIDE { + const GrEdgeEffect& edgeEffect = drawEffect.castEffect<GrEdgeEffect>(); + GrEdgeEffect::EdgeType type = edgeEffect.edgeType(); + + const char *vsName, *fsName; + const SkString* attrName = + builder->getEffectAttributeName(drawEffect.getVertexAttribIndices()[0]); + builder->fsCodeAppendf("\t\tfloat edgeAlpha;\n"); + + switch (type) { + case GrEdgeEffect::kHairLine_EdgeType: + builder->addVarying(kVec4f_GrSLType, "HairEdge", &vsName, &fsName); + + builder->fsCodeAppendf("\t\tedgeAlpha = abs(dot(vec3(%s.xy,1), %s.xyz));\n", + builder->fragmentPosition(), fsName); + builder->fsCodeAppendf("\t\tedgeAlpha = max(1.0 - edgeAlpha, 0.0);\n"); + break; + case GrEdgeEffect::kQuad_EdgeType: + GrAssert(builder->ctxInfo().caps()->shaderDerivativeSupport()); + builder->addVarying(kVec4f_GrSLType, "QuadEdge", &vsName, &fsName); + + // keep the derivative instructions outside the conditional + builder->fsCodeAppendf("\t\tvec2 duvdx = dFdx(%s.xy);\n", fsName); + builder->fsCodeAppendf("\t\tvec2 duvdy = dFdy(%s.xy);\n", fsName); + builder->fsCodeAppendf("\t\tif (%s.z > 0.0 && %s.w > 0.0) {\n", fsName, fsName); + // today we know z and w are in device space. We could use derivatives + builder->fsCodeAppendf("\t\t\tedgeAlpha = min(min(%s.z, %s.w) + 0.5, 1.0);\n", fsName, + fsName); + builder->fsCodeAppendf ("\t\t} else {\n"); + builder->fsCodeAppendf("\t\t\tvec2 gF = vec2(2.0*%s.x*duvdx.x - duvdx.y,\n" + "\t\t\t 2.0*%s.x*duvdy.x - duvdy.y);\n", + fsName, fsName); + builder->fsCodeAppendf("\t\t\tedgeAlpha = (%s.x*%s.x - %s.y);\n", fsName, fsName, + fsName); + builder->fsCodeAppendf("\t\t\tedgeAlpha = " + "clamp(0.5 - edgeAlpha / length(gF), 0.0, 1.0);\n\t\t}\n"); + if (kES2_GrGLBinding == builder->ctxInfo().binding()) { + builder->fHeader.append("#extension GL_OES_standard_derivatives: enable\n"); + } + break; + case GrEdgeEffect::kHairQuad_EdgeType: + GrAssert(builder->ctxInfo().caps()->shaderDerivativeSupport()); + builder->addVarying(kVec4f_GrSLType, "HairQuadEdge", &vsName, &fsName); + + builder->fsCodeAppendf("\t\tvec2 duvdx = dFdx(%s.xy);\n", fsName); + builder->fsCodeAppendf("\t\tvec2 duvdy = dFdy(%s.xy);\n", fsName); + builder->fsCodeAppendf("\t\tvec2 gF = vec2(2.0*%s.x*duvdx.x - duvdx.y,\n" + "\t\t 2.0*%s.x*duvdy.x - duvdy.y);\n", + fsName, fsName); + builder->fsCodeAppendf("\t\tedgeAlpha = (%s.x*%s.x - %s.y);\n", fsName, fsName, + fsName); + builder->fsCodeAppend("\t\tedgeAlpha = sqrt(edgeAlpha*edgeAlpha / dot(gF, gF));\n"); + builder->fsCodeAppend("\t\tedgeAlpha = max(1.0 - edgeAlpha, 0.0);\n"); + if (kES2_GrGLBinding == builder->ctxInfo().binding()) { + builder->fHeader.append("#extension GL_OES_standard_derivatives: enable\n"); + } + break; + }; + + SkString modulate; + GrGLSLModulate4f(&modulate, inputColor, "edgeAlpha"); + builder->fsCodeAppendf("\t%s = %s;\n", outputColor, modulate.c_str()); + + builder->vsCodeAppendf("\t%s = %s;\n", vsName, attrName->c_str()); + } + + static inline EffectKey GenKey(const GrDrawEffect& drawEffect, const GrGLCaps&) { + const GrEdgeEffect& QuadEffect = drawEffect.castEffect<GrEdgeEffect>(); + + return QuadEffect.edgeType(); + } + + virtual void setData(const GrGLUniformManager&, const GrDrawEffect&) SK_OVERRIDE { + } + +private: + typedef GrGLEffect INHERITED; +}; + +/////////////////////////////////////////////////////////////////////////////// + +GrEdgeEffect::GrEdgeEffect(EdgeType edgeType) : GrEffect() { + if (edgeType == kQuad_EdgeType) { + this->addVertexAttrib(kVec4f_GrSLType); + } else { + this->addVertexAttrib(kVec4f_GrSLType); // TODO: use different vec sizes for differnt edge + // types. + } + fEdgeType = edgeType; +} + +void GrEdgeEffect::getConstantColorComponents(GrColor* color, uint32_t* validFlags) const { + *validFlags = 0; +} + +const GrBackendEffectFactory& GrEdgeEffect::getFactory() const { + return GrTBackendEffectFactory<GrEdgeEffect>::getInstance(); +} + +/////////////////////////////////////////////////////////////////////////////// + +GR_DEFINE_EFFECT_TEST(GrEdgeEffect); + +GrEffectRef* GrEdgeEffect::TestCreate(SkMWCRandom* random, + GrContext*, + const GrDrawTargetCaps& caps, + GrTexture*[]) { + // Only kHairLine works without derivative instructions. + EdgeType edgeType; + if (caps.shaderDerivativeSupport()) { + edgeType = static_cast<EdgeType>(random->nextULessThan(kEdgeTypeCount)); + } else { + edgeType = kHairLine_EdgeType; + } + return GrEdgeEffect::Create(edgeType); +} |