1 /*
2 * Copyright 2014 Google Inc.
3 *
4 * Use of this source code is governed by a BSD-style license that can be
5 * found in the LICENSE file.
6 */
7 #include "src/gpu/ganesh/glsl/GrGLSLFragmentShaderBuilder.h"
8
9 #include "include/private/base/SkAssert.h"
10 #include "include/private/base/SkDebug.h"
11 #include "src/core/SkSLTypeShared.h"
12 #include "src/gpu/Blend.h"
13 #include "src/gpu/ganesh/GrShaderCaps.h"
14 #include "src/gpu/ganesh/GrShaderVar.h"
15 #include "src/gpu/ganesh/glsl/GrGLSLProgramBuilder.h"
16 #include "src/gpu/ganesh/glsl/GrGLSLVarying.h"
17
GrGLSLFragmentShaderBuilder(GrGLSLProgramBuilder * program)18 GrGLSLFragmentShaderBuilder::GrGLSLFragmentShaderBuilder(GrGLSLProgramBuilder* program)
19 : GrGLSLShaderBuilder(program) {}
20
dstColor()21 const char* GrGLSLFragmentShaderBuilder::dstColor() {
22 SkDEBUGCODE(fHasReadDstColorThisStage_DebugOnly = true;)
23
24 const GrShaderCaps* shaderCaps = fProgramBuilder->shaderCaps();
25 if (shaderCaps->fFBFetchSupport) {
26 this->addFeature(1 << kFramebufferFetch_GLSLPrivateFeature,
27 shaderCaps->fFBFetchExtensionString);
28
29 // Some versions of this extension string require declaring custom color output on ES 3.0+
30 const char* fbFetchColorName = "sk_LastFragColor";
31 if (shaderCaps->fFBFetchNeedsCustomOutput) {
32 fPrimaryColorIsInOut = true;
33 fbFetchColorName = DeclaredColorOutputName();
34 // Set the dstColor to an intermediate variable so we don't override it with the output
35 this->codeAppendf("half4 %s = %s;", kDstColorName, fbFetchColorName);
36 } else {
37 return fbFetchColorName;
38 }
39 }
40 return kDstColorName;
41 }
42
enableAdvancedBlendEquationIfNeeded(skgpu::BlendEquation equation)43 void GrGLSLFragmentShaderBuilder::enableAdvancedBlendEquationIfNeeded(
44 skgpu::BlendEquation equation) {
45 SkASSERT(skgpu::BlendEquationIsAdvanced(equation));
46
47 if (fProgramBuilder->shaderCaps()->mustEnableAdvBlendEqs()) {
48 this->addFeature(1 << kBlendEquationAdvanced_GLSLPrivateFeature,
49 "GL_KHR_blend_equation_advanced");
50 this->addLayoutQualifier("blend_support_all_equations", kOut_InterfaceQualifier);
51 }
52 }
53
enableSecondaryOutput()54 void GrGLSLFragmentShaderBuilder::enableSecondaryOutput() {
55 SkASSERT(!fHasSecondaryOutput);
56 fHasSecondaryOutput = true;
57 const GrShaderCaps& caps = *fProgramBuilder->shaderCaps();
58 if (const char* extension = caps.fSecondaryOutputExtensionString) {
59 this->addFeature(1 << kBlendFuncExtended_GLSLPrivateFeature, extension);
60 }
61
62 // If the primary output is declared, we must declare also the secondary output
63 // and vice versa, since it is not allowed to use a built-in gl_FragColor and a custom
64 // output. The condition also co-incides with the condition in which GLSL ES 2.0
65 // requires the built-in gl_SecondaryFragColorEXT, whereas 3.0 requires a custom output.
66 if (caps.mustDeclareFragmentShaderOutput()) {
67 fOutputs.emplace_back(DeclaredSecondaryColorOutputName(), SkSLType::kHalf4,
68 GrShaderVar::TypeModifier::Out);
69 fProgramBuilder->finalizeFragmentSecondaryColor(fOutputs.back());
70 }
71 }
72
getPrimaryColorOutputName() const73 const char* GrGLSLFragmentShaderBuilder::getPrimaryColorOutputName() const {
74 return DeclaredColorOutputName();
75 }
76
primaryColorOutputIsInOut() const77 bool GrGLSLFragmentShaderBuilder::primaryColorOutputIsInOut() const {
78 return fPrimaryColorIsInOut;
79 }
80
getSecondaryColorOutputName() const81 const char* GrGLSLFragmentShaderBuilder::getSecondaryColorOutputName() const {
82 if (this->hasSecondaryOutput()) {
83 return (fProgramBuilder->shaderCaps()->mustDeclareFragmentShaderOutput())
84 ? DeclaredSecondaryColorOutputName()
85 : "sk_SecondaryFragColor";
86 }
87 return nullptr;
88 }
89
getSurfaceOrigin() const90 GrSurfaceOrigin GrGLSLFragmentShaderBuilder::getSurfaceOrigin() const {
91 return fProgramBuilder->origin();
92 }
93
onFinalize()94 void GrGLSLFragmentShaderBuilder::onFinalize() {
95 fProgramBuilder->varyingHandler()->getFragDecls(&this->inputs(), &this->outputs());
96 }
97