1 /*
2 * Copyright 2015 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/GrGLSLVarying.h"
8
9 #include "src/gpu/ganesh/GrGeometryProcessor.h"
10 #include "src/gpu/ganesh/GrShaderCaps.h"
11 #include "src/gpu/ganesh/glsl/GrGLSLFragmentShaderBuilder.h"
12 #include "src/gpu/ganesh/glsl/GrGLSLProgramBuilder.h"
13 #include "src/gpu/ganesh/glsl/GrGLSLShaderBuilder.h"
14 #include "src/gpu/ganesh/glsl/GrGLSLVertexGeoBuilder.h"
15 #include "src/sksl/SkSLGLSL.h"
16
addPassThroughAttribute(const GrShaderVar & vsVar,const char * output,Interpolation interpolation)17 void GrGLSLVaryingHandler::addPassThroughAttribute(const GrShaderVar& vsVar,
18 const char* output,
19 Interpolation interpolation) {
20 SkASSERT(vsVar.getType() != SkSLType::kVoid);
21 GrGLSLVarying v(vsVar.getType());
22 this->addVarying(vsVar.c_str(), &v, interpolation);
23 fProgramBuilder->fVS.codeAppendf("%s = %s;", v.vsOut(), vsVar.c_str());
24 fProgramBuilder->fFS.codeAppendf("%s = %s;", output, v.fsIn());
25 }
26
use_flat_interpolation(GrGLSLVaryingHandler::Interpolation interpolation,const GrShaderCaps & shaderCaps)27 static bool use_flat_interpolation(GrGLSLVaryingHandler::Interpolation interpolation,
28 const GrShaderCaps& shaderCaps) {
29 switch (interpolation) {
30 using Interpolation = GrGLSLVaryingHandler::Interpolation;
31 case Interpolation::kInterpolated:
32 return false;
33 case Interpolation::kCanBeFlat:
34 SkASSERT(!shaderCaps.fPreferFlatInterpolation || shaderCaps.fFlatInterpolationSupport);
35 return shaderCaps.fPreferFlatInterpolation;
36 case Interpolation::kMustBeFlat:
37 SkASSERT(shaderCaps.fFlatInterpolationSupport);
38 return true;
39 }
40 SK_ABORT("Invalid interpolation");
41 }
42
addVarying(const char * name,GrGLSLVarying * varying,Interpolation interpolation)43 void GrGLSLVaryingHandler::addVarying(const char* name, GrGLSLVarying* varying,
44 Interpolation interpolation) {
45 SkASSERT(SkSLTypeIsFloatType(varying->type()) || Interpolation::kMustBeFlat == interpolation);
46 VaryingInfo& v = fVaryings.push_back();
47
48 SkASSERT(varying);
49 SkASSERT(SkSLType::kVoid != varying->fType);
50 v.fType = varying->fType;
51 v.fIsFlat = use_flat_interpolation(interpolation, *fProgramBuilder->shaderCaps());
52 v.fVsOut = fProgramBuilder->nameVariable('v', name);
53 v.fVisibility = kNone_GrShaderFlags;
54 if (varying->isInVertexShader()) {
55 varying->fVsOut = v.fVsOut.c_str();
56 v.fVisibility |= kVertex_GrShaderFlag;
57 }
58 if (varying->isInFragmentShader()) {
59 varying->fFsIn = v.fVsOut.c_str();
60 v.fVisibility |= kFragment_GrShaderFlag;
61 }
62 }
63
emitAttributes(const GrGeometryProcessor & gp)64 void GrGLSLVaryingHandler::emitAttributes(const GrGeometryProcessor& gp) {
65 for (auto attr : gp.vertexAttributes()) {
66 this->addAttribute(attr.asShaderVar());
67 }
68 for (auto attr : gp.instanceAttributes()) {
69 this->addAttribute(attr.asShaderVar());
70 }
71 }
72
addAttribute(const GrShaderVar & var)73 void GrGLSLVaryingHandler::addAttribute(const GrShaderVar& var) {
74 SkASSERT(GrShaderVar::TypeModifier::In == var.getTypeModifier());
75 for (const GrShaderVar& attr : fVertexInputs.items()) {
76 // if attribute already added, don't add it again
77 if (attr.getName().equals(var.getName())) {
78 return;
79 }
80 }
81 fVertexInputs.push_back(var);
82 }
83
setNoPerspective()84 void GrGLSLVaryingHandler::setNoPerspective() {
85 const GrShaderCaps& caps = *fProgramBuilder->shaderCaps();
86 if (!caps.fNoPerspectiveInterpolationSupport) {
87 return;
88 }
89 if (const char* extension = caps.noperspectiveInterpolationExtensionString()) {
90 int bit = 1 << GrGLSLShaderBuilder::kNoPerspectiveInterpolation_GLSLPrivateFeature;
91 fProgramBuilder->fVS.addFeature(bit, extension);
92 fProgramBuilder->fFS.addFeature(bit, extension);
93 }
94 fDefaultInterpolationModifier = "noperspective";
95 }
96
finalize()97 void GrGLSLVaryingHandler::finalize() {
98 for (const VaryingInfo& v : fVaryings.items()) {
99 const char* modifier = v.fIsFlat ? "flat" : fDefaultInterpolationModifier;
100 if (v.fVisibility & kVertex_GrShaderFlag) {
101 fVertexOutputs.emplace_back(v.fVsOut, v.fType, GrShaderVar::TypeModifier::Out,
102 GrShaderVar::kNonArray, SkString(), SkString(modifier));
103 }
104 if (v.fVisibility & kFragment_GrShaderFlag) {
105 const char* fsIn = v.fVsOut.c_str();
106 fFragInputs.emplace_back(SkString(fsIn), v.fType, GrShaderVar::TypeModifier::In,
107 GrShaderVar::kNonArray, SkString(), SkString(modifier));
108 }
109 }
110 this->onFinalize();
111 }
112
appendDecls(const VarArray & vars,SkString * out) const113 void GrGLSLVaryingHandler::appendDecls(const VarArray& vars, SkString* out) const {
114 for (const GrShaderVar& varying : vars.items()) {
115 varying.appendDecl(fProgramBuilder->shaderCaps(), out);
116 out->append(";");
117 }
118 }
119
getVertexDecls(SkString * inputDecls,SkString * outputDecls) const120 void GrGLSLVaryingHandler::getVertexDecls(SkString* inputDecls, SkString* outputDecls) const {
121 this->appendDecls(fVertexInputs, inputDecls);
122 this->appendDecls(fVertexOutputs, outputDecls);
123 }
124
getFragDecls(SkString * inputDecls,SkString * outputDecls) const125 void GrGLSLVaryingHandler::getFragDecls(SkString* inputDecls, SkString* outputDecls) const {
126 // We should not have any outputs in the fragment shader when using version 1.10
127 SkASSERT(SkSL::GLSLGeneration::k110 != fProgramBuilder->shaderCaps()->fGLSLGeneration ||
128 fFragOutputs.empty());
129 this->appendDecls(fFragInputs, inputDecls);
130 this->appendDecls(fFragOutputs, outputDecls);
131 }
132