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
8 #include "src/gpu/GrShaderCaps.h"
9 #include "src/gpu/glsl/GrGLSLProgramBuilder.h"
10 #include "src/gpu/glsl/GrGLSLVarying.h"
11
addPassThroughAttribute(const GrShaderVar & vsVar,const char * output,Interpolation interpolation)12 void GrGLSLVaryingHandler::addPassThroughAttribute(const GrShaderVar& vsVar,
13 const char* output,
14 Interpolation interpolation) {
15 SkASSERT(vsVar.getType() != kVoid_GrSLType);
16 GrGLSLVarying v(vsVar.getType());
17 this->addVarying(vsVar.c_str(), &v, interpolation);
18 fProgramBuilder->fVS.codeAppendf("%s = %s;", v.vsOut(), vsVar.c_str());
19 fProgramBuilder->fFS.codeAppendf("%s = %s;", output, v.fsIn());
20 }
21
use_flat_interpolation(GrGLSLVaryingHandler::Interpolation interpolation,const GrShaderCaps & shaderCaps)22 static bool use_flat_interpolation(GrGLSLVaryingHandler::Interpolation interpolation,
23 const GrShaderCaps& shaderCaps) {
24 switch (interpolation) {
25 using Interpolation = GrGLSLVaryingHandler::Interpolation;
26 case Interpolation::kInterpolated:
27 return false;
28 case Interpolation::kCanBeFlat:
29 SkASSERT(!shaderCaps.preferFlatInterpolation() ||
30 shaderCaps.flatInterpolationSupport());
31 return shaderCaps.preferFlatInterpolation();
32 case Interpolation::kMustBeFlat:
33 SkASSERT(shaderCaps.flatInterpolationSupport());
34 return true;
35 }
36 SK_ABORT("Invalid interpolation");
37 }
38
addVarying(const char * name,GrGLSLVarying * varying,Interpolation interpolation)39 void GrGLSLVaryingHandler::addVarying(const char* name, GrGLSLVarying* varying,
40 Interpolation interpolation) {
41 SkASSERT(GrSLTypeIsFloatType(varying->type()) || Interpolation::kMustBeFlat == interpolation);
42 VaryingInfo& v = fVaryings.push_back();
43
44 SkASSERT(varying);
45 SkASSERT(kVoid_GrSLType != varying->fType);
46 v.fType = varying->fType;
47 v.fIsFlat = use_flat_interpolation(interpolation, *fProgramBuilder->shaderCaps());
48 v.fVsOut = fProgramBuilder->nameVariable('v', name);
49 v.fVisibility = kNone_GrShaderFlags;
50 if (varying->isInVertexShader()) {
51 varying->fVsOut = v.fVsOut.c_str();
52 v.fVisibility |= kVertex_GrShaderFlag;
53 }
54 if (varying->isInFragmentShader()) {
55 varying->fFsIn = v.fVsOut.c_str();
56 v.fVisibility |= kFragment_GrShaderFlag;
57 }
58 }
59
emitAttributes(const GrGeometryProcessor & gp)60 void GrGLSLVaryingHandler::emitAttributes(const GrGeometryProcessor& gp) {
61 for (const auto& attr : gp.vertexAttributes()) {
62 this->addAttribute(attr.asShaderVar());
63 }
64 for (const auto& attr : gp.instanceAttributes()) {
65 this->addAttribute(attr.asShaderVar());
66 }
67 }
68
addAttribute(const GrShaderVar & var)69 void GrGLSLVaryingHandler::addAttribute(const GrShaderVar& var) {
70 SkASSERT(GrShaderVar::TypeModifier::In == var.getTypeModifier());
71 for (const GrShaderVar& attr : fVertexInputs.items()) {
72 // if attribute already added, don't add it again
73 if (attr.getName().equals(var.getName())) {
74 return;
75 }
76 }
77 fVertexInputs.push_back(var);
78 }
79
setNoPerspective()80 void GrGLSLVaryingHandler::setNoPerspective() {
81 const GrShaderCaps& caps = *fProgramBuilder->shaderCaps();
82 if (!caps.noperspectiveInterpolationSupport()) {
83 return;
84 }
85 if (const char* extension = caps.noperspectiveInterpolationExtensionString()) {
86 int bit = 1 << GrGLSLShaderBuilder::kNoPerspectiveInterpolation_GLSLPrivateFeature;
87 fProgramBuilder->fVS.addFeature(bit, extension);
88 fProgramBuilder->fFS.addFeature(bit, extension);
89 }
90 fDefaultInterpolationModifier = "noperspective";
91 }
92
finalize()93 void GrGLSLVaryingHandler::finalize() {
94 for (const VaryingInfo& v : fVaryings.items()) {
95 const char* modifier = v.fIsFlat ? "flat" : fDefaultInterpolationModifier;
96 if (v.fVisibility & kVertex_GrShaderFlag) {
97 fVertexOutputs.emplace_back(v.fVsOut, v.fType, GrShaderVar::TypeModifier::Out,
98 GrShaderVar::kNonArray, SkString(), SkString(modifier));
99 }
100 if (v.fVisibility & kFragment_GrShaderFlag) {
101 const char* fsIn = v.fVsOut.c_str();
102 fFragInputs.emplace_back(SkString(fsIn), v.fType, GrShaderVar::TypeModifier::In,
103 GrShaderVar::kNonArray, SkString(), SkString(modifier));
104 }
105 }
106 this->onFinalize();
107 }
108
appendDecls(const VarArray & vars,SkString * out) const109 void GrGLSLVaryingHandler::appendDecls(const VarArray& vars, SkString* out) const {
110 for (const GrShaderVar& varying : vars.items()) {
111 varying.appendDecl(fProgramBuilder->shaderCaps(), out);
112 out->append(";");
113 }
114 }
115
getVertexDecls(SkString * inputDecls,SkString * outputDecls) const116 void GrGLSLVaryingHandler::getVertexDecls(SkString* inputDecls, SkString* outputDecls) const {
117 this->appendDecls(fVertexInputs, inputDecls);
118 this->appendDecls(fVertexOutputs, outputDecls);
119 }
120
getFragDecls(SkString * inputDecls,SkString * outputDecls) const121 void GrGLSLVaryingHandler::getFragDecls(SkString* inputDecls, SkString* outputDecls) const {
122 // We should not have any outputs in the fragment shader when using version 1.10
123 SkASSERT(k110_GrGLSLGeneration != fProgramBuilder->shaderCaps()->generation() ||
124 fFragOutputs.empty());
125 this->appendDecls(fFragInputs, inputDecls);
126 this->appendDecls(fFragOutputs, outputDecls);
127 }
128