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
8 #include "gl/GrGLXferProcessor.h"
9
10 #include "GrXferProcessor.h"
11 #include "gl/builders/GrGLFragmentShaderBuilder.h"
12 #include "gl/builders/GrGLProgramBuilder.h"
13
emitCode(const EmitArgs & args)14 void GrGLXferProcessor::emitCode(const EmitArgs& args) {
15 if (args.fXP.getDstCopyTexture()) {
16 bool topDown = kTopLeft_GrSurfaceOrigin == args.fXP.getDstCopyTexture()->origin();
17
18 GrGLXPFragmentBuilder* fsBuilder = args.fPB->getFragmentShaderBuilder();
19
20 if (args.fXP.readsCoverage()) {
21 // We don't think any shaders actually output negative coverage, but just as a safety
22 // check for floating point precision errors we compare with <= here
23 fsBuilder->codeAppendf("if (all(lessThanEqual(%s, vec4(0)))) {"
24 " discard;"
25 "}", args.fInputCoverage);
26 }
27
28 const char* dstColor = fsBuilder->dstColor();
29
30 const char* dstCopyTopLeftName;
31 const char* dstCopyCoordScaleName;
32
33 fDstCopyTopLeftUni = args.fPB->addUniform(GrGLProgramBuilder::kFragment_Visibility,
34 kVec2f_GrSLType,
35 kDefault_GrSLPrecision,
36 "DstCopyUpperLeft",
37 &dstCopyTopLeftName);
38 fDstCopyScaleUni = args.fPB->addUniform(GrGLProgramBuilder::kFragment_Visibility,
39 kVec2f_GrSLType,
40 kDefault_GrSLPrecision,
41 "DstCopyCoordScale",
42 &dstCopyCoordScaleName);
43 const char* fragPos = fsBuilder->fragmentPosition();
44
45 fsBuilder->codeAppend("// Read color from copy of the destination.\n");
46 fsBuilder->codeAppendf("vec2 _dstTexCoord = (%s.xy - %s) * %s;",
47 fragPos, dstCopyTopLeftName, dstCopyCoordScaleName);
48
49 if (!topDown) {
50 fsBuilder->codeAppend("_dstTexCoord.y = 1.0 - _dstTexCoord.y;");
51 }
52
53 fsBuilder->codeAppendf("vec4 %s = ", dstColor);
54 fsBuilder->appendTextureLookup(args.fSamplers[0], "_dstTexCoord", kVec2f_GrSLType);
55 fsBuilder->codeAppend(";");
56 }
57
58 this->onEmitCode(args);
59 }
60
setData(const GrGLProgramDataManager & pdm,const GrXferProcessor & xp)61 void GrGLXferProcessor::setData(const GrGLProgramDataManager& pdm, const GrXferProcessor& xp) {
62 if (xp.getDstCopyTexture()) {
63 if (fDstCopyTopLeftUni.isValid()) {
64 pdm.set2f(fDstCopyTopLeftUni, static_cast<GrGLfloat>(xp.dstCopyTextureOffset().fX),
65 static_cast<GrGLfloat>(xp.dstCopyTextureOffset().fY));
66 pdm.set2f(fDstCopyScaleUni, 1.f / xp.getDstCopyTexture()->width(),
67 1.f / xp.getDstCopyTexture()->height());
68 } else {
69 SkASSERT(!fDstCopyScaleUni.isValid());
70 }
71 } else {
72 SkASSERT(!fDstCopyTopLeftUni.isValid());
73 SkASSERT(!fDstCopyScaleUni.isValid());
74 }
75 this->onSetData(pdm, xp);
76 }
77
78