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 "GrGLSLVertexShaderBuilder.h"
9 #include "glsl/GrGLSLProgramBuilder.h"
10 #include "glsl/GrGLSLUniformHandler.h"
11 #include "glsl/GrGLSLVarying.h"
12 
GrGLSLVertexBuilder(GrGLSLProgramBuilder * program)13 GrGLSLVertexBuilder::GrGLSLVertexBuilder(GrGLSLProgramBuilder* program)
14     : INHERITED(program)
15     , fRtAdjustName(nullptr) {
16 }
17 
transformToNormalizedDeviceSpace(const GrShaderVar & posVar)18 void GrGLSLVertexBuilder::transformToNormalizedDeviceSpace(const GrShaderVar& posVar) {
19     SkASSERT(!fRtAdjustName);
20 
21     // setup RT Uniform
22     fProgramBuilder->addRTAdjustmentUniform(kHigh_GrSLPrecision,
23                                             fProgramBuilder->rtAdjustment(),
24                                             &fRtAdjustName);
25     if (this->getProgramBuilder()->desc().header().fSnapVerticesToPixelCenters) {
26         if (kVec3f_GrSLType == posVar.getType()) {
27             const char* p = posVar.c_str();
28             this->codeAppendf("{vec2 _posTmp = vec2(%s.x/%s.z, %s.y/%s.z);", p, p, p, p);
29         } else {
30             SkASSERT(kVec2f_GrSLType == posVar.getType());
31             this->codeAppendf("{vec2 _posTmp = %s;", posVar.c_str());
32         }
33         this->codeAppendf("_posTmp = floor(_posTmp) + vec2(0.5, 0.5);"
34                           "gl_Position = vec4(_posTmp.x * %s.x + %s.y,"
35                                              "_posTmp.y * %s.z + %s.w, 0, 1);}",
36                           fRtAdjustName, fRtAdjustName, fRtAdjustName, fRtAdjustName);
37     } else if (kVec3f_GrSLType == posVar.getType()) {
38         this->codeAppendf("gl_Position = vec4(dot(%s.xz, %s.xy), dot(%s.yz, %s.zw), 0, %s.z);",
39                           posVar.c_str(), fRtAdjustName,
40                           posVar.c_str(), fRtAdjustName,
41                           posVar.c_str());
42     } else {
43         SkASSERT(kVec2f_GrSLType == posVar.getType());
44         this->codeAppendf("gl_Position = vec4(%s.x * %s.x + %s.y, %s.y * %s.z + %s.w, 0, 1);",
45                           posVar.c_str(), fRtAdjustName, fRtAdjustName,
46                           posVar.c_str(), fRtAdjustName, fRtAdjustName);
47     }
48     // We could have the GrGeometryProcessor do this, but its just easier to have it performed
49     // here. If we ever need to set variable pointsize, then we can reinvestigate
50     this->codeAppend("gl_PointSize = 1.0;");
51 }
52 
onFinalize()53 void GrGLSLVertexBuilder::onFinalize() {
54     fProgramBuilder->varyingHandler()->getVertexDecls(&this->inputs(), &this->outputs());
55 }
56 
57