| /* |
| * Copyright 2017 Google Inc. |
| * |
| * Use of this source code is governed by a BSD-style license that can be |
| * found in the LICENSE file. |
| */ |
| |
| #ifndef GrAtlasedShaderHelpers_DEFINED |
| #define GrAtlasedShaderHelpers_DEFINED |
| |
| #include "glsl/GrGLSLPrimitiveProcessor.h" |
| #include "glsl/GrGLSLFragmentShaderBuilder.h" |
| #include "glsl/GrGLSLVarying.h" |
| #include "glsl/GrGLSLVertexShaderBuilder.h" |
| |
| static void append_index_uv_varyings(GrGLSLPrimitiveProcessor::EmitArgs& args, |
| const char* inTexCoordsName, |
| const char* atlasSizeInvName, |
| GrGLSLVertToFrag *uv, |
| GrGLSLVertToFrag *texIdx, |
| GrGLSLVertToFrag *st) { |
| // This extracts the texture index and texel coordinates from the same variable |
| // Packing structure: texel coordinates are multiplied by 2 (or shifted left 1) |
| // texture index is stored as lower bits of both x and y |
| args.fVertBuilder->codeAppendf("float2 indexTexCoords = float2(%s.x, %s.y);", |
| inTexCoordsName, inTexCoordsName); |
| args.fVertBuilder->codeAppend("float2 intCoords = floor(0.5*indexTexCoords);"); |
| args.fVertBuilder->codeAppend("float2 diff = indexTexCoords - 2.0*intCoords;"); |
| args.fVertBuilder->codeAppend("float texIdx = 2.0*diff.x + diff.y;"); |
| |
| // Multiply by 1/atlasSize to get normalized texture coordinates |
| args.fVaryingHandler->addVarying("TextureCoords", uv, kHigh_GrSLPrecision); |
| args.fVertBuilder->codeAppendf("%s = intCoords * %s;", uv->vsOut(), atlasSizeInvName); |
| |
| args.fVaryingHandler->addVarying("TexIndex", texIdx); |
| args.fVertBuilder->codeAppendf("%s = texIdx;", texIdx->vsOut()); |
| |
| if (st) { |
| args.fVaryingHandler->addVarying("IntTextureCoords", st, kHigh_GrSLPrecision); |
| args.fVertBuilder->codeAppendf("%s = intCoords;", st->vsOut()); |
| } |
| } |
| |
| static void append_multitexture_lookup(GrGLSLPrimitiveProcessor::EmitArgs& args, |
| int numTextureSamplers, |
| const GrGLSLVertToFrag &texIdx, |
| const char* coordName, |
| const char* colorName) { |
| // conditionally load from the indexed texture sampler |
| for (int i = 0; i < numTextureSamplers-1; ++i) { |
| args.fFragBuilder->codeAppendf("if (%s == %d) { %s = ", texIdx.fsIn(), i, colorName); |
| args.fFragBuilder->appendTextureLookup(args.fTexSamplers[i], coordName, kVec2f_GrSLType); |
| args.fFragBuilder->codeAppend("; } else "); |
| } |
| args.fFragBuilder->codeAppendf("{ %s = ", colorName); |
| args.fFragBuilder->appendTextureLookup(args.fTexSamplers[numTextureSamplers-1], coordName, |
| kVec2f_GrSLType); |
| args.fFragBuilder->codeAppend("; }"); |
| } |
| |
| #endif |