| /* |
| * 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 "GrShaderCaps.h" |
| #include "glsl/GrGLSLPrimitiveProcessor.h" |
| #include "glsl/GrGLSLFragmentShaderBuilder.h" |
| #include "glsl/GrGLSLVarying.h" |
| #include "glsl/GrGLSLVertexGeoBuilder.h" |
| |
| static void append_index_uv_varyings(GrGLSLPrimitiveProcessor::EmitArgs& args, |
| const char* inTexCoordsName, |
| const char* atlasSizeInvName, |
| GrGLSLVarying *uv, |
| GrGLSLVarying *texIdx, |
| GrGLSLVarying *st) { |
| // 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 unormTexCoords = floor(0.5*indexTexCoords);"); |
| args.fVertBuilder->codeAppend("float2 diff = indexTexCoords - 2.0*unormTexCoords;"); |
| 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); |
| args.fVertBuilder->codeAppendf("%s = unormTexCoords * %s;", uv->vsOut(), atlasSizeInvName); |
| |
| args.fVaryingHandler->addVarying("TexIndex", texIdx); |
| args.fVertBuilder->codeAppendf("%s = texIdx;", texIdx->vsOut()); |
| |
| if (st) { |
| args.fVaryingHandler->addVarying("IntTextureCoords", st); |
| args.fVertBuilder->codeAppendf("%s = unormTexCoords;", st->vsOut()); |
| } |
| } |
| |
| static void append_multitexture_lookup(GrGLSLPrimitiveProcessor::EmitArgs& args, |
| int numTextureSamplers, |
| const GrGLSLVarying &texIdx, |
| const char* coordName, |
| const char* colorName) { |
| // Conditionally load from the indexed texture sampler. |
| // We treat an interval of values around each int as corresponding to that int |
| // (basically round to int) to correct for floating point variation in the frag shader |
| for (int i = numTextureSamplers-1; i > 0; --i) { |
| args.fFragBuilder->codeAppendf("if (%s > %d - 0.5) { %s = ", texIdx.fsIn(), i, colorName); |
| args.fFragBuilder->appendTextureLookup(args.fTexSamplers[i], coordName, |
| kFloat2_GrSLType); |
| args.fFragBuilder->codeAppend("; } else "); |
| } |
| args.fFragBuilder->codeAppendf("{ %s = ", colorName); |
| args.fFragBuilder->appendTextureLookup(args.fTexSamplers[0], coordName, |
| kFloat2_GrSLType); |
| args.fFragBuilder->codeAppend("; }"); |
| } |
| |
| #endif |