| /* |
| * 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 "src/gpu/ganesh/GrDrawOpAtlas.h" |
| #include "src/gpu/ganesh/GrShaderCaps.h" |
| #include "src/gpu/ganesh/glsl/GrGLSLFragmentShaderBuilder.h" |
| #include "src/gpu/ganesh/glsl/GrGLSLVarying.h" |
| #include "src/gpu/ganesh/glsl/GrGLSLVertexGeoBuilder.h" |
| |
| static inline void append_index_uv_varyings(GrGeometryProcessor::ProgramImpl::EmitArgs& args, |
| int numTextureSamplers, |
| const char* inTexCoordsName, |
| const char* atlasDimensionsInvName, |
| GrGLSLVarying* uv, |
| GrGLSLVarying* texIdx, |
| GrGLSLVarying* st) { |
| using Interpolation = GrGLSLVaryingHandler::Interpolation; |
| // This extracts the texture index and texel coordinates from the same variable |
| // Packing structure: texel coordinates have the 2-bit texture page encoded in bits 13 & 14 of |
| // the x coordinate. It would be nice to use bits 14 and 15, but iphone6 has problem with those |
| // bits when in gles. Iphone6 works fine with bits 14 and 15 in metal. |
| if (args.fShaderCaps->fIntegerSupport) { |
| if (numTextureSamplers <= 1) { |
| args.fVertBuilder->codeAppendf( |
| "int texIdx = 0;" |
| "float2 unormTexCoords = float2(%s.x, %s.y);" |
| , inTexCoordsName, inTexCoordsName); |
| } else { |
| args.fVertBuilder->codeAppendf( |
| "int2 coords = int2(%s.x, %s.y);" |
| "int texIdx = coords.x >> 13;" |
| "float2 unormTexCoords = float2(coords.x & 0x1FFF, coords.y);" |
| , inTexCoordsName, inTexCoordsName); |
| } |
| } else { |
| if (numTextureSamplers <= 1) { |
| args.fVertBuilder->codeAppendf( |
| "float texIdx = 0;" |
| "float2 unormTexCoords = float2(%s.x, %s.y);" |
| , inTexCoordsName, inTexCoordsName); |
| } else { |
| args.fVertBuilder->codeAppendf( |
| "float2 coord = float2(%s.x, %s.y);" |
| "float texIdx = floor(coord.x * exp2(-13));" |
| "float2 unormTexCoords = float2(coord.x - texIdx * exp2(13), coord.y);" |
| , inTexCoordsName, inTexCoordsName); |
| } |
| } |
| |
| // Multiply by 1/atlasDimensions to get normalized texture coordinates |
| uv->reset(SkSLType::kFloat2); |
| args.fVaryingHandler->addVarying("TextureCoords", uv); |
| args.fVertBuilder->codeAppendf( |
| "%s = unormTexCoords * %s;", uv->vsOut(), atlasDimensionsInvName); |
| |
| // On ANGLE there is a significant cost to using an int varying. We don't know of any case where |
| // it is worse to use a float so for now we always do. |
| texIdx->reset(SkSLType::kFloat); |
| // If we computed the local var "texIdx" as an int we will need to cast it to float |
| const char* cast = args.fShaderCaps->fIntegerSupport ? "float" : ""; |
| args.fVaryingHandler->addVarying("TexIndex", texIdx, Interpolation::kCanBeFlat); |
| args.fVertBuilder->codeAppendf("%s = %s(texIdx);", texIdx->vsOut(), cast); |
| |
| if (st) { |
| st->reset(SkSLType::kFloat2); |
| args.fVaryingHandler->addVarying("IntTextureCoords", st); |
| args.fVertBuilder->codeAppendf("%s = unormTexCoords;", st->vsOut()); |
| } |
| } |
| |
| static inline void append_multitexture_lookup(GrGeometryProcessor::ProgramImpl::EmitArgs& args, |
| int numTextureSamplers, |
| const GrGLSLVarying& texIdx, |
| const char* coordName, |
| const char* colorName) { |
| SkASSERT(numTextureSamplers > 0); |
| // This shouldn't happen, but will avoid a crash if it does |
| if (numTextureSamplers <= 0) { |
| args.fFragBuilder->codeAppendf("%s = float4(1, 1, 1, 1);", colorName); |
| return; |
| } |
| |
| // 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); |
| args.fFragBuilder->codeAppend("; } else "); |
| } |
| args.fFragBuilder->codeAppendf("{ %s = ", colorName); |
| args.fFragBuilder->appendTextureLookup(args.fTexSamplers[numTextureSamplers - 1], coordName); |
| args.fFragBuilder->codeAppend("; }"); |
| } |
| |
| #endif |