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- /*
- * Copyright 2014 Google Inc.
- *
- * Use of this source code is governed by a BSD-style license that can be
- * found in the LICENSE file.
- */
- #include "src/gpu/glsl/GrGLSLXferProcessor.h"
- #include "include/gpu/GrTexture.h"
- #include "src/gpu/GrShaderCaps.h"
- #include "src/gpu/GrXferProcessor.h"
- #include "src/gpu/glsl/GrGLSLFragmentShaderBuilder.h"
- #include "src/gpu/glsl/GrGLSLProgramDataManager.h"
- #include "src/gpu/glsl/GrGLSLUniformHandler.h"
- // This is only called for cases where we are doing LCD coverage and not using in shader blending.
- // For these cases we assume the the src alpha is 1, thus we can just use the max for the alpha
- // coverage since src alpha will always be greater than or equal to dst alpha.
- static void adjust_for_lcd_coverage(GrGLSLXPFragmentBuilder* fragBuilder,
- const char* srcCoverage,
- const GrXferProcessor& proc) {
- if (srcCoverage && proc.isLCD()) {
- fragBuilder->codeAppendf("%s.a = max(max(%s.r, %s.g), %s.b);",
- srcCoverage, srcCoverage, srcCoverage, srcCoverage);
- }
- }
- void GrGLSLXferProcessor::emitCode(const EmitArgs& args) {
- if (!args.fXP.willReadDstColor()) {
- adjust_for_lcd_coverage(args.fXPFragBuilder, args.fInputCoverage, args.fXP);
- this->emitOutputsForBlendState(args);
- } else {
- GrGLSLXPFragmentBuilder* fragBuilder = args.fXPFragBuilder;
- GrGLSLUniformHandler* uniformHandler = args.fUniformHandler;
- const char* dstColor = fragBuilder->dstColor();
- bool needsLocalOutColor = false;
- if (args.fDstTextureSamplerHandle.isValid()) {
- bool flipY = kBottomLeft_GrSurfaceOrigin == args.fDstTextureOrigin;
- if (args.fInputCoverage) {
- // We don't think any shaders actually output negative coverage, but just as a
- // safety check for floating point precision errors we compare with <= here. We just
- // check the rgb values of the coverage since the alpha may not have been set when
- // using lcd. If we are using single channel coverage alpha will equal to rgb
- // anyways.
- //
- // The discard here also helps for batching text draws together which need to read
- // from a dst copy for blends. Though this only helps the case where the outer
- // bounding boxes of each letter overlap and not two actually parts of the text.
- fragBuilder->codeAppendf("if (all(lessThanEqual(%s.rgb, half3(0)))) {"
- " discard;"
- "}", args.fInputCoverage);
- }
- const char* dstTopLeftName;
- const char* dstCoordScaleName;
- fDstTopLeftUni = uniformHandler->addUniform(kFragment_GrShaderFlag,
- kHalf2_GrSLType,
- "DstTextureUpperLeft",
- &dstTopLeftName);
- fDstScaleUni = uniformHandler->addUniform(kFragment_GrShaderFlag,
- kHalf2_GrSLType,
- "DstTextureCoordScale",
- &dstCoordScaleName);
- fragBuilder->codeAppend("// Read color from copy of the destination.\n");
- fragBuilder->codeAppendf("half2 _dstTexCoord = (half2(sk_FragCoord.xy) - %s) * %s;",
- dstTopLeftName, dstCoordScaleName);
- if (flipY) {
- fragBuilder->codeAppend("_dstTexCoord.y = 1.0 - _dstTexCoord.y;");
- }
- fragBuilder->codeAppendf("half4 %s = ", dstColor);
- fragBuilder->appendTextureLookup(args.fDstTextureSamplerHandle, "_dstTexCoord",
- kHalf2_GrSLType);
- fragBuilder->codeAppend(";");
- } else {
- needsLocalOutColor = args.fShaderCaps->requiresLocalOutputColorForFBFetch();
- }
- const char* outColor = "_localColorOut";
- if (!needsLocalOutColor) {
- outColor = args.fOutputPrimary;
- } else {
- fragBuilder->codeAppendf("half4 %s;", outColor);
- }
- this->emitBlendCodeForDstRead(fragBuilder,
- uniformHandler,
- args.fInputColor,
- args.fInputCoverage,
- dstColor,
- outColor,
- args.fOutputSecondary,
- args.fXP);
- if (needsLocalOutColor) {
- fragBuilder->codeAppendf("%s = %s;", args.fOutputPrimary, outColor);
- }
- }
- // Swizzle the fragment shader outputs if necessary.
- this->emitOutputSwizzle(
- args.fXPFragBuilder, args.fOutputSwizzle, args.fOutputPrimary, args.fOutputSecondary);
- }
- void GrGLSLXferProcessor::emitOutputSwizzle(
- GrGLSLXPFragmentBuilder* x, const GrSwizzle& swizzle, const char* outColor,
- const char* outColorSecondary) const {
- if (GrSwizzle::RGBA() != swizzle) {
- x->codeAppendf("%s = %s.%s;", outColor, outColor, swizzle.c_str());
- if (outColorSecondary) {
- x->codeAppendf("%s = %s.%s;", outColorSecondary, outColorSecondary, swizzle.c_str());
- }
- }
- }
- void GrGLSLXferProcessor::setData(const GrGLSLProgramDataManager& pdm, const GrXferProcessor& xp,
- const GrTexture* dstTexture, const SkIPoint& dstTextureOffset) {
- if (dstTexture) {
- if (fDstTopLeftUni.isValid()) {
- pdm.set2f(fDstTopLeftUni, static_cast<float>(dstTextureOffset.fX),
- static_cast<float>(dstTextureOffset.fY));
- pdm.set2f(fDstScaleUni, 1.f / dstTexture->width(), 1.f / dstTexture->height());
- } else {
- SkASSERT(!fDstScaleUni.isValid());
- }
- } else {
- SkASSERT(!fDstTopLeftUni.isValid());
- SkASSERT(!fDstScaleUni.isValid());
- }
- this->onSetData(pdm, xp);
- }
- void GrGLSLXferProcessor::DefaultCoverageModulation(GrGLSLXPFragmentBuilder* fragBuilder,
- const char* srcCoverage,
- const char* dstColor,
- const char* outColor,
- const char* outColorSecondary,
- const GrXferProcessor& proc) {
- if (proc.dstReadUsesMixedSamples()) {
- if (srcCoverage) {
- // TODO: Once we are no longer using legacy mesh ops, it will not be possible to even
- // create a mixed sample with lcd so we can uncomment the below assert. In practice
- // today this never happens except for GLPrograms test which can make one. skia:6661
- // SkASSERT(!proc.isLCD());
- fragBuilder->codeAppendf("%s *= %s;", outColor, srcCoverage);
- fragBuilder->codeAppendf("%s = %s;", outColorSecondary, srcCoverage);
- } else {
- fragBuilder->codeAppendf("%s = half4(1.0);", outColorSecondary);
- }
- } else if (srcCoverage) {
- if (proc.isLCD()) {
- fragBuilder->codeAppendf("half lerpRed = mix(%s.a, %s.a, %s.r);",
- dstColor, outColor, srcCoverage);
- fragBuilder->codeAppendf("half lerpBlue = mix(%s.a, %s.a, %s.g);",
- dstColor, outColor, srcCoverage);
- fragBuilder->codeAppendf("half lerpGreen = mix(%s.a, %s.a, %s.b);",
- dstColor, outColor, srcCoverage);
- }
- fragBuilder->codeAppendf("%s = %s * %s + (half4(1.0) - %s) * %s;",
- outColor, srcCoverage, outColor, srcCoverage, dstColor);
- if (proc.isLCD()) {
- fragBuilder->codeAppendf("%s.a = max(max(lerpRed, lerpBlue), lerpGreen);", outColor);
- }
- }
- }
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