Use uint16s for texture coordinates when rendering text.

src/gpu/effects/GrDistanceFieldTextureEffect.cpp

 /*
  * Copyright 2013 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "GrDistanceFieldTextureEffect.h"
+#include "GrFontAtlasSizes.h"
 #include "GrInvariantOutput.h"
 #include "GrTexture.h"
 #include "SkDistanceFieldGen.h"
 #include "gl/GrGLProcessor.h"
 #include "gl/GrGLSL.h"
 #include "gl/GrGLTexture.h"
 #include "gl/GrGLGeometryProcessor.h"
 #include "gl/builders/GrGLProgramBuilder.h"
 
 // Assuming a radius of the diagonal of the fragment, hence a factor of sqrt(2)/2
 #define SK_DistanceFieldAAFactor     "0.7071"
 
 struct DistanceFieldBatchTracker {
     GrGPInput fInputColorType;
     GrColor fColor;
     bool fUsesLocalCoords;
 };
 
 class GrGLDistanceFieldTextureEffect : public GrGLGeometryProcessor {
 public:
     GrGLDistanceFieldTextureEffect(const GrGeometryProcessor&,
                                    const GrBatchTracker&)
         : fColor(GrColor_ILLEGAL)
-        , fTextureSize(SkISize::Make(-1,-1))
 #ifdef SK_GAMMA_APPLY_TO_A8
         , fLuminance(-1.0f)
 #endif
         {}
 
     void onEmitCode(EmitArgs& args, GrGPArgs* gpArgs) SK_OVERRIDE{
         const GrDistanceFieldTextureEffect& dfTexEffect =
                 args.fGP.cast<GrDistanceFieldTextureEffect>();
         const DistanceFieldBatchTracker& local = args.fBT.cast<DistanceFieldBatchTracker>();
         GrGLGPBuilder* pb = args.fPB;
         GrGLGPFragmentBuilder* fsBuilder = args.fPB->getFragmentShaderBuilder();
         SkAssertResult(fsBuilder->enableFeature(
                 GrGLFragmentShaderBuilder::kStandardDerivatives_GLSLFeature));
 
         GrGLVertexBuilder* vsBuilder = args.fPB->getVertexShaderBuilder();
 
         // emit attributes
         vsBuilder->emitAttributes(dfTexEffect);
 
-        GrGLVertToFrag v(kVec2f_GrSLType);
-        args.fPB->addVarying("TextureCoords", &v);
-        vsBuilder->codeAppendf("%s = %s;", v.vsOut(), dfTexEffect.inTextureCoords()->fName);
+        GrGLVertToFrag st(kVec2f_GrSLType);
+        args.fPB->addVarying("IntTextureCoords", &st);
+        vsBuilder->codeAppendf("%s = %s;", st.vsOut(), dfTexEffect.inTextureCoords()->fName);
+        
+        GrGLVertToFrag uv(kVec2f_GrSLType);
+        args.fPB->addVarying("TextureCoords", &uv);
+        // this is only used with text, so our texture bounds always match the glyph atlas
+        vsBuilder->codeAppendf("%s = vec2(" GR_FONT_ATLAS_RECIP_WIDTH ", "
+                               GR_FONT_ATLAS_RECIP_HEIGHT ")*%s;", uv.vsOut(),
+                               dfTexEffect.inTextureCoords()->fName);
 
         // Setup pass through color
         this->setupColorPassThrough(pb, local.fInputColorType, args.fOutputColor,
                                     dfTexEffect.inColor(), &fColorUniform);
 
         // Setup position
         this->setupPosition(pb, gpArgs, dfTexEffect.inPosition()->fName, dfTexEffect.viewMatrix());
 
         // emit transforms
         this->emitTransforms(args.fPB, gpArgs->fPositionVar, dfTexEffect.inPosition()->fName,
                              dfTexEffect.localMatrix(), args.fTransformsIn, args.fTransformsOut);
 
-        const char* textureSizeUniName = NULL;
-        fTextureSizeUni = args.fPB->addUniform(GrGLProgramBuilder::kFragment_Visibility,
-                                               kVec2f_GrSLType, kDefault_GrSLPrecision,
-                                               "TextureSize", &textureSizeUniName);
-
         // Use highp to work around aliasing issues
         fsBuilder->codeAppend(GrGLShaderVar::PrecisionString(kHigh_GrSLPrecision,
                                                              pb->ctxInfo().standard()));
-        fsBuilder->codeAppendf("vec2 uv = %s;\n", v.fsIn());
+        fsBuilder->codeAppendf("vec2 uv = %s;\n", uv.fsIn());
 
         fsBuilder->codeAppend("\tfloat texColor = ");
         fsBuilder->appendTextureLookup(args.fSamplers[0],
                                        "uv",
                                        kVec2f_GrSLType);
         fsBuilder->codeAppend(".r;\n");
         fsBuilder->codeAppend("\tfloat distance = "
                        SK_DistanceFieldMultiplier "*(texColor - " SK_DistanceFieldThreshold ");");
 
         // we adjust for the effect of the transformation on the distance by using
         // the length of the gradient of the texture coordinates. We use st coordinates
         // to ensure we're mapping 1:1 from texel space to pixel space.
         fsBuilder->codeAppend(GrGLShaderVar::PrecisionString(kHigh_GrSLPrecision,
                                                              pb->ctxInfo().standard()));
-        fsBuilder->codeAppendf("vec2 st = uv*%s;\n", textureSizeUniName);
+        fsBuilder->codeAppendf("vec2 st = %s;\n", st.fsIn());
         fsBuilder->codeAppend("\tfloat afwidth;\n");
         if (dfTexEffect.getFlags() & kSimilarity_DistanceFieldEffectFlag) {
             // this gives us a smooth step across approximately one fragment
             fsBuilder->codeAppend("\tafwidth = abs(" SK_DistanceFieldAAFactor "*dFdx(st.x));\n");
         } else {
             fsBuilder->codeAppend("\tvec2 Jdx = dFdx(st);\n");
             fsBuilder->codeAppend("\tvec2 Jdy = dFdy(st);\n");
 
             fsBuilder->codeAppend("\tvec2 uv_grad;\n");
             if (args.fPB->ctxInfo().caps()->dropsTileOnZeroDivide()) {
@@ skipping 29 matching lines @@
         fsBuilder->codeAppend(";\n");
         fsBuilder->codeAppend("\tval = gammaColor.r;\n");
 #endif
 
         fsBuilder->codeAppendf("%s = vec4(val);", args.fOutputCoverage);
     }
 
     virtual void setData(const GrGLProgramDataManager& pdman,
                          const GrPrimitiveProcessor& proc,
                          const GrBatchTracker& bt) SK_OVERRIDE {
-        SkASSERT(fTextureSizeUni.isValid());
-
-        GrTexture* texture = proc.texture(0);
-        if (texture->width() != fTextureSize.width() ||
-            texture->height() != fTextureSize.height()) {
-            fTextureSize = SkISize::Make(texture->width(), texture->height());
-            pdman.set2f(fTextureSizeUni,
-                        SkIntToScalar(fTextureSize.width()),
-                        SkIntToScalar(fTextureSize.height()));
-        }
 #ifdef SK_GAMMA_APPLY_TO_A8
         const GrDistanceFieldTextureEffect& dfTexEffect =
                 proc.cast<GrDistanceFieldTextureEffect>();
         float luminance = dfTexEffect.getLuminance();
         if (luminance != fLuminance) {
             pdman.set1f(fLuminanceUni, luminance);
             fLuminance = luminance;
         }
 #endif
 
@@ skipping 17 matching lines @@
         uint32_t key = dfTexEffect.getFlags();
         key |= local.fInputColorType << 16;
         key |= local.fUsesLocalCoords && gp.localMatrix().hasPerspective() ? 0x1 << 24: 0x0;
         key |= ComputePosKey(gp.viewMatrix()) << 25;
         b->add32(key);
     }
 
 private:
     GrColor       fColor;
     UniformHandle fColorUniform;
-    UniformHandle fTextureSizeUni;
-    SkISize       fTextureSize;
+#ifdef SK_GAMMA_APPLY_TO_A8
     UniformHandle fLuminanceUni;
-#ifdef SK_GAMMA_APPLY_TO_A8
     float         fLuminance;
 #endif
 
     typedef GrGLGeometryProcessor INHERITED;
 };
 
 ///////////////////////////////////////////////////////////////////////////////
 
 GrDistanceFieldTextureEffect::GrDistanceFieldTextureEffect(GrColor color,
                                                            const SkMatrix& viewMatrix,
@@ skipping 14 matching lines @@
     , fFlags(flags & kNonLCD_DistanceFieldEffectMask)
     , fInColor(NULL) {
     SkASSERT(!(flags & ~kNonLCD_DistanceFieldEffectMask));
     this->initClassID<GrDistanceFieldTextureEffect>();
     fInPosition = &this->addVertexAttrib(Attribute("inPosition", kVec2f_GrVertexAttribType));
     if (flags & kColorAttr_DistanceFieldEffectFlag) {
         fInColor = &this->addVertexAttrib(Attribute("inColor", kVec4ub_GrVertexAttribType));
         this->setHasVertexColor();
     }
     fInTextureCoords = &this->addVertexAttrib(Attribute("inTextureCoords",
-                                                          kVec2f_GrVertexAttribType));
+                                                          kVec2s_GrVertexAttribType));
     this->addTextureAccess(&fTextureAccess);
 #ifdef SK_GAMMA_APPLY_TO_A8
     this->addTextureAccess(&fGammaTextureAccess);
 #endif
 }
 
 bool GrDistanceFieldTextureEffect::onIsEqual(const GrGeometryProcessor& other) const {
     const GrDistanceFieldTextureEffect& cte = other.cast<GrDistanceFieldTextureEffect>();
     return
 #ifdef SK_GAMMA_APPLY_TO_A8
@@ skipping 329 matching lines @@
     GrGPInput fInputColorType;
     GrColor fColor;
     bool fUsesLocalCoords;
 };
 
 class GrGLDistanceFieldLCDTextureEffect : public GrGLGeometryProcessor {
 public:
     GrGLDistanceFieldLCDTextureEffect(const GrGeometryProcessor&,
                                       const GrBatchTracker&)
     : fColor(GrColor_ILLEGAL)
-    , fTextureSize(SkISize::Make(-1,-1))
     , fTextColor(GrColor_ILLEGAL) {}
 
     void onEmitCode(EmitArgs& args, GrGPArgs* gpArgs) SK_OVERRIDE{
         const GrDistanceFieldLCDTextureEffect& dfTexEffect =
                 args.fGP.cast<GrDistanceFieldLCDTextureEffect>();
         const DistanceFieldLCDBatchTracker& local = args.fBT.cast<DistanceFieldLCDBatchTracker>();
         GrGLGPBuilder* pb = args.fPB;
 
         GrGLVertexBuilder* vsBuilder = args.fPB->getVertexShaderBuilder();
 
         // emit attributes
         vsBuilder->emitAttributes(dfTexEffect);
 
-        GrGLVertToFrag v(kVec2f_GrSLType);
-        args.fPB->addVarying("TextureCoords", &v);
-        vsBuilder->codeAppendf("%s = %s;", v.vsOut(), dfTexEffect.inTextureCoords()->fName);
-
+        GrGLVertToFrag st(kVec2f_GrSLType);
+        args.fPB->addVarying("IntTextureCoords", &st);
+        vsBuilder->codeAppendf("%s = %s;", st.vsOut(), dfTexEffect.inTextureCoords()->fName);
+        
+        GrGLVertToFrag uv(kVec2f_GrSLType);
+        args.fPB->addVarying("TextureCoords", &uv);
+        // this is only used with text, so our texture bounds always match the glyph atlas
+        vsBuilder->codeAppendf("%s = vec2(" GR_FONT_ATLAS_RECIP_WIDTH ", "
+                               GR_FONT_ATLAS_RECIP_HEIGHT ")*%s;", uv.vsOut(),
+                               dfTexEffect.inTextureCoords()->fName);
+        
         // setup pass through color
         this->setupColorPassThrough(pb, local.fInputColorType, args.fOutputColor, NULL,
                                     &fColorUniform);
 
         // Setup position
         this->setupPosition(pb, gpArgs, dfTexEffect.inPosition()->fName, dfTexEffect.viewMatrix());
 
         // emit transforms
         this->emitTransforms(args.fPB, gpArgs->fPositionVar, dfTexEffect.inPosition()->fName,
                              dfTexEffect.localMatrix(), args.fTransformsIn, args.fTransformsOut);
 
-        const char* textureSizeUniName = NULL;
-        // width, height, 1/(3*width)
-        fTextureSizeUni = args.fPB->addUniform(GrGLProgramBuilder::kFragment_Visibility,
-                                              kVec3f_GrSLType, kDefault_GrSLPrecision,
-                                              "TextureSize", &textureSizeUniName);
-
         GrGLGPFragmentBuilder* fsBuilder = args.fPB->getFragmentShaderBuilder();
 
         SkAssertResult(fsBuilder->enableFeature(
                 GrGLFragmentShaderBuilder::kStandardDerivatives_GLSLFeature));
 
         // create LCD offset adjusted by inverse of transform
         // Use highp to work around aliasing issues
         fsBuilder->codeAppend(GrGLShaderVar::PrecisionString(kHigh_GrSLPrecision,
                                                              pb->ctxInfo().standard()));
-        fsBuilder->codeAppendf("vec2 uv = %s;\n", v.fsIn());
+        fsBuilder->codeAppendf("vec2 uv = %s;\n", uv.fsIn());
         fsBuilder->codeAppend(GrGLShaderVar::PrecisionString(kHigh_GrSLPrecision,
                                                              pb->ctxInfo().standard()));
-        fsBuilder->codeAppendf("vec2 st = uv*%s.xy;\n", textureSizeUniName);
+        fsBuilder->codeAppendf("vec2 st = %s;\n", st.fsIn());
         bool isUniformScale = !!(dfTexEffect.getFlags() & kUniformScale_DistanceFieldEffectMask);
+        
+        if (dfTexEffect.getFlags() & kBGR_DistanceFieldEffectFlag) {
+            fsBuilder->codeAppend("float delta = -" GR_FONT_ATLAS_LCD_DELTA ";\n");
+        } else {
+            fsBuilder->codeAppend("float delta = " GR_FONT_ATLAS_LCD_DELTA ";\n");
+        }
         if (isUniformScale) {
             fsBuilder->codeAppend("\tfloat dx = dFdx(st.x);\n");
-            fsBuilder->codeAppendf("\tvec2 offset = vec2(dx*%s.z, 0.0);\n", textureSizeUniName);
+            fsBuilder->codeAppend("\tvec2 offset = vec2(dx*delta, 0.0);\n");
         } else {
             fsBuilder->codeAppend("\tvec2 Jdx = dFdx(st);\n");
             fsBuilder->codeAppend("\tvec2 Jdy = dFdy(st);\n");
-            fsBuilder->codeAppendf("\tvec2 offset = %s.z*Jdx;\n", textureSizeUniName);
+            fsBuilder->codeAppend("\tvec2 offset = delta*Jdx;\n");
         }
 
         // green is distance to uv center
         fsBuilder->codeAppend("\tvec4 texColor = ");
         fsBuilder->appendTextureLookup(args.fSamplers[0], "uv", kVec2f_GrSLType);
         fsBuilder->codeAppend(";\n");
         fsBuilder->codeAppend("\tvec3 distance;\n");
         fsBuilder->codeAppend("\tdistance.y = texColor.r;\n");
         // red is distance to left offset
         fsBuilder->codeAppend("\tvec2 uv_adjusted = uv - offset;\n");
@@ skipping 40 matching lines @@
             fsBuilder->codeAppend("\t                 uv_grad.x*Jdx.y + uv_grad.y*Jdy.y);\n");
 
             // this gives us a smooth step across approximately one fragment
             fsBuilder->codeAppend("\tafwidth = " SK_DistanceFieldAAFactor "*length(grad);\n");
         }
 
         fsBuilder->codeAppend("\tvec4 val = vec4(smoothstep(vec3(-afwidth), vec3(afwidth), distance), 1.0);\n");
 
         // adjust based on gamma
         const char* textColorUniName = NULL;
-        // width, height, 1/(3*width)
         fTextColorUni = args.fPB->addUniform(GrGLProgramBuilder::kFragment_Visibility,
                                              kVec3f_GrSLType, kDefault_GrSLPrecision,
                                              "TextColor", &textColorUniName);
 
         fsBuilder->codeAppendf("\tuv = vec2(val.x, %s.x);\n", textColorUniName);
         fsBuilder->codeAppend("float gammaColor = ");
         fsBuilder->appendTextureLookup(args.fSamplers[1], "uv", kVec2f_GrSLType);
         fsBuilder->codeAppend(".r;\n");
         fsBuilder->codeAppend("\tval.x = gammaColor;\n");
 
         fsBuilder->codeAppendf("\tuv = vec2(val.y, %s.y);\n", textColorUniName);
         fsBuilder->codeAppend("\tgammaColor = ");
         fsBuilder->appendTextureLookup(args.fSamplers[1], "uv", kVec2f_GrSLType);
         fsBuilder->codeAppend(".r;\n");
         fsBuilder->codeAppend("\tval.y = gammaColor;\n");
 
         fsBuilder->codeAppendf("\tuv = vec2(val.z, %s.z);\n", textColorUniName);
         fsBuilder->codeAppend("\tgammaColor = ");
         fsBuilder->appendTextureLookup(args.fSamplers[1], "uv", kVec2f_GrSLType);
         fsBuilder->codeAppend(".r;\n");
         fsBuilder->codeAppend("\tval.z = gammaColor;\n");
 
         fsBuilder->codeAppendf("%s = vec4(val);", args.fOutputCoverage);
     }
 
     virtual void setData(const GrGLProgramDataManager& pdman,
                          const GrPrimitiveProcessor& processor,
                          const GrBatchTracker& bt) SK_OVERRIDE {
-        SkASSERT(fTextureSizeUni.isValid());
         SkASSERT(fTextColorUni.isValid());
 
         const GrDistanceFieldLCDTextureEffect& dfTexEffect =
                 processor.cast<GrDistanceFieldLCDTextureEffect>();
-        GrTexture* texture = processor.texture(0);
-        if (texture->width() != fTextureSize.width() ||
-            texture->height() != fTextureSize.height()) {
-            fTextureSize = SkISize::Make(texture->width(), texture->height());
-            float delta = 1.0f/(3.0f*texture->width());
-            if (dfTexEffect.getFlags() & kBGR_DistanceFieldEffectFlag) {
-                delta = -delta;
-            }
-            pdman.set3f(fTextureSizeUni,
-                        SkIntToScalar(fTextureSize.width()),
-                        SkIntToScalar(fTextureSize.height()),
-                        delta);
-        }
-
         GrColor textColor = dfTexEffect.getTextColor();
         if (textColor != fTextColor) {
             static const float ONE_OVER_255 = 1.f / 255.f;
             pdman.set3f(fTextColorUni,
                         GrColorUnpackR(textColor) * ONE_OVER_255,
                         GrColorUnpackG(textColor) * ONE_OVER_255,
                         GrColorUnpackB(textColor) * ONE_OVER_255);
             fTextColor = textColor;
         }
 
@@ skipping 19 matching lines @@
         uint32_t key = dfTexEffect.getFlags();
         key |= local.fInputColorType << 16;
         key |= local.fUsesLocalCoords && gp.localMatrix().hasPerspective() ? 0x1 << 24: 0x0;
         key |= ComputePosKey(gp.viewMatrix()) << 25;
         b->add32(key);
     }
 
 private:
     GrColor       fColor;
     UniformHandle fColorUniform;
-    UniformHandle fTextureSizeUni;
-    SkISize       fTextureSize;
     UniformHandle fTextColorUni;
     SkColor       fTextColor;
 
     typedef GrGLGeometryProcessor INHERITED;
 };
 
 ///////////////////////////////////////////////////////////////////////////////
 
 GrDistanceFieldLCDTextureEffect::GrDistanceFieldLCDTextureEffect(
                                                   GrColor color, const SkMatrix& viewMatrix,
                                                   GrTexture* texture, const GrTextureParams& params,
                                                   GrTexture* gamma, const GrTextureParams& gParams,
                                                   SkColor textColor,
                                                   uint32_t flags)
     : INHERITED(color, viewMatrix, SkMatrix::I())
     , fTextureAccess(texture, params)
     , fGammaTextureAccess(gamma, gParams)
     , fTextColor(textColor)
     , fFlags(flags & kLCD_DistanceFieldEffectMask){
     SkASSERT(!(flags & ~kLCD_DistanceFieldEffectMask) && (flags & kUseLCD_DistanceFieldEffectFlag));
     this->initClassID<GrDistanceFieldLCDTextureEffect>();
     fInPosition = &this->addVertexAttrib(Attribute("inPosition", kVec2f_GrVertexAttribType));
     fInTextureCoords = &this->addVertexAttrib(Attribute("inTextureCoords",
-                                                          kVec2f_GrVertexAttribType));
+                                                          kVec2s_GrVertexAttribType));
     this->addTextureAccess(&fTextureAccess);
     this->addTextureAccess(&fGammaTextureAccess);
 }
 
 bool GrDistanceFieldLCDTextureEffect::onIsEqual(const GrGeometryProcessor& other) const {
     const GrDistanceFieldLCDTextureEffect& cte = other.cast<GrDistanceFieldLCDTextureEffect>();
     return (fTextColor == cte.fTextColor &&
             fFlags == cte.fFlags);
 }
 
@@ skipping 64 matching lines @@
     uint32_t flags = kUseLCD_DistanceFieldEffectFlag;
     flags |= random->nextBool() ? kUniformScale_DistanceFieldEffectMask : 0;
     flags |= random->nextBool() ? kBGR_DistanceFieldEffectFlag : 0;
     return GrDistanceFieldLCDTextureEffect::Create(GrRandomColor(random),
                                                    GrProcessorUnitTest::TestMatrix(random),
                                                    textures[texIdx], params,
                                                    textures[texIdx2], params2,
                                                    textColor,
                                                    flags);
 }