Create swizzle table inside of glsl caps

src/gpu/gl/GrGLGpu.cpp

 /*
  * Copyright 2011 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 
 #include "GrGLGpu.h"
 #include "GrGLGLSL.h"
@@ skipping 2378 matching lines @@
         GR_GL_REPEAT,
         GR_GL_MIRRORED_REPEAT
     };
     GR_STATIC_ASSERT(SkShader::kTileModeCount == SK_ARRAY_COUNT(gWrapModes));
     GR_STATIC_ASSERT(0 == SkShader::kClamp_TileMode);
     GR_STATIC_ASSERT(1 == SkShader::kRepeat_TileMode);
     GR_STATIC_ASSERT(2 == SkShader::kMirror_TileMode);
     return gWrapModes[tm];
 }
 
-const GrGLenum* GrGLGpu::GetTexParamSwizzle(GrPixelConfig config, const GrGLCaps& caps) {
-    if (caps.textureSwizzleSupport() && GrPixelConfigIsAlphaOnly(config)) {
-        if (caps.textureRedSupport()) {
-            static const GrGLenum gRedSmear[] = { GR_GL_RED, GR_GL_RED, GR_GL_RED, GR_GL_RED };
-            return gRedSmear;
-        } else {
-            static const GrGLenum gAlphaSmear[] = { GR_GL_ALPHA, GR_GL_ALPHA,
-                                                    GR_GL_ALPHA, GR_GL_ALPHA };
-            return gAlphaSmear;
-        }
-    } else {
-        static const GrGLenum gStraight[] = { GR_GL_RED, GR_GL_GREEN, GR_GL_BLUE, GR_GL_ALPHA };
-        return gStraight;
+static GrGLenum get_component_enum_from_char(char component) {
+    switch (component) {
+        case 'r':
+           return GR_GL_RED;
+        case 'g':
+           return GR_GL_GREEN;
+        case 'b':
+           return GR_GL_BLUE;
+        case 'a':
+           return GR_GL_ALPHA;
+        default:
+            SkFAIL("Unsupported component");
+            return 0;
     }
 }
 
+/** If texture swizzling is available using tex parameters then it is preferred over mangling
+  the generated shader code. This potentially allows greater reuse of cached shaders. */
+static void get_tex_param_swizzle(GrPixelConfig config,
+                                  const GrGLSLCaps& caps,
+                                  GrGLenum* glSwizzle) {
+    const char* swizzle = caps.getSwizzleMap(config);
+    for (int i = 0; i < 4; ++i) {
+        glSwizzle[i] = get_component_enum_from_char(swizzle[i]);
+    }
+}
+
 void GrGLGpu::bindTexture(int unitIdx, const GrTextureParams& params, GrGLTexture* texture) {
     SkASSERT(texture);
 
 #ifdef SK_DEBUG
     if (!this->caps()->npotTextureTileSupport()) {
         const bool tileX = SkShader::kClamp_TileMode != params.getTileModeX();
         const bool tileY = SkShader::kClamp_TileMode != params.getTileModeY();
         if (tileX || tileY) {
             const int w = texture->width();
             const int h = texture->height();
@@ skipping 45 matching lines @@
     newTexParams.fMagFilter = glMagFilterModes[filterMode];
 
     if (GrTextureParams::kMipMap_FilterMode == filterMode &&
         texture->texturePriv().mipMapsAreDirty()) {
         GL_CALL(GenerateMipmap(target));
         texture->texturePriv().dirtyMipMaps(false);
     }
 
     newTexParams.fWrapS = tile_to_gl_wrap(params.getTileModeX());
     newTexParams.fWrapT = tile_to_gl_wrap(params.getTileModeY());
-    memcpy(newTexParams.fSwizzleRGBA,
-           GetTexParamSwizzle(texture->config(), this->glCaps()),
-           sizeof(newTexParams.fSwizzleRGBA));
+    get_tex_param_swizzle(texture->config(), *this->glCaps().glslCaps(), newTexParams.fSwizzleRGBA);
     if (setAll || newTexParams.fMagFilter != oldTexParams.fMagFilter) {
         this->setTextureUnit(unitIdx);
         GL_CALL(TexParameteri(target, GR_GL_TEXTURE_MAG_FILTER, newTexParams.fMagFilter));
     }
     if (setAll || newTexParams.fMinFilter != oldTexParams.fMinFilter) {
         this->setTextureUnit(unitIdx);
         GL_CALL(TexParameteri(target, GR_GL_TEXTURE_MIN_FILTER, newTexParams.fMinFilter));
     }
     if (setAll || newTexParams.fWrapS != oldTexParams.fWrapS) {
         this->setTextureUnit(unitIdx);
         GL_CALL(TexParameteri(target, GR_GL_TEXTURE_WRAP_S, newTexParams.fWrapS));
     }
     if (setAll || newTexParams.fWrapT != oldTexParams.fWrapT) {
         this->setTextureUnit(unitIdx);
         GL_CALL(TexParameteri(target, GR_GL_TEXTURE_WRAP_T, newTexParams.fWrapT));
     }
-    if (this->glCaps().textureSwizzleSupport() &&
+    if (!this->glCaps().glslCaps()->mustSwizzleInShader() &&
         (setAll || memcmp(newTexParams.fSwizzleRGBA,
                           oldTexParams.fSwizzleRGBA,
                           sizeof(newTexParams.fSwizzleRGBA)))) {
         this->setTextureUnit(unitIdx);
         if (this->glStandard() == kGLES_GrGLStandard) {
             // ES3 added swizzle support but not GL_TEXTURE_SWIZZLE_RGBA.
             const GrGLenum* swizzle = newTexParams.fSwizzleRGBA;
             GL_CALL(TexParameteri(target, GR_GL_TEXTURE_SWIZZLE_R, swizzle[0]));
             GL_CALL(TexParameteri(target, GR_GL_TEXTURE_SWIZZLE_G, swizzle[1]));
             GL_CALL(TexParameteri(target, GR_GL_TEXTURE_SWIZZLE_B, swizzle[2]));
@@ skipping 801 matching lines @@
             this->setVertexArrayID(gpu, 0);
         }
         int attrCount = gpu->glCaps().maxVertexAttributes();
         if (fDefaultVertexArrayAttribState.count() != attrCount) {
             fDefaultVertexArrayAttribState.resize(attrCount);
         }
         attribState = &fDefaultVertexArrayAttribState;
     }
     return attribState;
 }