Create swizzle table inside of glsl caps

BUG=skia:

Review URL: https://codereview.chromium.org/1420033005

1 files changed, 6 insertions, 19 deletions

diff --git a/src/gpu/gl/GrGLProgramDesc.cpp b/src/gpu/gl/GrGLProgramDesc.cpp
index a232a63514..8ff25575c6 100644
--- a/src/gpu/gl/GrGLProgramDesc.cpp
+++ b/src/gpu/gl/GrGLProgramDesc.cpp
@@ -18,26 +18,14 @@
  * present in the texture's config. swizzleComponentMask indicates the channels present in the
  * shader swizzle.
  */
-static bool swizzle_requires_alpha_remapping(const GrGLCaps& caps,
-                                             uint32_t configComponentMask,
-                                             uint32_t swizzleComponentMask) {
-    if (caps.textureSwizzleSupport()) {
+static bool swizzle_requires_alpha_remapping(const GrGLSLCaps& caps, GrPixelConfig config) {
+    if (!caps.mustSwizzleInShader()) {
         // Any remapping is handled using texture swizzling not shader modifications.
         return false;
     }
-    // check if the texture is alpha-only
-    if (kA_GrColorComponentFlag == configComponentMask) {
-        if (caps.textureRedSupport() && (kA_GrColorComponentFlag & swizzleComponentMask)) {
-            // we must map the swizzle 'a's to 'r'.
-            return true;
-        }
-        if (kRGB_GrColorComponentFlags & swizzleComponentMask) {
-            // The 'r', 'g', and/or 'b's must be mapped to 'a' according to our semantics that
-            // alpha-only textures smear alpha across all four channels when read.
-            return true;
-        }
-    }
-    return false;
+    const char* swizzleMap = caps.getSwizzleMap(config);
+    
+    return SkToBool(memcmp(swizzleMap, "rgba", 4));
 }
 
 static uint32_t gen_texture_key(const GrProcessor& proc, const GrGLCaps& caps) {
@@ -45,8 +33,7 @@ static uint32_t gen_texture_key(const GrProcessor& proc, const GrGLCaps& caps) {
     int numTextures = proc.numTextures();
     for (int t = 0; t < numTextures; ++t) {
         const GrTextureAccess& access = proc.textureAccess(t);
-        uint32_t configComponentMask = GrPixelConfigComponentMask(access.getTexture()->config());
-        if (swizzle_requires_alpha_remapping(caps, configComponentMask, access.swizzleMask())) {
+        if (swizzle_requires_alpha_remapping(*caps.glslCaps(), access.getTexture()->config())) {
             key |= 1 << t;
         }
     }