Re-adding red texture support (by rolling back r3800)

http://code.google.com/p/skia/source/detail?r=3622 - for original review
http://crbug.com/125596 ('M20 windows renderer stability maze') - for issue



git-svn-id: http://skia.googlecode.com/svn/trunk@3802 2bbb7eff-a529-9590-31e7-b0007b416f81

1 files changed, 32 insertions, 12 deletions

diff --git a/src/gpu/gl/GrGpuGL.cpp b/src/gpu/gl/GrGpuGL.cpp
index 5f8772e6e5..3b5fffe7ef 100644
--- a/src/gpu/gl/GrGpuGL.cpp
+++ b/src/gpu/gl/GrGpuGL.cpp
@@ -322,7 +322,8 @@ void GrGpuGL::fillInConfigRenderableTable() {
         }
     } else {
         // On ES we can only hope for R8
-        fConfigRenderSupport[kAlpha_8_GrPixelConfig] = false;
+        fConfigRenderSupport[kAlpha_8_GrPixelConfig] = 
+                                this->glCaps().textureRedSupport();
     }
 
     if (kDesktop_GrGLBinding != this->glBinding()) {
@@ -2043,12 +2044,20 @@ unsigned gr_to_gl_filter(GrSamplerState::Filter filter) {
     }
 }
 
-const GrGLenum* get_swizzle(GrPixelConfig config,
-                            const GrSamplerState& sampler) {
+// get_swizzle is only called from this .cpp so it is OK to inline it here
+inline const GrGLenum* get_swizzle(GrPixelConfig config,
+                                   const GrSamplerState& sampler,
+                                   const GrGLCaps& glCaps) {
     if (GrPixelConfigIsAlphaOnly(config)) {
-        static const GrGLenum gAlphaSmear[] = { GR_GL_ALPHA, GR_GL_ALPHA,
-                                                GR_GL_ALPHA, GR_GL_ALPHA };
-        return gAlphaSmear;
+        if (glCaps.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 if (sampler.swapsRAndB()) {
         static const GrGLenum gRedBlueSwap[] = { GR_GL_BLUE, GR_GL_GREEN,
                                                  GR_GL_RED,  GR_GL_ALPHA };
@@ -2128,7 +2137,7 @@ bool GrGpuGL::flushGLStateCommon(GrPrimitiveType type) {
             newTexParams.fWrapS = wraps[sampler.getWrapX()];
             newTexParams.fWrapT = wraps[sampler.getWrapY()];
             memcpy(newTexParams.fSwizzleRGBA,
-                   get_swizzle(nextTexture->config(), sampler),
+                   get_swizzle(nextTexture->config(), sampler, this->glCaps()),
                    sizeof(newTexParams.fSwizzleRGBA));
             if (setAll || newTexParams.fFilter != oldTexParams.fFilter) {
                 setTextureUnit(s);
@@ -2370,14 +2379,25 @@ bool GrGpuGL::configToGLFormats(GrPixelConfig config,
             }
             break;
         case kAlpha_8_GrPixelConfig:
-            *internalFormat = GR_GL_ALPHA;
-            *externalFormat = GR_GL_ALPHA;
-            if (getSizedInternalFormat) {
-                *internalFormat = GR_GL_ALPHA8;
+            if (this->glCaps().textureRedSupport()) {
+                *internalFormat = GR_GL_RED;
+                *externalFormat = GR_GL_RED;
+                if (getSizedInternalFormat) {
+                    *internalFormat = GR_GL_R8;
+                } else {
+                    *internalFormat = GR_GL_RED;
+                }
+                *externalType = GR_GL_UNSIGNED_BYTE;
             } else {
                 *internalFormat = GR_GL_ALPHA;
+                *externalFormat = GR_GL_ALPHA;
+                if (getSizedInternalFormat) {
+                    *internalFormat = GR_GL_ALPHA8;
+                } else {
+                    *internalFormat = GR_GL_ALPHA;
+                }
+                *externalType = GR_GL_UNSIGNED_BYTE;
             }
-            *externalType = GR_GL_UNSIGNED_BYTE;
             break;
         default:
             return false;