Start the process of choosing the correct compression format

R=robertphillips@google.com

Author: krajcevski@google.com

Review URL: https://codereview.chromium.org/427093004

src/gpu/GrSWMaskHelper.cpp

@@ -50,6 +50,37 @@ static inline GrPixelConfig fmt_to_config(SkTextureCompressor::Format fmt) {
     return configMap[fmt];
 }
 
+#if GR_COMPRESS_ALPHA_MASK
+static bool choose_compressed_fmt(const GrDrawTargetCaps* caps,
+                                  SkTextureCompressor::Format *fmt) {
+    if (NULL == fmt) {
+        return false;
+    }
+
+    // We can't use scratch textures without the ability to update
+    // compressed textures...
+    if (!(caps->compressedTexSubImageSupport())) {
+        return false;
+    }
+
+    // Figure out what our preferred texture type is. If ASTC is available, that always
+    // gives the biggest win. Otherwise, in terms of compression speed and accuracy,
+    // LATC has a slight edge over R11 EAC.
+    if (caps->isConfigTexturable(kASTC_12x12_GrPixelConfig)) {
+        *fmt = SkTextureCompressor::kASTC_12x12_Format;
+        return true;
+    } else if (caps->isConfigTexturable(kLATC_GrPixelConfig)) {
+        *fmt = SkTextureCompressor::kLATC_Format;
+        return true;
+    } else if (caps->isConfigTexturable(kR11_EAC_GrPixelConfig)) {
+        *fmt = SkTextureCompressor::kR11_EAC_Format;
+        return true;
+    }
+
+    return false;
+}
+#endif
+
 }
 
 /**
@@ -117,18 +148,23 @@ bool GrSWMaskHelper::init(const SkIRect& resultBounds,
                                      resultBounds.height());
 
 #if GR_COMPRESS_ALPHA_MASK
-    fCompressedFormat = SkTextureCompressor::kR11_EAC_Format;
+    fCompressMask = choose_compressed_fmt(fContext->getGpu()->caps(), &fCompressedFormat);
+#else
+    fCompressMask = false;
+#endif
 
     // Make sure that the width is a multiple of 16 so that we can use
     // specialized SIMD instructions that compress 4 blocks at a time.
+    int cmpWidth, cmpHeight;
+    if (fCompressMask) {
         int dimX, dimY;
         SkTextureCompressor::GetBlockDimensions(fCompressedFormat, &dimX, &dimY);
-    const int cmpWidth = dimX * ((bounds.fRight + (dimX - 1)) / dimX);
+        cmpWidth = dimX * ((bounds.fRight + (dimX - 1)) / dimX);
-    const int cmpHeight = dimY * ((bounds.fBottom + (dimY - 1)) / dimY);
+        cmpHeight = dimY * ((bounds.fBottom + (dimY - 1)) / dimY);
-#else
+    } else {
-    const int cmpWidth = bounds.fRight;
+        cmpWidth = bounds.fRight;
-    const int cmpHeight = bounds.fBottom;
+        cmpHeight = bounds.fBottom;
-#endif
+    }
 
     if (!fBM.allocPixels(SkImageInfo::MakeA8(cmpWidth, cmpHeight))) {
         return false;
@@ -153,8 +189,9 @@ bool GrSWMaskHelper::getTexture(GrAutoScratchTexture* texture) {
     GrTextureDesc desc;
     desc.fWidth = fBM.width();
     desc.fHeight = fBM.height();
+    desc.fConfig = kAlpha_8_GrPixelConfig;
 
-#if GR_COMPRESS_ALPHA_MASK
+    if (fCompressMask) {
 
 #ifdef SK_DEBUG
         int dimX, dimY;
@@ -167,11 +204,10 @@ bool GrSWMaskHelper::getTexture(GrAutoScratchTexture* texture) {
 
         // If this config isn't supported then we should fall back to A8
         if (!(fContext->getGpu()->caps()->isConfigTexturable(desc.fConfig))) {
+            SkDEBUGFAIL("Determining compression should be set from choose_compressed_fmt");
             desc.fConfig = kAlpha_8_GrPixelConfig;
         }
-#else
+    }
-    desc.fConfig = kAlpha_8_GrPixelConfig;
-#endif
 
     texture->set(fContext, desc);
     return NULL != texture->texture();
@@ -195,23 +231,9 @@ void GrSWMaskHelper::sendTextureData(GrTexture *texture, const GrTextureDesc& de
 void GrSWMaskHelper::compressTextureData(GrTexture *texture, const GrTextureDesc& desc) {
 
     SkASSERT(GrPixelConfigIsCompressed(desc.fConfig));
+    SkASSERT(fmt_to_config(fCompressedFormat) == desc.fConfig);
 
-    SkTextureCompressor::Format format = SkTextureCompressor::kLATC_Format;
+    SkAutoDataUnref cmpData(SkTextureCompressor::CompressBitmapToFormat(fBM, fCompressedFormat));
-
-    // Choose the format required by the texture descriptor.
-    switch(desc.fConfig) {
-        case kLATC_GrPixelConfig:
-            format = SkTextureCompressor::kLATC_Format;
-            break;
-        case kR11_EAC_GrPixelConfig:
-            format = SkTextureCompressor::kR11_EAC_Format;
-            break;
-        default:
-            SkFAIL("Unrecognized texture compression format.");
-            break;
-    }
-
-    SkAutoDataUnref cmpData(SkTextureCompressor::CompressBitmapToFormat(fBM, format));
     SkASSERT(NULL != cmpData);
 
     this->sendTextureData(texture, desc, cmpData->data(), 0);
@@ -229,7 +251,7 @@ void GrSWMaskHelper::toTexture(GrTexture *texture) {
     desc.fConfig = texture->config();
         
     // First see if we should compress this texture before uploading.
-    if (GrPixelConfigIsCompressed(texture->config())) {
+    if (fCompressMask) {
         this->compressTextureData(texture, desc);
     } else {
         // Looks like we have to send a full A8 texture. 

src/gpu/GrSWMaskHelper.h

@@ -42,7 +42,7 @@ class GrDrawTarget;
 class GrSWMaskHelper : SkNoncopyable {
 public:
     GrSWMaskHelper(GrContext* context)
-    : fContext(context) {
+    : fContext(context), fCompressMask(false) {
     }
 
     // set up the internal state in preparation for draws. Since many masks
@@ -102,9 +102,13 @@ private:
     SkDraw          fDraw;
     SkRasterClip    fRasterClip;
 
-#if GR_COMPRESS_ALPHA_MASK
+    // This flag says whether or not we should compress the mask. If
+    // it is true, then fCompressedFormat is always valid.
+    bool                        fCompressMask;
+
+    // This is the desired format within which to compress the
+    // texture. This value is only valid if fCompressMask is true.
     SkTextureCompressor::Format fCompressedFormat;
-#endif
 
     // Actually sends the texture data to the GPU. This is called from
     // toTexture with the data filled in depending on the texture config.

src/gpu/gl/GrGLCaps.cpp

@@ -558,11 +558,10 @@ void GrGLCaps::initConfigTexturableTable(const GrGLContextInfo& ctxInfo, const G
     fConfigTextureSupport[kLATC_GrPixelConfig] = hasLATC;
     fLATCAlias = alias;
 
-    // Check for R11_EAC
+    // Check for R11_EAC ... We don't support R11_EAC on desktop, as most
-    if (kGL_GrGLStandard == standard) {
+    // cards default to decompressing the textures in the driver, and is
-        fConfigTextureSupport[kR11_EAC_GrPixelConfig] =
+    // generally slower.
-            version >= GR_GL_VER(4, 3) || ctxInfo.hasExtension("GL_ARB_ES3_compatibility");
+    if (kGL_GrGLStandard != standard) {
-    } else {
         fConfigTextureSupport[kR11_EAC_GrPixelConfig] = version >= GR_GL_VER(3, 0);
     }