Add support for reading non-rendertarget textures.

src/gpu/GrContext.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 "GrContext.h"
@@ skipping 1220 matching lines @@
                                     config, buffer, rowBytes);
 }
 
 bool GrContext::readTexturePixels(GrTexture* texture,
                                   int left, int top, int width, int height,
                                   GrPixelConfig config, void* buffer, size_t rowBytes,
                                   uint32_t flags) {
     SK_TRACE_EVENT0("GrContext::readTexturePixels");
     ASSERT_OWNED_RESOURCE(texture);
 
-    // TODO: code read pixels for textures that aren't also rendertargets
     GrRenderTarget* target = texture->asRenderTarget();
     if (NULL != target) {
         return this->readRenderTargetPixels(target,
                                             left, top, width, height,
                                             config, buffer, rowBytes,
                                             flags);
     } else {
+        // TODO: make this more efficient for cases where we're reading the entire
+        //       texture, i.e., use GetTexImage() instead
+
+        // create scratch rendertarget and read from that
+        GrAutoScratchTexture ast;
+        GrTextureDesc desc;
+        desc.fFlags = kRenderTarget_GrTextureFlagBit;
+        desc.fWidth = width;
+        desc.fHeight = height;
+        desc.fConfig = config;
+        desc.fOrigin = kTopLeft_GrSurfaceOrigin;
+        ast.set(this, desc, kExact_ScratchTexMatch);
+        GrTexture* dst = ast.texture();

[robertphillips, 2013/10/18 18:19:45]

NULL != dst

+        if (dst && NULL != (target = dst->asRenderTarget())) {
+            this->copyTexture(texture, target, NULL);
+            return this->readRenderTargetPixels(target,
+                                                left, top, width, height,
+                                                config, buffer, rowBytes,
+                                                flags);
+        }
+       
         return false;
     }
 }
 
 #include "SkConfig8888.h"
 
 namespace {
 /**
  * Converts a GrPixelConfig to a SkCanvas::Config8888. Only byte-per-channel
  * formats are representable as Config8888 and so the function returns false
@@ skipping 512 matching lines @@
         return NULL;
     }
 }
 
 ///////////////////////////////////////////////////////////////////////////////
 #if GR_CACHE_STATS
 void GrContext::printCacheStats() const {
     fTextureCache->printStats();
 }
 #endif