Set GL_PACK_ALIGNMENT before calling glReadPixels

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 630 matching lines @@
     }
 
     if (success) {
         glTex->texturePriv().dirtyMipMaps(true);
         return true;
     }
 
     return false;
 }
 
+// For GL_[UN]PACK_ALIGNMENT.
+static inline GrGLint config_alignment(GrPixelConfig config) {
+    SkASSERT(!GrPixelConfigIsCompressed(config));
+    switch (config) {
+        case kAlpha_8_GrPixelConfig:
+            return 1;
+        case kRGB_565_GrPixelConfig:
+        case kRGBA_4444_GrPixelConfig:
+        case kAlpha_half_GrPixelConfig:
+        case kRGBA_half_GrPixelConfig:
+            return 2;
+        case kRGBA_8888_GrPixelConfig:
+        case kBGRA_8888_GrPixelConfig:
+        case kSRGBA_8888_GrPixelConfig:
+        case kRGBA_float_GrPixelConfig:
+            return 4;
+        default:
+            return 0;
+    }
+}
+
 static inline GrGLenum check_alloc_error(const GrSurfaceDesc& desc,
                                          const GrGLInterface* interface) {
     if (SkToBool(desc.fFlags & kCheckAllocation_GrSurfaceFlag)) {
         return GR_GL_GET_ERROR(interface);
     } else {
         return CHECK_ALLOC_ERROR(interface);
     }
 }
 
 bool GrGLGpu::uploadTexData(const GrSurfaceDesc& desc,
@@ skipping 100 matching lines @@
                     }
                     dst += trimRowBytes;
                 }
                 // now point data to our copied version
                 data = tempStorage.get();
             }
         }
         if (glFlipY) {
             GL_CALL(PixelStorei(GR_GL_UNPACK_FLIP_Y, GR_GL_TRUE));
         }
-        GL_CALL(PixelStorei(GR_GL_UNPACK_ALIGNMENT,
-              static_cast<GrGLint>(GrUnpackAlignment(dataConfig))));
+        GL_CALL(PixelStorei(GR_GL_UNPACK_ALIGNMENT, config_alignment(dataConfig)));
     }
     bool succeeded = true;
     if (isNewTexture &&
         0 == left && 0 == top &&
         desc.fWidth == width && desc.fHeight == height) {
         CLEAR_ERROR_BEFORE_ALLOC(this->glInterface());
         if (useTexStorage) {
             // We never resize  or change formats of textures.
             GL_ALLOC_CALL(this->glInterface(),
                           TexStorage2D(target,
@@ skipping 1291 matching lines @@
                                 static_cast<GrGLint>(rowBytes / sizeof(GrColor))));
             readDstRowBytes = rowBytes;
         } else {
             scratch.reset(tightRowBytes * height);
             readDst = scratch.get();
         }
     }
     if (flipY && this->glCaps().packFlipYSupport()) {
         GL_CALL(PixelStorei(GR_GL_PACK_REVERSE_ROW_ORDER, 1));
     }
+    GL_CALL(PixelStorei(GR_GL_PACK_ALIGNMENT, config_alignment(config)));
+
     GL_CALL(ReadPixels(readRect.fLeft, readRect.fBottom,
                        readRect.fWidth, readRect.fHeight,
                        format, type, readDst));
     if (readDstRowBytes != tightRowBytes) {
         SkASSERT(this->glCaps().packRowLengthSupport());
         GL_CALL(PixelStorei(GR_GL_PACK_ROW_LENGTH, 0));
     }
     if (flipY && this->glCaps().packFlipYSupport()) {
         GL_CALL(PixelStorei(GR_GL_PACK_REVERSE_ROW_ORDER, 0));
         flipY = false;
@@ skipping 1533 matching lines @@
             this->setVertexArrayID(gpu, 0);
         }
         int attrCount = gpu->glCaps().maxVertexAttributes();
         if (fDefaultVertexArrayAttribState.count() != attrCount) {
             fDefaultVertexArrayAttribState.resize(attrCount);
         }
         attribState = &fDefaultVertexArrayAttribState;
     }
     return attribState;
 }