Only discard the storage texture when there is a mismatch with its mipmap chain

src/libGLESv2/Texture.cpp

@@ -1311,6 +1311,11 @@ int TextureStorage::getLodOffset() const
     return mLodOffset;
 }
 
+int TextureStorage::levelCount()
+{
+    return getBaseTexture() ? getBaseTexture()->GetLevelCount() - getLodOffset() : 0;
+}
+
 Texture::Texture(GLuint id) : RefCountObject(id)
 {
     mMinFilter = GL_NEAREST_MIPMAP_LINEAR;
@@ -1798,9 +1803,21 @@ void Texture2D::redefineImage(GLint level, GLint internalformat, GLsizei width,
 {
     releaseTexImage();
 
-    bool redefined = mImageArray[level].redefine(internalformat, width, height, false);
+    // If there currently is a corresponding storage texture image, it has these parameters
+    const int storageWidth = std::max(1, mImageArray[0].getWidth() >> level);
+    const int storageHeight = std::max(1, mImageArray[0].getHeight() >> level);
+    const int storageFormat = mImageArray[0].getInternalFormat();
+
+     mImageArray[level].redefine(internalformat, width, height, false);
+
+    if (mTexStorage)
+    {
+        const int storageLevels = mTexStorage->levelCount();
         
-    if (mTexStorage && redefined)
+        if ((level >= storageLevels && storageLevels != 0) ||
+            width != storageWidth ||
+            height != storageHeight ||
+            internalformat != storageFormat)   // Discard mismatched storage
         {
             for (int i = 0; i < IMPLEMENTATION_MAX_TEXTURE_LEVELS; i++)
             {
@@ -1811,6 +1828,7 @@ void Texture2D::redefineImage(GLint level, GLint internalformat, GLsizei width,
             mTexStorage = NULL;
             mDirtyImages = true;
         }
+    }
 }
 
 void Texture2D::setImage(GLint level, GLsizei width, GLsizei height, GLenum format, GLenum type, GLint unpackAlignment, const void *pixels)
@@ -2821,9 +2839,21 @@ unsigned int TextureCubeMap::faceIndex(GLenum face)
 
 void TextureCubeMap::redefineImage(int face, GLint level, GLint internalformat, GLsizei width, GLsizei height)
 {
-    bool redefined = mImageArray[face][level].redefine(internalformat, width, height, false);
+    // If there currently is a corresponding storage texture image, it has these parameters
+    const int storageWidth = std::max(1, mImageArray[0][0].getWidth() >> level);
+    const int storageHeight = std::max(1, mImageArray[0][0].getHeight() >> level);
+    const int storageFormat = mImageArray[0][0].getInternalFormat();
 
-    if (mTexStorage && redefined)
+    mImageArray[face][level].redefine(internalformat, width, height, false);
+
+    if (mTexStorage)
+    {
+        const int storageLevels = mTexStorage->levelCount();
+
+        if ((level >= storageLevels && storageLevels != 0) ||
+            width != storageWidth ||
+            height != storageHeight ||
+            internalformat != storageFormat)   // Discard mismatched storage
         {
             for (int i = 0; i < IMPLEMENTATION_MAX_TEXTURE_LEVELS; i++)
             {
@@ -2838,6 +2868,7 @@ void TextureCubeMap::redefineImage(int face, GLint level, GLint internalformat,
 
             mDirtyImages = true;
         }
+    }
 }
 
 void TextureCubeMap::copyImage(GLenum target, GLint level, GLenum format, GLint x, GLint y, GLsizei width, GLsizei height, Framebuffer *source)

src/libGLESv2/Texture.h

 //
-// Copyright (c) 2002-2012 The ANGLE Project Authors. All rights reserved.
+// Copyright (c) 2002-2013 The ANGLE Project Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 //
@@ -147,8 +147,10 @@ class TextureStorage
     D3DPOOL getPool() const;
     DWORD getUsage() const;
     unsigned int getTextureSerial() const;
+    virtual IDirect3DBaseTexture9 *getBaseTexture() const = 0;
     virtual unsigned int getRenderTargetSerial(GLenum target) const = 0;
     int getLodOffset() const;
+    int levelCount();
 
   protected:
     int mLodOffset;
@@ -258,7 +260,7 @@ class TextureStorage2D : public TextureStorage
     virtual ~TextureStorage2D();
 
     IDirect3DSurface9 *getSurfaceLevel(int level, bool dirty);
-    IDirect3DBaseTexture9 *getBaseTexture() const;
+    virtual IDirect3DBaseTexture9 *getBaseTexture() const;
 
     virtual unsigned int getRenderTargetSerial(GLenum target) const;
 
@@ -345,7 +347,7 @@ class TextureStorageCubeMap : public TextureStorage
     virtual ~TextureStorageCubeMap();
 
     IDirect3DSurface9 *getCubeMapSurface(GLenum faceTarget, int level, bool dirty);
-    IDirect3DBaseTexture9 *getBaseTexture() const;
+    virtual IDirect3DBaseTexture9 *getBaseTexture() const;
 
     virtual unsigned int getRenderTargetSerial(GLenum target) const;