Use nearest neighbor filtering for non-translated quads

cc/resource_provider.h

 // Copyright 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CC_RESOURCE_PROVIDER_H_
 #define CC_RESOURCE_PROVIDER_H_
 
 #include "base/basictypes.h"
 #include "base/hash_tables.h"
 #include "base/memory/scoped_ptr.h"
@@ skipping 114 matching lines @@
     // NOTE: if the syncPoint filed in TransferableResourceList is set, this
     // will wait on it.
     void receiveFromChild(int child, const TransferableResourceList&);
 
     // Receives resources from the parent, moving them from mailboxes. Resource IDs
     // passed are in the child namespace.
     // NOTE: if the syncPoint filed in TransferableResourceList is set, this
     // will wait on it.
     void receiveFromParent(const TransferableResourceList&);
 
+    // Bind the given GL resource to a texture target for sampling using the
+    // specified minification and magnification filters. The resource must be
+    // locked for reading.
+    void bindForSampling(ResourceProvider::ResourceId, GLenum target, GLenum minFilter = GL_LINEAR, GLenum magFilter = GL_LINEAR);

[jamesr, 2012/11/26 06:54:26]

chrome style forbids default parameter values. can you figure out a way to do
this that doesn't involve them?

[Sami, 2012/11/30 17:49:27]

Ah, I wasn't exactly sure what style guide we're following here. Let's have just
one filter instead of min/mag, so always passing the filter will be manageable.

+
     // The following lock classes are part of the ResourceProvider API and are
     // needed to read and write the resource contents. The user must ensure
     // that they only use GL locks on GL resources, etc, and this is enforced
     // by assertions.
     class CC_EXPORT ScopedReadLockGL {
     public:
         ScopedReadLockGL(ResourceProvider*, ResourceProvider::ResourceId);
         ~ScopedReadLockGL();
 
         unsigned textureId() const { return m_textureId; }
 
     private:
         ResourceProvider* m_resourceProvider;
         ResourceProvider::ResourceId m_resourceId;
         unsigned m_textureId;
 
         DISALLOW_COPY_AND_ASSIGN(ScopedReadLockGL);
     };
 
+    class CC_EXPORT ScopedSamplerGL : public ScopedReadLockGL {
+    public:
+        ScopedSamplerGL(ResourceProvider*, ResourceProvider::ResourceId, GLenum target, GLenum minFilter = GL_LINEAR, GLenum magFilter = GL_LINEAR);
+
+    private:
+        DISALLOW_COPY_AND_ASSIGN(ScopedSamplerGL);
+    };
+
     class CC_EXPORT ScopedWriteLockGL {
     public:
         ScopedWriteLockGL(ResourceProvider*, ResourceProvider::ResourceId);
         ~ScopedWriteLockGL();
 
         unsigned textureId() const { return m_textureId; }
 
     private:
         ResourceProvider* m_resourceProvider;
         ResourceProvider::ResourceId m_resourceId;
@@ skipping 29 matching lines @@
         ResourceProvider::ResourceId m_resourceId;
         SkBitmap m_skBitmap;
         scoped_ptr<SkCanvas> m_skCanvas;
 
         DISALLOW_COPY_AND_ASSIGN(ScopedWriteLockSoftware);
     };
 
 private:
     struct Resource {
         Resource();
-        Resource(unsigned textureId, int pool, const gfx::Size& size, GLenum format);
-        Resource(uint8_t* pixels, int pool, const gfx::Size& size, GLenum format);
+        Resource(unsigned textureId, int pool, const gfx::Size& size, GLenum format, GLenum minFilter, GLenum magFilter);
+        Resource(uint8_t* pixels, int pool, const gfx::Size& size, GLenum format, GLenum minFilter, GLenum magFilter);
 
         unsigned glId;
         Mailbox mailbox;
         uint8_t* pixels;
         int pool;
         int lockForReadCount;
         bool lockedForWrite;
         bool external;
         bool exported;
         bool markedForDeletion;
         gfx::Size size;
         GLenum format;
+        // TODO: Use a separate sampler object for filter state.

[jamesr, 2012/11/26 06:54:26]

not sure what this means.

in chromium style, TODOs have a name i.e. TODO(skyostil)

[Sami, 2012/11/30 17:49:27]

In more recent OpenGL versions the sampling state has been split out of the
texture object. This way you can more easily mix and match different sampling
scenarios and textures without having to poke at the texture object state. At
some point we might want to have the same separation, but for now I wanted to
keep them together.

+        GLenum minFilter;
+        GLenum magFilter;

[jamesr, 2012/11/26 06:54:26]

do we really need to support separate minification and magnification filters? in
this patch they always appear to be a matched set

[Sami, 2012/11/30 17:49:27]

For now we only need matching filters so I'll go with that.

         ResourceType type;
     };
     typedef base::hash_map<ResourceId, Resource> ResourceMap;
     struct Child {
         Child();
         ~Child();
 
         int pool;
         ResourceIdMap childToParentMap;
         ResourceIdMap parentToChildMap;
@@ skipping 27 matching lines @@
     int m_maxTextureSize;
 
     base::ThreadChecker m_threadChecker;
 
     DISALLOW_COPY_AND_ASSIGN(ResourceProvider);
 };
 
 }
 
 #endif  // CC_RESOURCE_PROVIDER_H_