Use vertex array objects on core profiles.

src/gpu/gl/GrGLVertexArray.h

Index: src/gpu/gl/GrGLVertexArray.h
===================================================================
--- src/gpu/gl/GrGLVertexArray.h	(revision 0)
+++ src/gpu/gl/GrGLVertexArray.h	(revision 0)
@@ -0,0 +1,144 @@
+/*
+ * Copyright 2013 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifndef GrGLVertexArray_DEFINED
+#define GrGLVertexArray_DEFINED
+
+#include "GrResource.h"
+#include "gl/GrGLFunctions.h"
+
+#include "SkTArray.h"
+
+class GrGLVertexBuffer;
+class GrGLIndexBuffer;
+class GrGpuGL;
+
+/**
+ * This sets and tracks the vertex attribute array state. It is used internally by GrGLVertexArray
+ * (below) but is separate because it is also used to track the state of vertex array object 0.
+ */
+class GrGLAttribArrayState {
+public:
+    explicit GrGLAttribArrayState(int arrayCount = 0) { this->resize(arrayCount); }
+
+    void resize(int newCount) {
+        fAttribArrays.resize_back(newCount);
+        for (int i = 0; i < newCount; ++i) {
+            fAttribArrays[i].invalidate();
+        }
+    }
+
+    /**
+     * This function enables and sets vertex attrib state for the specified attrib index. It is
+     * assumed that the GrGLAttribArrayState is tracking the state of the currently bound vertex
+     * array object.
+     */
+    void set(const GrGpuGL*,
+             int index,
+             GrGLVertexBuffer*,
+             GrGLint size,
+             GrGLenum type,
+             GrGLboolean normalized,
+             GrGLsizei stride,
+             GrGLvoid* offset);
+
+    /**
+     * This function disables vertex attribs not present in the mask. It is assumed that the
+     * GrGLAttribArrayState is tracking the state of the currently bound vertex array object.
+     */
+    void disableUnusedAttribArrays(const GrGpuGL*, uint64_t usedAttribArrayMask);
+
+    void invalidate() {
+        int count = fAttribArrays.count();
+        for (int i = 0; i < count; ++i) {
+            fAttribArrays[i].invalidate();
+        }
+    }
+
+    void notifyVertexBufferDelete(GrGLuint id) {
+        int count = fAttribArrays.count();
+        for (int i = 0; i < count; ++i) {
+            if (id == fAttribArrays[i].fVertexBufferID) {
+                fAttribArrays[i].invalidate();
+            }
+        }
+    }
+
+    /**
+     * The number of attrib arrays that this object is configured to track.
+     */
+    int count() const { return fAttribArrays.count(); }
+
+private:
+    struct AttribArray {

[jvanverth1, 2013/03/06 17:50:12]

I think this struct name is confusing -- isn't it an array element (an Attrib?)
more than an array?

[bsalomon, 2013/03/06 18:31:07]

Hmm... I get what you mean. It isn't a C array but it does hold the state of a
GL attribute array set by glVertexAttribArray.  Does making it not end in Array
make it clearer? e.g. AttribArrayState.

[robertphillips, 2013/03/06 21:00:16]

I think that is clearer (AttribArrayState that is) - and perhaps a comment?

[bsalomon, 2013/03/06 21:32:53]

Done.

+            void invalidate() {
+                fEnableIsValid = false;
+                fAttribPointerIsValid = false;
+            }
+
+            bool        fEnableIsValid;
+            bool        fAttribPointerIsValid;
+            bool        fEnabled;
+            GrGLuint    fVertexBufferID;
+            GrGLint     fSize;
+            GrGLenum    fType;
+            GrGLboolean fNormalized;
+            GrGLsizei   fStride;
+            GrGLvoid*   fOffset;
+    };
+
+    SkSTArray<16, AttribArray, true> fAttribArrays;
+};
+
+/**
+ * This class represents an OpenGL vertex array object. It manages the lifetime of the vertex array
+ * and is used to track the state of the vertex array to avoid redundant GL calls.
+ */
+class GrGLVertexArray : public GrResource {
+public:
+    GrGLVertexArray(GrGpuGL* gpu, GrGLint id, int attribCount);
+
+    /**
+     * Binds this vertex array. If the ID has been deleted or abandoned then NULL is returned.
+     * Otherwise, the GrGLAttribArrayState that is tracking this vertex array's attrib bindings is
+     * returned.
+     */
+    GrGLAttribArrayState* bind();
+
+    /**
+     * This is a version of the above function that also binds an index buffer to the vertex
+     * array object.
+     */
+    GrGLAttribArrayState* bindWithIndexBuffer(const GrGLIndexBuffer* indexBuffer);
+
+    void notifyIndexBufferDelete(GrGLuint bufferID);
+
+    void notifyVertexBufferDelete(GrGLuint id) {
+        fAttribArrays.notifyVertexBufferDelete(id);
+    }
+
+    GrGLuint arrayID() const { return fID; }
+
+    void invalidateCachedState();
+
+    virtual size_t sizeInBytes() const SK_OVERRIDE { return 0; }
+
+protected:
+    virtual void onAbandon() SK_OVERRIDE;
+
+    virtual void onRelease() SK_OVERRIDE;
+
+private:
+    GrGLuint                fID;
+    GrGLAttribArrayState    fAttribArrays;
+    GrGLuint                fIndexBufferID;
+    bool                    fIndexBufferIDIsValid;
+
+    typedef GrResource INHERITED;
+};
+
+#endif