Implements GetBufferParameteriv

TRAC #11720

Author:    Shannon Woods

git-svn-id: https://angleproject.googlecode.com/svn/trunk@151 736b8ea6-26fd-11df-bfd4-992fa37f6226

src/libGLESv2/Buffer.cpp

@@ -65,6 +65,8 @@ GLenum Buffer::bufferData(const void* data, GLsizeiptr size, GLenum usage)
         mContents.assign(newdata, newdata + size);
     }
 
+    mUsage = usage;
+
     return copyToIdentityBuffer(0, size);
 }
 

src/libGLESv2/Buffer.h

@@ -36,6 +36,7 @@ class Buffer
 
     void *data() { return &mContents[0]; }
     GLsizeiptr size() const { return mContents.size(); }
+    GLenum usage() const { return mUsage; }
 
     TranslatedVertexBuffer *identityBuffer() { return mIdentityTranslation; }
 
@@ -43,6 +44,7 @@ class Buffer
     DISALLOW_COPY_AND_ASSIGN(Buffer);
 
     std::vector<GLubyte> mContents;
+    GLenum mUsage;
 
     BufferBackEnd *mBackEnd;
     TranslatedVertexBuffer *mIdentityTranslation;

src/libGLESv2/libGLESv2.cpp

@@ -2031,7 +2031,40 @@ void __stdcall glGetBufferParameteriv(GLenum target, GLenum pname, GLint* params
 
     try
     {
-        UNIMPLEMENTED();   // FIXME
+        gl::Context *context = gl::getContext();
+
+        if (context)
+        {
+            gl::Buffer *buffer;
+
+            switch (target)
+            {
+              case GL_ARRAY_BUFFER:
+                buffer = context->getArrayBuffer();
+                break;
+              case GL_ELEMENT_ARRAY_BUFFER:
+                buffer = context->getElementArrayBuffer();
+                break;
+              default: return error(GL_INVALID_ENUM);
+            }
+
+            if (!buffer)
+            {
+                // A null buffer means that "0" is bound to the requested buffer target
+                return error(GL_INVALID_OPERATION);
+            }
+
+            switch (pname)
+            {
+              case GL_BUFFER_USAGE:
+                *params = buffer->usage();
+                break;
+              case GL_BUFFER_SIZE:
+                *params = buffer->size();
+                break;
+              default: return error(GL_INVALID_ENUM);
+            }
+        }
     }
     catch(std::bad_alloc&)
     {