Axiom.RenderSystems.OpenGL.GLHardwareVertexBuffer.LockImpl C# (CSharp) Метод

		protected override IntPtr LockImpl( int offset, int length, BufferLocking locking )
		{
			int access = 0;

			if ( isLocked )
			{
				throw new Exception( "Invalid attempt to lock an index buffer that has already been locked." );
			}

			// bind this buffer
			Gl.glBindBufferARB( Gl.GL_ARRAY_BUFFER_ARB, bufferID );

			if ( locking == BufferLocking.Discard )
			{
				// fixes issues with ATI cards
				//Gl.glBufferDataARB(Gl.GL_ARRAY_BUFFER_ARB, length, IntPtr.Zero, GLHelper.ConvertEnum(usage));

				// find out how we shall access this buffer
				access = ( usage == BufferUsage.Dynamic ) ?
					Gl.GL_READ_WRITE_ARB : Gl.GL_WRITE_ONLY_ARB;
			}
			else if ( locking == BufferLocking.ReadOnly )
			{
				if ( usage == BufferUsage.WriteOnly )
				{
					LogManager.Instance.Write( "Invalid attempt to lock a write-only vertex buffer as read-only." );
				}

				access = Gl.GL_READ_ONLY_ARB;
			}
			else if ( locking == BufferLocking.Normal || locking == BufferLocking.NoOverwrite )
			{
				access = ( usage == BufferUsage.Dynamic ) ?
					Gl.GL_READ_WRITE_ARB : Gl.GL_WRITE_ONLY_ARB;
			}

			IntPtr ptr = Gl.glMapBufferARB( Gl.GL_ARRAY_BUFFER_ARB, access );

			if ( ptr == IntPtr.Zero )
			{
				throw new Exception( "GL Vertex Buffer: Out of memory" );
			}

			isLocked = true;

			return new IntPtr( ptr.ToInt64() + offset );
		}