Clears the pixel and/or depth buffers.
buffer - [Unsigned Integer]
Following values are used to clear different buffers:
0 : Both Buffers
1 : Pixel Buffer
2 : Depth Buffer
Success - [Boolean]
Returns 0/false if an error is detected, else returns 1/true.
This will reset the buffer to their initial state. The pixel buffer will be filled will whatever colour is set in clearColor, and the depth buffer will be set to the furtherest rendering point. If no number is provided, then it is assumed to be 0 and both buffer are cleared.