The OpenGL renderer has been revised, with the following changes:
- Initialization and rendering have been refactored to reduce the number of
redundant objects used.
- Framebuffer rotation is now done directly, using texture mapping.
- Vertex coordinates are now given in pixels, and the projection matrix
isn't hardcoded anymore.
Screen contents are now displayed using textured quads. This can be updated to expose an FBO once an OpenGL backend for when Pica rendering is being worked on. That FBO's texture can then be applied to the quads.
Previously, FBO blitting was used in order to display screen contents, which did not work on OS X. The new textured quad approach is less of a compatibility risk.
