initial OpenGL renderer implementation
stub fragment shader
small refactor
display something...
cut surface patch
simplify logic
add back software renderer functions that are not implemented yet
fix image format
try to fix texturing
do not cut image if not needed
try not use pointer
rewrite positioning
fix vertex shader
try to make things faster
try to implement frame buffer
enable rendering to buffer
fix rendering a little
replace 4 values with 1 vector
Merge branch 'master' into openGL
allow disabling framebuffer object
do not cut out image patches. For now it slows down rendering because we load whole surfaces to GPU
do not recreate textures each frame, store textures in openGL textures initially