Blender Git Loki

Cleanup: GPU: Make icon drawing use GPUTexture

This remove all gl function calls. Adds a new sampler only
for icon drawing.

GPUTexture: Add better swizzle support

GPU: Add immBindTexture and immBindTextureSampler

Cleanup: ClipDraw: Remove usage of GPU_SHADER_3D_IMAGE_MODULATE_ALPHA

Cleanup: PaintCursor: Use GPUTexture instead of opengl calls

Cleanup: GPUShader: Remove unused builtin shader

Cleanup: ClipDraw: Use GPUTexture api and fix a vmem leak

Leak was silent as it was an opengl handle.

Cleanup: glutil: Use GPUTexture in immDrawPixelsTexScaled_clipping

This also cleanup the code for readability.

Cleanup: WM: Use GPUTexture for radial control drawing

Cleanup: GPU: Set default GL_UNPACK_ALIGNMENT to 1

Ogl default is 4 but for almost all cases, blender use tightly
packed format. This avoid confusion and state change for the
common case.

The only case that __might__ need alignement is DDS loader
(untested) so leaving this as it is.

Cleanup: GPU: Wrap GL_UNPACK_ROW_LENGTH in GPU_state

Also go back to default value of 0 after usage.

Cleanup: Sequencer: Use GPUTexture instead of opengl calls

Cleanup: GPU: Encapsulate glViewport calls

Cleanup: GPU: Encapsulate glScissor

Cleanup: GPU: Encapsulate scissor test

Cleanup: View3D: Encapsulate OpenGL calls

Removes GL_DEPTH_RANGE query as it is not changed anywhere.

Cleanup: GPU: Encapsulate Backface culling

Cleanup: GPU: Encapsulate glFrontFace

Cleanup: GPU: Encapsulate glProvokingVertex

Cleanup: WM: Encapsulate stereo draw buffers binding