GLES2: Get sin/cos out of vertex shader
The only place angle is activated and causes effect is RenderCopyEx. All other
methods which use vertex shader, leave angle disabled and cause useless sin/cos
calculation in shader.
To get around shader's interface is changed to a vector that contains results
of sin and cos. To behave properly when disabled, cos value is set with offset
-1.0 making 0.0 default when deactivated.
As nice side effect it simplifies GLES2_UpdateVertexBuffer: All attributes are
vectors now.
Additional background:
* On RaspberryPi it gives a performace win for operations. Tested with
[1] numbers go down for 5-10% (not easy to estimate due to huge variation).
* SDL_RenderCopyEx was tested with [2]
* It works around left rotated display caused by low accuracy sin implemetation
in RaspberryPi/VC4 [3]
[1] https://github.com/schnitzeltony/sdl2box
[2] https://github.com/schnitzeltony/sdl2rendercopyex
[3] https://github.com/anholt/mesa/issues/110
Signed-off-by: Andreas Müller <schnitzeltony@gmail.com>
2 files changed
