tree 4ae936ca5f5150b22a29b0be632be95354bbb749
parent 9fe7e16399aa9739b63ce9add1d04fd8ef00678f
author Romain Guy <romainguy@google.com> 1486495265 -0800
committer Romain Guy <romainguy@google.com> 1486506634 +0000

Apply transfer function when rendering with linear textures

RGBA16F bitmaps are always encoded in linear space, which means we must
apply the opto-electronic transfer function before we can render them
in the framebuffer.

Since our linear bitmaps are assumed to be scRGB, values can be negative.
The OETF is a slightly modified sRGB OETF:

sign(x) * OETF_sRGB(abs(x))

This effectively mirrors the OETF over the negative domain.

This CL also removes the "optimized" shader generation path. With
current compilers, the optimized path doesn't do anything of value
and makes ProgramCache difficult to maintain. Shader compilers inline
everything and are really good at folding expressions and removing
unused code.

Bug: 32984164
Test: CtsUiRenderingTestCases
Change-Id: Ieb458ad53574e3a8959aa6bccbbd2d1fe203cbc5