'static const' means, there must be at most one of these, and initialize it at
compile time if possible or runtime if necessary. This leads to unexpected
code execution, and TSAN* will complain about races on the guard variables.
Generally 'constexpr' or 'const' are better choices. Neither can cause races:
they're either intialized at compile time (constexpr) or intialized each time
independently (const).
This CL prefers constexpr where possible, and uses const where not. It even
prefers constexpr over const where they don't make a difference... I want to have
lots of examples of constexpr for people to see and mimic.
The scoped-to-class static has nothing to do with any of this, and is not changed.
* Not yet on the bots, which use an older TSAN.
BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2300623005
Review-Url: https://codereview.chromium.org/2300623005
Uses textureSize() to unnormalize texture coords when reading from a RECTANGLE texture. Because of this we also require a later GLSL version to use rectangle textures (1.40).
Note that this causes a issue with the bicubic effect. The texture coords seem to have poor precision and the result is ugly. textureSize() is intended as a workaround until effects can be updated to handle unnormalized coords themselves.
Updates places where we were looking for OpenGL version 3.2 for rectangle support. It was actually added in 3.1.
BUG=skia:3868
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1594483003
Review URL: https://codereview.chromium.org/1594483003
