There is supposedly an OpenGL ES2 target that does not support precision specifiers. However, the existing logic to detect this is currently broken in two ways:
1) There's a typo of the `#ifdef` as `#if`.
2) Checking for `GL_FRAGMENT_PRECISION_HIGH` can not be the correct way to detect this platform. Other targets, including some desktops, will also not have this defined (for various reasons).
Because some of the shader code is missing precision specifiers, and because a default is ONLY provided if `GL_FRAGMENT_PRECISION_HIGH` is set, these other targets break.
Instead of 'hard-coding' the prologue string into shaders in the C source, use our ability to provide a list of strings to `glShaderSource` instead, leaving the determination to run-time.
This commit closes https://github.com/libsdl-org/SDL/pull/6182
New functions get and set the YUV colorspace conversion mode:
SDL_SetYUVConversionMode()
SDL_GetYUVConversionMode()
SDL_GetYUVConversionModeForResolution()
SDL_ConvertPixels() converts between all supported RGB and YUV formats, with SSE acceleration for converting from planar YUV formats (YV12, NV12, etc) to common RGB/RGBA formats.
Added a new test program, testyuv, to verify correctness and speed of YUV conversion functionality.
The internal function SDL_EGL_LoadLibrary() did not delete and remove a mostly
uninitialized data structure if loading the library first failed. A later try to
use EGL then skipped initialization and assumed it was previously successful
because the data structure now already existed. This led to at least one crash
in the internal function SDL_EGL_ChooseConfig() because a NULL pointer was
dereferenced to make a call to eglBindAPI().
