GLSL Version : >= 150
Purpose:
Allow users to use features by enabling this extension, even in low versions.
Extension Name:
ARB_gpu_shader_fp64
Builtin-variables:
Nah
Builtin-functions:
functions overloaded for this extension, please check registry in reference.
Keywords:
Double
Features:
add support for type "double"
Reference:
https://www.khronos.org/registry/OpenGL/extensions/ARB/ARB_gpu_shader_fp64.txt
Add support for implicit conversion
1. Remove builtin double vertex (this is introduced by vertex_attrib_64bit
2. Add extension check and implicit conversion as double has been introduced
3. Add test results.
The order of error checking was not quite being correct (maybe there is no correct
ordering, when many checks must be done and they affect each other).
So, check for block-name reuse twice.
