Implement GL_COMBINE.

Bug 21278131

Change-Id: If0cf8aa09b582e0252c4cedd73426764fd4dff53
Reviewed-on: https://swiftshader-review.googlesource.com/3232
Reviewed-by: Alexis Hétu <sugoi@google.com>
Reviewed-by: Nicolas Capens <capn@google.com>
Tested-by: Nicolas Capens <capn@google.com>
3 files changed