Implement texture environment src, operand, and color.

Change-Id: I8c683a783f0a7f8a82206de77ae9d139f4b1bb10
Reviewed-on: https://swiftshader-review.googlesource.com/3762
Reviewed-by: Nicolas Capens <capn@google.com>
Tested-by: Nicolas Capens <capn@google.com>
3 files changed