Added FORMAT_X32B32G32R32F as a renderable format

Added code to properly render to alphaless floating point formats.

Change-Id: I2e226fb787d8456f61a2946fb9c0d8a9dbb58243
Reviewed-on: https://swiftshader-review.googlesource.com/5128
Tested-by: Alexis Hétu <sugoi@google.com>
Reviewed-by: Nicolas Capens <capn@google.com>
diff --git a/src/OpenGL/common/Image.cpp b/src/OpenGL/common/Image.cpp
index cb8c76d..abdd9d4 100644
--- a/src/OpenGL/common/Image.cpp
+++ b/src/OpenGL/common/Image.cpp
@@ -650,6 +650,7 @@
 				return sw::FORMAT_G32R32F;
 			case GL_RGB:
 			case GL_RGB32F:
+				return sw::FORMAT_X32B32G32R32F;
 			case GL_RGBA:
 			case GL_RGBA32F:
 				return sw::FORMAT_A32B32G32R32F;