GL_NV_viewport_swizzle
https://www.khronos.org/registry/OpenGL/extensions/NV/NV_viewport_swizzle.txt
GL_NV_viewport_swizzle

	GL_VIEWPORT_SWIZZLE_POSITIVE_X_NV 0x9350
	GL_VIEWPORT_SWIZZLE_NEGATIVE_X_NV 0x9351
	GL_VIEWPORT_SWIZZLE_POSITIVE_Y_NV 0x9352
	GL_VIEWPORT_SWIZZLE_NEGATIVE_Y_NV 0x9353
	GL_VIEWPORT_SWIZZLE_POSITIVE_Z_NV 0x9354
	GL_VIEWPORT_SWIZZLE_NEGATIVE_Z_NV 0x9355
	GL_VIEWPORT_SWIZZLE_POSITIVE_W_NV 0x9356
	GL_VIEWPORT_SWIZZLE_NEGATIVE_W_NV 0x9357
	GL_VIEWPORT_SWIZZLE_X_NV 0x9358
	GL_VIEWPORT_SWIZZLE_Y_NV 0x9359
	GL_VIEWPORT_SWIZZLE_Z_NV 0x935A
	GL_VIEWPORT_SWIZZLE_W_NV 0x935B
	void glViewportSwizzleNV (GLuint index, GLenum swizzlex, GLenum swizzley, GLenum swizzlez, GLenum swizzlew)