This option limits visibility of the glew.h header to just bf_gpu and intern_gawain

this is to highlight areas in the code that still directly do opengl calls or use
opengl types.

This is in preparation for supporting alternative rendering back-ends.

Reviewers: brecht, fclem

Differential Revision: https://developer.blender.org/D3304

CMakeLists.txt

@@ -458,11 +458,13 @@ endif()
 
 # OpenGL
 
+option(WITH_OPENGL              "When off limits visibility of the opengl headers to just bf_gpu and gawain (temporary option for development purposes)" ON)
 option(WITH_GLEW_ES             "Switches to experimental copy of GLEW that has support for OpenGL ES. (temporary option for development purposes)" OFF)
 option(WITH_GL_EGL              "Use the EGL OpenGL system library instead of the platform specific OpenGL system library (CGL, glX, or WGL)"       OFF)
 option(WITH_GL_PROFILE_ES20     "Support using OpenGL ES 2.0. (thru either EGL or the AGL/WGL/XGL 'es20' profile)"                                  OFF)
 
 mark_as_advanced(
+	WITH_OPENGL
 	WITH_GLEW_ES
 	WITH_GL_EGL
 	WITH_GL_PROFILE_ES20
@@ -1003,6 +1005,10 @@ endif()
 find_package(OpenGL)
 blender_include_dirs_sys("${OPENGL_INCLUDE_DIR}")
 
+if(WITH_OPENGL)
+	add_definitions(-DWITH_OPENGL)
+endif()
+
 if(WITH_SYSTEM_GLES)
 	find_package_wrapper(OpenGLES)
 endif()

intern/gawain/CMakeLists.txt

@@ -1,3 +1,10 @@
+# WITH_OPENGL limits the visibility of the opengl headers to just gawain and bg_gpu,
+# to more easily highlight codepadths in other libraries that need to be refactored, 
+# bf_intern_gawain is allowed to have opengl regardless of this option.
+
+if(NOT WITH_OPENGL)
+	add_definitions(-DWITH_OPENGL)
+endif()
 
 set(INC
 	gawain

intern/gawain/gawain/gwn_common.h

@@ -20,7 +20,10 @@
   #define TRUST_NO_ONE 1
 #endif
 
-#include <GL/glew.h>
+#if defined(WITH_OPENGL)
+  #include <GL/glew.h>
+#endif
+
 #include <stdbool.h>
 #include <stdint.h>
 

source/blender/gpu/CMakeLists.txt

@@ -23,6 +23,14 @@
 #
 # ***** END GPL LICENSE BLOCK *****
 
+# WITH_OPENGL limits the visibility of the opengl headers to just gawain and bg_gpu,
+# to more easily highlight codepadths in other libraries that need to be refactored, 
+# bf_gpu is allowed to have opengl regardless of this option.
+
+if(NOT WITH_OPENGL)
+	add_definitions(-DWITH_OPENGL)
+endif()
+
 set(INC
 	.
 	../blenkernel

source/blender/gpu/GPU_glew.h

@@ -32,10 +32,12 @@
 #ifndef __GPU_GLEW_H__
 #define __GPU_GLEW_H__
 
-#include "glew-mx.h"
+#if defined(WITH_OPENGL)
+	#include "glew-mx.h"
 
-#ifndef WITH_LEGACY_OPENGL
-#include "GPU_legacy_stubs.h"
+	#ifndef WITH_LEGACY_OPENGL
+		#include "GPU_legacy_stubs.h"
+	#endif
 #endif
 
 #endif /* __GPU_GLEW_H__ */