RenderEngine API: add viewport draw utility functions to bind a GLSL fragment

shader for converting colors from linear to display space, based on the scene
color management settings.

if engine.support_display_space_shader(scene): # test graphics card support
	engine.bind_display_space_shader(scene)
	# draw pixels ..
	engine.unbind_display_space_shader()

5 files changed, 21 insertions, 5 deletions

diff --git a/intern/opencolorio/fallback_impl.cc b/intern/opencolorio/fallback_impl.cc
index 37f624e1f8b..9d6561fb4cb 100644
--- a/intern/opencolorio/fallback_impl.cc
+++ b/intern/opencolorio/fallback_impl.cc
@@ -381,6 +381,11 @@ void FallbackImpl::matrixTransformScale(float * , float * , const float *)
 {
 }
 
+bool FallbackImpl::supportGLSLDraw(void)
+{
+	return false;
+}
+
 bool FallbackImpl::setupGLSLDraw(struct OCIO_GLSLDrawState **state_r, OCIO_ConstProcessorRcPtr *processor, bool predivide)
 {
 	return false;
diff --git a/intern/opencolorio/ocio_capi.cc b/intern/opencolorio/ocio_capi.cc
index c8db2c2b531..49f8d2ca41e 100644
--- a/intern/opencolorio/ocio_capi.cc
+++ b/intern/opencolorio/ocio_capi.cc
@@ -283,6 +283,11 @@ void OCIO_matrixTransformScale(float * m44, float * offset4, const float *scale4
 	impl->matrixTransformScale(m44, offset4, scale4f);
 }
 
+int OCIO_supportGLSLDraw(void)
+{
+	return (int) impl->supportGLSLDraw();
+}
+
 int OCIO_setupGLSLDraw(struct OCIO_GLSLDrawState **state_r, OCIO_ConstProcessorRcPtr *processor, int predivide)
 {
 	return (int) impl->setupGLSLDraw(state_r, processor, (bool) predivide);
diff --git a/intern/opencolorio/ocio_capi.h b/intern/opencolorio/ocio_capi.h
index 3632a0da1c6..0b3102a290d 100644
--- a/intern/opencolorio/ocio_capi.h
+++ b/intern/opencolorio/ocio_capi.h
@@ -121,6 +121,7 @@ void OCIO_matrixTransformRelease(OCIO_MatrixTransformRcPtr *mt);
 
 void OCIO_matrixTransformScale(float * m44, float * offset4, const float * scale4);
 
+int OCIO_supportGLSLDraw(void);
 int OCIO_setupGLSLDraw(struct OCIO_GLSLDrawState **state_r, OCIO_ConstProcessorRcPtr *processor, int predivide);
 void OCIO_finishGLSLDraw(struct OCIO_GLSLDrawState *state);
 void OCIO_freeOGLState(struct OCIO_GLSLDrawState *state);
diff --git a/intern/opencolorio/ocio_impl.h b/intern/opencolorio/ocio_impl.h
index a328470ccb5..a1e743bf2f6 100644
--- a/intern/opencolorio/ocio_impl.h
+++ b/intern/opencolorio/ocio_impl.h
@@ -96,6 +96,7 @@ public:
 
 	virtual void matrixTransformScale(float * m44, float * offset4, const float * scale4) = 0;
 
+	virtual bool supportGLSLDraw(void) = 0;
 	virtual bool setupGLSLDraw(struct OCIO_GLSLDrawState **state_r, OCIO_ConstProcessorRcPtr *processor, bool predivide) = 0;
 	virtual void finishGLSLDraw(struct OCIO_GLSLDrawState *state) = 0;
 	virtual void freeGLState(struct OCIO_GLSLDrawState *state_r) = 0;
@@ -169,6 +170,7 @@ public:
 
 	void matrixTransformScale(float * m44, float * offset4, const float * scale4);
 
+	bool supportGLSLDraw(void);
 	bool setupGLSLDraw(struct OCIO_GLSLDrawState **state_r, OCIO_ConstProcessorRcPtr *processor, bool predivide);
 	void finishGLSLDraw(struct OCIO_GLSLDrawState *state);
 	void freeGLState(struct OCIO_GLSLDrawState *state_r);
@@ -243,6 +245,7 @@ public:
 
 	void matrixTransformScale(float * m44, float * offset4, const float * scale4);
 
+	bool supportGLSLDraw(void);
 	bool setupGLSLDraw(struct OCIO_GLSLDrawState **state_r, OCIO_ConstProcessorRcPtr *processor, bool predivide);
 	void finishGLSLDraw(struct OCIO_GLSLDrawState *state);
 	void freeGLState(struct OCIO_GLSLDrawState *state_r);
diff --git a/intern/opencolorio/ocio_impl_glsl.cc b/intern/opencolorio/ocio_impl_glsl.cc
index 54be1e0f339..1a3132fa4b3 100644
--- a/intern/opencolorio/ocio_impl_glsl.cc
+++ b/intern/opencolorio/ocio_impl_glsl.cc
@@ -36,12 +36,7 @@
 #include <sstream>
 #include <string.h>
 
-#ifdef __APPLE__
-#include <OpenGL/gl.h>
-#include <OpenGL/glu.h>
-#else
 #include <GL/glew.h>
-#endif
 
 #include <OpenColorIO/OpenColorIO.h>
 
@@ -202,6 +197,13 @@ static bool ensureLUT3DAllocated(OCIO_GLSLDrawState *state)
 	return state->lut3d_texture_valid;
 }
 
+/* Detect if we can support GLSL drawing */
+bool OCIOImpl::supportGLSLDraw()
+{
+	/* GLSL and GL_RGB16F_ARB */
+	return GLEW_VERSION_2_0 && (GLEW_VERSION_3_0 || GLEW_ARB_texture_float);
+}
+
 /**
  * Setup OpenGL contexts for a transform defined by processor using GLSL
  * All LUT allocating baking and shader compilation happens here.