Colour Management

- 1st stage: Linear Workflow

This implements automatic linear workflow in Blender's renderer. With the 
new Colour Management option on in the Render buttons, all inputs to the 
renderer and compositor are converted to linear colour space before 
rendering, and gamma corrected afterwards. In essence, this makes all 
manual gamma correction with nodes, etc unnecessary, since it's done 
automatically through the pipeline.

It's all explained much better in the notes/doc here, so please have a look:
http://wiki.blender.org/index.php/Dev:Source/Blender/Architecture/Colour_Management

And an example of the sort of difference it makes:
http://mke3.net/blender/devel/rendering/b25_colormanagement_test01.jpg

This also enables Colour Management in the default B.blend, and changes the 
default lamp falloff to inverse square, which is more correct, and much 
easier to use now it's all gamma corrected properly.

Next step is to look into profiles/soft proofing for the compositor.

Thanks to brecht for reviewing and fixing some oversights!

2 files changed, 19 insertions, 11 deletions

diff --git a/source/blender/editors/space_image/image_draw.c b/source/blender/editors/space_image/image_draw.c
index e5d74e6dddd..da1f050cfd3 100644
--- a/source/blender/editors/space_image/image_draw.c
+++ b/source/blender/editors/space_image/image_draw.c
@@ -106,7 +106,7 @@ static int image_curves_active(SpaceImage *sima)
 	return 0;
 }
 
-static void image_verify_buffer_float(SpaceImage *sima, ImBuf *ibuf)
+static void image_verify_buffer_float(SpaceImage *sima, Image *ima, ImBuf *ibuf, int color_manage)
 {
 	/* detect if we need to redo the curve map.
 	   ibuf->rect is zero for compositor and render results after change 
@@ -121,6 +121,12 @@ static void image_verify_buffer_float(SpaceImage *sima, ImBuf *ibuf)
 				curvemapping_do_ibuf(sima->cumap, ibuf);
 			}
 			else {
+				if (color_manage) {
+						if (ima && ima->source == IMA_SRC_VIEWER)
+							ibuf->profile = IB_PROFILE_SRGB;
+				} else {
+					ibuf->profile = IB_PROFILE_NONE;
+				}
 				IMB_rect_from_float(ibuf);
 			}
 		}
@@ -371,9 +377,10 @@ static void sima_draw_zbuffloat_pixels(Scene *scene, float x1, float y1, int rec
 	MEM_freeN(rectf);
 }
 
-static void draw_image_buffer(SpaceImage *sima, ARegion *ar, Scene *scene, ImBuf *ibuf, float fx, float fy, float zoomx, float zoomy)
+static void draw_image_buffer(SpaceImage *sima, ARegion *ar, Scene *scene, Image *ima, ImBuf *ibuf, float fx, float fy, float zoomx, float zoomy)
 {
 	int x, y;
+	int color_manage = scene->r.color_mgt_flag & R_COLOR_MANAGEMENT;
 
 	/* set zoom */
 	glPixelZoom(zoomx, zoomy);
@@ -398,7 +405,7 @@ static void draw_image_buffer(SpaceImage *sima, ARegion *ar, Scene *scene, ImBuf
 	}
 #ifdef WITH_LCMS
 	else if(sima->flag & SI_COLOR_CORRECTION) {
-		image_verify_buffer_float(sima, ibuf);
+		image_verify_buffer_float(sima, ima, ibuf, color_manage);
 		
 		sima_draw_colorcorrected_pixels(x, y, ibuf);
 
@@ -414,7 +421,7 @@ static void draw_image_buffer(SpaceImage *sima, ARegion *ar, Scene *scene, ImBuf
 
 		/* we don't draw floats buffers directly but
 		 * convert them, and optionally apply curves */
-		image_verify_buffer_float(sima, ibuf);
+		image_verify_buffer_float(sima, ima, ibuf, color_manage);
 
 		if(ibuf->rect)
 			glaDrawPixelsSafe(x, y, ibuf->x, ibuf->y, ibuf->x, GL_RGBA, GL_UNSIGNED_BYTE, ibuf->rect);
@@ -451,10 +458,11 @@ static unsigned int *get_part_from_ibuf(ImBuf *ibuf, short startx, short starty,
 	return rectmain;
 }
 
-static void draw_image_buffer_tiled(SpaceImage *sima, ARegion *ar, Image *ima, ImBuf *ibuf, float fx, float fy, float zoomx, float zoomy)
+static void draw_image_buffer_tiled(SpaceImage *sima, ARegion *ar, Scene *scene, Image *ima, ImBuf *ibuf, float fx, float fy, float zoomx, float zoomy)
 {
 	unsigned int *rect;
 	int dx, dy, sx, sy, x, y;
+	int color_manage = scene->r.color_mgt_flag & R_COLOR_MANAGEMENT;
 
 	/* verify valid values, just leave this a while */
 	if(ima->xrep<1) return;
@@ -466,7 +474,7 @@ static void draw_image_buffer_tiled(SpaceImage *sima, ARegion *ar, Image *ima, I
 		sima->curtile = ima->xrep*ima->yrep - 1; 
 	
 	/* create char buffer from float if needed */
-	image_verify_buffer_float(sima, ibuf);
+	image_verify_buffer_float(sima, ima, ibuf, color_manage);
 
 	/* retrieve part of image buffer */
 	dx= ibuf->x/ima->xrep;
@@ -499,9 +507,9 @@ static void draw_image_buffer_repeated(SpaceImage *sima, ARegion *ar, Scene *sce
 	for(x=floor(ar->v2d.cur.xmin); x<ar->v2d.cur.xmax; x += 1.0f) { 
 		for(y=floor(ar->v2d.cur.ymin); y<ar->v2d.cur.ymax; y += 1.0f) { 
 			if(ima && (ima->tpageflag & IMA_TILES))
-				draw_image_buffer_tiled(sima, ar, ima, ibuf, x, y, zoomx, zoomy);
+				draw_image_buffer_tiled(sima, ar, scene, ima, ibuf, x, y, zoomx, zoomy);
 			else
-				draw_image_buffer(sima, ar, scene, ibuf, x, y, zoomx, zoomy);
+				draw_image_buffer(sima, ar, scene, ima, ibuf, x, y, zoomx, zoomy);
 
 			/* only draw until running out of time */
 			if((PIL_check_seconds_timer() - time_current) > 0.25)
@@ -673,9 +681,9 @@ void draw_image_main(SpaceImage *sima, ARegion *ar, Scene *scene)
 	else if(sima->flag & SI_DRAW_TILE)
 		draw_image_buffer_repeated(sima, ar, scene, ima, ibuf, zoomx, zoomy);
 	else if(ima && (ima->tpageflag & IMA_TILES))
-		draw_image_buffer_tiled(sima, ar, ima, ibuf, 0.0f, 0.0, zoomx, zoomy);
+		draw_image_buffer_tiled(sima, ar, scene, ima, ibuf, 0.0f, 0.0, zoomx, zoomy);
 	else
-		draw_image_buffer(sima, ar, scene, ibuf, 0.0f, 0.0f, zoomx, zoomy);
+		draw_image_buffer(sima, ar, scene, ima, ibuf, 0.0f, 0.0f, zoomx, zoomy);
 
 	/* grease pencil */
 	draw_image_grease_pencil(sima, ibuf);
diff --git a/source/blender/editors/space_image/image_render.c b/source/blender/editors/space_image/image_render.c
index 381e12267c6..617749937cb 100644
--- a/source/blender/editors/space_image/image_render.c
+++ b/source/blender/editors/space_image/image_render.c
@@ -119,7 +119,7 @@ void imagewindow_progress(SpaceImage *sima, RenderResult *rr, volatile rcti *ren
 	if(rect32)
 		glaDrawPixelsSafe(x1, y1, xmax, ymax, rr->rectx, GL_RGBA, GL_UNSIGNED_BYTE, rect32);
 	else
-		glaDrawPixelsSafe_to32(x1, y1, xmax, ymax, rr->rectx, rectf);
+		glaDrawPixelsSafe_to32(x1, y1, xmax, ymax, rr->rectx, rectf, 0);
 	
 	glPixelZoom(1.0, 1.0);