Fix T37670: Paint mode + procedural map colours error

Summary:
Seems to be known TODO in the code, but no idea why it
was never solved, especially since tweak is so much easy.

It might be arguable that we need to support painting
color space, but it's still much better to convert to
sRGB space. It's gonna to cover 90% of cases anyway.

Reviewers: campbellbarton, brecht

Reviewed By: brecht

Maniphest Tasks: T37670

Differential Revision: http://developer.blender.org/D65

3 files changed, 21 insertions, 1 deletions

diff --git a/source/blender/blenkernel/intern/brush.c b/source/blender/blenkernel/intern/brush.c
index 33c6f3eb7c0..de81ef179d7 100644
--- a/source/blender/blenkernel/intern/brush.c
+++ b/source/blender/blenkernel/intern/brush.c
@@ -45,6 +45,7 @@
 #include "BKE_texture.h"
 #include "BKE_icons.h"
 
+#include "IMB_colormanagement.h"
 #include "IMB_imbuf.h"
 #include "IMB_imbuf_types.h"
 
@@ -639,6 +640,16 @@ float BKE_brush_sample_tex_3D(const Scene *scene, Brush *br,
 		rgba[2] = intensity;
 		rgba[3] = 1.0f;
 	}
+	else {
+		if (br->mtex.tex->type == TEX_IMAGE && br->mtex.tex->ima) {
+			ImBuf *tex_ibuf = BKE_image_pool_acquire_ibuf(br->mtex.tex->ima, &br->mtex.tex->iuser, pool);
+			/* For consistency, sampling always returns color in linear space */
+			if (tex_ibuf->rect_float == NULL) {
+				IMB_colormanagement_colorspace_to_scene_linear_v3(rgba, tex_ibuf->rect_colorspace);
+			}
+			BKE_image_pool_release_ibuf(br->mtex.tex->ima, tex_ibuf, pool);
+		}
+	}
 
 	return intensity;
 }
diff --git a/source/blender/editors/sculpt_paint/paint_image_2d.c b/source/blender/editors/sculpt_paint/paint_image_2d.c
index 1a19341acec..5f4594703ee 100644
--- a/source/blender/editors/sculpt_paint/paint_image_2d.c
+++ b/source/blender/editors/sculpt_paint/paint_image_2d.c
@@ -275,6 +275,10 @@ static ImBuf *brush_painter_imbuf_new(BrushPainter *painter, int size)
 			if (is_texbrush) {
 				brush_imbuf_tex_co(&tex_mapping, x, y, texco);
 				BKE_brush_sample_tex_3D(scene, brush, texco, rgba, thread, pool);
+				/* TODO(sergey): Support texture paint color space. */
+				if (!use_float) {
+					linearrgb_to_srgb_v3_v3(rgba, rgba);
+				}
 				mul_v3_v3(rgba, brush_rgb);
 			}
 			else {
@@ -362,6 +366,10 @@ static void brush_painter_imbuf_update(BrushPainter *painter, ImBuf *oldtexibuf,
 				if (is_texbrush) {
 					brush_imbuf_tex_co(&tex_mapping, x, y, texco);
 					BKE_brush_sample_tex_3D(scene, brush, texco, rgba, thread, pool);
+					/* TODO(sergey): Support texture paint color space. */
+					if (!use_float) {
+						linearrgb_to_srgb_v3_v3(rgba, rgba);
+					}
 					mul_v3_v3(rgba, brush_rgb);
 				}
 				else {
diff --git a/source/blender/editors/sculpt_paint/paint_image_proj.c b/source/blender/editors/sculpt_paint/paint_image_proj.c
index 59f398a8719..fccd9cf0a19 100644
--- a/source/blender/editors/sculpt_paint/paint_image_proj.c
+++ b/source/blender/editors/sculpt_paint/paint_image_proj.c
@@ -3758,8 +3758,9 @@ static void do_projectpaint_draw(ProjPaintState *ps, ProjPixel *projPixel, const
 	copy_v3_v3(rgb, ps->brush->rgb);
 
 	if (ps->is_texbrush) {
-		/* XXX actually should convert texrgb from linear to srgb here */
 		mul_v3_v3(rgb, texrgb);
+		/* TODO(sergey): Support texture paint color space. */
+		linearrgb_to_srgb_v3_v3(rgb, rgb);
 	}
 
 	rgb_float_to_uchar(rgba_ub, rgb);