Vertex Paint: Alpha Support

GSOC 2017 by Darshan Kadu, see: D2859.

This is a partial merge of some of the features from
the soc-2017-vertex_paint branch.

- Alpha painting & drawing.
- 10 new color blending modes.
- Support for vertex select in vertex paint mode.

3 files changed, 19 insertions, 4 deletions

diff --git a/source/blender/blenkernel/BKE_paint.h b/source/blender/blenkernel/BKE_paint.h
index 88693600653..015fd7c8a14 100644
--- a/source/blender/blenkernel/BKE_paint.h
+++ b/source/blender/blenkernel/BKE_paint.h
@@ -220,6 +220,7 @@ typedef struct SculptSession {
 
 			/* For non-airbrush painting to re-apply from the original (MLoop aligned). */
 			unsigned int *previous_color;
+			unsigned int *previous_accum;
 		} vpaint;
 
 		struct {
diff --git a/source/blender/blenkernel/intern/cdderivedmesh.c b/source/blender/blenkernel/intern/cdderivedmesh.c
index e97de07752e..2ed5cc450a4 100644
--- a/source/blender/blenkernel/intern/cdderivedmesh.c
+++ b/source/blender/blenkernel/intern/cdderivedmesh.c
@@ -752,8 +752,18 @@ static void cdDM_drawMappedFaces(
 		/* avoid buffer problems in following code */
 	}
 	else if (setDrawOptions == NULL) {
+		const bool show_alpha = true;
+		if (show_alpha) {
+			glEnable(GL_BLEND);
+			glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
+		}
+
 		/* just draw the entire face array */
 		GPU_buffer_draw_elements(dm->drawObject->triangles, GL_TRIANGLES, 0, tot_tri_elem);
+
+		if (show_alpha) {
+			glDisable(GL_BLEND);
+		}
 	}
 	else {
 		for (mat_index = 0; mat_index < dm->drawObject->totmaterial; mat_index++) {
@@ -1525,8 +1535,8 @@ static void cdDM_buffer_copy_mcol(
 
 	for (i = 0; i < totpoly; i++, mpoly++) {
 		for (j = 0; j < mpoly->totloop; j++) {
-			copy_v3_v3_uchar(&varray[start], &mloopcol[mpoly->loopstart + j].r);
-			start += 3;
+			copy_v4_v4_uchar(&varray[start], &mloopcol[mpoly->loopstart + j].r);
+			start += 4;
 		}
 	}
 }
diff --git a/source/blender/blenkernel/intern/paint.c b/source/blender/blenkernel/intern/paint.c
index 25ea6ad079f..05d53ae4771 100644
--- a/source/blender/blenkernel/intern/paint.c
+++ b/source/blender/blenkernel/intern/paint.c
@@ -466,7 +466,7 @@ bool BKE_paint_select_vert_test(Object *ob)
 	         (ob->type == OB_MESH) &&
 	         (ob->data != NULL) &&
 	         (((Mesh *)ob->data)->editflag & ME_EDIT_PAINT_VERT_SEL) &&
-	         (ob->mode & OB_MODE_WEIGHT_PAINT)
+	         (ob->mode & OB_MODE_WEIGHT_PAINT || ob->mode & OB_MODE_VERTEX_PAINT)
 	         );
 }
 
@@ -680,6 +680,7 @@ void BKE_sculptsession_free_vwpaint_data(struct SculptSession *ss)
 		gmap = &ss->mode.vpaint.gmap;
 
 		MEM_SAFE_FREE(ss->mode.vpaint.previous_color);
+		MEM_SAFE_FREE(ss->mode.vpaint.previous_accum);
 	}
 	else if (ss->mode_type == OB_MODE_WEIGHT_PAINT) {
 		gmap = &ss->mode.wpaint.gmap;
@@ -737,7 +738,10 @@ void BKE_sculptsession_bm_to_me_for_render(Object *object)
 			 */
 			BKE_object_free_derived_caches(object);
 
-			MEM_SAFE_FREE(object->sculpt->pbvh);
+			if (object->sculpt->pbvh) {
+				BKE_pbvh_free(object->sculpt->pbvh);
+				object->sculpt->pbvh = NULL;
+			}
 
 			sculptsession_bm_to_me_update_data_only(object, false);