[Bf-blender-cvs] [1806db0] GPencil_Editing_Stage3: GPencil Eraser: Operates on all visible + editable layers instead of active only

[Joshua Leung]

Commit: 1806db07e7617a565dec0c154d2225ea5129c394
Author: Joshua Leung
Date:   Fri Dec 11 17:29:48 2015 +1300
Branches: GPencil_Editing_Stage3
https://developer.blender.org/rB1806db07e7617a565dec0c154d2225ea5129c394

GPencil Eraser: Operates on all visible + editable layers instead of active only

The GPencil eraser now operates on all visible and editable layers, instead of
only operating on the active layer. There was really no reason why it needed to
only consider the active layer, as doing so only made it confusing for the user when
the strokes they were trying to erase wouldn't be affected. Besides, if you really
needed to restrict the eraser to working on a particular layer, you could just
lock all the others (which is now very easy with the new operators)

===================================================================

M	source/blender/editors/gpencil/gpencil_paint.c

===================================================================

diff --git a/source/blender/editors/gpencil/gpencil_paint.c b/source/blender/editors/gpencil/gpencil_paint.c
index 753aa3b..7d401b5 100644
--- a/source/blender/editors/gpencil/gpencil_paint.c
+++ b/source/blender/editors/gpencil/gpencil_paint.c
@@ -943,7 +943,7 @@ static void gp_stroke_eraser_dostroke(tGPsdata *p,
 /* erase strokes which fall under the eraser strokes */
 static void gp_stroke_doeraser(tGPsdata *p)
 {
-	bGPDframe *gpf = p->gpf;
+	bGPDlayer *gpl;
 	bGPDstroke *gps, *gpn;
 	rcti rect;
 	
@@ -962,15 +962,31 @@ static void gp_stroke_doeraser(tGPsdata *p)
 		}
 	}
 	
-	/* loop over strokes, checking segments for intersections */
-	for (gps = gpf->strokes.first; gps; gps = gpn) {
-		gpn = gps->next;
+	/* loop over all layers too, since while it's easy to restrict editing to
+	 * only a subset of layers, it is harder to perform the same erase operation
+	 * on multiple layers...
+	 */
+	for (gpl = p->gpd->layers.first; gpl; gpl = gpl->next) {
+		bGPDframe *gpf = gpl->actframe;
 		
-		/* Not all strokes in the datablock may be valid in the current editor/context
-		 * (e.g. 2D space strokes in the 3D view, if the same datablock is shared)
-		 */
-		if (ED_gpencil_stroke_can_use_direct(p->sa, gps)) {
-			gp_stroke_eraser_dostroke(p, p->mval, p->mvalo, p->radius, &rect, gpf, gps);
+		/* only affect layer if it's editable (and visible) */
+		if (gpl->flag & (GP_LAYER_HIDE | GP_LAYER_LOCKED)) {
+			continue;
+		}
+		else if (gpf == NULL) {
+			continue;
+		}
+		
+		/* loop over strokes, checking segments for intersections */
+		for (gps = gpf->strokes.first; gps; gps = gpn) {
+			gpn = gps->next;
+			
+			/* Not all strokes in the datablock may be valid in the current editor/context
+			 * (e.g. 2D space strokes in the 3D view, if the same datablock is shared)
+			 */
+			if (ED_gpencil_stroke_can_use_direct(p->sa, gps)) {
+				gp_stroke_eraser_dostroke(p, p->mval, p->mvalo, p->radius, &rect, gpf, gps);
+			}
 		}
 	}
 }
@@ -1216,8 +1232,7 @@ static void gp_session_cleanup(tGPsdata *p)
 /* init new stroke */
 static void gp_paint_initstroke(tGPsdata *p, short paintmode)
 {
-	ToolSettings *ts = p->scene->toolsettings;
-	eGP_GetFrame_Mode add_frame_mode;
+	Scene *scene = p->scene;
 	
 	/* get active layer (or add a new one if non-existent) */
 	p->gpl = gpencil_layer_getactive(p->gpd);
@@ -1235,21 +1250,60 @@ static void gp_paint_initstroke(tGPsdata *p, short paintmode)
 	}
 	
 	/* get active frame (add a new one if not matching frame) */
-	if ((paintmode == GP_PAINTMODE_ERASER) || (ts->gpencil_flags & GP_TOOL_FLAG_RETAIN_LAST))
-		add_frame_mode = GP_GETFRAME_ADD_COPY;
-	else
-		add_frame_mode = GP_GETFRAME_ADD_NEW;
+	if (paintmode == GP_PAINTMODE_ERASER) {
+		/* Eraser mode:
+		 * 1) Add new frames to all frames that we might touch,
+		 * 2) Ensure that p->gpf refers to the frame used for the active layer
+		 *    (to avoid problems with other tools which expect it to exist)
+		 */
+		bGPDlayer *gpl;
+		for (gpl = p->gpd->layers.first; gpl; gpl = gpl->next) {
+			/* Skip if layer not editable */
+			if (gpl->flag & (GP_LAYER_HIDE | GP_LAYER_LOCKED))
+				continue;
+			
+			/* Add a new frame if needed (and based off the active frame,
+			 * as we need some existing strokes to erase)
+			 */
+			gpl->actframe = gpencil_layer_getframe(gpl, CFRA, GP_GETFRAME_ADD_COPY);
+			
+			/* XXX: we omit GP_FRAME_PAINT here for now,
+			 * as it is only really useful for doing
+			 * paintbuffer drawing
+			 */
+		}
 		
-	p->gpf = gpencil_layer_getframe(p->gpl, p->scene->r.cfra, add_frame_mode);
-	
-	if (p->gpf == NULL) {
-		p->status = GP_STATUS_ERROR;
-		if (G.debug & G_DEBUG)
-			printf("Error: No frame created (gpencil_paint_init)\n");
-		return;
+		/* Ensure this gets set... */
+		p->gpf = p->gpl->actframe;
+		
+		if (p->gpf == NULL) {
+			p->status = GP_STATUS_ERROR;
+			//if (G.debug & G_DEBUG)
+				printf("Error: No frame created (gpencil_paint_init)\n");
+			return;
+		}
 	}
 	else {
-		p->gpf->flag |= GP_FRAME_PAINT;
+		/* Drawing Modes - Add a new frame if needed on the active layer */
+		ToolSettings *ts = p->scene->toolsettings;
+		short add_frame_mode;
+		
+		if (ts->gpencil_flags & GP_TOOL_FLAG_RETAIN_LAST)
+			add_frame_mode = GP_GETFRAME_ADD_COPY;
+		else
+			add_frame_mode = GP_GETFRAME_ADD_NEW;
+			
+		p->gpf = gpencil_layer_getframe(p->gpl, CFRA, add_frame_mode);
+		
+		if (p->gpf == NULL) {
+			p->status = GP_STATUS_ERROR;
+			if (G.debug & G_DEBUG)
+				printf("Error: No frame created (gpencil_paint_init)\n");
+			return;
+		}
+		else {
+			p->gpf->flag |= GP_FRAME_PAINT;
+		}
 	}
 	
 	/* set 'eraser' for this stroke if using eraser */