== Grease Pencil - Drawing + Eraser Improvements ==

Drawing Improvements:
* Single 'dots' now draw rounded
* Strokes being drawn are drawn 'solid' instead of as dotted lines

Eraser:
* Now operates interactively, so no more wait to see if stuff was erased
* An influence circle is now drawn - the radius of this is defined as the thickness^2

source/blender/include/BIF_editview.h

@@ -40,6 +40,7 @@ void	arrows_move_cursor(unsigned short event);
 void 	lasso_select_boundbox(struct rcti *rect, short mcords[][2], short moves);
 int		lasso_inside(short mcords[][2], short moves, short sx, short sy);
 int 	lasso_inside_edge(short mcords[][2], short moves, int x0, int y0, int x1, int y1);
+int 	edge_inside_circle(short centx, short centy, short rad, short x1, short y1, short x2, short y2);
 void	borderselect(void);
 void	circle_select(void);
 void	deselectall(void);

source/blender/makesdna/DNA_gpencil_types.h

@@ -61,7 +61,7 @@ typedef struct bGPDstroke {
 #define GP_STROKE_2DSPACE		(1<<1)
 	/* stroke is in 2d-space (but with special 'image' scaling) */
 #define GP_STROKE_2DIMAGE		(1<<2)
-	/* stroke is an "eraser" stroke */
+	/* only for use with stroke-buffer (while drawing eraser) */
 #define GP_STROKE_ERASER		(1<<15)
 
 

source/blender/src/drawgpencil.c

@@ -323,6 +323,9 @@ enum {
 	GP_DRAWDATA_ONLYI2D		= (1<<3),	/* only draw 'image' strokes */
 };
 
+/* thickness above which we should use special drawing */
+#define GP_DRAWTHICKNESS_SPECIAL 	3
+
 /* ----- Tool Buffer Drawing ------ */
 
 /* draw stroke defined in buffer (simple ogl lines/points for now, as dotted lines) */
@@ -347,23 +350,13 @@ static void gp_draw_stroke_buffer (tGPspoint *points, int totpoints, short thick
 		glEnd();
 	}
 	else if (sflag & GP_STROKE_ERASER) {
-		/* draw stroke curve - just standard thickness */
+		/* don't draw stroke at all! */
-		setlinestyle(4);
-		glLineWidth(1.0f);
-		
-		glBegin(GL_LINE_STRIP);
-		for (i=0, pt=points; i < totpoints && pt; i++, pt++) {
-			glVertex2f(pt->x, pt->y);
-		}
-		glEnd();
-		
-		setlinestyle(0);
 	}
 	else {
 		float oldpressure = 0.0f;
 		
 		/* draw stroke curve */
-		setlinestyle(2);
+		if (G.f & G_DEBUG) setlinestyle(2);
 		
 		glBegin(GL_LINE_STRIP);
 		for (i=0, pt=points; i < totpoints && pt; i++, pt++) {
@@ -381,14 +374,14 @@ static void gp_draw_stroke_buffer (tGPspoint *points, int totpoints, short thick
 		}
 		glEnd();
 		
-		setlinestyle(0);
+		if (G.f & G_DEBUG) setlinestyle(0);
 	}
 }
 
 /* ----- Existing Strokes Drawing (3D and Point) ------ */
 
 /* draw a given stroke - just a single dot (only one point) */
-static void gp_draw_stroke_point (bGPDspoint *points, short sflag, int winx, int winy)
+static void gp_draw_stroke_point (bGPDspoint *points, short thickness, short sflag, int winx, int winy)
 {
 	/* draw point */
 	if (sflag & GP_STROKE_3DSPACE) {
@@ -396,18 +389,38 @@ static void gp_draw_stroke_point (bGPDspoint *points, short sflag, int winx, int
 			glVertex3f(points->x, points->y, points->z);
 		glEnd();
 	}
-	else if (sflag & GP_STROKE_2DSPACE) {
-		glBegin(GL_POINTS);
-			glVertex2f(points->x, points->y);
-		glEnd();
-	}
 	else {
-		const float x= (points->x / 1000 * winx);
+		float co[2];
-		const float y= (points->y / 1000 * winy);
 		
-		glBegin(GL_POINTS);
+		/* get coordinates of point */
-			glVertex2f(x, y);
+		if (sflag & GP_STROKE_2DSPACE) {
-		glEnd();
+			co[0]= points->x;
+			co[1]= points->y;
+		}
+		else {
+			co[0]= (points->x / 1000 * winx);
+			co[1]= (points->y / 1000 * winy);
+		}
+		
+		/* if thickness is less than GP_DRAWTHICKNESS_SPECIAL, simple opengl point will do */
+		if (thickness < GP_DRAWTHICKNESS_SPECIAL) {
+			glBegin(GL_POINTS);
+				glVertex2fv(co);
+			glEnd();
+		}
+		else {
+			/* draw filled circle as is done in circf (but without the matrix push/pops which screwed things up) */
+			GLUquadricObj *qobj = gluNewQuadric(); 
+			
+			gluQuadricDrawStyle(qobj, GLU_FILL); 
+			
+			/* need to translate drawing position, but must reset after too! */
+			glTranslatef(co[0],  co[1], 0.); 
+			gluDisk( qobj, 0.0,  thickness, 32, 1); 
+			glTranslatef(-co[0],  -co[1], 0.);
+			
+			gluDeleteQuadric(qobj);
+		}
 	}
 }
 
@@ -449,8 +462,8 @@ static void gp_draw_stroke_3d (bGPDspoint *points, int totpoints, short thicknes
 /* draw a given stroke in 2d */
 static void gp_draw_stroke (bGPDspoint *points, int totpoints, short thickness, short dflag, short sflag, short debug, int winx, int winy)
 {	
-	/* if thickness is less than 3, 'smooth' opengl lines look better */
+	/* if thickness is less than GP_DRAWTHICKNESS_SPECIAL, 'smooth' opengl lines look better */
-	if (thickness < 3) {
+	if (thickness < GP_DRAWTHICKNESS_SPECIAL) {
 		bGPDspoint *pt;
 		int i;
 		
@@ -671,7 +684,7 @@ static void gp_draw_strokes (bGPDframe *gpf, int winx, int winy, int dflag, shor
 		
 		/* check which stroke-drawer to use */
 		if (gps->totpoints == 1)
-			gp_draw_stroke_point(gps->points, gps->flag, winx, winy);
+			gp_draw_stroke_point(gps->points, lthick, gps->flag, winx, winy);
 		else if (dflag & GP_DRAWDATA_ONLY3D)
 			gp_draw_stroke_3d(gps->points, gps->totpoints, lthick, dflag, gps->flag, debug, winx, winy);
 		else if (gps->totpoints > 1)	

source/blender/src/editview.c

@@ -1631,7 +1631,7 @@ void mouse_select(void)
 
 /* ------------------------------------------------------------------------- */
 
-static int edge_inside_circle(short centx, short centy, short rad, short x1, short y1, short x2, short y2)
+int edge_inside_circle(short centx, short centy, short rad, short x1, short y1, short x2, short y2)
 {
 	int radsq= rad*rad;
 	float v1[2], v2[2], v3[2];

source/blender/src/gpencil.c

@@ -707,6 +707,10 @@ typedef struct tGPsdata {
 	
 	short status;		/* current status of painting */
 	short paintmode;	/* mode for painting */
+	
+	short mval[2];		/* current mouse-position */
+	short mvalo[2];		/* previous recorded mouse-position */
+	short radius;		/* radius of influence for eraser */
 } tGPsdata;
 
 /* values for tGPsdata->status */
@@ -1037,30 +1041,6 @@ static void gp_stroke_newfrombuffer (tGPsdata *p)
 }
 
 /* --- 'Eraser' for 'Paint' Tool ------ */
-/* User should draw 'circles' around the parts of the sketches they wish to 
- * delete instead of drawing squiggles over existing lines. This should be 
- * easier to manage than if it was done otherwise.
- */
-
-/* convert gp-buffer stroke into mouse-coordinates array */
-static short (*gp_stroke_eraser_2mco (bGPdata *gpd))[2]
-{
-	tGPspoint *pt;
-	short (*mcoords)[2]; 
-	int i;
-	
-	/* allocate memory for coordinates array */
-	mcoords= MEM_mallocN(sizeof(*mcoords)*gpd->sbuffer_size,"gp_buf_mcords");
-	
-	/* copy coordinates */
-	for (pt=gpd->sbuffer, i=0; i < gpd->sbuffer_size; i++, pt++) {
-		mcoords[i][0]= pt->x;
-		mcoords[i][1]= pt->y;
-	}
-	
-	/* return */
-	return mcoords;
-}
 
 /* eraser tool - remove segment from stroke/split stroke (after lasso inside) */
 static short gp_stroke_eraser_splitdel (bGPDframe *gpf, bGPDstroke *gps, int i)
@@ -1130,8 +1110,20 @@ static short gp_stroke_eraser_splitdel (bGPDframe *gpf, bGPDstroke *gps, int i)
 	}
 }
 
+/* eraser tool - check if part of stroke occurs within last segment drawn by eraser */
+static short gp_stroke_eraser_strokeinside (short mval[], short mvalo[], short rad, short x0, short y0, short x1, short y1)
+{
+	/* step 1: check if within the radius for the new one */
+		/* simple within-radius check */
+	if (edge_inside_circle(mval[0], mval[1], rad, x0, y0, x1, y1))
+		return 1;
+	
+	/* step 2: check if within the quad formed between the two eraser coords */
+	return 0;
+} 
+
 /* eraser tool - evaluation per stroke */
-static void gp_stroke_eraser_dostroke (tGPsdata *p, short mcoords[][2], short moves, rcti *rect, bGPDframe *gpf, bGPDstroke *gps)
+static void gp_stroke_eraser_dostroke (tGPsdata *p, short mval[], short mvalo[], short rad, rcti *rect, bGPDframe *gpf, bGPDstroke *gps)
 {
 	bGPDspoint *pt1, *pt2;
 	short x0=0, y0=0, x1=0, y1=0;
@@ -1147,10 +1139,9 @@ static void gp_stroke_eraser_dostroke (tGPsdata *p, short mcoords[][2], short mo
 	else if (gps->totpoints == 1) {
 		/* get coordinates */
 		if (gps->flag & GP_STROKE_3DSPACE) {
-			// FIXME: this may not be the correct correction
 			project_short(&gps->points->x, xyval);
 			x0= xyval[0];
-			x1= xyval[1];
+			y0= xyval[1];
 		}
 		else if (gps->flag & GP_STROKE_2DSPACE) {			
 			ipoco_to_areaco_noclip(p->v2d, &gps->points->x, xyval);
@@ -1165,7 +1156,7 @@ static void gp_stroke_eraser_dostroke (tGPsdata *p, short mcoords[][2], short mo
 		/* do boundbox check first */
 		if (BLI_in_rcti(rect, x0, y0)) {
 			/* only check if point is inside */
-			if (lasso_inside(mcoords, moves, x0, y0)) {
+			if ( ((x0-mval[0])*(x0-mval[0]) + (y0-mval[1])*(y0-mval[1])) <= rad*rad ) {
 				/* free stroke */
 				MEM_freeN(gps->points);
 				BLI_freelinkN(&gpf->strokes, gps);
@@ -1183,10 +1174,9 @@ static void gp_stroke_eraser_dostroke (tGPsdata *p, short mcoords[][2], short mo
 			
 			/* get coordinates */
 			if (gps->flag & GP_STROKE_3DSPACE) {
-				// FIXME: may not be correct correction
 				project_short(&gps->points->x, xyval);
 				x0= xyval[0];
-				x1= xyval[1];
+				y0= xyval[1];
 			}
 			else if (gps->flag & GP_STROKE_2DSPACE) {
 				ipoco_to_areaco_noclip(p->v2d, &pt1->x, xyval);
@@ -1211,7 +1201,7 @@ static void gp_stroke_eraser_dostroke (tGPsdata *p, short mcoords[][2], short mo
 				 * 	- this assumes that linewidth is irrelevant
 				 *	- handled using the lasso-select checking code
 				 */
-				if (lasso_inside_edge(mcoords, moves, x0, y0, x1, x1)) {
+				if (gp_stroke_eraser_strokeinside(mval, mvalo, rad, x0, y0, x1, y1)) {
 					/* if function returns true, break this loop (as no more point to check) */
 					if (gp_stroke_eraser_splitdel(gpf, gps, i))
 						break;
@@ -1226,24 +1216,21 @@ static void gp_stroke_eraser_dostroke (tGPsdata *p, short mcoords[][2], short mo
 /* erase strokes which fall under the eraser strokes */
 static void gp_stroke_doeraser (tGPsdata *p)
 {
-	bGPdata *gpd= p->gpd;
 	bGPDframe *gpf= p->gpf;
 	bGPDstroke *gps, *gpn;
-	short (*mcoords)[2];
 	rcti rect;
 	
-	/* get buffer-stroke coordinates as shorts array, and then get bounding box */
+	/* rect is rectangle of eraser */
-	mcoords= gp_stroke_eraser_2mco(gpd);
+	rect.xmin= p->mval[0] - p->radius;
-	lasso_select_boundbox(&rect, mcoords, gpd->sbuffer_size);
+	rect.ymin= p->mval[1] - p->radius;
+	rect.xmax= p->mval[0] + p->radius;
+	rect.ymax= p->mval[1] + p->radius;
 	
 	/* loop over strokes, checking segments for intersections */
 	for (gps= gpf->strokes.first; gps; gps= gpn) {
 		gpn= gps->next;
-		gp_stroke_eraser_dostroke(p, mcoords, gpd->sbuffer_size, &rect, gpf, gps);
+		gp_stroke_eraser_dostroke(p, p->mval, p->mvalo, p->radius, &rect, gpf, gps);
 	}
-	
-	/* free mcoords array */
-	MEM_freeN(mcoords);
 }
 
 /* ---------- 'Paint' Tool ------------ */
@@ -1308,8 +1295,7 @@ static void gp_paint_strokeend (tGPsdata *p)
 {
 	/* check if doing eraser or not */
 	if (p->gpd->sbuffer_sflag & GP_STROKE_ERASER) {
-		/* get rid of relevant sections of strokes */
+		/* don't do anything */
-		gp_stroke_doeraser(p);
 	}
 	else {
 		/* transfer stroke to frame */
@@ -1345,7 +1331,6 @@ static void gp_paint_cleanup (tGPsdata *p)
 short gpencil_paint (short mousebutton, short paintmode)
 {
 	tGPsdata p;
-	short prevmval[2], mval[2];
 	float opressure, pressure;
 	short ok = GP_STROKEADD_NORMAL;
 	
@@ -1365,31 +1350,51 @@ short gpencil_paint (short mousebutton, short paintmode)
 	setcursor_space(p.sa->spacetype, CURSOR_VPAINT);
 	
 	/* init drawing-device settings */
-	getmouseco_areawin(mval);
+	getmouseco_areawin(p.mval);
 	pressure = get_pressure();
 	
-	prevmval[0]= mval[0];
+	p.mvalo[0]= p.mval[0];
-	prevmval[1]= mval[1];
+	p.mvalo[1]= p.mval[1];
 	opressure= pressure;
 	
+	/* radius for eraser circle is thickness^2 */
+	p.radius= p.gpl->thickness * p.gpl->thickness;
+	
+	/* start drawing eraser-circle (if applicable) */
+	if (paintmode == GP_PAINTMODE_ERASER)
+		draw_sel_circle(p.mval, NULL, p.radius, p.radius, 0); // draws frontbuffer, but sets backbuf again
+	
 	/* only allow painting of single 'dots' if: 
 	 *	- pressure is not excessive (as it can be on some windows tablets)
 	 *	- draw-mode for active datablock is turned on
+	 * 	- not erasing
 	 */
-	if (!(pressure >= 0.99f) || (p.gpd->flag & GP_DATA_EDITPAINT)) { 
+	if (paintmode != GP_PAINTMODE_ERASER) {
-		gp_stroke_addpoint(&p, mval, pressure);
+		if (!(pressure >= 0.99f) || (p.gpd->flag & GP_DATA_EDITPAINT)) { 
+			gp_stroke_addpoint(&p, p.mval, pressure);
+		}
 	}
 	
 	/* paint loop */
 	do {
 		/* get current user input */
-		getmouseco_areawin(mval);
+		getmouseco_areawin(p.mval);
 		pressure = get_pressure();
 		
 		/* only add current point to buffer if mouse moved (otherwise wait until it does) */
-		if (gp_stroke_filtermval(&p, mval, prevmval)) {
+		if (paintmode == GP_PAINTMODE_ERASER) {
+			/* do 'live' erasing now */
+			gp_stroke_doeraser(&p);
+			
+			draw_sel_circle(p.mval, p.mvalo, p.radius, p.radius, 0);
+			force_draw(0);
+			
+			p.mvalo[0]= p.mval[0];
+			p.mvalo[1]= p.mval[1];
+		}
+		else if (gp_stroke_filtermval(&p, p.mval, p.mvalo)) {
 			/* try to add point */
-			ok= gp_stroke_addpoint(&p, mval, pressure);
+			ok= gp_stroke_addpoint(&p, p.mval, pressure);
 			
 			/* handle errors while adding point */
 			if ((ok == GP_STROKEADD_FULL) || (ok == GP_STROKEADD_OVERFLOW)) {
@@ -1397,8 +1402,8 @@ short gpencil_paint (short mousebutton, short paintmode)
 				gp_paint_strokeend(&p);
 				
 				/* start a new stroke, starting from previous point */
-				gp_stroke_addpoint(&p, prevmval, opressure);
+				gp_stroke_addpoint(&p, p.mvalo, opressure);
-				ok= gp_stroke_addpoint(&p, mval, pressure);
+				ok= gp_stroke_addpoint(&p, p.mval, pressure);
 			}
 			else if (ok == GP_STROKEADD_INVALID) {
 				/* the painting operation cannot continue... */
@@ -1411,8 +1416,8 @@ short gpencil_paint (short mousebutton, short paintmode)
 			}
 			force_draw(0);
 			
-			prevmval[0]= mval[0];
+			p.mvalo[0]= p.mval[0];
-			prevmval[1]= mval[1];
+			p.mvalo[1]= p.mval[1];
 			opressure= pressure;
 		}
 		else
@@ -1430,8 +1435,10 @@ short gpencil_paint (short mousebutton, short paintmode)
 	setcursor_space(p.sa->spacetype, CURSOR_STD);
 	
 	/* check size of buffer before cleanup, to determine if anything happened here */
-	if (paintmode == GP_PAINTMODE_ERASER)
+	if (paintmode == GP_PAINTMODE_ERASER) {
-		ok= (p.gpd->sbuffer_size > 1);
+		ok= 1; // fixme
+		draw_sel_circle(NULL, p.mvalo, 0, p.radius, 0);
+	}
 	else
 		ok= p.gpd->sbuffer_size;