Image paint: 2D painting now supports texture masks and does masking more

consistent with projection painting.

Also did some refactoring of this code, moving the brush image creation code
out of brush.c and making it consistent with image updating code.

2 files changed, 33 insertions, 31 deletions

diff --git a/source/blender/imbuf/IMB_imbuf.h b/source/blender/imbuf/IMB_imbuf.h
index 7253a61092c..819026facc6 100644
--- a/source/blender/imbuf/IMB_imbuf.h
+++ b/source/blender/imbuf/IMB_imbuf.h
@@ -179,7 +179,7 @@ void IMB_rectclip(struct ImBuf *dbuf, struct ImBuf *sbuf, int *destx,
 void IMB_rectcpy(struct ImBuf *drect, struct ImBuf *srect, int destx,
 	int desty, int srcx, int srcy, int width, int height);
 void IMB_rectblend(struct ImBuf *dbuf, struct ImBuf *obuf, struct ImBuf *sbuf,
-	unsigned short *mask, unsigned short mask_max,
+	unsigned short *dmask, unsigned short *smask, unsigned short mask_max,
 	int destx,  int desty, int origx, int origy, int srcx, int srcy,
 	int width, int height, IMB_BlendMode mode);
 
diff --git a/source/blender/imbuf/intern/rectop.c b/source/blender/imbuf/intern/rectop.c
index 3d80be93ded..71f81239547 100644
--- a/source/blender/imbuf/intern/rectop.c
+++ b/source/blender/imbuf/intern/rectop.c
@@ -226,20 +226,22 @@ static void imb_rectclip3(ImBuf *dbuf, ImBuf *obuf, ImBuf *sbuf, int *destx,
 void IMB_rectcpy(ImBuf *dbuf, ImBuf *sbuf, int destx, 
                  int desty, int srcx, int srcy, int width, int height)
 {
-	IMB_rectblend(dbuf, dbuf, sbuf, NULL, 0, destx, desty, destx, desty, srcx, srcy, width, height, IMB_BLEND_COPY);
+	IMB_rectblend(dbuf, dbuf, sbuf, NULL, NULL, 0, destx, desty, destx, desty, srcx, srcy, width, height, IMB_BLEND_COPY);
 }
 
 typedef void (*IMB_blend_func)(unsigned char *dst, const unsigned char *src1, const unsigned char *src2);
 typedef void (*IMB_blend_func_float)(float *dst, const float *src1, const float *src2);
 
 
-void IMB_rectblend(ImBuf *dbuf, ImBuf *obuf, ImBuf *sbuf, unsigned short *maskrect, unsigned short mask_max,
+void IMB_rectblend(ImBuf *dbuf, ImBuf *obuf, ImBuf *sbuf, unsigned short *dmask,
+                   unsigned short *smask, unsigned short mask_max,
                    int destx,  int desty, int origx, int origy, int srcx, int srcy, int width, int height,
                    IMB_BlendMode mode)
 {
 	unsigned int *drect = NULL, *orect, *srect = NULL, *dr, *or, *sr;
 	float *drectf = NULL, *orectf, *srectf = NULL, *drf, *orf, *srf;
-	unsigned short *mr;
+	unsigned short *smaskrect = smask, *smr;
+	unsigned short *dmaskrect = dmask, *dmr;
 	int do_float, do_char, srcskip, destskip, origskip, x;
 	IMB_blend_func func = NULL;
 	IMB_blend_func_float func_float = NULL;
@@ -264,8 +266,8 @@ void IMB_rectblend(ImBuf *dbuf, ImBuf *obuf, ImBuf *sbuf, unsigned short *maskre
 		orectf = obuf->rect_float + (origy * obuf->x + origx) * 4;
 	}
 
-	if (maskrect)
-		maskrect += origy * obuf->x + origx;
+	if (dmaskrect)
+		dmaskrect += origy * obuf->x + origx;
 
 	destskip = dbuf->x;
 	origskip = obuf->x;
@@ -274,6 +276,9 @@ void IMB_rectblend(ImBuf *dbuf, ImBuf *obuf, ImBuf *sbuf, unsigned short *maskre
 		if (do_char) srect = sbuf->rect + srcy * sbuf->x + srcx;
 		if (do_float) srectf = sbuf->rect_float + (srcy * sbuf->x + srcx) * 4;
 		srcskip = sbuf->x;
+
+		if (smaskrect)
+			smaskrect += srcy * sbuf->x + srcx;
 	}
 	else {
 		srect = drect;
@@ -392,32 +397,34 @@ void IMB_rectblend(ImBuf *dbuf, ImBuf *obuf, ImBuf *sbuf, unsigned short *maskre
 				or = orect;
 				sr = srect;
 
-				if (maskrect) {
+				if (dmaskrect && smaskrect) {
 					/* mask accumulation for painting */
-					mr = maskrect;
+					dmr = dmaskrect;
+					smr = smaskrect;
 
-					for (x = width; x > 0; x--, dr++, or++, sr++, mr++) {
+					for (x = width; x > 0; x--, dr++, or++, sr++, dmr++, smr++) {
 						unsigned char *src = (unsigned char *)sr;
 
-						if (src[3]) {
-							unsigned short mask = *mr + divide_round_i((mask_max - *mr) * src[3], 255);
+						if (src[3] && *smr) {
+							unsigned short mask = *dmr + (((mask_max - *dmr) * (*smr)) / 65535);
 
-							if (mask > *mr) {
+							if (mask > *dmr) {
 								unsigned char mask_src[4];
 
-								*mr = mask;
+								*dmr = mask;
 
 								mask_src[0] = src[0];
 								mask_src[1] = src[1];
 								mask_src[2] = src[2];
-								mask_src[3] = mask >> 8;
+								mask_src[3] = divide_round_i(src[3] * mask, 65535);
 
 								func((unsigned char *)dr, (unsigned char *)or, mask_src);
 							}
 						}
 					}
 
-					maskrect += origskip;
+					dmaskrect += origskip;
+					smaskrect += srcskip;
 				}
 				else {
 					/* regular blending */
@@ -437,33 +444,28 @@ void IMB_rectblend(ImBuf *dbuf, ImBuf *obuf, ImBuf *sbuf, unsigned short *maskre
 				orf = orectf;
 				srf = srectf;
 
-				if (maskrect) {
+				if (dmaskrect && smaskrect) {
 					/* mask accumulation for painting */
-					mr = maskrect;
+					dmr = dmaskrect;
+					smr = smaskrect;
 
-					for (x = width; x > 0; x--, drf += 4, orf += 4, srf += 4, mr++) {
-						if (srf[3] != 0) {
-							float alpha = CLAMPIS(srf[3], 0.0f, 1.0f);
-							unsigned short mask = (unsigned short)(*mr + (mask_max - *mr) * alpha);
+					for (x = width; x > 0; x--, drf += 4, orf += 4, srf += 4, dmr++, smr++) {
+						if (srf[3] != 0 && *smr) {
+							unsigned short mask = *dmr + (((mask_max - *dmr) * (*smr)) / 65535);
 
-							if (mask > *mr) {
+							if (mask > *dmr) {
 								float mask_srf[4];
-								float new_alpha = mask * (1.0f / 65535.0f);
-								float map_alpha = new_alpha / srf[3];
-
-								*mr = mask;
 
-								mask_srf[0] = map_alpha * srf[0];
-								mask_srf[1] = map_alpha * srf[1];
-								mask_srf[2] = map_alpha * srf[2];
-								mask_srf[3] = new_alpha;
+								*dmr = mask;
+								mul_v4_v4fl(mask_srf, srf, mask * (1.0f / 65535.0f));
 
 								func_float(drf, orf, mask_srf);
 							}
 						}
 					}
 
-					maskrect += origskip;
+					dmaskrect += origskip;
+					smaskrect += srcskip;
 				}
 				else {
 					/* regular blending */