AlphaOver node feature: "Premul" slider allows to mix between the

using alpha as premul or nonpremul. Quite useful for brightness
tweaks.

Todo: version-patch this so ConvertPremul button goes away
Todo: make entire compositer accept non-premul by default... or both

3 files changed, 50 insertions, 13 deletions

diff --git a/source/blender/makesdna/DNA_node_types.h b/source/blender/makesdna/DNA_node_types.h
index b5c0afe59d7..0b462a46753 100644
--- a/source/blender/makesdna/DNA_node_types.h
+++ b/source/blender/makesdna/DNA_node_types.h
@@ -238,6 +238,10 @@ typedef struct NodeTwoXYs {
 	short x1, x2, y1, y2;
 } NodeTwoXYs;
 
+typedef struct NodeTwoFloats {
+	float x, y;
+} NodeTwoFloats;
+
 typedef struct NodeGeometry {
 	char uvname[32];
 	char colname[32];
diff --git a/source/blender/nodes/intern/CMP_nodes/CMP_alphaOver.c b/source/blender/nodes/intern/CMP_nodes/CMP_alphaOver.c
index f108098750c..8e8eb07c1cc 100644
--- a/source/blender/nodes/intern/CMP_nodes/CMP_alphaOver.c
+++ b/source/blender/nodes/intern/CMP_nodes/CMP_alphaOver.c
@@ -47,16 +47,16 @@ static void do_alphaover_premul(bNode *node, float *out, float *src, float *over
 	if(over[3]<=0.0f) {
 		QUATCOPY(out, src);
 	}
-	else if(*fac==1.0f && over[3]>=1.0f) {
+	else if(fac[0]==1.0f && over[3]>=1.0f) {
 		QUATCOPY(out, over);
 	}
 	else {
-		float mul= 1.0f - *fac*over[3];
+		float mul= 1.0f - fac[0]*over[3];
 
-		out[0]= (mul*src[0]) + *fac*over[0];
-		out[1]= (mul*src[1]) + *fac*over[1];
-		out[2]= (mul*src[2]) + *fac*over[2];
-		out[3]= (mul*src[3]) + *fac*over[3];
+		out[0]= (mul*src[0]) + fac[0]*over[0];
+		out[1]= (mul*src[1]) + fac[0]*over[1];
+		out[2]= (mul*src[2]) + fac[0]*over[2];
+		out[3]= (mul*src[3]) + fac[0]*over[3];
 	}	
 }
 
@@ -67,7 +67,7 @@ static void do_alphaover_key(bNode *node, float *out, float *src, float *over, f
 	if(over[3]<=0.0f) {
 		QUATCOPY(out, src);
 	}
-	else if(*fac==1.0f && over[3]>=1.0f) {
+	else if(fac[0]==1.0f && over[3]>=1.0f) {
 		QUATCOPY(out, over);
 	}
 	else {
@@ -81,6 +81,31 @@ static void do_alphaover_key(bNode *node, float *out, float *src, float *over, f
 	}
 }
 
+/* result will be still premul, but the over part is premulled */
+static void do_alphaover_mixed(bNode *node, float *out, float *src, float *over, float *fac)
+{
+	
+	if(over[3]<=0.0f) {
+		QUATCOPY(out, src);
+	}
+	else if(fac[0]==1.0f && over[3]>=1.0f) {
+		QUATCOPY(out, over);
+	}
+	else {
+		NodeTwoFloats *ntf= node->storage;
+		float addfac= 1.0f - ntf->x + over[3]*ntf->x;
+		float premul= fac[0]*addfac;
+		float mul= 1.0f - fac[0]*over[3];
+		
+		out[0]= (mul*src[0]) + premul*over[0];
+		out[1]= (mul*src[1]) + premul*over[1];
+		out[2]= (mul*src[2]) + premul*over[2];
+		out[3]= (mul*src[3]) + fac[0]*over[3];
+	}
+}
+
+
+
 
 static void node_composit_exec_alphaover(void *data, bNode *node, bNodeStack **in, bNodeStack **out)
 {
@@ -97,8 +122,11 @@ static void node_composit_exec_alphaover(void *data, bNode *node, bNodeStack **i
 		/* make output size of input image */
 		CompBuf *cbuf= in[1]->data?in[1]->data:in[2]->data;
 		CompBuf *stackbuf= alloc_compbuf(cbuf->x, cbuf->y, CB_RGBA, 1); /* allocs */
+		NodeTwoFloats *ntf= node->storage;
 		
-		if(node->custom1)
+		if(ntf->x != 0.0f)
+			composit3_pixel_processor(node, stackbuf, in[1]->data, in[1]->vec, in[2]->data, in[2]->vec, in[0]->data, in[0]->vec, do_alphaover_mixed, CB_RGBA, CB_RGBA, CB_VAL);
+		else if(node->custom1)
 			composit3_pixel_processor(node, stackbuf, in[1]->data, in[1]->vec, in[2]->data, in[2]->vec, in[0]->data, in[0]->vec, do_alphaover_key, CB_RGBA, CB_RGBA, CB_VAL);
 		else
 			composit3_pixel_processor(node, stackbuf, in[1]->data, in[1]->vec, in[2]->data, in[2]->vec, in[0]->data, in[0]->vec, do_alphaover_premul, CB_RGBA, CB_RGBA, CB_VAL);
@@ -115,12 +143,12 @@ bNodeType cmp_node_alphaover= {
 	/* class+opts  */	NODE_CLASS_OP_COLOR, NODE_OPTIONS,
 	/* input sock  */	cmp_node_alphaover_in,
 	/* output sock */	cmp_node_alphaover_out,
-	/* storage     */	"",
+	/* storage     */	"NodeTwoFloats",
 	/* execfunc    */	node_composit_exec_alphaover,
 	/* butfunc     */	NULL,
 	/* initfunc    */	NULL,
-	/* freestoragefunc    */	NULL,
-	/* copystoragefunc    */	NULL,
+	/* freestoragefunc    */	node_free_standard_storage,
+	/* copystoragefunc    */	node_copy_standard_storage,
 	/* id          */	NULL
 	
 };
diff --git a/source/blender/src/drawnode.c b/source/blender/src/drawnode.c
index 9d72d4578e8..561c193dfdb 100644
--- a/source/blender/src/drawnode.c
+++ b/source/blender/src/drawnode.c
@@ -1563,13 +1563,18 @@ static int node_composit_buts_map_value(uiBlock *block, bNodeTree *ntree, bNode
 static int node_composit_buts_alphaover(uiBlock *block, bNodeTree *ntree, bNode *node, rctf *butr)
 {
 	if(block) {
+		NodeTwoFloats *ntf= node->storage;
 		
 		/* alpha type */
 		uiDefButS(block, TOG, B_NODE_EXEC+node->nr, "ConvertPremul",
-				  butr->xmin, butr->ymin, butr->xmax-butr->xmin, 19, 
+				  butr->xmin, butr->ymin+19, butr->xmax-butr->xmin, 19, 
 				  &node->custom1, 0, 0, 0, 0, "");
+		/* mix factor */
+		uiDefButF(block, NUM, B_NODE_EXEC+node->nr, "Premul: ",
+				  butr->xmin, butr->ymin, butr->xmax-butr->xmin, 19, 
+				  &ntf->x, 0.0f, 1.0f, 100, 0, "");
 	}
-	return 19;
+	return 38;
 }
 
 static int node_composit_buts_hue_sat(uiBlock *block, bNodeTree *ntree, bNode *node, rctf *butr)