bugfix [#22638] Alpha channel not saved when using texture paint

check for alpha channel while saving images that have been painted onto.
It would be nicer to do this while in paint mode except this isn't so simple with project paint using multiple images at once.

1 files changed, 23 insertions, 0 deletions

diff --git a/source/blender/blenkernel/intern/image.c b/source/blender/blenkernel/intern/image.c
index b624feeaf9d..31eae70f159 100644
--- a/source/blender/blenkernel/intern/image.c
+++ b/source/blender/blenkernel/intern/image.c
@@ -1188,6 +1188,29 @@ void BKE_stamp_info(Scene *scene, struct ImBuf *ibuf)
 	if (stamp_data.rendertime[0]) IMB_metadata_change_field (ibuf, "RenderTime", stamp_data.rendertime);
 }
 
+int BKE_alphatest_ibuf(ImBuf *ibuf)
+{
+	int tot;
+	if(ibuf->rect_float) {
+		float *buf= ibuf->rect_float;
+		for(tot= ibuf->x * ibuf->y; tot--; buf+=4) {
+			if(buf[3] < 1.0f) {
+				return TRUE;
+			}
+		}
+	}
+	else if (ibuf->rect) {
+		unsigned char *buf= (unsigned char *)ibuf->rect;
+		for(tot= ibuf->x * ibuf->y; tot--; buf+=4) {
+			if(buf[3] != 255) {
+				return TRUE;
+			}
+		}
+	}
+
+	return FALSE;
+}
+
 int BKE_write_ibuf(Scene *scene, ImBuf *ibuf, const char *name, int imtype, int subimtype, int quality)
 {
 	int ok;