fix [#27782] Tileable displacement map issue in Blender 2.58

this bug was introduced in 2.58 (r37342), when adding filtering support to imagewrap(), the problem is boxsample was getting float values which were not wrapped as int values are.

1 files changed, 19 insertions, 9 deletions

diff --git a/source/blender/render/intern/source/imagetexture.c b/source/blender/render/intern/source/imagetexture.c
index cb08ae96bf7..6d264951204 100644
--- a/source/blender/render/intern/source/imagetexture.c
+++ b/source/blender/render/intern/source/imagetexture.c
@@ -76,7 +76,7 @@
 extern struct Render R;
 /* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ */
 
-static void boxsample(ImBuf *ibuf, float minx, float miny, float maxx, float maxy, TexResult *texres, int imaprepeat, int imapextend);
+static void boxsample(ImBuf *ibuf, float minx, float miny, float maxx, float maxy, TexResult *texres, const short imaprepeat, const short imapextend);
 
 /* *********** IMAGEWRAPPING ****************** */
 
@@ -115,6 +115,7 @@ int imagewrap(Tex *tex, Image *ima, ImBuf *ibuf, float *texvec, TexResult *texre
 {
 	float fx, fy, val1, val2, val3;
 	int x, y, retval;
+	int xi, yi; /* original values */
 
 	texres->tin= texres->ta= texres->tr= texres->tg= texres->tb= 0.0f;
 	
@@ -166,8 +167,8 @@ int imagewrap(Tex *tex, Image *ima, ImBuf *ibuf, float *texvec, TexResult *texre
 		}
 	}
 
-	x = (int)floorf(fx*ibuf->x);
-	y = (int)floorf(fy*ibuf->y);
+	x= xi= (int)floorf(fx*ibuf->x);
+	y= yi= (int)floorf(fy*ibuf->y);
 
 	if(tex->extend == TEX_CLIPCUBE) {
 		if(x<0 || y<0 || x>=ibuf->x || y>=ibuf->y || texvec[2]<-1.0f || texvec[2]>1.0f) {
@@ -209,10 +210,17 @@ int imagewrap(Tex *tex, Image *ima, ImBuf *ibuf, float *texvec, TexResult *texre
 		filterx = (0.5f * tex->filtersize) / ibuf->x;
 		filtery = (0.5f * tex->filtersize) / ibuf->y;
 
+		/* important that this value is wrapped [#27782]
+		 * this applies the modifications made by the checks above,
+		 * back to the floating point values */
+		fx -= (float)(xi - x) / (float)ibuf->x;
+		fy -= (float)(yi - y) / (float)ibuf->y;
+
 		boxsample(ibuf, fx-filterx, fy-filtery, fx+filterx, fy+filtery, texres, (tex->extend==TEX_REPEAT), (tex->extend==TEX_EXTEND));
 	}
-	else /* no filtering */
+	else { /* no filtering */
 		ibuf_get_color(&texres->tr, ibuf, x, y);
+	}
 	
 	if( (R.flag & R_SEC_FIELD) && (ibuf->flags & IB_fields) ) {
 		ibuf->rect-= (ibuf->x*ibuf->y);
@@ -524,15 +532,17 @@ static void boxsampleclip(struct ImBuf *ibuf, rctf *rf, TexResult *texres)
 	}
 }
 
-static void boxsample(ImBuf *ibuf, float minx, float miny, float maxx, float maxy, TexResult *texres, int imaprepeat, int imapextend)
+static void boxsample(ImBuf *ibuf, float minx, float miny, float maxx, float maxy, TexResult *texres, const short imaprepeat, const short imapextend)
 {
 	/* Sample box, performs clip. minx etc are in range 0.0 - 1.0 .
-   * Enlarge with antialiased edges of pixels.
-   * If variable 'imaprepeat' has been set, the
-   * clipped-away parts are sampled as well.
-   */
+	 * Enlarge with antialiased edges of pixels.
+	 * If variable 'imaprepeat' has been set, the
+	 * clipped-away parts are sampled as well.
+	 */
 	/* note: actually minx etc isnt in the proper range... this due to filter size and offset vectors for bump */
 	/* note: talpha must be initialized */
+	/* note: even when 'imaprepeat' is set, this can only repeate once in any direction.
+	 * the point which min/max is derived from is assumed to be wrapped */
 	TexResult texr;
 	rctf *rf, stack[8];
 	float opp, tot, alphaclip= 1.0;