And there's another annoyance I got poked for:

Image texture "Filter size" was not well usable for making the
appearance soft filtered, this because it multiplied the sample 
values, and such values could be extreme small.

Added next to "Filter" buton a new "Min" option, which enforces
a filter size to be a minimum of 'filter' pixels in size.

3 files changed, 13 insertions, 2 deletions

diff --git a/source/blender/makesdna/DNA_texture_types.h b/source/blender/makesdna/DNA_texture_types.h
index 14ece2b31b2..182ac6025fd 100644
--- a/source/blender/makesdna/DNA_texture_types.h
+++ b/source/blender/makesdna/DNA_texture_types.h
@@ -248,6 +248,7 @@ typedef struct TexMapping {
 #define TEX_CALCALPHA	32
 #define TEX_NORMALMAP	2048
 #define TEX_GAUSS_MIP	4096
+#define TEX_FILTER_MIN	8192
 
 /* imaflag unused, only for version check */
 #define TEX_FIELDS_		8
diff --git a/source/blender/render/intern/source/imagetexture.c b/source/blender/render/intern/source/imagetexture.c
index 23b5e597070..cc0ce57bb99 100644
--- a/source/blender/render/intern/source/imagetexture.c
+++ b/source/blender/render/intern/source/imagetexture.c
@@ -702,6 +702,15 @@ int imagewraposa(Tex *tex, Image *ima, ImBuf *ibuf, float *texvec, float *dxt, f
 	minx= tex->filtersize*(maxx-minx)/2.0f;
 	miny= tex->filtersize*(maxy-miny)/2.0f;
 	
+	if(tex->imaflag & TEX_FILTER_MIN) {
+		/* make sure the filtersize is minimal in pixels (normal, ref map can have miniature pixel dx/dy) */
+	 	float addval= (0.5f * tex->filtersize) / (float) MIN2(ibuf->x, ibuf->y);
+ 		
+		if(addval > minx)
+			minx= addval;
+		if(addval > miny)
+			miny= addval;
+	}
 	if(tex->filtersize!=1.0f) {
 		dxt[0]*= tex->filtersize;
 		dxt[1]*= tex->filtersize;
diff --git a/source/blender/src/buttons_shading.c b/source/blender/src/buttons_shading.c
index 3b597e47fa5..c82aee0155a 100644
--- a/source/blender/src/buttons_shading.c
+++ b/source/blender/src/buttons_shading.c
@@ -1244,9 +1244,10 @@ static void texture_panel_image_map(Tex *tex, MTex *mtex)
 	uiDefButBitS(block, TOG, TEX_USEALPHA, B_TEXPRV, "UseAlpha",	10, 160, 100, 20, &tex->imaflag, 0, 0, 0, 0, "Click to use Image's alpha channel");
 	uiDefButBitS(block, TOG, TEX_CALCALPHA, B_TEXPRV, "CalcAlpha",	110, 160, 100, 20, &tex->imaflag, 0, 0, 0, 0, "Click to calculate an alpha channel based on Image RGB values");
 	uiDefButBitS(block, TOG, TEX_NEGALPHA, B_TEXPRV, "NegAlpha",	210, 160, 100, 20, &tex->flag, 0, 0, 0, 0, "Click to invert the alpha values");
-	uiBlockEndAlign(block);
 
-	uiDefButF(block, NUM, B_TEXPRV, "Filter :",						10,120,150,20, &tex->filtersize, 0.1, 25.0, 10, 3, "Sets the filter size used by mipmap and interpol");
+	uiBlockBeginAlign(block);
+	uiDefButBitS(block, TOG, TEX_FILTER_MIN, B_TEXPRV, "Min",	10, 120, 30, 20, &tex->imaflag, 0, 0, 0, 0, "Use Filtersize as a minimal filter value in pixels");
+	uiDefButF(block, NUM, B_TEXPRV, "Filter: ",					40,120,120,20, &tex->filtersize, 0.1, 25.0, 10, 3, "Multiplies the filter size used by mipmap and interpol");
 	
 	uiBlockBeginAlign(block);
 	uiDefButBitS(block, TOG, TEX_NORMALMAP, B_NOP, "Normal Map",	160,120,(mtex)? 75: 150,20, &tex->imaflag,