GSDX: Fixed GetTextureMinMax's vertex tracer interaction properly and added some comments.

It wasn't the suspicious code, that actually seems to be correct.  The rempty() case should now be unnecessary except in case of bad register settings, but that's outside of our control so it needs to stay until code's added for that case.  A console warning would be appropriate.

git-svn-id: http://pcsx2.googlecode.com/svn/trunk@5612 96395faa-99c1-11dd-bbfe-3dabce05a288

plugins/GSdx/GSState.cpp

@@ -2562,10 +2562,7 @@ void GSState::GetTextureMinMax(GSVector4i& r, const GIFRegTEX0& TEX0, const GIFR
 		__assume(0);
 	}
 
-// Kingdom Hearts 2's tron section shows a bug with the CLAMP_REPEAT code here.
+	if(wms != CLAMP_REGION_REPEAT || wmt != CLAMP_REGION_REPEAT)
-// This is just an optimisation so it's disabled until the bug is found.
-#if 0
-	if(wms + wmt < 6)
 	{
 		GSVector4 st = m_vt.m_min.t.xyxy(m_vt.m_max.t);
 
@@ -2580,7 +2577,7 @@ void GSState::GetTextureMinMax(GSVector4i& r, const GIFRegTEX0& TEX0, const GIFR
 
 		int mask = 0;
 
-		// This part is suspicious, as far as I can tell it zeroes fields if tw/th aren't 0, which is probably not the intent
+		// See commented code below for the meaning of mask
 		if(wms == CLAMP_REPEAT || wmt == CLAMP_REPEAT)
 		{
 			u = uv & GSVector4i::xffffffff().srl32(32 - tw);
@@ -2592,11 +2589,17 @@ void GSState::GetTextureMinMax(GSVector4i& r, const GIFRegTEX0& TEX0, const GIFR
 			mask = (uu.upl32(vv) == uu.uph32(vv)).mask();
 		}
 
-		uv = uv.rintersect(tr);
+		uv = uv.rintersect(vr - GSVector4i(0,0,1,1));
 
 		switch(wms)
 		{
 		case CLAMP_REPEAT:
+			// This commented code cannot be used directly because it needs uv before the intersection
+			/*if (uv_.x >> tw == uv_.z >> tw)
+			{
+				vr.x = max(vr.x, (uv_.x & ((1 << tw) - 1)));
+				vr.z = min(vr.z, (uv_.z & ((1 << tw) - 1)) + 1);
+			}*/
 			if(mask & 0x000f) {if(vr.x < u.x) vr.x = u.x; if(vr.z > u.z + 1) vr.z = u.z + 1;}
 			break;
 		case CLAMP_CLAMP:
@@ -2613,6 +2616,11 @@ void GSState::GetTextureMinMax(GSVector4i& r, const GIFRegTEX0& TEX0, const GIFR
 		switch(wmt)
 		{
 		case CLAMP_REPEAT:
+			/*if (uv_.y >> th == uv_.w >> th)
+			{
+				vr.y = max(vr.y, (uv_.y & ((1 << th) - 1)));
+				vr.w = min(vr.w, (uv_.w & ((1 << th) - 1)) + 1);
+			}*/
 			if(mask & 0xf000) {if(vr.y < v.y) vr.y = v.y; if(vr.w > v.w + 1) vr.w = v.w + 1;}
 			break;
 		case CLAMP_CLAMP:
@@ -2626,16 +2634,16 @@ void GSState::GetTextureMinMax(GSVector4i& r, const GIFRegTEX0& TEX0, const GIFR
 			__assume(0);
 		}
 	}
-#endif
 
 	vr = vr.rintersect(tr);
 
+	// This really shouldn't happen now except with the clamping region set entirely outside the texture,
+	// special handling should be written for that case.
 	if(vr.rempty())
 	{
 		// NOTE: this can happen when texcoords are all outside the texture or clamping area is zero, but we can't 
 		// let the texture cache update nothing, the sampler will still need a single texel from the border somewhere
 		// examples: 
-		// - ICO opening menu (texture looks like the miniature silhouette of everything except the sky)
 		// - THPS (no visible problems)
 		// - NFSMW (strange rectangles on screen, might be unrelated)