allow downscaling wad textures

only updates the texture info and coordinates. The texture in the WAD still needs to be updated separately.

src/bsp/Bsp.cpp

@@ -2982,7 +2982,7 @@ void Bsp::fix_bad_surface_extents(bool scaleNotSubdivide, bool downscaleOnly, in
 				continue;
 			}
 
-			if (maxTextureDim > 0 && downscale_texture(info.iMiptex, maxTextureDim)) {
+			if (maxTextureDim > 0 && downscale_texture(info.iMiptex, maxTextureDim, false)) {
 				// retry after downscaling
 				numShrink++;
 				fa--;
@@ -3125,44 +3125,7 @@ bool Bsp::downscale_texture(int textureId, int newWidth, int newHeight) {
 		tex.nOffsets[i] = newOffset[i];
 	}
 
-	// scale up face texture coordinates
-	float scaleX = tex.nWidth / (float)oldWidth;
-	float scaleY = tex.nHeight / (float)oldHeight;
-
-	for (int i = 0; i < faceCount; i++) {
-		BSPFACE& face = faces[i];
-
-		if (texinfos[face.iTextureInfo].iMiptex != textureId)
-			continue;
-
-		// each affected face should have a unique texinfo because
-		// the shift amount may be different for every face after scaling
-		BSPTEXTUREINFO* info = get_unique_texinfo(i);
-
-		// get any vert on the face to use a reference point. Why?
-		// When textures are scaled, the texture relative to the face will depend on how far away its
-		// vertices are from the world origin. This means faces far away from the world origin shift many
-		// pixels per scale unit, and faces aligned with the world origin don't shift at all when scaled.
-		int32_t edgeIdx = surfedges[face.iFirstEdge];
-		BSPEDGE& edge = edges[abs(edgeIdx)];
-		int vertIdx = edgeIdx >= 0 ? edge.iVertex[1] : edge.iVertex[0];
-		vec3 vert = verts[vertIdx];
-
-		vec3 oldvs = info->vS;
-		vec3 oldvt = info->vT;
-		info->vS *= scaleX;
-		info->vT *= scaleY;
-
-		// get before/after uv coordinates
-		float oldu = (dotProduct(oldvs, vert) + info->shiftS) * (1.0f / (float)oldWidth);
-		float oldv = (dotProduct(oldvt, vert) + info->shiftT) * (1.0f / (float)oldHeight);
-		float u = dotProduct(info->vS, vert) + info->shiftS;
-		float v = dotProduct(info->vT, vert) + info->shiftT;
-
-		// undo the shift in uv coordinates for this face
-		info->shiftS += (oldu * tex.nWidth) - u;
-		info->shiftT += (oldv * tex.nHeight) - v;
-	}
+	adjust_downscaled_texture_coordinates(textureId, oldWidth, oldHeight);
 
 	// shrink texture lump
 	int removedBytes = palette - newPalette;
@@ -3184,15 +3147,10 @@ bool Bsp::downscale_texture(int textureId, int newWidth, int newHeight) {
 	return true;
 }
 
-bool Bsp::downscale_texture(int textureId, int maxDim) {
+bool Bsp::downscale_texture(int textureId, int maxDim, bool allowWad) {
 	int32_t texOffset = ((int32_t*)textures)[textureId + 1];
 	BSPMIPTEX& tex = *((BSPMIPTEX*)(textures + texOffset));
 
-	if (tex.nOffsets[0] == 0) {
-		logf("Can't downscale WAD texture %s\n", tex.szName);
-		return false;
-	}
-
 	int oldWidth = tex.nWidth;
 	int oldHeight = tex.nHeight;
 	int newWidth = tex.nWidth;
@@ -3223,9 +3181,70 @@ bool Bsp::downscale_texture(int textureId, int maxDim) {
 		return false;
 	}
 
+	if (tex.nOffsets[0] == 0) {
+		if (allowWad) {
+			tex.nWidth = newWidth;
+			tex.nHeight = newHeight;
+			adjust_downscaled_texture_coordinates(textureId, oldWidth, oldHeight);
+			logf("Texture coords were updated for %s. The WAD texture must be updated separately.\n", tex.szName);
+		}
+		else {
+			logf("Can't downscale WAD texture %s\n", tex.szName);
+		}
+
+		return false;
+	}
+
 	return downscale_texture(textureId, newWidth, newHeight);
 }
 
+void Bsp::adjust_downscaled_texture_coordinates(int textureId, int oldWidth, int oldHeight) {
+	int32_t texOffset = ((int32_t*)textures)[textureId + 1];
+	BSPMIPTEX& tex = *((BSPMIPTEX*)(textures + texOffset));
+
+	int newWidth = tex.nWidth;
+	int newHeight = tex.nHeight;
+
+	// scale up face texture coordinates
+	float scaleX = newWidth / (float)oldWidth;
+	float scaleY = newHeight / (float)oldHeight;
+
+	for (int i = 0; i < faceCount; i++) {
+		BSPFACE& face = faces[i];
+
+		if (texinfos[face.iTextureInfo].iMiptex != textureId)
+			continue;
+
+		// each affected face should have a unique texinfo because
+		// the shift amount may be different for every face after scaling
+		BSPTEXTUREINFO* info = get_unique_texinfo(i);
+
+		// get any vert on the face to use a reference point. Why?
+		// When textures are scaled, the texture relative to the face will depend on how far away its
+		// vertices are from the world origin. This means faces far away from the world origin shift many
+		// pixels per scale unit, and faces aligned with the world origin don't shift at all when scaled.
+		int32_t edgeIdx = surfedges[face.iFirstEdge];
+		BSPEDGE& edge = edges[abs(edgeIdx)];
+		int vertIdx = edgeIdx >= 0 ? edge.iVertex[1] : edge.iVertex[0];
+		vec3 vert = verts[vertIdx];
+
+		vec3 oldvs = info->vS;
+		vec3 oldvt = info->vT;
+		info->vS *= scaleX;
+		info->vT *= scaleY;
+
+		// get before/after uv coordinates
+		float oldu = (dotProduct(oldvs, vert) + info->shiftS) * (1.0f / (float)oldWidth);
+		float oldv = (dotProduct(oldvt, vert) + info->shiftT) * (1.0f / (float)oldHeight);
+		float u = dotProduct(info->vS, vert) + info->shiftS;
+		float v = dotProduct(info->vT, vert) + info->shiftT;
+
+		// undo the shift in uv coordinates for this face
+		info->shiftS += (oldu * newWidth) - u;
+		info->shiftT += (oldv * newHeight) - v;
+	}
+}
+
 void Bsp::downscale_invalid_textures() {
 	int count = 0;
 

src/bsp/Bsp.h

@@ -216,11 +216,15 @@ class Bsp
 	void downscale_textures(int maxDim);
 
 	// downscales a texture to the maximum specified width/height
-	// true if was downscaled
-	bool downscale_texture(int textureId, int maxDim);
+	// allowWad:true = texture coordinates will be scaled even if the the texture is from a WAD and must be scaled separately
+	// returns true if was downscaled
+	bool downscale_texture(int textureId, int maxDim, bool allowWad);
 
 	bool downscale_texture(int textureId, int newWidth, int newHeight);
 
+	// updates texture coordinates after a texture has been downscaled
+	void adjust_downscaled_texture_coordinates(int textureId, int oldWidth, int oldHeight);
+
 	vec3 get_face_center(int faceIdx);
 
 	// scales up texture sizes on models that aren't used by visible entities

src/editor/Gui.cpp

@@ -544,7 +544,7 @@ void Gui::draw3dContextMenus() {
 					else if (maxDim > 32) { nextBestDim = 32; }
 
 					downscaled.insert(info.iMiptex);
-					map->downscale_texture(info.iMiptex, nextBestDim);
+					map->downscale_texture(info.iMiptex, nextBestDim, true);
 				}
 
 				app->deselectFaces();