fix custom model blocks render (with some conditions)

src/content/ContentBuilder.cpp

@@ -26,17 +26,18 @@ std::unique_ptr<Content> ContentBuilder::build() {
             def.rt.tags.insert(tags.add(tag));
         }
 
+        auto isSolid = [](const Variant& variant) {
+            return variant.model.type == BlockModelType::BLOCK ||
+                   variant.culling == CullingMode::OPTIONAL;
+        };
+
         if (def.variants) {
             for (auto& variant : def.variants->variants) {
-                variant.rt.solid =
+                variant.rt.solid = isSolid(variant) || def.explictlySolid;
-                    variant.model.type == BlockModelType::BLOCK ||
-                    def.explictlySolid;
             }
             def.defaults = def.variants->variants.at(0);
         } else {
-            def.defaults.rt.solid =
+            def.defaults.rt.solid = isSolid(def.defaults) || def.explictlySolid;
-                def.defaults.model.type == BlockModelType::BLOCK ||
-                def.explictlySolid;
         }
 
         const float EPSILON = 0.01f;

src/frontend/ContentGfxCache.cpp

@@ -30,6 +30,7 @@ void ContentGfxCache::refreshVariant(
     uint8_t variantIndex,
     const Atlas& atlas
 ) {
+    std::unordered_map<std::string, std::string> optionalTextures;
     bool denseRender = settings.denseRender.get();
     for (uint side = 0; side < 6; side++) {
         std::string tex = variant.textureFaces[side];
@@ -43,6 +44,7 @@ void ContentGfxCache::refreshVariant(
             texOpaque = tex;
         } else if (variant.culling == CullingMode::OPTIONAL && !denseRender) {
             tex = texOpaque;
+            optionalTextures[variant.textureFaces[side]] = texOpaque;
         }
         size_t index = getRegionIndex(def.rt.id, variantIndex, side, false);
         sideregions[index] = atlas.get(tex);
@@ -56,7 +58,12 @@ void ContentGfxCache::refreshVariant(
             if (pos == std::string::npos) {
                 continue;
             }
-            if (auto region = atlas.getIf(mesh.texture.substr(pos+1))) {
+            std::string texture = mesh.texture.substr(pos+1);
+            const auto& found = optionalTextures.find(texture);
+            if (found != optionalTextures.end()) {
+                texture = found->second;
+            }
+            if (auto region = atlas.getIf(texture)) {
                 for (auto& vertex : mesh.vertices) {
                     vertex.uv = region->apply(vertex.uv);
                 }

src/graphics/render/BlocksRenderer.cpp

@@ -538,7 +538,6 @@ void BlocksRenderer::render(
                     break;
                 }
                 case BlockModelType::CUSTOM: {
-                    if (!denseRender)
                     blockCustomModel(
                         {x, y, z},
                         def,