Merge pull request #660 from eliotbyte/fix/custom-model-variants

Fix/custom model variants

doc/en/block-properties.md

@@ -98,6 +98,32 @@ Properties available for variance:
 
 Variants are managed via `block.set_variant(x, y, z, index)`.
 
+### Custom model variants (geometry switching)
+
+You can use different custom models for different variants. Provide a separate `model-name` for each variant that needs different geometry. The renderer caches geometry per (block id, variant).
+
+The base model (specified in root) becomes variant 0. The variants array maps to indices 1+.
+
+Example (default + two custom variants):
+```json
+{
+    "model": "custom",
+    "model-name": "stairs_middle",
+    "state-based": {
+        "bits": 4,
+        "variants": [
+            { "model": "custom", "model-name": "stairs_left" },
+            { "model": "custom", "model-name": "stairs_right" }
+        ]
+    }
+}
+```
+
+In this example:
+- Variant 0 = `stairs_middle` (from root)
+- Variant 1 = `stairs_left` (from variants[0])
+- Variant 2 = `stairs_right` (from variants[1])
+
 ## Lighting
 
 ### *emission*

doc/ru/block-properties.md

@@ -106,6 +106,32 @@
 
 Управление состоянием производится через `block.set_variant(x, y, z, index)`.
 
+### Кастомные модели по вариантам (переключение геометрии)
+
+Для custom-моделей можно переключать геометрию по варианту. Укажите отдельный `model-name` в нужных вариантах — рендерер кэширует геометрию по паре (id блока, вариант).
+
+Базовая модель (из корня) становится вариантом 0. Массив variants соответствует индексам 1+.
+
+Пример (база + два кастомных варианта):
+```json
+{
+    "model": "custom",
+    "model-name": "stairs_middle",
+    "state-based": {
+        "bits": 4,
+        "variants": [
+            { "model": "custom", "model-name": "stairs_left" },
+            { "model": "custom", "model-name": "stairs_right" }
+        ]
+    }
+}
+```
+
+В этом примере:
+- Вариант 0 = `stairs_middle` (из корня)
+- Вариант 1 = `stairs_left` (из variants[0])
+- Вариант 2 = `stairs_right` (из variants[1])
+
 ## Освещение
 
 ### Излучение - *emission*:

src/frontend/ContentGfxCache.cpp

@@ -62,7 +62,7 @@ void ContentGfxCache::refreshVariant(
                 }
             }
         }
-        models[def.rt.id] = std::move(model);
+        models[modelKey(def.rt.id, variantIndex)] = std::move(model);
     }
 }
 
@@ -94,8 +94,8 @@ void ContentGfxCache::refresh() {
 
 ContentGfxCache::~ContentGfxCache() = default;
 
-const model::Model& ContentGfxCache::getModel(blockid_t id) const {
-    const auto& found = models.find(id);
+const model::Model& ContentGfxCache::getModel(blockid_t id, uint8_t variant) const {
+    const auto& found = models.find(modelKey(id, variant));
     if (found == models.end()) {
         throw std::runtime_error("model not found");
     }

src/frontend/ContentGfxCache.hpp

@@ -27,7 +27,11 @@ class ContentGfxCache {
 
     // array of block sides uv regions (6 per block)
     std::unique_ptr<UVRegion[]> sideregions;
-    std::unordered_map<blockid_t, model::Model> models;
+    std::unordered_map<uint64_t, model::Model> models;
+    
+    static inline uint64_t modelKey(blockid_t id, uint8_t variant) {
+        return (uint64_t(id) << 8) | uint64_t(variant & 0xFF);
+    }
 
     void refreshVariant(
         const Block& def,
@@ -53,7 +57,7 @@ public:
         return sideregions[getRegionIndex(id, variant, side, !dense)];
     }
 
-    const model::Model& getModel(blockid_t id) const;
+    const model::Model& getModel(blockid_t id, uint8_t variant) const;
 
     void refresh(const Block& block, const Atlas& atlas);
 

src/graphics/render/BlocksPreview.cpp

@@ -67,7 +67,7 @@ std::unique_ptr<ImageData> BlocksPreview::draw(
             glm::vec3 poff = glm::vec3(0.0f, 0.0f, 1.0f);
             offset.y += (1.0f - hitbox).y * 0.5f;
             shader.uniformMatrix("u_apply", glm::translate(glm::mat4(1.0f), offset));
-            const auto& model = cache.getModel(def.rt.id);
+            const auto& model = cache.getModel(def.rt.id, 0);
             
             for (const auto& mesh : model.meshes) {
                 for (const auto& vertex : mesh.vertices) {

src/graphics/render/BlocksRenderer.cpp

@@ -308,7 +308,7 @@ void BlocksRenderer::blockCustomModel(
         Z = orient.axes[2];
     }
 
-    const auto& model = cache.getModel(block.rt.id);
+    const auto& model = cache.getModel(block.rt.id, block.getVariantIndex(states.userbits));
     for (const auto& mesh : model.meshes) {
         if (vertexCount + mesh.vertices.size() >= capacity) {
             overflow = true;