From 6dfabe9ff305a5edde3364f7c2191d4176da5251 Mon Sep 17 00:00:00 2001
From: MihailRis <mexaruc@gmail.com>
Date: Thu, 17 Jul 2025 00:10:45 +0300
Subject: [PATCH] fix variant indexing

---
 src/graphics/render/BlocksRenderer.cpp | 12 ++++++------
 src/graphics/render/BlocksRenderer.hpp |  2 +-
 src/voxels/Block.hpp                   | 16 ++++++++++++++--
 3 files changed, 21 insertions(+), 9 deletions(-)

diff --git a/src/graphics/render/BlocksRenderer.cpp b/src/graphics/render/BlocksRenderer.cpp
index ed22b427..ae9e5d99 100644
--- a/src/graphics/render/BlocksRenderer.cpp
+++ b/src/graphics/render/BlocksRenderer.cpp
@@ -294,7 +294,7 @@ static bool is_aligned(const glm::vec3& v, float e = 1e-6f) {
 void BlocksRenderer::blockCustomModel(
     const glm::ivec3& icoord, const Block& block, blockstate states, bool lights, bool ao
 ) {
-    const auto& variant = block.getVariant(states.userbits);
+    const auto& variant = block.getVariantByBits(states.userbits);
     glm::vec3 X(1, 0, 0);
     glm::vec3 Y(0, 1, 0);
     glm::vec3 Z(0, 0, 1);
@@ -370,7 +370,7 @@ void BlocksRenderer::blockCube(
     bool lights,
     bool ao
 ) {
-    const auto& variant = block.getVariant(states.userbits);
+    const auto& variant = block.getVariantByBits(states.userbits);
     glm::ivec3 X(1, 0, 0);
     glm::ivec3 Y(0, 1, 0);
     glm::ivec3 Z(0, 0, 1);
@@ -488,8 +488,8 @@ void BlocksRenderer::render(
             blockid_t id = vox.id;
             blockstate state = vox.state;
             const auto& def = *blockDefsCache[id];
-            const auto& variant = def.getVariant(state.userbits);
-            uint8_t variantId = state.userbits;
+            uint8_t variantId = def.getVariantIndex(state.userbits);
+            const auto& variant = def.getVariant(variantId);
             if (id == 0 || variant.drawGroup != drawGroup || state.segment) {
                 continue;
             }
@@ -561,7 +561,7 @@ SortingMeshData BlocksRenderer::renderTranslucent(
             blockid_t id = vox.id;
             blockstate state = vox.state;
             const auto& def = *blockDefsCache[id];
-            uint8_t variantId = state.userbits;
+            uint8_t variantId = def.getVariantIndex(state.userbits);
             const auto& variant = def.getVariant(variantId);
             if (id == 0 || variant.drawGroup != drawGroup || state.segment) {
                 continue;
@@ -687,7 +687,7 @@ void BlocksRenderer::build(const Chunk* chunk, const Chunks* chunks) {
         const voxel& vox = voxels[i];
         blockid_t id = vox.id;
         const auto& def = *blockDefsCache[id];
-        const auto& variant = def.getVariant(vox.state.userbits);
+        const auto& variant = def.getVariantByBits(vox.state.userbits);
 
         if (beginEnds[variant.drawGroup][0] == 0) {
             beginEnds[variant.drawGroup][0] = i+1;
diff --git a/src/graphics/render/BlocksRenderer.hpp b/src/graphics/render/BlocksRenderer.hpp
index 54f7f44e..7d950ac4 100644
--- a/src/graphics/render/BlocksRenderer.hpp
+++ b/src/graphics/render/BlocksRenderer.hpp
@@ -130,7 +130,7 @@ class BlocksRenderer {
             return false;
         }
         const auto& block = *blockDefsCache[vox.id];
-        const auto& blockVariant = block.getVariant(vox.state.userbits);
+        const auto& blockVariant = block.getVariantByBits(vox.state.userbits);
         uint8_t otherDrawGroup = blockVariant.drawGroup;
         if ((otherDrawGroup && (otherDrawGroup != variant.drawGroup)) || !blockVariant.rt.solid) {
             return true;
diff --git a/src/voxels/Block.hpp b/src/voxels/Block.hpp
index 2ffe99e2..e1c25979 100644
--- a/src/voxels/Block.hpp
+++ b/src/voxels/Block.hpp
@@ -294,7 +294,13 @@ public:
 
     void cloneTo(Block& dst);
 
-    constexpr const Variant& getVariant(uint8_t userbits) const {
+    constexpr uint8_t getVariantIndex(uint8_t userbits) const {
+        if (variants == nullptr)
+            return 0;
+        return (userbits >> variants->offset) & variants->mask;
+    }
+
+    constexpr const Variant& getVariantByBits(uint8_t userbits) const {
         if (userbits == 0 || variants == nullptr)
             return defaults;
         return variants->variants[
@@ -302,8 +308,14 @@ public:
         ];
     }
 
+    constexpr const Variant& getVariant(uint8_t index) const {
+        if (index == 0)
+            return defaults;
+        return variants->variants[index];
+    }
+
     constexpr const BlockModel& getModel(uint8_t bits) const {
-        return getVariant(bits).model;
+        return getVariantByBits(bits).model;
     }
 
     static bool isReservedBlockField(std::string_view view);