fix: 'box' primitive uv & update stairs model

src/graphics/commons/Model.cpp

@@ -77,13 +77,13 @@ void Mesh::addBox(
     if (enabledSides[1]) // south
         addPlane(pos-Z*size, -X*size, Y*size, -Z, uvs[1]);
     if (enabledSides[2]) // top
-        addPlane(pos+Y*size, X*size, -Z*size, Y, uvs[2]);
+        addPlane(pos+Y*size, X*size, -Z*size, Y, uvs[2] * glm::vec2(-1));
     if (enabledSides[3]) // bottom
-        addPlane(pos-Y*size, X*size, Z*size, -Y, uvs[3]);
+        addPlane(pos-Y*size, X*size, Z*size, -Y, uvs[3] * glm::vec2(-1, 1));
     if (enabledSides[4]) // west
         addPlane(pos+X*size, -Z*size, Y*size, X, uvs[4]);
     if (enabledSides[5]) // east
-        addPlane(pos-X*size, Z*size, Y*size, -X, uvs[5]);
+        addPlane(pos-X*size, Z*size, Y*size, -X, uvs[5] * glm::vec2(-1, 1));
 }
 
 void Mesh::scale(const glm::vec3& size) {

src/graphics/render/ModelsGenerator.cpp

@@ -98,7 +98,7 @@ model::Model ModelsGenerator::fromCustom(
     for (size_t i = 0; i < modelBoxes.size(); i++) {
         auto& mesh = model.addMesh("blocks:");
         mesh.lighting = lighting;
-        const UVRegion boxtexfaces[6] = {
+        UVRegion boxtexfaces[6] = {
             get_region_for(modelTextures[i * 6 + 5], assets),
             get_region_for(modelTextures[i * 6 + 4], assets),
             get_region_for(modelTextures[i * 6 + 3], assets),
@@ -106,6 +106,9 @@ model::Model ModelsGenerator::fromCustom(
             get_region_for(modelTextures[i * 6 + 1], assets),
             get_region_for(modelTextures[i * 6 + 0], assets)
         };
+        boxtexfaces[2].scale(glm::vec2(-1));
+        boxtexfaces[5].scale(glm::vec2(-1, 1));
+
         bool enabled[6] {1,1,1,1,1,1};
         mesh.addBox(
             modelBoxes[i].center(),

src/graphics/ui/elements/ModelViewer.cpp

@@ -95,6 +95,7 @@ void ModelViewer::draw(const DrawContext& pctx, const Assets& assets) {
         ctx.setFramebuffer(fbo.get());
         ctx.setViewport({size.x, size.y});
         ctx.setDepthTest(true);
+        ctx.setCullFace(true);
         display::clear();
         
         auto& ui3dShader = assets.require<Shader>("ui3d");
@@ -111,8 +112,8 @@ void ModelViewer::draw(const DrawContext& pctx, const Assets& assets) {
                     "blocks:dbg_south",
                     "blocks:dbg_top",
                     "blocks:dbg_bottom",
-                    "blocks:dbg_east",
                     "blocks:dbg_west",
+                    "blocks:dbg_east",
                 };
                 region = util::get_texture_region(
                     assets,