新的PrimitiveComponent::GetWorldOBBMatrix函数，进一步减少中间计算步骤，直接出OBBMATRIX

example/Basic/RenderBoundBox.cpp

@@ -240,7 +240,8 @@ private:
         {
             for(int i=0;i<6;i++)
             {
-                cci.mat=AxisYRotate(deg2rad(i*30.0f));
+                cci.mat=AxisYRotate(deg2rad(i*30.0f))*ScaleMatrix((i+1)*1.0f);
+
                 rm_torus->component[i]=CreateComponent<MeshComponent>(&cci,rm_torus->cdp);
                 rm_torus->component[i]->SetOverrideMaterial(solid.mi[i]);
             }
@@ -257,13 +258,12 @@ private:
 
         for(int i=0;i<6;i++)
         {
-            PrimitiveComponent *component=rm_torus->component[i];
+            MeshComponent *component=rm_torus->component[i];
 
-            component->GetWorldOBB(obb);
+            if(!component->GetWorldOBBMatrix(cci.mat))
+                continue;
 
-            cci.mat=obb.GetMatrix();
-
-            CreateComponent<MeshComponent>(&cci,rm_box->cdp);
+            auto *box_component=CreateComponent<MeshComponent>(&cci,rm_box->cdp);
         }
 
         return(true);

inc/hgl/component/PrimitiveComponent.h

@@ -31,6 +31,34 @@ public:
 
         return true;
     }
+
+    const bool GetWorldOBBMatrix(Matrix4f &obb_matrix,const float cube_size=1.0f)
+    {
+        AABB aabb;
+
+        if(!GetLocalAABB(aabb))
+            return false;
+
+        //这两行也是对的
+        //OBB obb(GetLocalToWorldMatrix(),aabb);
+        //obb_matrix=obb.GetMatrix(cube_size);
+
+        // 1. 计算最终的缩放向量
+        const Vector3f scale_vector = aabb.GetLength() * cube_size;
+
+        // 2. 直接构建局部空间的变换矩阵 (Translate * Scale)
+        Matrix4f local_aabb_matrix;
+
+        local_aabb_matrix[0] = Vector4f(scale_vector.x, 0.0f, 0.0f, 0.0f);
+        local_aabb_matrix[1] = Vector4f(0.0f, scale_vector.y, 0.0f, 0.0f);
+        local_aabb_matrix[2] = Vector4f(0.0f, 0.0f, scale_vector.z, 0.0f);
+        local_aabb_matrix[3] = Vector4f(aabb.GetCenter(), 1.0f);
+
+        // 3. 将局部 AABB 矩阵与组件的 LocalToWorld 矩阵相乘，得到最终的世界 OBB 矩阵
+        obb_matrix = GetLocalToWorldMatrix() * local_aabb_matrix;
+
+        return(true);
+    }
 };//class PrimitiveComponent
 
 COMPONENT_NAMESPACE_END