Fix bug that getPrimitiveRenderer function redundantly creates the pipeline even if it doesn't have to.

Author: stripe2933

interface/vulkan/SharedData.cppm

@@ -27,7 +27,7 @@ import :vulkan.sampler.SingleTexelSampler;
  * It combines the hash of each field using <tt>boost::hash_combine</tt>.
  *
  * @tparam T Aggregate struct type.
- * @note Currently this is only for <tt>SharedData::PrimitivePipelineKey</tt> (whose members are 3), therefore number of the structured bindings is assumed as 3. Need fix.
+ * @note Currently this is only for <tt>SharedData::PrimitivePipelineKey</tt> (whose members are 4), therefore number of the structured bindings is assumed as 4. Need fix.
  */
 template <typename T> requires std::is_aggregate_v<T>
 struct AggregateHasher {
@@ -129,13 +129,16 @@ namespace vk_gltf_viewer::vulkan {
          * @return Vulkan pipeline for the given key.
          */
         [[nodiscard]] vk::Pipeline getPrimitiveRenderer(const PrimitivePipelineKey &key) const {
-            if (key.unlit) {
-                return primitivePipelines.try_emplace(key, createUnlitPrimitiveRenderer(
-                    gpu.device, primitivePipelineLayout, sceneRenderPass, key.alphaMode)).first->second;
+            if (auto it = primitivePipelines.find(key); it != primitivePipelines.end()) {
+                return it->second;
+            }
+            else if (key.unlit) {
+                return primitivePipelines.try_emplace(it, key, createUnlitPrimitiveRenderer(
+                    gpu.device, primitivePipelineLayout, sceneRenderPass, key.alphaMode))->second;
             }
             else {
-                return primitivePipelines.try_emplace(key, createPrimitiveRenderer(
-                    gpu.device, primitivePipelineLayout, sceneRenderPass, key.fragmentShaderGeneratedTBN, key.alphaMode)).first->second;
+                return primitivePipelines.try_emplace(it, key, createPrimitiveRenderer(
+                    gpu.device, primitivePipelineLayout, sceneRenderPass, key.fragmentShaderGeneratedTBN, key.alphaMode))->second;
             }
         }