From 40a458b743950fa35cfa9764e087d5bf936e9b0d Mon Sep 17 00:00:00 2001
From: Swung0x48 <swung0x48@outlook.com>
Date: Sun, 8 Jun 2025 20:19:06 +0800
Subject: [PATCH] [Fix]: save order of uniform names, and apply it at linking
 and buffer mapping

---
 MG/MG_GL/Implementations/EGL/Diligent/EGL_impl.cpp | 4 ++--
 MG/MG_GL/Implementations/EGL/Diligent/EGL_impl.h   | 6 +++++-
 MG/MG_GL/Implementations/GL/Drawing/GL_Drawing.cpp | 3 ++-
 MG/MG_GL/Implementations/GL/Program/GL_Program.cpp | 5 +++--
 MG/MG_UTIL/Program/GLSLTool.cpp                    | 6 +++++-
 MG/MG_UTIL/Program/GLSLTool.h                      | 2 +-
 6 files changed, 18 insertions(+), 8 deletions(-)

diff --git a/MG/MG_GL/Implementations/EGL/Diligent/EGL_impl.cpp b/MG/MG_GL/Implementations/EGL/Diligent/EGL_impl.cpp
index d00b6e4a..cc6f1900 100644
--- a/MG/MG_GL/Implementations/EGL/Diligent/EGL_impl.cpp
+++ b/MG/MG_GL/Implementations/EGL/Diligent/EGL_impl.cpp
@@ -286,7 +286,7 @@ namespace MG_Diligent {
 
     void PipelineStateManager::ConfigureResourceLayout(
             Diligent::GraphicsPipelineStateCreateInfo& PSOCreateInfo,
-            const GLProgramInfo& programInfo)
+            GLProgramInfo& programInfo)
     {
         MG_Util::Debug::LogD("Begin configuring resource layout for pipeline");
 
@@ -308,7 +308,7 @@ namespace MG_Diligent {
             }
         }
 
-        MG_Util::Program::GenerateDefaultUBOForGLSL_Multi(shaderSourcesMap);
+        MG_Util::Program::GenerateDefaultUBOForGLSL_Multi(shaderSourcesMap, programInfo.uniformBufferNames);
         
         for (auto shader : programInfo.AttachedShaders) {
             GLuint shaderId = 0;
diff --git a/MG/MG_GL/Implementations/EGL/Diligent/EGL_impl.h b/MG/MG_GL/Implementations/EGL/Diligent/EGL_impl.h
index 1abcf904..94d80752 100644
--- a/MG/MG_GL/Implementations/EGL/Diligent/EGL_impl.h
+++ b/MG/MG_GL/Implementations/EGL/Diligent/EGL_impl.h
@@ -43,6 +43,10 @@ namespace MG_Diligent {
         std::vector<Diligent::LayoutElement> inputLayout;
         GLuint DefaultFBO = 0;
         ProgramObject programObj;
+
+        // Uniform names, in the order of their index in uniform buffer
+        std::vector<std::string> uniformBufferNames;
+
         Diligent::IBuffer* pDefaultUBO = nullptr;
 
         std::unordered_map<std::string, Diligent::SHADER_TYPE> uniformStages;
@@ -239,7 +243,7 @@ namespace MG_Diligent {
 
         void ConfigureResourceLayout(
                 Diligent::GraphicsPipelineStateCreateInfo& PSOCreateInfo,
-                const GLProgramInfo& programInfo);
+                GLProgramInfo& programInfo);
     };
 
     extern PipelineStateManager g_PSOManager;
diff --git a/MG/MG_GL/Implementations/GL/Drawing/GL_Drawing.cpp b/MG/MG_GL/Implementations/GL/Drawing/GL_Drawing.cpp
index 85a3c704..6b33a4fe 100644
--- a/MG/MG_GL/Implementations/GL/Drawing/GL_Drawing.cpp
+++ b/MG/MG_GL/Implementations/GL/Drawing/GL_Drawing.cpp
@@ -232,7 +232,8 @@ namespace MG_GL::GL {
             MG_Util::Debug::LogD("UBO mapped successfully for program %u. Updating uniform values.", program);
             uint8_t* uboData = static_cast<uint8_t*>(mapped);
 
-            for (auto& [name, uniform] : programObj.uniformValues) {
+            for (auto& name: programInfo.uniformBufferNames) {
+                auto& uniform = programObj.uniformValues[name];
                 if (IsSamplerType(uniform.type)) continue;
 
                 auto it = programInfo.uniformOffsets.find(name);
diff --git a/MG/MG_GL/Implementations/GL/Program/GL_Program.cpp b/MG/MG_GL/Implementations/GL/Program/GL_Program.cpp
index f7bd197e..5d938990 100644
--- a/MG/MG_GL/Implementations/GL/Program/GL_Program.cpp
+++ b/MG/MG_GL/Implementations/GL/Program/GL_Program.cpp
@@ -86,7 +86,8 @@ namespace MG_GL::GL {
         size_t offset = 0;
         programInfo.uniformOffsets.clear();
 
-        for (auto& [name, uniform] : programInfo.programObj.uniformValues) {
+        for (auto& name: programInfo.uniformBufferNames) {
+            auto& uniform = programInfo.programObj.uniformValues[name];
             if (IsSamplerType(uniform.type)) continue;
 
             size_t size = GetUniformSize(uniform.type);
@@ -255,7 +256,7 @@ namespace MG_GL::GL {
                 shaderSources[shaderId] = shaderObj.source;
             }
 
-            MG_Util::Program::GenerateDefaultUBOForGLSL_Multi(shaderSources);
+            MG_Util::Program::GenerateDefaultUBOForGLSL_Multi(shaderSources, programInfo.uniformBufferNames);
             
             // Compile attached shaders
             for (GLuint shaderId : programInfo.AttachedShadersID) {
diff --git a/MG/MG_UTIL/Program/GLSLTool.cpp b/MG/MG_UTIL/Program/GLSLTool.cpp
index f89d2319..d7784c4e 100644
--- a/MG/MG_UTIL/Program/GLSLTool.cpp
+++ b/MG/MG_UTIL/Program/GLSLTool.cpp
@@ -324,9 +324,11 @@ namespace MG_Util::Program {
     }
 
     void GenerateDefaultUBOForGLSL_Multi(
-            MG_Global::unordered_map<GLuint, std::string> &shaderSources) {
+            MG_Global::unordered_map<GLuint, std::string> &shaderSources, std::vector<std::string>& outUniformBufferNames) {
         if (shaderSources.empty()) return;
 
+        outUniformBufferNames.clear();
+
         std::unordered_map<GLuint, std::vector<bool>> commentMasks;
         for (auto const& [id, source] : shaderSources) {
             commentMasks[id] = buildCommentMask(source);
@@ -405,6 +407,8 @@ namespace MG_Util::Program {
                 if (allUniformNames.find(varName) == allUniformNames.end()) {
                     mergedUniforms.push_back(declaration);
                     allUniformNames.insert(varName);
+                    // save the uniform names in order
+                    outUniformBufferNames.emplace_back(varName);
                 }
 
                 size_t removeStart = declStart;
diff --git a/MG/MG_UTIL/Program/GLSLTool.h b/MG/MG_UTIL/Program/GLSLTool.h
index 4e9156d3..fd9d0313 100644
--- a/MG/MG_UTIL/Program/GLSLTool.h
+++ b/MG/MG_UTIL/Program/GLSLTool.h
@@ -181,7 +181,7 @@ namespace MG_Util::Program {
     std::pair<std::string, std::string> GenerateDefaultUBOForGLSL(const std::pair<std::string,
                                                                   std::string>& glslSources);
     void GenerateDefaultUBOForGLSL_Multi(
-            MG_Global::unordered_map<GLuint, std::string> &shaderSources);
+            MG_Global::unordered_map<GLuint, std::string> &shaderSources, std::vector<std::string>& outUniformBufferNames);
 }
 
 #endif //MOBILEGL_GLSLTOOL_H