fix shader header defines (#20077)

Author: Mee-gu

cocos/renderer/backend/opengl/ProgramGL.cpp

@@ -32,21 +32,18 @@
 #include "renderer/backend/opengl/UtilsGL.h"
 
 CC_BACKEND_BEGIN
-
+namespace {
+    std::string vsPreDefine("#version 100\n precision highp float;\n precision highp int;\n");
+    std::string fsPreDefine("precision mediump float;\n precision mediump int;\n");
+}
 
 ProgramGL::ProgramGL(const std::string& vertexShader, const std::string& fragmentShader)
 : Program(vertexShader, fragmentShader)
 {
 #if CC_TARGET_PLATFORM == CC_PLATFORM_ANDROID
     //some device required manually specify the precision qualifiers for vertex shader.
-    std::string vsPreDefine("#version 100\n precision highp float;\n precision highp int;\n");
-    std::string fsPreDefine("precision mediump float;\n precision mediump int;\n");
-    vsPreDefine.append(vertexShader);
-    fsPreDefine.append(fragmentShader);
-    _vertexShader = std::move(vsPreDefine);
-    _fragmentShader = std::move(fsPreDefine);
-    _vertexShaderModule = static_cast<ShaderModuleGL*>(ShaderCache::newVertexShaderModule(_vertexShader));
-    _fragmentShaderModule = static_cast<ShaderModuleGL*>(ShaderCache::newFragmentShaderModule(_fragmentShader));
+    _vertexShaderModule = static_cast<ShaderModuleGL*>(ShaderCache::newVertexShaderModule(std::move(vsPreDefine + _vertexShader)));
+    _fragmentShaderModule = static_cast<ShaderModuleGL*>(ShaderCache::newFragmentShaderModule(std::move(fsPreDefine +  _fragmentShader)));
 #else
     _vertexShaderModule = static_cast<ShaderModuleGL*>(ShaderCache::newVertexShaderModule(_vertexShader));
     _fragmentShaderModule = static_cast<ShaderModuleGL*>(ShaderCache::newFragmentShaderModule(_fragmentShader));
@@ -91,8 +88,8 @@ void ProgramGL::reloadProgram()
     _activeUniformInfos.clear();
     _mapToCurrentActiveLocation.clear();
     _mapToOriginalLocation.clear();
-    static_cast<ShaderModuleGL*>(_vertexShaderModule)->compileShader(backend::ShaderStage::VERTEX, _vertexShader);
-    static_cast<ShaderModuleGL*>(_fragmentShaderModule)->compileShader(backend::ShaderStage::FRAGMENT, _fragmentShader);
+    static_cast<ShaderModuleGL*>(_vertexShaderModule)->compileShader(backend::ShaderStage::VERTEX, std::move(vsPreDefine + _vertexShader));
+    static_cast<ShaderModuleGL*>(_fragmentShaderModule)->compileShader(backend::ShaderStage::FRAGMENT, std::move(fsPreDefine + _fragmentShader));
     compileProgram();
     computeUniformInfos();