Added GLFrameBufferObj class

Author: TheMostDiligent

Graphics/GraphicsEngineOpenGL/include/GLObjectWrapper.hpp

@@ -1,5 +1,5 @@
 /*
- *  Copyright 2019-2024 Diligent Graphics LLC
+ *  Copyright 2019-2025 Diligent Graphics LLC
  *  Copyright 2015-2019 Egor Yusov
  *
  *  Licensed under the Apache License, Version 2.0 (the "License");
@@ -192,7 +192,7 @@ class GLBufferObjCreateReleaseHelper
 private:
     GLuint m_ExternalGLBufferHandle;
 };
-typedef GLObjWrapper<GLBufferObjCreateReleaseHelper> GLBufferObj;
+using GLBufferObj = GLObjWrapper<GLBufferObjCreateReleaseHelper>;
 
 
 class GLProgramObjCreateReleaseHelper
@@ -204,7 +204,7 @@ class GLProgramObjCreateReleaseHelper
     static const char* Name;
     static GLenum      Type;
 };
-typedef GLObjWrapper<GLProgramObjCreateReleaseHelper> GLProgramObj;
+using GLProgramObj = GLObjWrapper<GLProgramObjCreateReleaseHelper>;
 
 
 class GLShaderObjCreateReleaseHelper
@@ -221,7 +221,7 @@ class GLShaderObjCreateReleaseHelper
 private:
     GLenum m_ShaderType;
 };
-typedef GLObjWrapper<GLShaderObjCreateReleaseHelper> GLShaderObj;
+using GLShaderObj = GLObjWrapper<GLShaderObjCreateReleaseHelper>;
 
 
 class GLPipelineObjCreateReleaseHelper
@@ -233,7 +233,7 @@ class GLPipelineObjCreateReleaseHelper
     static const char* Name;
     static GLenum      Type;
 };
-typedef GLObjWrapper<GLPipelineObjCreateReleaseHelper> GLPipelineObj;
+using GLPipelineObj = GLObjWrapper<GLPipelineObjCreateReleaseHelper>;
 
 
 class GLVAOCreateReleaseHelper
@@ -245,7 +245,7 @@ class GLVAOCreateReleaseHelper
     static const char* Name;
     static GLenum      Type;
 };
-typedef GLObjWrapper<GLVAOCreateReleaseHelper> GLVertexArrayObj;
+using GLVertexArrayObj = GLObjWrapper<GLVAOCreateReleaseHelper>;
 
 
 class GLTextureCreateReleaseHelper
@@ -277,7 +277,7 @@ class GLTextureCreateReleaseHelper
 private:
     GLuint m_ExternalGLTextureHandle;
 };
-typedef GLObjWrapper<GLTextureCreateReleaseHelper> GLTextureObj;
+using GLTextureObj = GLObjWrapper<GLTextureCreateReleaseHelper>;
 
 class GLSamplerCreateReleaseHelper
 {
@@ -288,7 +288,7 @@ class GLSamplerCreateReleaseHelper
     static const char* Name;
     static GLenum      Type;
 };
-typedef GLObjWrapper<GLSamplerCreateReleaseHelper> GLSamplerObj;
+using GLSamplerObj = GLObjWrapper<GLSamplerCreateReleaseHelper>;
 
 
 class GLFBOCreateReleaseHelper
@@ -320,7 +320,71 @@ class GLFBOCreateReleaseHelper
 private:
     GLuint m_ExternalFBOHandle;
 };
-typedef GLObjWrapper<GLFBOCreateReleaseHelper> GLFrameBufferObj;
+
+class GLFrameBufferObj : public GLObjWrapper<GLFBOCreateReleaseHelper>
+{
+public:
+    using TBase = GLObjWrapper<GLFBOCreateReleaseHelper>;
+
+    explicit GLFrameBufferObj(bool CreateObject, GLFBOCreateReleaseHelper CreateReleaseHelper = GLFBOCreateReleaseHelper{}) :
+        TBase{CreateObject, CreateReleaseHelper}
+    {}
+
+    GLFrameBufferObj(GLFrameBufferObj&& Wrapper) noexcept :
+        TBase{std::move(Wrapper)},
+        m_NumDrawBuffers{Wrapper.m_NumDrawBuffers},
+        m_DrawBuffersMask{Wrapper.m_DrawBuffersMask}
+    {
+        Wrapper.m_NumDrawBuffers  = 0;
+        Wrapper.m_DrawBuffersMask = 0;
+    }
+
+    GLFrameBufferObj& operator=(GLFrameBufferObj&& Wrapper) noexcept
+    {
+        TBase::operator=(std::move(Wrapper));
+
+        m_NumDrawBuffers  = Wrapper.m_NumDrawBuffers;
+        m_DrawBuffersMask = Wrapper.m_DrawBuffersMask;
+
+        Wrapper.m_NumDrawBuffers  = 0;
+        Wrapper.m_DrawBuffersMask = 0;
+        return *this;
+    }
+
+    // clang-format off
+    GLFrameBufferObj           (const GLFrameBufferObj&) = delete;
+    GLFrameBufferObj& operator=(const GLFrameBufferObj&) = delete;
+    // clang-format on
+
+    void SetDrawBuffers(uint32_t NumDrawBuffers, uint32_t DrawBuffersMask = ~0u)
+    {
+        if (!*this)
+            return;
+
+        if (NumDrawBuffers == 0)
+            return;
+
+        DrawBuffersMask &= (1u << NumDrawBuffers) - 1u;
+        if (m_NumDrawBuffers == NumDrawBuffers && m_DrawBuffersMask == DrawBuffersMask)
+            return;
+
+        m_NumDrawBuffers  = NumDrawBuffers;
+        m_DrawBuffersMask = DrawBuffersMask;
+
+        GLenum DrawBuffers[8];
+        VERIFY_EXPR(m_NumDrawBuffers <= _countof(DrawBuffers));
+        for (uint32_t rt = 0; rt < m_NumDrawBuffers; ++rt)
+            DrawBuffers[rt] = (m_DrawBuffersMask & (1u << rt)) ? GL_COLOR_ATTACHMENT0 + rt : GL_NONE;
+
+        // The state set by glDrawBuffers() is part of the state of the framebuffer.
+        glDrawBuffers(m_NumDrawBuffers, DrawBuffers);
+        DEV_CHECK_ERR(glGetError() == GL_NO_ERROR, "Failed to set draw buffers via glDrawBuffers()");
+    }
+
+private:
+    uint32_t m_NumDrawBuffers  = 0;
+    uint32_t m_DrawBuffersMask = 0;
+};
 
 
 class GLRBOCreateReleaseHelper
@@ -332,7 +396,7 @@ class GLRBOCreateReleaseHelper
     static const char* Name;
     static GLenum      Type;
 };
-typedef GLObjWrapper<GLRBOCreateReleaseHelper> GLRenderBufferObj;
+using GLRenderBufferObj = GLObjWrapper<GLRBOCreateReleaseHelper>;
 
 struct GLSyncObj
 {
@@ -386,6 +450,6 @@ class GLQueryCreateReleaseHelper
     static const char* Name;
     static GLenum      Type;
 };
-typedef GLObjWrapper<GLQueryCreateReleaseHelper> GLQueryObj;
+using GLQueryObj = GLObjWrapper<GLQueryCreateReleaseHelper>;
 
 } // namespace GLObjectWrappers

Graphics/GraphicsEngineOpenGL/src/FBOCache.cpp

@@ -189,33 +189,7 @@ GLObjectWrappers::GLFrameBufferObj FBOCache::CreateFBO(GLContextState&    Contex
 
     if (NumRenderTargets > 0)
     {
-        // We now need to set mapping between shader outputs and
-        // color attachments. This largely redundant step is performed
-        // by glDrawBuffers()
-        static constexpr GLenum DrawBuffers[] =
-            {
-                GL_COLOR_ATTACHMENT0,
-                GL_COLOR_ATTACHMENT1,
-                GL_COLOR_ATTACHMENT2,
-                GL_COLOR_ATTACHMENT3,
-                GL_COLOR_ATTACHMENT4,
-                GL_COLOR_ATTACHMENT5,
-                GL_COLOR_ATTACHMENT6,
-                GL_COLOR_ATTACHMENT7,
-                GL_COLOR_ATTACHMENT8,
-                GL_COLOR_ATTACHMENT9,
-                GL_COLOR_ATTACHMENT10,
-                GL_COLOR_ATTACHMENT11,
-                GL_COLOR_ATTACHMENT12,
-                GL_COLOR_ATTACHMENT13,
-                GL_COLOR_ATTACHMENT14,
-                GL_COLOR_ATTACHMENT15,
-            };
-
-        // The state set by glDrawBuffers() is part of the state of the framebuffer.
-        // So it can be set up once and left it set.
-        glDrawBuffers(NumRenderTargets, DrawBuffers);
-        DEV_CHECK_GL_ERROR("Failed to set draw buffers via glDrawBuffers()");
+        FBO.SetDrawBuffers(NumRenderTargets);
     }
     else if (pDSV == nullptr)
     {