基础结构

struct FramebufferSpecification
    {
        uint32_t Width, Height;
        // FramebufferFormat Format = 
        uint32_t Samples = 1;
        bool SwapChainTarget = false;
    };
    class Framebuffer
    {
    public:
        virtual void Bind() = 0;
        virtual void Unbind() = 0;
        virtual uint32_t GetColorAttachmentRendererID() const = 0;
        virtual const FramebufferSpecification& GetSpecification() const = 0;
        static Ref<Framebuffer> Create(const FramebufferSpecification& spec);
    };

OpenGL结构

    class OpenGLFramebuffer : public Framebuffer
    {
    public:
        OpenGLFramebuffer(const FramebufferSpecification& spec);
        virtual ~OpenGLFramebuffer();
        void Invalidate(); //作废，重新创建帧缓冲
        virtual void Bind() override;
        virtual void Unbind() override;
        virtual uint32_t GetColorAttachmentRendererID() const override { return m_ColorAttachment; }
        virtual const FramebufferSpecification& GetSpecification() const override { return m_Specification; }
    private:
        uint32_t m_RendererID;
        uint32_t m_ColorAttachment, m_DepthAttachment;
        FramebufferSpecification m_Specification;
    };

创建细节

帧缓冲->颜色附件->深度/模板附件->颜色附件纹理参数

        void OpenGLFramebuffer::Invalidate()
    {
        glCreateFramebuffers(1, &m_RendererID); //创建绑定帧缓冲
        glBindFramebuffer(GL_FRAMEBUFFER, m_RendererID);

        glCreateTextures(GL_TEXTURE_2D, 1, &m_ColorAttachment); //创建颜色附件纹理
        glBindTexture(GL_TEXTURE_2D, m_ColorAttachment);

        glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA8, m_Specification.Width, m_Specification.Height, 0, GL_RGBA, GL_UNSIGNED_BYTE, nullptr);
        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);

        glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, m_ColorAttachment, 0); //帧缓冲纹理

        //创建深度-模板附件纹理
        glCreateTextures(GL_TEXTURE_2D, 1, &m_DepthAttachment);
        glBindTexture(GL_TEXTURE_2D, m_DepthAttachment);
        glTexStorage2D(GL_TEXTURE_2D, 1, GL_DEPTH24_STENCIL8, m_Specification.Width, m_Specification.Height);
        // glTexImage2D(GL_TEXTURE_2D, 0, GL_DEPTH24_STENCIL8, m_Specification.Width, m_Specification.Height, 0,
        //  GL_DEPTH_STENCIL, GL_UNSIGNED_INT_24_8, NULL);
        glFramebufferTexture2D(GL_FRAMEBUFFER, GL_DEPTH_STENCIL_ATTACHMENT, GL_TEXTURE_2D, m_DepthAttachment, 0);

        //帧缓冲完整性检查
        CORE_DEBUG_ASSERT(glCheckFramebufferStatus(GL_FRAMEBUFFER) == GL_FRAMEBUFFER_COMPLETE, "Framebuffer is incomplete!");
        glBindFramebuffer(GL_FRAMEBUFFER, 0);
    }

把帧缓冲显示到ImGUI上，做成场景的效果