[DirectX] Imgui Texture Image 출력

1. 개발 현황

2. 상세 개발 내용

Imgui::Image를 활용하기 위해서는 D3D12_GPU_DESCRIPTOR_HANDLE를 활용해 Texture가 저장된 위치를 접근하는 방식을 활용해야 함.

3. TODO

렌더링 된 이미지를 출력하는 방식으로 기능 개선

4. 참고자료

https://github.com/ocornut/imgui/wiki/Image-Loading-and-Displaying-Examples#example-for-directx12-users

Image Loading and Displaying Examples

imgui_demo.cpp 중 Image 관련 항목

    if (ImGui::TreeNode("Images"))
    {
        ImGuiIO& io = ImGui::GetIO();
        ImGui::TextWrapped(
            "Below we are displaying the font texture (which is the only texture we have access to in this demo). "
            "Use the 'ImTextureID' type as storage to pass pointers or identifier to your own texture data. "
            "Hover the texture for a zoomed view!");

        // Below we are displaying the font texture because it is the only texture we have access to inside the demo!
        // Remember that ImTextureID is just storage for whatever you want it to be. It is essentially a value that
        // will be passed to the rendering backend via the ImDrawCmd structure.
        // If you use one of the default imgui_impl_XXXX.cpp rendering backend, they all have comments at the top
        // of their respective source file to specify what they expect to be stored in ImTextureID, for example:
        // - The imgui_impl_dx11.cpp renderer expect a 'ID3D11ShaderResourceView*' pointer
        // - The imgui_impl_opengl3.cpp renderer expect a GLuint OpenGL texture identifier, etc.
        // More:
        // - If you decided that ImTextureID = MyEngineTexture*, then you can pass your MyEngineTexture* pointers
        //   to ImGui::Image(), and gather width/height through your own functions, etc.
        // - You can use ShowMetricsWindow() to inspect the draw data that are being passed to your renderer,
        //   it will help you debug issues if you are confused about it.
        // - Consider using the lower-level ImDrawList::AddImage() API, via ImGui::GetWindowDrawList()->AddImage().
        // - Read https://github.com/ocornut/imgui/blob/master/docs/FAQ.md
        // - Read https://github.com/ocornut/imgui/wiki/Image-Loading-and-Displaying-Examples
        ImTextureID my_tex_id = io.Fonts->TexID;
        float my_tex_w = (float)io.Fonts->TexWidth;
        float my_tex_h = (float)io.Fonts->TexHeight;
        {
            static bool use_text_color_for_tint = false;
            ImGui::Checkbox("Use Text Color for Tint", &use_text_color_for_tint);
            ImGui::Text("%.0fx%.0f", my_tex_w, my_tex_h);
            ImVec2 pos = ImGui::GetCursorScreenPos();
            ImVec2 uv_min = ImVec2(0.0f, 0.0f);                 // Top-left
            ImVec2 uv_max = ImVec2(1.0f, 1.0f);                 // Lower-right
            ImVec4 tint_col = use_text_color_for_tint ? ImGui::GetStyleColorVec4(ImGuiCol_Text) : ImVec4(1.0f, 1.0f, 1.0f, 1.0f); // No tint
            ImVec4 border_col = ImGui::GetStyleColorVec4(ImGuiCol_Border);
            ImGui::Image(my_tex_id, ImVec2(my_tex_w, my_tex_h), uv_min, uv_max, tint_col, border_col);
            if (ImGui::BeginItemTooltip())
            {
                float region_sz = 32.0f;
                float region_x = io.MousePos.x - pos.x - region_sz * 0.5f;
                float region_y = io.MousePos.y - pos.y - region_sz * 0.5f;
                float zoom = 4.0f;
                if (region_x < 0.0f) { region_x = 0.0f; }
                else if (region_x > my_tex_w - region_sz) { region_x = my_tex_w - region_sz; }
                if (region_y < 0.0f) { region_y = 0.0f; }
                else if (region_y > my_tex_h - region_sz) { region_y = my_tex_h - region_sz; }
                ImGui::Text("Min: (%.2f, %.2f)", region_x, region_y);
                ImGui::Text("Max: (%.2f, %.2f)", region_x + region_sz, region_y + region_sz);
                ImVec2 uv0 = ImVec2((region_x) / my_tex_w, (region_y) / my_tex_h);
                ImVec2 uv1 = ImVec2((region_x + region_sz) / my_tex_w, (region_y + region_sz) / my_tex_h);
                ImGui::Image(my_tex_id, ImVec2(region_sz * zoom, region_sz * zoom), uv0, uv1, tint_col, border_col);
                ImGui::EndTooltip();
            }
        }

        IMGUI_DEMO_MARKER("Widgets/Images/Textured buttons");
        ImGui::TextWrapped("And now some textured buttons..");
        static int pressed_count = 0;
        for (int i = 0; i < 8; i++)
        {
            // UV coordinates are often (0.0f, 0.0f) and (1.0f, 1.0f) to display an entire textures.
            // Here are trying to display only a 32x32 pixels area of the texture, hence the UV computation.
            // Read about UV coordinates here: https://github.com/ocornut/imgui/wiki/Image-Loading-and-Displaying-Examples
            ImGui::PushID(i);
            if (i > 0)
                ImGui::PushStyleVar(ImGuiStyleVar_FramePadding, ImVec2(i - 1.0f, i - 1.0f));
            ImVec2 size = ImVec2(32.0f, 32.0f);                         // Size of the image we want to make visible
            ImVec2 uv0 = ImVec2(0.0f, 0.0f);                            // UV coordinates for lower-left
            ImVec2 uv1 = ImVec2(32.0f / my_tex_w, 32.0f / my_tex_h);    // UV coordinates for (32,32) in our texture
            ImVec4 bg_col = ImVec4(0.0f, 0.0f, 0.0f, 1.0f);             // Black background
            ImVec4 tint_col = ImVec4(1.0f, 1.0f, 1.0f, 1.0f);           // No tint
            if (ImGui::ImageButton("", my_tex_id, size, uv0, uv1, bg_col, tint_col))
                pressed_count += 1;
            if (i > 0)
                ImGui::PopStyleVar();
            ImGui::PopID();
            ImGui::SameLine();
        }
        ImGui::NewLine();
        ImGui::Text("Pressed %d times.", pressed_count);
        ImGui::TreePop();
    }