Function RenderDrawLists

imgui-SFML.cpp:947–1076

Rendering callback

// Rendering callback
void RenderDrawLists(ImDrawData* draw_data)
{
    ImGui::GetDrawData();
    if (draw_data->CmdListsCount == 0)
    {
        return;
    }

    const ImGuiIO& io = ImGui::GetIO();
    assert(io.Fonts->TexID != (ImTextureID) nullptr); // You forgot to create and set font texture

    // Avoid rendering when minimized, scale coordinates for retina displays (screen coordinates !=
    // framebuffer coordinates)
    const int fb_width  = (int)(draw_data->DisplaySize.x * draw_data->FramebufferScale.x);
    const int fb_height = (int)(draw_data->DisplaySize.y * draw_data->FramebufferScale.y);
    if (fb_width == 0 || fb_height == 0)
        return;
    draw_data->ScaleClipRects(io.DisplayFramebufferScale);

    // Backup GL state
    // Backup GL state
    GLint last_texture = 0;
    glGetIntegerv(GL_TEXTURE_BINDING_2D, &last_texture);
    GLint last_polygon_mode[2];
    glGetIntegerv(GL_POLYGON_MODE, last_polygon_mode);
    GLint last_viewport[4];
    glGetIntegerv(GL_VIEWPORT, last_viewport);
    GLint last_scissor_box[4];
    glGetIntegerv(GL_SCISSOR_BOX, last_scissor_box);
    GLint last_shade_model = 0;
    glGetIntegerv(GL_SHADE_MODEL, &last_shade_model);
    GLint last_tex_env_mode = 0;
    glGetTexEnviv(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, &last_tex_env_mode);

#ifdef GL_VERSION_ES_CL_1_1
    GLint last_array_buffer;
    glGetIntegerv(GL_ARRAY_BUFFER_BINDING, &last_array_buffer);
    GLint last_element_array_buffer;
    glGetIntegerv(GL_ELEMENT_ARRAY_BUFFER_BINDING, &last_element_array_buffer);
#else
    glPushAttrib(GL_ENABLE_BIT | GL_COLOR_BUFFER_BIT | GL_TRANSFORM_BIT);
#endif

    // Setup desired GL state
    SetupRenderState(draw_data, fb_width, fb_height);

    // Will project scissor/clipping rectangles into framebuffer space
    const ImVec2 clip_off   = draw_data->DisplayPos;       // (0,0) unless using multi-viewports
    const ImVec2 clip_scale = draw_data->FramebufferScale; // (1,1) unless using retina display
                                                           // which are often (2,2)

    // Render command lists
    for (int n = 0; n < draw_data->CmdListsCount; n++)
    {
        const ImDrawList* cmd_list   = draw_data->CmdLists[n];
        const ImDrawVert* vtx_buffer = cmd_list->VtxBuffer.Data;
        const ImDrawIdx*  idx_buffer = cmd_list->IdxBuffer.Data;
        glVertexPointer(2, GL_FLOAT, sizeof(ImDrawVert), (const GLvoid*)((const char*)vtx_buffer + offsetof(ImDrawVert, pos)));