The UImGui::RendererUtils
interface gives you utility
functions for creating custom renderers. It looks like this:
class RendererUtils
{
public:
// Call this inside the window hints interface function of the GenericRenderer class
// Event safety - startup, post-startup
static void setupManually();
// Returns a pointer to the current renderer
// Event safety - any-time
static GenericRenderer* getRenderer();
// Renderer a new dear imgui frame
// Event safety - post-begin
static void beginImGuiFrame();
class OpenGL
{
public:
// Call this inside the window hints interface function of the GenericRenderer class
//
// Recommended args:
// Emscripten/Web targets - UIMGUI_LATEST_OPENGL_VERSION, UIMGUI_RENDERER_CLIENT_API_OPENGL_ES, UIMGUI_OPENGL_PROFILE_ANY,
// Desktop - UIMGUI_LATEST_OPENGL_VERSION, UIMGUI_RENDERER_CLIENT_API_OPENGL, UIMGUI_OPENGL_PROFILE_CORE, true
//
// Event safety - startup, post-startup
static void setHints(int majorVersion, int minorVersion, RendererClientAPI clientApi, Profile profile, bool bForwardCompatible);
// Swaps buffers for OpenGL.
// Event safety - post-begin
static void swapFramebuffer();
};
class WebGPU
{
public:
// Check for WebGPU support
// Event safety - any time
static bool supported();
};
private:
};
Platform-independent functions
The following members are platform-independent:
setupManually()
- tells the windowing library to set up your custom renderer manually, instead of creating a rendering context for you(Call this for every non-OpenGL renderer)getRenderer()
- return an abstractGenericRenderer
pointer to the current active rendererbeginImGuiFrame()
- begins a dear imgui frame. Should be called after the rendering API calls its own begin frame function from its corresponding dear imgui backend
OpenGL functions
OpenGL requires some additional setup.
The setHints
member
The set setHints
function allows you to initialise a
custom renderer context for OpenGL.
It looks like this:
void setHints(int majorVersion, int minorVersion, RendererClientAPI clientApi, Profile profile, bool bForwardCompatible);
The majorVersion
and minorVersion
arguments
should be set to a corresponding OpenGL/OpenGL ES version. You can use
the UIMGUI_LATEST_OPENGL_VERSION
macro to set it to the
latest version that's supported on your system
The clientApi
argument is an enum of type
RendererClientAPI
, which looks like this:
enum RendererClientAPI
{
,
UIMGUI_RENDERER_CLIENT_API_MANUAL,
UIMGUI_RENDERER_CLIENT_API_OPENGL
UIMGUI_RENDERER_CLIENT_API_OPENGL_ES};
On desktop systems it should be set to
UIMGUI_RENDERER_CLIENT_API_OPENGL
, while when targeting the
web it should be set to
UIMGUI_RENDERER_CLIENT_API_OPENGL_ES
.
The profile
argument is an enum of type
OpenGLProfile
, which looks like this:
enum OpenGLProfile
{
,
UIMGUI_OPENGL_PROFILE_ANY,
UIMGUI_OPENGL_PROFILE_CORE,
UIMGUI_OPENGL_PROFILE_COMPAT};
On desktop systems is should be set to
UIMGUI_OPENGL_PROFILE_CORE
, while when targeting the web it
should be set to UIMGUI_OPENGL_PROFILE_ANY
.
Finally, the bForwardCompatible
argument toggles OpenGL
forward compatibility. It should be set to true on desktop systems and
to false on the web
The swapBuffers()
function
This function swaps the current framebuffer to the next frame. This should be called every frame.
WebGPU functions
There is only 1 WebGPU function, which is the
supported()
function. This function returns
true
if WebGPU is supported in the client's browser.
Macros
The RendererUtils
' header also includes a number of
useful macros. They look like this:
#define UIMGUI_EMSCRIPTEN_LATEST_OPENGL_VERSION 2, 0
#define UIMGUI_EMSCRIPTEN_LATEST_GLSL_VERSION "#version 100"
#define UIMGUI_APPLE_LATEST_OPENGL_VERSION 4, 1
#define UIMGUI_APPLE_LATEST_GLSL_VERSION "#version 410"
#define UIMGUI_ANY_LATEST_OPENGL_VERSION 4, 5
#define UIMGUI_ANY_LATEST_GLSL_VERSION "#version 450"
#ifdef __EMSCRIPTEN__
#define UIMGUI_LATEST_OPENGL_VERSION UIMGUI_EMSCRIPTEN_LATEST_OPENGL_VERSION
#define UIMGUI_LATEST_GLSL_VERSION UIMGUI_EMSCRIPTEN_LATEST_GLSL_VERSION
#else
#ifdef __APPLE__
#define UIMGUI_LATEST_OPENGL_VERSION UIMGUI_APPLE_LATEST_OPENGL_VERSION
#define UIMGUI_LATEST_GLSL_VERSION UIMGUI_APPLE_LATEST_GLSL_VERSION
#else
#define UIMGUI_LATEST_OPENGL_VERSION UIMGUI_ANY_LATEST_OPENGL_VERSION
#define UIMGUI_LATEST_GLSL_VERSION UIMGUI_ANY_LATEST_GLSL_VERSION
#endif
#endif
We already showcased how the macros for the OpenGL versions are used.
For OpenGL custom renderers, one should also provide a GLSL version
to dear imgui when calling ImGui_ImplOpenGL3_Init()
. This
is where the UIMGUI_LATEST_GLSL_VERSION
macro is used.
C API
The C API is the same as the C++ one, but using standard C API
semantics such as prefixing each function with
UImGui_RendererUtils_
, as defined here.
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