knut0815 / imgui_software_renderer

A Software Renderer for Dear ImGui

Dear ImGui software renderer

This is a software renderer for Dear ImGui. I built it not out of a specific need, but because it was fun. The goal was to get something accurate and decently fast in not too many lines of code. It renders a complex GUI in 1-10 milliseconds on a modern laptop.

What it is:

As the name implies, this is a software renderer for ImGui. It does not handle any windows or input. In the supplied example I use SDL2 for that.

How to use it

Just copy imgui_sw.hpp and imgui_sw.cpp. There are no other dependencies beside Dear ImGui. Requires C++11.

How to test it

git clone https://github.com/emilk/imgui_software_renderer.git
cd imgui_software_renderer
git submodule update --init --recursive
./build_and_run.sh

For the example to work you will need to have SDL2 on your system.

Example:

This renders in 7 ms on my MacBook Pro:

Alternatives

There is another software rasterizer for ImGui (which I did not know about when I wrote mine) at https://github.com/sronsse/imgui/tree/sw_rasterizer_example/examples/sdl_sw_example. I have not compared the two (yet).

Future work:

• We do not yet support painting with any other texture than the default font texture.
• Optimize rendering of gradient rectangles (common for color pickers)
• Compare my software renderer to the one by @sronsse

License:

This software is dual-licensed to the public domain and under the following license: you are granted a perpetual, irrevocable license to copy, modify, publish, and distribute this file as you see fit.