-- NOTE: If this is file is edited, please also copy and paste it into
-- README.md.
{-# language OverloadedStrings #-}
module Main ( main ) where
import DearImGui
import DearImGui.OpenGL3
import DearImGui.SDL
import DearImGui.SDL.OpenGL
import Graphics.GL
import SDL
import Control.Monad.Managed
import Control.Monad.IO.Class ()
import Control.Monad (when, unless)
import Control.Exception (bracket, bracket_)
main :: IO ()
main = do
-- Initialize SDL
initializeAll
runManaged $ do
-- Create a window using SDL; as we're using OpenGL, we enable OpenGL too
window <- do
let title = "Hello, Dear ImGui!"
let config = defaultWindow { windowGraphicsContext = OpenGLContext defaultOpenGL }
managed $ bracket (createWindow title config) destroyWindow
-- Create an OpenGL context
glContext <- managed $ bracket (glCreateContext window) glDeleteContext
-- Create an ImGui context
_ <- managed $ bracket createContext destroyContext
-- Initialize ImGui's SDL2 backend
managed_ $ bracket_ (sdl2InitForOpenGL window glContext) sdl2Shutdown
-- Initialize ImGui's OpenGL backend
managed_ $ bracket_ openGL3Init openGL3Shutdown
liftIO $ mainLoop window
mainLoop :: Window -> IO ()
mainLoop window = unlessQuit $ do
-- Tell ImGui we're starting a new frame
openGL3NewFrame
sdl2NewFrame
newFrame
-- Build the GUI
withWindowOpen "Hello, ImGui!" $ do
-- Add a text widget
text "Hello, ImGui!"
-- Add a button widget, and call 'putStrLn' when it's clicked
button "Clickety Click" >>= \clicked ->
when clicked $ putStrLn "Ow!"
-- Show the ImGui demo window
showDemoWindow
-- Render
glClear GL_COLOR_BUFFER_BIT
render
openGL3RenderDrawData =<< getDrawData
glSwapWindow window
mainLoop window
where
-- Process the event loop
unlessQuit action = do
shouldQuit <- gotQuitEvent
unless shouldQuit action
gotQuitEvent = do
ev <- pollEventWithImGui
case ev of
Nothing ->
return False
Just event ->
(isQuit event ||) <$> gotQuitEvent
isQuit event =
eventPayload event == QuitEvent
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