Main.hs

{-# LANGUAGE PatternSynonyms #-}

module Main where

import Control.Monad (when)
import Raylib.Core (clearBackground, disableCursor, getWorldToScreen)
import Raylib.Core.Camera (updateCamera)
import Raylib.Core.Models (drawBoundingBox, getRayCollisionQuad)
import Raylib.Core.Text (drawFPS)
import Raylib.Types
  ( BoundingBox (BoundingBox),
    Camera3D (Camera3D),
    CameraMode (CameraModeFirstPerson),
    CameraProjection (CameraPerspective),
    RayCollision (rayCollision'hit, rayCollision'point),
    pattern Vector3,
  )
import Raylib.Util (cameraDirectionRay, drawing, mode3D, whileWindowOpen_, withWindow)
import Raylib.Util.Colors (black, red, white)
import Raylib.Core.Shapes (drawCircleV)

main :: IO ()
main = do
  withWindow
    600
    450
    "raylib [core] example - camera ray collision"
    60
    ( \_ -> do
        disableCursor

        let camera = Camera3D (Vector3 0 0 0) (Vector3 2 0 1) (Vector3 0 1 0) 70 CameraPerspective

        whileWindowOpen_
          ( \c ->
              drawing
                ( do
                    clearBackground black
                    drawFPS 10 20

                    let collision = getRayCollisionQuad (cameraDirectionRay c) (Vector3 0 0 0) (Vector3 0 2 0) (Vector3 0 2 4) (Vector3 0 0 4)
                    let color = if rayCollision'hit collision then red else white

                    mode3D c $ drawBoundingBox (BoundingBox (Vector3 0 0 0) (Vector3 0 2 4)) color
                    when (rayCollision'hit collision) $ do
                      p <- getWorldToScreen (rayCollision'point collision) c
                      drawCircleV p 1 red
                )
                >> updateCamera c CameraModeFirstPerson
          )
          camera
    )