examples/hello-window.sgl

1;;; hello-window.sgl - Minimal Sigil Studio Example

2;;;

3;;; Opens a window and clears it to a cycling color.

4;;; Demonstrates the coroutine-based game loop where Scheme owns the main loop.

6(import (sigil app)

7 (sigil graphics)

8 (sigil math))

10;; Simple color cycling using sine waves

11(define (get-color t)

12 ;; Returns a list of (r g b) using offset sine waves

13 (let ((r (+ 0.5 (* 0.5 (sin t))))

14 (g (+ 0.5 (* 0.5 (sin (+ t 2.094))))) ; offset by 2*pi/3

15 (b (+ 0.5 (* 0.5 (sin (+ t 4.189)))))) ; offset by 4*pi/3

16 (list r g b)))

18;; Run the game using cooperative frame scheduling

19(run-game "Hello Sigil Studio" 800 600

20 (lambda ()

21 ;; Initialization

22 (gfx-setup)

23 (display "Hello, Sigil Studio!")

24 (newline)

26 ;; Main loop - Scheme owns this!

27 (let loop ((time 0.0))

28 (let ((dt (wait-frame))) ; Yield to C, get delta time

29 ;; Update time

30 (let ((new-time (+ time dt)))

31 ;; Get cycling color and render

32 (begin-frame)

33 (let ((color (get-color new-time)))

34 (clear-screen (car color) (cadr color) (caddr color)))

35 (end-frame)

37 ;; Continue unless quit requested

38 (if (key-pressed? 'escape)

39 (begin

40 (display "Goodbye!")

41 (newline)

42 (gfx-shutdown))

43 (loop new-time)))))))