62 lines
2.7 KiB
Plaintext
62 lines
2.7 KiB
Plaintext
;;;; raylib [core] example - window should close
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;;;;
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;;;; examples/core/core_window_should_close.c. Needed set-exit-key, and one
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;;;; enum member to go with it: raylib.fln's `Key` now has `null 0`, read off
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;;;; KEY_NULL in raylib.h. The binding is hand-written rather than taken from
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;;;; the generated half because the Flan face differs — raylib declares
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;;;; `void SetExitKey(int key)` and the generated line therefore takes an i32,
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;;;; where this one takes a Key, so `rl/set-exit-key(:key-null)` is checked
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;;;; against the enum and `:nul` is a compile error instead of a 0.
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;;;;
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;;;; The whole example is about what window-should-close means. It is not a
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;;;; flag raylib latches: it is "the close button was clicked, or the exit key
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;;;; is down", recomputed each frame, and it goes back to false on its own.
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;;;; That is what lets this program ask for confirmation and then carry on —
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;;;; and it is also why the loop is driven by a `once` of its own rather
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;;;; than by the predicate, which is the one structural difference from every
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;;;; other example in this directory.
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;;;;
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;;;; `set-exit-key(:null)` takes ESC away from raylib so the program can read
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;;;; it itself. The window's X button still works and is still what
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;;;; window-should-close reports.
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import rl "vendor:raylib"
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const screen-width = 800
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const screen-height = 450
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once exit-requested: bool
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once exiting: bool
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fn main() -> ()
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rl/init-window(screen-width, screen-height,
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"raylib [core] example - window should close")
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defer rl/close-window()
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;; No key closes the window any more. ESC is an ordinary key from here on.
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rl/set-exit-key(:key-null)
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rl/set-target-fps(60)
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until exiting
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;; Update. Either way of asking to leave raises the question; only Y and N
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;; answer it. window-should-close is false again on the next frame, so
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;; the request has to be remembered in a variable.
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if rl/window-should-close() or rl/is-key-pressed(:key-escape)
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exit-requested = true
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;; The C's `if (Y) ... else if (N) ...`, which is an `if` with a `when`
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;; in its else and not a `cond`: a `cond` needs an `:else` arm and there
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;; is nothing to do when neither key was pressed.
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if exit-requested
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if rl/is-key-pressed(:key-y)
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exiting = true
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elif rl/is-key-pressed(:key-n)
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exit-requested = false
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;; Draw
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rl/with-drawing:
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rl/clear-background(rl/raywhite)
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if exit-requested
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rl/draw-rectangle(0, 100, screen-width, 200, rl/black)
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rl/draw-text("Are you sure you want to exit program? [Y/N]", 40, 180,
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30, rl/white)
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else
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rl/draw-text("Try to close the window to get confirmation message!",
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120, 200, 20, rl/lightgray)
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