67 lines
2.8 KiB
Plaintext
67 lines
2.8 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.flan'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 `defonce` 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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(defconst screen-width 800)
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(defconst screen-height 450)
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(defonce exit-requested bool)
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(defonce exiting bool)
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(defn 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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(when (or (rl/window-should-close) (rl/is-key-pressed :key-escape))
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(set 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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(when exit-requested
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(if (rl/is-key-pressed :key-y)
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(set exiting true)
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(when (rl/is-key-pressed :key-n) (set 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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(do
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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 30
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rl/white))
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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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