47 lines
1.8 KiB
Plaintext
47 lines
1.8 KiB
Plaintext
;;;; raylib [core] example - input keys
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;;;;
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;;;; examples/core/core_input_keys.c. Faithful, and the only thing worth noting
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;;;; is a Flan rule rather than a raylib one.
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;;;;
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;;;; The C moves the ball by writing `ballPosition.x += 2.0f` on a local
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;;;; struct. Flan has the same thing — a local IS an assignable place
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;;;; (spec-memory.md) — but the local has to be a `defonce` here rather than a
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;;;; `let` inside the loop, because a `let` binding is rebound every iteration
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;;;; and the position has to survive between frames. The C's variable is
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;;;; outside its while loop for the same reason; this is that, spelled with the
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;;;; storage the language has.
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;;;;
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;;;; `(set (.x ball) ...)` works on a struct field of a global: a field of an
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;;;; assignable place is itself one.
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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 ball rl/Vector2)
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(defn main [] ()
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(rl/init-window screen-width screen-height
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"raylib [core] example - input keys")
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(defer (rl/close-window))
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(set ball (rl/Vector2 {.x (f32 (/ screen-width 2))
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.y (f32 (/ screen-height 2))}))
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(rl/set-target-fps 60)
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(until (rl/window-should-close)
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;; Update. is-key-down and not is-key-pressed: this is meant to repeat for as
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;; long as the key is held, which is the whole difference between the two.
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(when (rl/is-key-down :key-right) (set (.x ball) (+ (.x ball) 2.0)))
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(when (rl/is-key-down :key-left) (set (.x ball) (- (.x ball) 2.0)))
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(when (rl/is-key-down :key-up) (set (.y ball) (- (.y ball) 2.0)))
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(when (rl/is-key-down :key-down) (set (.y ball) (+ (.y ball) 2.0)))
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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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(rl/draw-text "move the ball with arrow keys" 10 10 20 rl/darkgray)
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(rl/draw-circle-v ball 50.0 rl/maroon))))
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