Joseph Ferano
25f56c24a8
vendor/raylib/modes.flan: five macros over the five pairs the package binds -- with-drawing, with-mode-2d, with-mode-3d, with-texture-mode, with-scissor-mode. A second file with no declare-c in it, split out on vector.flan's reasoning: raylib.flan is the package's statement about C and nothing here names C, so nothing here can be made wrong by raylib changing. Each expands to (do (begin-... args) body... (end-...)) -- the calls the author used to type, in the order they typed them. No let, no gensym: nothing binds a name, so there is nothing for a caller's name to collide with. What it removes is the End* that is missing, wrong, or no longer beside its Begin*. What it cannot remove is a body leaving through the unwind path: a return or an invoke-restart skips the rest of the do and the End* with it. defer is the obvious fix and is refused inside a loop body, which is where a pair always lives -- checked, not assumed. So sand.flan's discipline stays: keep the restart boundary outside the pair. 35 call sites converted across examples/ and sand.flan. The one left is core-scissor-test.flan, whose Begin and End sit in two separate `when`s with the drawing between them -- a conditional pair is a shape a bracketing macro cannot express. test/programs/rl-with.flan covers with-scissor-mode, which no example can, with a frame function unreachable from main so it needs no libraylib; rl-with-reject.flan is the arity half.
138 lines
6.0 KiB
Plaintext
138 lines
6.0 KiB
Plaintext
;;;; raylib [core] example - 2d camera
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;;;;
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;;;; examples/core/core_2d_camera.c. Needed no new binding at all, which is
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;;;; the reason to port it: Camera2D, begin-mode-2d and end-mode-2d have been
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;;;; in vendor/raylib/raylib.flan since the beginning and nothing in the
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;;;; corpus had ever passed a whole Camera2D across the FFI on a frame's path.
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;;;; Two Vector2s, a float and a float, by value, sixty times a second — the
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;;;; acceptance table pins that layout with get-screen-to-world-2d, and this
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;;;; is the same struct going into the call that actually draws with it.
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;;;;
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;;;; The hundred buildings are a `defvar` of fixed arrays rather than a Vec:
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;;;; a global cannot hold a Vec (PORTING.md §3) and does not need to here,
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;;;; because the count is a constant in the C too. `(array n T)` is the zeroed
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;;;; fixed array, and the C's `= { 0 }` is exactly that.
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;;;;
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;;;; get-random-value comes from the generated half of the bindings. It is on
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;;;; no frame's path — it runs once, before the loop — and its Flan face is
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;;;; the C one, so PORTING.md §1's rule does not reach it.
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;;;;
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;;;; One deliberate difference from the C: `(- camera.rotation 1.0)` and the
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;;;; clamp after it are written with the prelude's `clamp` macro rather than
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;;;; two ifs. It is the same arithmetic; the C spells it out because C has no
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;;;; clamp.
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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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(defconst max-buildings 100)
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(defvar buildings [100 rl/Rectangle])
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(defvar build-colors [100 rl/Color])
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(defvar player rl/Rectangle)
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(defvar camera rl/Camera2D)
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(defn main [] ()
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(rl/init-window screen-width screen-height
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"raylib [core] example - 2d camera")
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(defer (rl/close-window))
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(set player (rl/Rectangle {.x 400.0 .y 280.0 .width 40.0 .height 40.0}))
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(set buildings (array max-buildings rl/Rectangle))
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(set build-colors (array max-buildings rl/Color))
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;; The skyline: each building is as wide as the last one left room for, so
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;; the spacing accumulates and the row starts 6000 units to the left.
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(let [spacing 0]
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(dotimes [i max-buildings]
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(let [w (f32 (rl/get-random-value 50 200))
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h (f32 (rl/get-random-value 100 800))]
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(set (at buildings i)
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(rl/Rectangle {.x (+ -6000.0 (f32 spacing))
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.y (- (- (f32 screen-height) 130.0) h)
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.width w
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.height h}))
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(set spacing (+ spacing (i32 w)))
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(set (at build-colors i)
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(rl/Color {.r (u8 (rl/get-random-value 200 240))
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.g (u8 (rl/get-random-value 200 240))
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.b (u8 (rl/get-random-value 200 250))
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.a 255})))))
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;; A fresh Camera2D is all zeroes and a zoom of 0 makes the transform
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;; singular, so the zoom is the one field that must be set — raylib.flan's
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;; own comment on the struct says so.
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(set camera (rl/Camera2D {.offset (rl/Vector2 {.x (/ (f32 screen-width) 2.0)
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.y (/ (f32 screen-height) 2.0)})
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.target (rl/Vector2 {.x (+ (.x player) 20.0)
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.y (+ (.y player) 20.0)})
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.rotation 0.0
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.zoom 1.0}))
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(rl/set-target-fps 60)
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(until (rl/window-should-close?)
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;; Update
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;; The C's `if (RIGHT) ... else if (LEFT) ...`: both held cancels to the
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;; right, which is the else-if and not an accident.
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(if (rl/key-down? :right)
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(set (.x player) (+ (.x player) 2.0))
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(when (rl/key-down? :left) (set (.x player) (- (.x player) 2.0))))
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;; The camera follows the player's centre.
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(set (.target camera) (rl/Vector2 {.x (+ (.x player) 20.0)
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.y (+ (.y player) 20.0)}))
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(if (rl/key-down? :a)
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(set (.rotation camera) (- (.rotation camera) 1.0))
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(when (rl/key-down? :s)
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(set (.rotation camera) (+ (.rotation camera) 1.0))))
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(set (.rotation camera) (clamp (.rotation camera) -40.0 40.0))
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(set (.zoom camera) (+ (.zoom camera) (* (rl/get-mouse-wheel-move) 0.05)))
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(set (.zoom camera) (clamp (.zoom camera) 0.1 3.0))
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(when (rl/key-pressed? :r)
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(set (.zoom camera) 1.0)
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(set (.rotation camera) 0.0))
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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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;; Everything inside with-mode-2d is in world space and goes through
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;; the camera. The ground and the crosshair lines are drawn far outside
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;; the window on purpose: at zoom 0.1 they still have to reach the edges.
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(rl/with-mode-2d camera
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(rl/draw-rectangle -6000 320 13000 8000 rl/darkgray)
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(dotimes [i max-buildings]
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(rl/draw-rectangle-rec (at buildings i) (at build-colors i)))
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(rl/draw-rectangle-rec player rl/red)
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(rl/draw-line (i32 (.x (.target camera))) (* screen-height -10)
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(i32 (.x (.target camera))) (* screen-height 10) rl/green)
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(rl/draw-line (* screen-width -10) (i32 (.y (.target camera)))
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(* screen-width 10) (i32 (.y (.target camera))) rl/green))
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;; And everything after it is in screen space again — the frame drawn
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;; around the window is how the example shows the difference.
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(rl/draw-text "SCREEN AREA" 640 10 20 rl/red)
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(rl/draw-rectangle 0 0 screen-width 5 rl/red)
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(rl/draw-rectangle 0 5 5 (- screen-height 10) rl/red)
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(rl/draw-rectangle (- screen-width 5) 5 5 (- screen-height 10) rl/red)
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(rl/draw-rectangle 0 (- screen-height 5) screen-width 5 rl/red)
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(rl/draw-rectangle 10 10 250 113 (rl/fade rl/skyblue 0.5))
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(rl/draw-rectangle-lines 10 10 250 113 rl/blue)
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(rl/draw-text "Free 2d camera controls:" 20 20 10 rl/black)
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(rl/draw-text "- Right/Left to move Offset" 40 40 10 rl/darkgray)
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(rl/draw-text "- Mouse Wheel to Zoom in-out" 40 60 10 rl/darkgray)
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(rl/draw-text "- A / S to Rotate" 40 80 10 rl/darkgray)
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(rl/draw-text "- R to reset Zoom and Rotation" 40 100 10 rl/darkgray))))
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