Joseph Ferano
a4c6b996ff
The trio the author decided on 2026-09-20 is now all built: def is CL's defparameter — its initialiser runs on every daemon re-run, unguarded, so an edited initialiser repaints the same storage on C-c C-c plus re-run — defonce (Clojure's name for CL's defvar, per the author) initialises once behind the .init~once. flag, and defconst stays the image. One parse arm reads both forms; the difference is Ast.reinit, carried to Tast.global's grerun. Emit.startup_plan gives a def no guard flag, and Check.check_global lifts every def initialiser — zero and literal included — into global/<n>, so the host's startup reaches it through the function cell and a re-evaluated def swaps it (Session's def_inits; Emit.redefinition declares the cell for a non-sibling target). The old defvar spelling is refused with the rename and both compiling spellings, and every program, test, doc and editor list is swept — except sand.flan, the author's live WIP, whose seven defvar lines are flagged in FIX.org and keep its three dependent tests red on this branch.
130 lines
6.0 KiB
Plaintext
130 lines
6.0 KiB
Plaintext
;;;; raylib [models] example - box collisions
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;;;;
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;;;; examples/models/models_box_collisions.c. The previous lane's finding was
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;;;; that the whole models category is refused by the importer for want of a
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;;;; defstruct, and that a models example is therefore mostly a binding
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;;;; exercise. That is true of the twenty that load a Model — but not of this
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;;;; one, which is why it is here: nothing in it is a Model, a Mesh or a
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;;;; Material. It is two cubes, a sphere and one aggregate the package did not
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;;;; describe.
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;;;;
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;;;; That aggregate is BoundingBox, and it is two Vector3s and nothing else —
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;;;; no owned pointer, no array, no lifetime. One `defstruct` in
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;;;; vendor/raylib/raylib.flan un-refuses four raylib functions at once
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;;;; (CheckCollisionBoxes, CheckCollisionBoxSphere, DrawBoundingBox and
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;;;; GetRayCollisionBox), and that is the cheapest widening of the 3D surface
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;;;; available anywhere in the tree. Ray and RayCollision went in beside it
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;;;; for examples/core-3d-picking.flan and for the same reason.
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;;;;
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;;;; So the answer to "is a models example just a binding exercise" is: the
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;;;; ones that need Model are, and this one is the counterexample. What
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;;;; separates them is not the category, it is whether the struct owns memory.
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;;;;
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;;;; What it also exercises, and what needed hand-writing rather than
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;;;; generating: draw-cube-v, draw-sphere and draw-sphere-wires. All three
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;;;; were in the generated half already, and all three moved to the
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;;;; hand-written one here on `bindings`'s own rule — they are inside a frame,
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;;;; in an example that ships in examples/. draw-cube-v in particular was
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;;;; named there as generated *because nothing called it*; something calls it
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;;;; now.
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;;;;
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;;;; The collision maths is written twice in the C, once per test, building
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;;;; the player's box inline both times. It is a function here for the reason
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;;;; the eyes example gives: two copies of the same eight expressions cannot
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;;;; be checked against each other by reading them.
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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 camera rl/Camera3D)
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(defonce player-position rl/Vector3)
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(defonce player-size rl/Vector3)
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(defonce player-color rl/Color)
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(defonce enemy-box-pos rl/Vector3)
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(defonce enemy-box-size rl/Vector3)
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(defonce enemy-sphere-pos rl/Vector3)
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(defconst enemy-sphere-size f32 1.5)
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;; A box centred on `centre` with the given extents. raylib's BoundingBox is
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;; min-corner/max-corner, not centre/size, and every collision call in the
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;; family takes the corner form — so this is the conversion the C writes out
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;; longhand at each of its two call sites.
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;;
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;; It used to be eight expressions of field arithmetic here too; it is the
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;; half-extent subtracted and added now that the package carries vector
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;; arithmetic — see vendor/raylib/vector.flan, which is Flan and not C
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;; because raymath is `static inline` and has no symbol to bind.
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(defn box-around [centre rl/Vector3 size rl/Vector3] rl/BoundingBox
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(let [half (rl/v3-scale size 0.5)]
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(rl/BoundingBox {.min (rl/v3-sub centre half)
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.max (rl/v3-add centre half)})))
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(defn main [] ()
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(rl/init-window screen-width screen-height
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"raylib [models] example - box collisions")
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(defer (rl/close-window))
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;; The C writes this camera as a brace initialiser with a trailing 0 for the
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;; projection, which is CAMERA_PERSPECTIVE. Named here, because the defenum
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;; exists precisely so that the 0 does not have to be remembered.
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(set camera (rl/Camera3D {.position (rl/Vector3 {.x 0.0 .y 10.0 .z 10.0})
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.target (rl/Vector3 {.x 0.0 .y 0.0 .z 0.0})
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.up (rl/Vector3 {.x 0.0 .y 1.0 .z 0.0})
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.fovy 45.0
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.projection :perspective}))
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(set player-position (rl/Vector3 {.x 0.0 .y 1.0 .z 2.0}))
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(set player-size (rl/Vector3 {.x 1.0 .y 2.0 .z 1.0}))
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(set player-color rl/green)
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(set enemy-box-pos (rl/Vector3 {.x -4.0 .y 1.0 .z 0.0}))
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(set enemy-box-size (rl/Vector3 {.x 2.0 .y 2.0 .z 2.0}))
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(set enemy-sphere-pos (rl/Vector3 {.x 4.0 .y 0.0 .z 0.0}))
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(rl/set-target-fps 60)
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(until (rl/window-should-close?)
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;; Update. The arrow keys move on the XZ plane, and the C's else-if chain
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;; means only one direction applies per frame — diagonal movement is not
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;; possible, deliberately.
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(cond
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(rl/key-down? :key-right) (set (.x player-position) (+ (.x player-position) 0.2))
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(rl/key-down? :key-left) (set (.x player-position) (- (.x player-position) 0.2))
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(rl/key-down? :key-down) (set (.z player-position) (+ (.z player-position) 0.2))
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(rl/key-down? :key-up) (set (.z player-position) (- (.z player-position) 0.2)))
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(let [player-box (box-around player-position player-size)
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hit (or (rl/check-collision-boxes player-box
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(box-around enemy-box-pos enemy-box-size))
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(rl/check-collision-box-sphere player-box enemy-sphere-pos
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enemy-sphere-size))]
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(set player-color (if hit rl/red rl/green)))
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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/with-mode-3d camera
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(rl/draw-cube enemy-box-pos (.x enemy-box-size) (.y enemy-box-size)
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(.z enemy-box-size) rl/gray)
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(rl/draw-cube-wires enemy-box-pos (.x enemy-box-size) (.y enemy-box-size)
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(.z enemy-box-size) rl/darkgray)
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;; draw-sphere is draw-sphere-ex at 16 rings and 16 slices; the wires form
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;; takes them because the tessellation is only visible in the wireframe.
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(rl/draw-sphere enemy-sphere-pos enemy-sphere-size rl/gray)
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(rl/draw-sphere-wires enemy-sphere-pos enemy-sphere-size 16 16 rl/darkgray)
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(rl/draw-cube-v player-position player-size player-color)
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(rl/draw-grid 10 1.0))
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(rl/draw-text "Move player with arrow keys to collide" 220 40 20 rl/gray)
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(rl/draw-fps 10 10))))
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