;;;; raylib [core] example - input multitouch
;;;;
;;;; examples/core/core_input_multitouch.c. No new bindings: the whole touch
;;;; surface was already there for sand.fln's read-out.
;;;;
;;;; The C keeps `Vector2 touchPositions[MAX_TOUCH_POINTS]`, and this is the
;;;; first example that needs a fixed array whose element type is a STRUCT
;;;; rather than a number. That works — `[10 rl/Vector2]` is ten Vector2s laid
;;;; out flat, no headers, and `touch-positions[i]` is a place that can be
;;;; assigned a whole struct. Nothing in the repository used one before, so it
;;;; is worth saying that it does.
;;;;
;;;; It is a top-level `once` and not a local, which is NOT a stylistic
;;;; choice. A `let` binding takes no type annotation, so the only way to make
;;;; a fixed array inside a function is to initialise it from a literal with
;;;; every element written out — ten `rl/Vector2{.x 0.0 .y 0.0}`s here, and
;;;; thirty-two in the gestures testbed. A zeroed local array of a given type
;;;; cannot be spelled. Static storage is what the C's `= { 0 }` gets anyway.
;;;;
;;;; On a desktop with no touchscreen get-touch-point-count is 0 and this draws
;;;; nothing at all, which is correct and is also what the C does. The window
;;;; opening and the help text appearing is the whole of what can be checked
;;;; without hardware.

import rl "vendor:raylib"

const screen-width = 800
const screen-height = 450

const max-touch-points = 10

once touch-positions: [max-touch-points rl/Vector2]

fn main() -> ()
  rl/init-window(screen-width, screen-height,
                 "raylib [core] example - input multitouch")
  defer rl/close-window()
  rl/set-target-fps(60)
  until rl/window-should-close()
    ;; Update
    let count = min(max-touch-points, rl/get-touch-point-count())
    for i in range(count)
      touch-positions[i] = rl/get-touch-position(i)
    ;; Draw
    rl/with-drawing:
      rl/clear-background(rl/raywhite)
      for i in range(count)
        let p = touch-positions[i]
        ;; raylib reports (0,0) for a slot that is not being touched, so the
        ;; C filters on it and so does this. It means a real touch in the
        ;; very top-left corner is dropped; that is raylib's ambiguity, not
        ;; something the port introduced.
        if p.x > 0.0 and p.y > 0.0
          rl/draw-circle-v(p, 34.0, rl/orange)
          ;; The C's TextFormat("%d", i). This used to need examples/digits.fln
          ;; and a table of one-character strings; (string b) makes the
          ;; number a string with no instructions, so it is one draw-text and
          ;; this file imports nothing but raylib.
          rl/draw-text(str(i64->bytes(i64(i))), i32(p.x) - 10, i32(p.y) - 70,
                       40, rl/black)
      rl/draw-text("touch the screen at multiple locations to get multiple balls",
                   10, 10, 20, rl/darkgray)
    ;; The numbers drawn this frame were formatted into the temp allocator;
    ;; this hands that memory back once the frame is drawn.
    free-temp()