simponic.xyz/euler-golf/js/game.js

276 lines
6.7 KiB
JavaScript

const DEFAULTS = {
max_rows: 80,
max_cols: 80,
min_gap: 30,
angle_multiplier: 10e-4,
};
const CANVAS = document.getElementById("canvas");
let state = {
grid_padding: 30,
gap: DEFAULTS.min_gap,
canvas: CANVAS,
ctx: CANVAS.getContext("2d"),
last_render: 0,
keys: {},
changes: {},
};
// Rendering
CanvasRenderingContext2D.prototype.circle = function (x, y, r, color) {
this.beginPath();
this.arc(x, y, r, 0, Math.PI * 2);
this.fillStyle = color;
this.fill();
this.closePath();
};
CanvasRenderingContext2D.prototype.line = function (
{ x_pos: x1, y_pos: y1 },
{ x_pos: x2, y_pos: y2 },
width,
color,
cap = "round"
) {
this.lineWidth = width;
this.strokeStyle = color;
this.lineCap = cap;
this.beginPath();
this.moveTo(x1, y1);
this.lineTo(x2, y2);
this.stroke();
this.closePath();
};
CanvasRenderingContext2D.prototype.draw_cartesian_path = function (
grid_spec,
cartesian_path,
width = 2,
color = "#fff"
) {
const path = cartesian_path.map((coord) => grid_to_canvas(coord, grid_spec));
path.slice(1).forEach((coord, i) => {
this.line(path[i], coord, width, color);
});
};
CanvasRenderingContext2D.prototype.do_grid = function (
rows,
cols,
draw_at_grid_pos = (ctx, x, y) => ctx.circle(x, y, 10, "#44ff44")
) {
for (let y = 0; y < rows; y++) {
for (let x = 0; x < cols; x++) {
draw_at_grid_pos(this, x, y);
}
}
};
CanvasRenderingContext2D.prototype.cartesian_grid = function (
rows,
cols,
grid_spec,
circle_spec_at_coords = (_x, _y) => ({ radius: 5, color: "#000" })
) {
this.do_grid(rows, cols, (ctx, x, y) => {
const { x_pos, y_pos } = grid_to_canvas({ x, y }, grid_spec);
const { radius, color } = circle_spec_at_coords(x, y);
ctx.circle(x_pos, y_pos, radius, color);
});
};
// Utilities
const move = (prev, curr, c) => cx.add(prev, cx.mult(c, cx.sub(curr, prev)));
const rand_between = (min, max) =>
Math.floor(Math.random() * (max - min + 1)) + min;
const rand_target = (rows, cols) => {
const r = Math.floor((rows - 1) / 2);
const c = Math.floor((cols - 1) / 2);
const res = new cx(rand_between(-c, c), rand_between(-r, r));
if (!sol(res)) return rand_target(rows, cols);
return res;
};
const calculate_grid_spec = ({ rows, cols, width, height, grid_padding }) => {
const dx = (width - 2 * grid_padding) / cols;
const dy = (height - 2 * grid_padding) / rows;
return {
dx,
dy,
start_x: grid_padding + dx / 2,
start_y: grid_padding + dy / 2,
};
};
const grid_to_canvas = ({ x, y }, { dx, dy, start_x, start_y }) => ({
x_pos: x * dx + start_x,
y_pos: y * dy + start_y,
});
const complex_to_grid = (c, rows, cols) => {
const { re, im } = c;
return {
x: re + Math.floor(cols / 2),
y: Math.floor(rows / 2) - im,
};
};
// Game loop
const maybe_add_state_angle_move = ({ angle } = state) => {
if (angle.im <= -1 || angle.im >= 1) {
angle.im = angle.im <= -1 ? -1 : 1;
state.path.push(move(state.path.at(-2), state.path.at(-1), angle));
state.angle = new cx(0, 0);
}
return state;
};
const handle_input = (state, dt) => {
if (state.keys.ArrowLeft) {
state.angle.im += DEFAULTS.angle_multiplier * dt;
} else if (state.keys.ArrowRight) {
state.angle.im -= DEFAULTS.angle_multiplier * dt;
}
state = maybe_add_state_angle_move(state);
};
const render = ({ width, height, ctx, rows, cols, target, gap } = state) => {
ctx.clearRect(0, 0, width, height);
ctx.fillStyle = "rgba(0, 0, 0, 0)";
ctx.fillRect(0, 0, width, height);
const grid_spec = calculate_grid_spec(state);
const curr = state.path.at(-1);
const prev = state.path.at(-2);
const v_diff = cx.sub(curr, prev);
const theta = (state.angle.im * Math.PI) / 2;
const angle_re = Math.cos(theta) * v_diff.re - Math.sin(theta) * v_diff.im;
const angle_im = Math.sin(theta) * v_diff.re + Math.cos(theta) * v_diff.im;
ctx.draw_cartesian_path(grid_spec, [
...state.path.map((c) => complex_to_grid(c, rows, cols)),
complex_to_grid(cx.add(new cx(angle_re, angle_im), prev), rows, cols),
]);
if (!(state.angle.im == state.angle.re && state.angle.re == 0)) {
// Draw path to next player's target
const [a, b] = [
curr,
move(prev, curr, new cx(0, state.angle.im < 0 ? -1 : 1)),
].map((c) => grid_to_canvas(complex_to_grid(c, rows, cols), grid_spec));
ctx.line(a, b, 6, "rgba(127, 127, 127, 0.3)");
}
const grid_target = complex_to_grid(target, rows, cols);
ctx.cartesian_grid(rows, cols, grid_spec, (x, y) => {
if (x == Math.floor(cols / 2) && y == Math.floor(rows / 2)) {
return {
radius: 7,
color: "#2f9c94",
};
} else if (x == grid_target.x && y == grid_target.y) {
return {
radius: 8,
color: "#fff",
};
} else {
return {
radius: 3,
color: `rgb(${255 * (x / cols)}, 100, 100)`, // todo: animate with last_render
};
}
});
// Render gap value in slider
document.getElementById("gap").value = gap;
};
const loop = (now) => {
const dt = now - state.last_render;
state.changes.last_render = now;
if (Object.keys(state.changes).length > 0) {
state = { ...state, ...state.changes };
if (state.changes.width || state.changes.height || state.changes.gap) {
state.rows = Math.floor(state.height / state.gap);
state.cols = Math.floor(state.width / state.gap);
}
state.changes = {};
}
if (!state.target) state.target = rand_target(state.rows, state.cols);
if (!state.solution) {
handle_input(state, dt);
} else {
if (!state?.solution.length) {
delete state.solution;
} else {
state.angle.im +=
(state.solution[0] === "-" ? 1 : -1) * DEFAULTS.angle_multiplier * dt;
state = maybe_add_state_angle_move(state);
if (cx.eq(state.angle, new cx(0, 0))) state.solution.shift();
}
}
render(state);
requestAnimationFrame(loop);
};
const reset_state = ({ rows, cols } = state) => ({
...state,
solution: null,
path: [new cx(0, 0), new cx(1, 0)],
angle: new cx(0, 0),
});
// DOM
const directions_modal = new Modal({
el: document.getElementById("directions-modal"),
});
const on_resize = () => {
CANVAS.width = document.body.clientWidth;
CANVAS.height = document.body.clientHeight;
state.changes.width = CANVAS.width;
state.changes.height = CANVAS.height;
};
const on_keyup = (e) => {
delete state.keys[e.key];
};
const on_keydown = (e) => {
state.keys[e.key] = true;
};
window.addEventListener("resize", on_resize);
window.addEventListener("keydown", on_keydown);
window.addEventListener("keyup", on_keyup);
// main
on_resize();
state = reset_state(state);
if (!sessionStorage.getItem("seen-instructions")) {
directions_modal.show();
sessionStorage.setItem("seen-instructions", true);
}
requestAnimationFrame(loop);