add chess example

examples/chess/Makefile

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+def:
+	cd _prosperon && make && cp build_dbg/prosperon ..
+	./prosperon

examples/chess/grid.js

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+var CELLS = Symbol()
+
+var key = function key(x,y) { return `${x},${y}` }
+
+function grid(w, h)
+{
+  this[CELLS] = new Map()
+  this.width = w;
+  this.height = h;
+}
+
+grid.prototype = {
+  cell(x,y) {
+    var k = key(x,y)
+    if (!this[CELLS].has(k)) this[CELLS].set(k,[])
+    return this[CELLS].get(k)
+  },
+  
+  add(entity, pos) {
+    this.cell(pos.x, pos.y).push(entity);
+    entity.coord = pos.slice();
+  },
+  
+  remove(entity, pos) {
+    var c = this.cell(pos.x, pos.y);
+    c.splice(c.indexOf(entity), 1);
+  },
+  
+  at(pos) {
+    return this.cell(pos.x, pos.y);
+  },
+  
+  inBounds(pos) {
+    return pos.x >= 0 && pos.x < this.width && pos.y >= 0 && pos.y < this.height;
+  },
+  
+  each(fn) {
+    for (var [k, list] of this[CELLS])
+      for (var p of list) fn(p, p.coord);
+  },
+  
+  toString() {
+    var out = `grid [${this.width}x${this.height}]
+`
+    for (var y = 0; y < this.height; y++) {
+      for (var x = 0; x < this.width; x++) {
+        var cell = this.at([x,y]);
+        out += cell.length
+      }
+      if (y !== this.height - 1) out += "\n"
+    }
+      
+    return out
+  },
+}
+
+return grid

examples/chess/main.js

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+/* main.js – runs the demo with your prototype-based grid */
+var res = 160
+var internal_res = 480
+var render = use('render');
+render.initialize({ width:res, height:res, resolution_x:internal_res, resolution_y:internal_res, mode:'letterbox' });
+
+var os     = use('os');
+var draw2d = use('draw2d');
+var gfx    = use('graphics');
+
+/* camera – unchanged */
+var camera = { size:[internal_res,internal_res], transform:os.make_transform(), fov:50, near_z:0,
+               far_z:1000, surface:undefined, viewport:{x:0,y:0,width:1,height:1},
+               ortho:true, anchor:[0,0] };
+
+/*──── import our pieces + systems ───────────────────────────────────*/
+var Grid           = use('grid');              // your new ctor
+var MovementSystem = use('movement').MovementSystem;
+var startingPos    = use('pieces').startingPosition;
+var rules          = use('rules');
+
+/*──── build board ───────────────────────────────────────────────────*/
+var grid = new Grid(8, 8);
+grid.width = 8;   // (the ctor didn’t store them)
+grid.height = 8;
+
+var mover = new MovementSystem(grid, rules);
+startingPos(grid);
+
+/*──── mouse → click-to-move ─────────────────────────────────────────*/
+var selectPos = null;
+prosperon.window.on_mousedown = function (btn, mx, my) {
+  if (btn !== 0) return;
+  var c = [Math.floor(mx / 60), Math.floor(my / 60)];
+  if (!grid.inBounds(c)) return;
+
+  var cell = grid.at(c);
+  if (selectPos && mover.tryMove(grid.at(selectPos)[0], c)) {
+    selectPos = null;                      // made a move
+    return;
+  }
+  if (cell.length && cell[0].colour === mover.turn) {
+    selectPos = c;                         // pick up piece
+  } else {
+    selectPos = null;
+  }
+};
+
+/*──── drawing helpers ───────────────────────────────────────────────*/
+/* ── constants ─────────────────────────────────────────────────── */
+var S = 60;                               // square size in px
+var light = [0.93,0.93,0.93,1];
+var dark  = [0.25,0.25,0.25,1];
+
+/* ── draw one 8×8 chess board ──────────────────────────────────── */
+function drawBoard() {
+  for (var y = 0; y < 8; ++y)
+    for (var x = 0; x < 8; ++x) {
+      draw2d.rectangle(
+        { x: x*S, y: y*S, width: S, height: S },
+        { thickness: 0, color: ((x+y)&1) ? dark : light }
+      );
+    }
+}
+
+/* ── draw every live piece ─────────────────────────────────────── */
+function drawPieces() {
+  grid.each(function (piece) {
+    if (piece.captured) return;
+
+    var r = { x: piece.coord[0]*S, y: piece.coord[1]*S,
+              width:S, height:S };
+
+    draw2d.image(piece.sprite, r, 0, [0,0], [0,0], {mode:"nearest"});
+  });
+}
+
+/*──── main loop ─────────────────────────────────────────────────────*/
+var last = os.now(), fpsTimer = 0, fpsCount = 0;
+
+function loop() {
+  var now = os.now(), dt = now - last; last = now;
+
+  render.clear([22/255, 120/255, 194/255, 1]);
+  render.camera(camera);
+  drawBoard();
+  drawPieces();
+  render.present();
+
+  fpsTimer += dt; fpsCount++;
+  if (fpsTimer >= 0.5) {
+    prosperon.window.title =
+      'Chess demo – ' + mover.turn + '\'s move – FPS ' + (fpsCount / fpsTimer).toFixed(1);
+    fpsTimer = fpsCount = 0;
+  }
+  $_.delay(loop, Math.max(0, (1 / 60) - (os.now() - now)));
+}
+loop();
+
+var os = use('os')
+var ioguy = {
+  __ACTORDATA__: {
+    id: os.ioactor()
+  }
+}
+
+$_.send(ioguy, {
+  type: "subscribe",
+  actor: $_
+})
+
+$_.receiver(e => {
+  if (e.type === 'quit')
+    os.exit()
+  else
+    console.log(json.encode(e))
+})

examples/chess/movement.js

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+var MovementSystem = function(grid, rules) {
+  this.grid  = grid;
+  this.rules = rules || {};      // expects { canMove: fn }
+  this.turn  = 'white';
+}
+
+MovementSystem.prototype.tryMove = function (piece, to) {
+  if (piece.colour !== this.turn) return false;
+
+  // normalise ‘to’ into our hybrid coord
+  var dest = [to.x !== undefined ? to.x : to[0],
+              to.y !== undefined ? to.y : to[1]];
+
+  if (!this.grid.inBounds(dest)) return false;
+  if (!this.rules.canMove(piece, piece.coord, dest, this.grid)) return false;
+
+  var victims = this.grid.at(dest);
+  if (victims.length && victims[0].colour === piece.colour) return false;
+  if (victims.length) victims[0].captured = true;
+
+  this.grid.remove(piece, piece.coord);
+  this.grid.add   (piece, dest);
+
+  // grid.add() re-creates coord; re-add .x/.y fields:
+  piece.coord.x = dest.x;
+  piece.coord.y = dest.y;
+
+  this.turn = (this.turn === 'white') ? 'black' : 'white';
+  return true;
+};
+
+return { MovementSystem: MovementSystem };

examples/chess/pieces.js

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+/* pieces.js – simple data holders + starting layout */
+function Piece(kind, colour) {
+  this.kind   = kind;                 // "pawn" etc.
+  this.colour = colour;               // "white"/"black"
+  this.sprite = colour + '_' + kind;  // for draw2d.image
+  this.captured = false;
+  this.coord    = [0,0];
+}
+Piece.prototype.toString = function () {
+  return this.colour.charAt(0) + this.kind.charAt(0).toUpperCase();
+};
+
+function startingPosition(grid) {
+  var W = 'white', B = 'black', x;
+
+  // pawns
+  for (x = 0; x < 8; x++) {
+    grid.add(new Piece('pawn', W), [x, 6]);
+    grid.add(new Piece('pawn', B), [x, 1]);
+  }
+  // major pieces
+  var back = ['rook','knight','bishop','queen','king','bishop','knight','rook'];
+  for (x = 0; x < 8; x++) {
+    grid.add(new Piece(back[x], W), [x, 7]);
+    grid.add(new Piece(back[x], B), [x, 0]);
+  }
+}
+
+return { Piece, startingPosition };

examples/chess/rules.js

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+/* helper – robust coord access */
+function cx(c) { return (c.x !== undefined) ? c.x : c[0]; }
+function cy(c) { return (c.y !== undefined) ? c.y : c[1]; }
+
+/* simple move-shape checks */
+var deltas = {
+  pawn: function (pc, dx, dy, grid, to) {
+    var dir  = (pc.colour === 'white') ? -1 : 1;
+    var base = (pc.colour === 'white') ? 6  : 1;
+    var one  = (dy === dir && dx === 0 && grid.at(to).length === 0);
+    var two  = (dy === 2 * dir && dx === 0 && cy(pc.coord) === base &&
+               grid.at({ x: cx(pc.coord), y: cy(pc.coord)+dir }).length === 0 &&
+               grid.at(to).length === 0);
+    var cap  = (dy === dir && Math.abs(dx) === 1 && grid.at(to).length);
+    return one || two || cap;
+  },
+  rook  : function (pc, dx, dy) { return (dx === 0 || dy === 0); },
+  bishop: function (pc, dx, dy) { return Math.abs(dx) === Math.abs(dy); },
+  queen : function (pc, dx, dy) { return (dx === 0 || dy === 0 || Math.abs(dx) === Math.abs(dy)); },
+  knight: function (pc, dx, dy) { return (Math.abs(dx) === 1 && Math.abs(dy) === 2) ||
+                                         (Math.abs(dx) === 2 && Math.abs(dy) === 1); },
+  king  : function (pc, dx, dy) { return Math.max(Math.abs(dx), Math.abs(dy)) === 1; }
+};
+
+function clearLine(from, to, grid) {
+  var dx = Math.sign(cx(to) - cx(from));
+  var dy = Math.sign(cy(to) - cy(from));
+  var x  = cx(from) + dx, y = cy(from) + dy;
+  while (x !== cx(to) || y !== cy(to)) {
+    if (grid.at({ x: x, y: y }).length) return false;
+    x += dx; y += dy;
+  }
+  return true;
+}
+
+function canMove(piece, from, to, grid) {
+  var dx = cx(to) - cx(from);
+  var dy = cy(to) - cy(from);
+  var f  = deltas[piece.kind];
+  if (!f || !f(piece, dx, dy, grid, to)) return false;
+  if (piece.kind === 'knight') return true;
+  return clearLine(from, to, grid);
+}
+
+return { canMove };