some code optimisation

diff --git a/engine.js b/engine.js
index faeecc2a97cb35576f71a30b90e4c39ff8842415..d0a87c4e7377a2c3052176f7e529bde82f920ac7 100644 (file)
--- a/engine.js
+++ b/engine.js
@@ -78,20 +78,26 @@ function Textfile(txtfile) {
 }
 
 function Map(textdef) {
-  this.frametime = performance.now();
   this.info = gamedata.load(textdef);
-  this.tileset = gamedata.load(this.info.header.tileset);
-  gfx.load(this.tileset.img);
+  const tileset = gamedata.load(this.info.header.tileset);
+  const frametime = performance.now();
+  gfx.load(tileset.img);
 
-  var  h = this.info.header.height,      w = this.info.header.width;
-  var th = this.info.header.tileheight, tw = this.info.header.tilewidth;
+  const  h = this.info.header.height,      w = this.info.header.width;
+  const th = this.info.header.tileheight, tw = this.info.header.tilewidth;
   var posx = canvas.canvas.width / 2, posy = canvas.canvas.height / 2 - h * th/2;
 
+  const dx = [], dy = [];  // precalculated tile positions
+  for ( let y = 0; y < h; y++ ) for ( let x = 0; x < w; x++ ) {
+    dx[y * w + x] = (w + x - y) * tw / 2;
+    dy[y * w + x] = (x + y) * th / 2;
+  }
+
   canvas.fillStyle = "rgba("+this.info.header.background_color+")";
 
   this.tileAt = function(x, y) {
-    nx = (y + th / 2) / th + (x - w * tw / 2) / tw |0;
-    ny = (y + th / 2) / th - (x - w * tw / 2) / tw |0;
+    var r = (y + th / 2) / th; var c = (x - w * tw /2) / tw;
+    var nx = r + c |0; var ny = r - c |0;
     return ny * w + nx;
   }
 
@@ -102,57 +108,56 @@ function Map(textdef) {
   }
 
   this.draw = function(mobs) {
-    var x, y, dx, dy, i;
-    var bg = this.info.layer.find(l => l.type == "background").data;
-    var ob = this.info.layer.find(l => l.type == "object").data;
-    var mm = [];
+    const bg = this.info.layer.find(l => l.type == "background").data;
+    const ob = this.info.layer.find(l => l.type == "object").data;
+    var x, y, i, mm = [];
+
     mobs.forEach(m => {
-      i = this.tileAt(m.position[0], m.position[1]);
+      let i = this.tileAt(m.position[0], m.position[1]);
       mm[i] = mobs.filter(m => i == this.tileAt(m.position[0], m.position[1]));
     });
     canvas.fillRect(0,0, canvas.canvas.width, canvas.canvas.height);
 
     for ( y = 0; y < h; y++ ) for ( x = 0; x < w; x++ ) {
       i = y * h + x;
-      dx = posx + (w + x - y) * tw /2;
-      dy = posy + (x + y) * th / 2;
-      this.draw_tile(bg[i], dx, dy);
+      draw_tile(bg[i], posx + dx[i], posy + dy[i]);
     }
     for ( y = 0; y < h; y++ ) for ( x = 0; x < w; x++ ) {
       i = y * h + x;
-      dx = posx + (w + x - y) * tw /2;
-      dy = posy + (x + y) * th / 2;
-      this.draw_tile(ob[i], dx, dy);
-      if (mm[i]) mm[i].forEach(m => m.draw(m.position[0] + posx, m.position[1] + posy));
+      draw_tile(ob[i], posx + dx[i], posy + dy[i]);
+      if (mm[i]) mm[i].forEach(m => m.draw(posx + m.position[0], posy + m.position[1]));
     }
   }
 
-  this.draw_tile = function(tile, x, y) {
+  function draw_tile(tile, x, y) {
+    const t = tileset.tile[tile];
+    const f = tileset.animation[tile];
     x = x |0; y = y |0;
-    var t = this.tileset.tile[tile];
-    var f = this.tileset.animation[tile];
 
     if (t && f) {
-      frame = ((performance.now() - this.frametime) / f[0][2] |0) % f.length;
-      canvas.drawImage(gfx[this.tileset.img], f[frame][0], f[frame][1], t[2], t[3],
-                                                    x - t[4], y - t[5], t[2], t[3]);
+      frame = ((performance.now() - frametime) / f[0][2] |0) % f.length;
+      canvas.drawImage(gfx[tileset.img], f[frame][0], f[frame][1], t[2], t[3],
+                                               x - t[4], y - t[5], t[2], t[3]);
     } else if (t) {
-      canvas.drawImage(gfx[this.tileset.img], t[0], t[1], t[2], t[3],
-                                      x - t[4], y - t[5], t[2], t[3]);
+      canvas.drawImage(gfx[tileset.img], t[0], t[1], t[2], t[3],
+                                 x - t[4], y - t[5], t[2], t[3]);
     }
   }
 }
 
 function Mob(textdef) {
   this.position = [0, 0];
-  var info = gamedata.load(textdef);
+  const info = gamedata.load(textdef);
   var direction = 0;
   var animation = "stance";
   var previous_animation = "";
   var frametime = performance.now();
   gfx.load(info.image)
 
-  this.place = function(x, y) { this.position = [x, y]; return this; }
+  this.place = function(x, y) {
+    this.position[0] = x, this.position[1] = y;
+    return this;
+  }
   this.direct = function(d) { direction = d % 8; return this; }
   this.animate = function(a) {
     if ( a != animation ) {
@@ -165,7 +170,7 @@ function Mob(textdef) {
 
   this.draw = function(x, y){
     var f, a = info[animation];
-    var frame = ( performance.now() - frametime ) * a.frames / a.duration | 0;
+    var f, frame = ( performance.now() - frametime ) * a.frames / a.duration | 0;
 
     switch(a.type){
       case "looped":
@@ -208,18 +213,18 @@ function Mob(textdef) {
 function Hero(gender = "female", hair = "short"){
   this.position = [0,0];
   this.stats = gamedata.load("/engine/stats.txt");
-  var layers = gamedata.load("/engine/hero_layers.txt");
-  var hair = (gender == "female")?"long":hair;
+  const layers = gamedata.load("/engine/hero_layers.txt");
   var direction = 0, animation = "stance";
+  hair = (gender == "female")?"long":hair;
 
-  limbs = {
+  var limbs = {
     head : new Mob("/animations/avatar/"+gender+"/head_"+hair+".txt"),
-    chest: new Mob("/animations/avatar/"+gender+"/default_chest.txt"),
+    chest: new Mob("/animations/avatar/"+gender+"/cloth_shirt.txt"),
     hands: new Mob("/animations/avatar/"+gender+"/default_hands.txt"),
-    legs : new Mob("/animations/avatar/"+gender+"/default_legs.txt"),
+    legs : new Mob("/animations/avatar/"+gender+"/cloth_pants.txt"),
     feet : new Mob("/animations/avatar/"+gender+"/default_feet.txt"),
-    main : new Mob("/animations/avatar/"+gender+"/dagger.txt"),
-    off  : new Mob("/animations/avatar/"+gender+"/shield.txt")
+    main : new Mob("/animations/avatar/"+gender+"/default_hands.txt"),
+    off  : new Mob("/animations/avatar/"+gender+"/default_hands.txt")
   }
 
   this.dress = function(limb, item) {
@@ -230,7 +235,7 @@ function Hero(gender = "female", hair = "short"){
   }
 
   this.place   = function(x,y) {
-    this.position = [x,y];
+    this.position[0] = x, this.position[1] = y;
     for (var limb in limbs) limbs[limb].place(x,y);
     return this;
   }
@@ -333,4 +338,4 @@ player.direct(5).stance();
 map.center(player.position[0], player.position[1]);
 c = new Controls(player, map);
 
-setInterval (() => map.draw([player]), 16.66 );
+setInterval (() => map.draw([player]), 33.33 );