init

js/cohesion.js

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+/*
+    Code for cohesion. 
+    Allows water to stick to itself.
+
+    radius: How far out of blocks will contribute to sticking
+    isAll: 
+        If this is false or undefined, cohesion occurs (sticks to self)
+        If this is true, adhesion and cohesion ocucrs (sticks to non-air)
+
+*/
+
+function cohesion(event, radius, isAll = 0) {
+    if (event.type != 'tick') return;
+    
+    let cx = event.data[0];
+    let cy = event.data[1];
+    let chunks = event.canvas;
+
+    let dir = [0, 0];
+    let force = [0,0];
+
+    let currBlock = chunks.getBlock(cx, cy);
+
+    for (let x = -radius; x <= radius; x ++) {
+        for (let y = -radius; y <= radius; y++) {
+            let blok = chunks.getBlock(cx + x, cy + y);
+
+            let factor = ((blok == currBlock) * (1-isAll)) + ((blok != air) * isAll);
+
+            if (factor == 0) continue;
+
+            let dist = 0.1 + (1/8 * (-x * -x - y * y + 8) * (x * x + y * y));
+
+            force[0] += x / dist * factor;
+            force[1] += y / dist * factor;
+        }
+    }
+
+    if (force[0] == 0 && force[1] == 0) return;
+
+    dir[0] = (Math.abs(force[0]) < radius*0.1) ? 0 : Math.sign(force[0]);
+    dir[1] = (Math.abs(force[1]) < radius*0.1) ? 0 : Math.sign(force[1]);
+
+    if (Math.abs(force[0]) < Math.abs(force[1])) {
+        force[0] = 0
+    } else {
+        force[1] = 0
+    }
+
+    let offBlock = chunks.getBlock(cx + dir[0], cy + dir[1]);
+
+    if (currBlock == -1 || offBlock == -1 || offBlock != air || currBlock == offBlock || chunks.noTick[(cx+dir[0])*chunks.height + (cy+dir[1])]) return;
+
+    chunks.setBlock(cx, cy, offBlock);
+    chunks.setBlock(cx + dir[0], cy + dir[1], currBlock);
+
+    let t = chunks.getBlock(cx, cy,true);
+    let t2 = chunks.getBlock(cx + dir[0], cy + dir[1],true);
+    
+    if (t != undefined && t2 != undefined) {
+        chunks.setBlock(cx, cy,t2, true);
+        chunks.setBlock(cx + dir[0], cy + dir[1], t, true);
+    }
+
+    return true;
+}
+
+Tile.prototype.cohesion = function (radius, isAll) {
+    this.interactions.push(function (event) {
+        cohesion(event, radius, isAll)
+    });
+    return this;
+}