Adding forward and backward (CTRL+Z and CTRL+Y)

2020-06-26 19:35:32 +02:00
parent 5cbf91f8fb
commit 1584f7af85
4 changed files with 110 additions and 77 deletions
@@ -0,0 +1,70 @@
+function drawLine(x0, y0, x1, y1) {
+  //Bresenham's line algorithm
+  let iterations = 0;
+  var dx = Math.abs(x1 - x0);
+  var dy = Math.abs(y1 - y0);
+  var sx = x0 < x1 ? 1 : -1;
+  var sy = y0 < y1 ? 1 : -1;
+  var err = dx - dy;
+  do {
+    drawPoint(x0, y0);
+    var e2 = 2 * err;
+    if (e2 > -dy) {
+      err -= dy;
+      x0 += sx;
+    }
+    if (e2 < dx) {
+      err += dx;
+      y0 += sy;
+    }
+    iterations++;
+    if (iterations > 1000) break;
+  } while (!(x0 == x1 && y0 == y1));
+}
+
+function fill(x, y) {
+  let iterations = 0;
+  drawGrid[y] = drawGrid[y] ? drawGrid[y] : [];
+  if (pencil != drawGrid[y][x]) {
+    const fillChar = drawGrid[y][x];
+    const pixelsToCheck = [x, y];
+    while (pixelsToCheck.length > 0) {
+      if (iterations > 100000) break;
+      iterations++;
+      const ypixel = pixelsToCheck.pop();
+      const xpixel = pixelsToCheck.pop();
+      drawGrid[ypixel] = drawGrid[ypixel] ? drawGrid[ypixel] : [];
+
+      if (
+        drawGrid[ypixel][xpixel] == fillChar &&
+        !(
+          xpixel > window.innerWidth / width ||
+          ypixel > window.innerHeight / height ||
+          xpixel < 0 ||
+          ypixel < 0
+        )
+      ) {
+        drawPoint(xpixel, ypixel);
+
+        pixelsToCheck.push(xpixel + 1, ypixel);
+        pixelsToCheck.push(xpixel - 1, ypixel);
+        pixelsToCheck.push(xpixel, ypixel + 1);
+        pixelsToCheck.push(xpixel, ypixel - 1);
+      }
+    }
+
+    render();
+  }
+}
+
+function drawPoint(x, y) {
+  if (
+    x > window.innerWidth / width ||
+    y > window.innerHeight / height ||
+    x < 0 ||
+    y < 0
+  )
+    return;
+  drawGrid[y] = drawGrid[y] ? drawGrid[y] : [];
+  drawGrid[y][x] = pencil;
+}