Skid-Steer Car Simulator

Track width = 0.2m, wheelbase = 0.4m

w (track width, m)

l (wheelbase, m)

max wheel speed (m/s)

wheel visual scale

trail points

max dt (s)

cam x (forward, m)

cam y (left, m)

cam z (up, m)

pitch down (deg)

fov horizontal (deg)

fov vertical (deg)

Code Control

// API demo: OpenCV line follower + telemetry overlays.
      // Uses: api.cv, api.getVisionFrame, api.drawRect, api.drawLine, api.drawCircle,
      //       api.setWheelSpeeds, api.clamp, api.mem.*, api.log

const cv = api.cv;
      api.clearOverlay();

if (!cv) {
  api.setWheelSpeeds(0, 0, 0, 0);
  if (!api.mem.get("opencvWaitLogged", false)) {
    api.log("Waiting for OpenCV.js to load...");
    api.mem.set("opencvWaitLogged", true);
  }
  return;
}
api.mem.set("opencvWaitLogged", false);

const frame = api.getVisionFrame();
if (!frame || !frame.imageData) {
  api.setWheelSpeeds(0, 0, 0, 0);
  return;
}

const src = cv.matFromImageData(frame.imageData);
const gray = new cv.Mat();
const binary = new cv.Mat();

cv.cvtColor(src, gray, cv.COLOR_RGBA2GRAY);
cv.threshold(gray, binary, 90, 255, cv.THRESH_BINARY_INV);

const y0 = Math.floor(frame.height * 0.45);
const h = Math.max(1, frame.height - y0);
const roiRect = new cv.Rect(0, y0, frame.width, h);
const roi = binary.roi(roiRect);
const m = cv.moments(roi, true);

// Overlay: ROI box + image center line
api.drawRect(0, y0, frame.width, h, { stroke: "#53a7ff", lineWidth: 2, alpha: 0.8 });
api.drawLine(frame.width * 0.5, y0, frame.width * 0.5, frame.height, { stroke: "#53a7ff", lineWidth: 2, alpha: 0.7 });

const prevError = api.mem.get("prevError", 0);
const lastTurn = api.mem.get("lastTurn", 1);

if (m.m00 > 1e-3) {
  const cx = m.m10 / m.m00;
  const cy = m.m01 / m.m00 + y0;
  const error = (cx - frame.width * 0.5) / (frame.width * 0.5);
  const dError = error - prevError;

// Overlay: detected centroid + steering line
  api.drawCircle(cx, cy, 6, { stroke: "#35dd72", fill: "#35dd72", lineWidth: 2, alpha: 0.9 });
  api.drawLine(frame.width * 0.5, frame.height - 6, cx, cy, { stroke: "#35dd72", lineWidth: 2, alpha: 0.85 });

const base = 0.34;
  const kP = 0.95;
  const kD = 0.55;
  const turn = kP * error + kD * dError;

const leftCmd = api.clamp(base + turn, -1.2, 1.2);
  const rightCmd = api.clamp(base - turn, -1.2, 1.2);
  api.setWheelSpeeds(leftCmd, rightCmd, leftCmd, rightCmd);

api.mem.set("prevError", error);
  api.mem.set("lastTurn", turn >= 0 ? 1 : -1);
} else {
  // Overlay: no line found state
  api.drawRect(8, 8, frame.width - 16, frame.height - 16, { stroke: "#ff5c6d", lineWidth: 2, alpha: 0.7 });
  const dir = lastTurn;
  const pivot = 0.30;
  api.setWheelSpeeds(dir * pivot, -dir * pivot, dir * pivot, -dir * pivot);
}

roi.delete();
binary.delete();
gray.delete();
src.delete();

Code mode disabled.

Full API List

api.time
api.dt
api.pose
api.wheelSpeeds
api.getVisionFrame()
api.drawLine(x1, y1, x2, y2, options)
api.drawRect(x, y, w, h, options)
api.drawCircle(x, y, r, options)
api.clearOverlay()
api.sensors
api.getSensor(name)
api.cv
api.setWheelSpeed(name, value)
api.setWheelSpeeds(vFL, vFR, vRL, vRR)
api.clamp(value, min, max)
api.log(...args)
api.clearLog()
api.mem.get(key, defaultValue)
api.mem.set(key, value)
api.mem.remove(key)
api.mem.clear()
api.mem.keys()

Script Memory Entries

(empty)

Wheel Controls

Telemetry

Vision ready. OpenCV.js: loading...

Track

track type line width (m)

svg path (meters, e.g. M -1 0 L 1 0)

Track ready.

IR Sensors

sensor config (JSON array in car local coords, x=forward, y=left)

Camera Controls

Offset X (px)

Offset Y (px)

Zoom (px/m)

220