I am trying to rotate these circles around the black shape. Currently, they are rotating in a circular motion, but I want them to travel from vertex to vertex.
Rotation code:
//central is the black shape
angle += delta * rotSpeed * direction;
x = MathUtils.cos(angle) * central.radius + central.x;
y = MathUtils.sin(angle) * central.radius + central.y;
Thank you guys very much for helping me!
Linearly interpolate between the vertices.
How can I get the vertice coords?
The black shape is being rendered like this:
sr.begin(ShapeRenderer.ShapeType.Filled);
sr.setColor(Color.BLACK);
sr.circle(this.x, this.y, this.radius, segments);
sr.setColor(Color.GREEN);
sr.circle(this.x, this.y, this.radius / 4);
sr.end();
You have to compute them yourself by inscribing the circle with a regular polygon. The vertices of that polygon, as libGDX draws them, are calculated in this method.
They once compute the angle in radians which is 2.0 * PI / segments, then compute the sine and cosine of that angle and then repeatedly apply a 2x2 matrix/vector multiplication to rotate the “running” vertex coordinates (cx, cy) around the circle. This avoids having to compute the sine/cosine of the increasing angle every iteration.
Alternately, you could calculate the tangent’s gradient of the circle at the center of each line, which would look something like this I think, but I haven’t tested this:
private float getSlope(int sides, float angle) {
float b = angle - angle % (int) (2 * Math.PI / sides);
return (float)(- Math.sin(b) / Math.cos(b));
}
Interpolation might not be necessary. You could do a procedural calculation by starting at the beginning and rotating at an angle relative to the circle. You would just need the distance of a side if it is linear.
Imagine moving around a 6gon in a circle. You have, on each vertex, an intersecting point on the path you take. You just need to rotate enough to hit that specific point and rotate from there.
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