scale_to_world

From sketch to physics world

Because of the peculiar choice by the processing guys down is up (dimensions in pixels) jbox2d doesn’t like to live in the pixel world (where up is really up), and prefers meters or feet and inches (whatever). What this means is that there is a need to scale between the two worlds using world_to_processing and processing_to_world methods provided. You should study the included example sketches.

The java code (PBox2D inherits this from Box2DProcessing)

public Vec2 scaleToWorld(float worldX, float worldY)

public Vec2 scaleToWorld(float pixelX, float pixelY) {
      float worldX = map(pixelX, parent.width / 2, parent.width / 2 + scaleFactor, 0f, 1f);
      float worldY = map(pixelY, parent.height / 2, parent.height / 2 + scaleFactor, 1f, 0f);
      return new Vec2(worldX, worldY);
}

Ruby usage

Use camel case

scale_to_world(x, y) # returns new Vec2 instance (in the PBox2D world)