Contents
When to use forces and impulses in Box2D?
This can be handy for games where you need a teleport feature, but bear in mind that this is not realistic physics! The whole point of a physics simulator like Box2D is to make things look real, and to this end I would recommend using forces and impulses to move bodies as much as you can.
How to override the keyboard function in Box2D?
Override the Keyboard function of the Test class to use a different method for each body: The SetTransform function we covered in the bodies topic. The ApplyForce and ApplyLinearImpulse functions take two parameters, the first is what direction the force should be, in this case straight up.
Why does the corner of the box rotate?
This time, you should see these boxes rotate when acted upon. The function GetWorldPoint is used to convert a location relative to the body (body coordinates) into world coordinates, so that we keep applying the force at the corner of the box even after it has rotated around.
How to offset the point at which you apply force?
Let’s offset the point at which we apply the force/impulse. Change the ApplyForce and ApplyLinearImpulse calls so that instead of using GetWorldCenter () to apply force at the center of mass, we’ll apply it at the top right corner of the box: This time, you should see these boxes rotate when acted upon.
How does a kinematic body move in Box2D?
A kinematic body moves under simulation according to its velocity. Kinematic bodies do not respond to forces. They can be moved manually by the user, but normally a kinematic body is moved by setting its velocity. A kinematic body behaves as if it has infinite mass, however, Box2D stores zero for the mass and the inverse mass.
How are bodies and fixtures related in Box2D?
Bodies are the backbone for fixtures (shapes). Bodies carry fixtures and move them around in the world. Bodies are always rigid bodies in Box2D. That means that two fixtures attached to the same rigid body never move relative to each other and fixtures attached to the same body don’t collide. Fixtures have collision geometry and density.
Are there limits to the range of rotation of revolute joints?
With only the properties covered so far the two bodies are free to rotate about their anchor points indefinitely, but revolute joints can also be given limits to restrict their range of rotation. A lower and upper limit can be specified, given in terms of the ‘joint angle’.
Where does the NPC start in Box2D?
In the image below… something crazy is going on. What should happen is that the NPC should start on the left side of the screen (he does), face towards the end of the black line (he does not) and then walk towards it (definitely does not).
What does Aisystem steertonextnode do in Box2D?
You can’t see if in the GIF, but the original angle of his body is 0 (pointing upwards), so he should smoothly rotate to the right and walk towards his target. AiSystem::steerToNextNode () gets called every game step.