Bullet + forces

Scripting Issues
1

So i found some force based movement code iin the bullet examples and implemented it inmy game. I relaized tho that the force is not relative to the models hpr that i want to be moved. I wan the direction its facing be the forward direction etc.

def processInput(self, dt):
        force = Vec3(0, 0, 0)
        
        if inputState.isSet('up'): force.setZ( 1.0)
        if inputState.isSet('down'): force.setZ(-1.0)
        if inputState.isSet('left'):    force.setX(-1.0)
        if inputState.isSet('right'):   force.setX( 1.0)
        
        force *= 10
        self.np.node().setActive(True)
        self.np.node().applyCentralForce(force)

This lets the models move around but wheni change the models hpr(which i parented the cameras hpr to, so to turn you just move the mouse - like an fps cmaera/movement control. Imso bad at explaining things)Im terrible with vectors and i only barely grasp whats happening in this code. and vec3 cant be reparented to the model. Any help wuld be great lol

2

The force vector is by default in global coordinates. So you have to transform the force vector into the global system before you apply it.

force = render.getRelativeVector(self.np, force)
3

:smiley: thanks! Ill give it a try once I’m home :smiley:

4

so i have this

def processInput(self, dt):
        force = Vec3(0, 0, 0)
        force = render.getRelativeVector(self.np, 0)
        
        if inputState.isSet('up'): force.setZ( 1.0)
        if inputState.isSet('down'): force.setZ(-1.0)
        if inputState.isSet('left'):    force.setX(-1.0)
        if inputState.isSet('right'):   force.setX( 1.0)
        
        force *= 10
        self.np.node().setActive(True)
        self.np.node().applyCentralForce(force)

but its still acting the same

5

No, this is not right. You have to transform it to global coordinates AFTER you have setup the force vector.

def processInput(self, dt):
        force = Vec3(0, 0, 0)
        
        if inputState.isSet('up'): force.setZ( 1.0)
        if inputState.isSet('down'): force.setZ(-1.0)
        if inputState.isSet('left'):    force.setX(-1.0)
        if inputState.isSet('right'):   force.setX( 1.0)
        
        force *= 10
        force = render.getRelativeVector(self.np, force)

        self.np.node().setActive(True)
        self.np.node().applyCentralForce(force)
6

aaah much better XD hehe thanks :slight_smile: