[SOLVED] Trying to build a robot arm grabber using Ammo.js

will · May 19, 2019, 9:48pm

Yeah, looking at the available API in PlayCanvas revision of ammo.js, the motor related functions for the slider constraint aren’t there. But then, they’re not even in the latest ammo.js either:

github.com

kripken/ammo.js/blob/master/ammo.idl#L618


void enableAngularMotor(boolean enableMotor, float targetVelocity, float maxMotorImpulse);
void setAngularOnly(boolean angularOnly);


void enableMotor(boolean enableMotor);
void setMaxMotorImpulse(float maxMotorImpulse);
//void setMotorTarget([Const,Ref] btQuaternion qAinB, float dt);
void setMotorTarget(float targetAngle, float dt);
};
btHingeConstraint implements btTypedConstraint;


interface btSliderConstraint {
void btSliderConstraint([Ref] btRigidBody rbA, [Ref] btRigidBody rbB, [Const,Ref] btTransform frameInA, [Const,Ref] btTransform frameInB, boolean useLinearReferenceFrameA);
void btSliderConstraint([Ref] btRigidBody rbB, [Const,Ref] btTransform frameInB, boolean useLinearReferenceFrameA);
void setLowerLinLimit(float lowerLimit);
void setUpperLinLimit(float upperLimit);
void setLowerAngLimit(float lowerAngLimit);
void setUpperAngLimit(float upperAngLimit);
};
btSliderConstraint implements btTypedConstraint;


interface btFixedConstraint {

We’d need to submit a PR to ammo.js and upgrade PlayCanvas’ version for motor powered slider constraints to work. TBH, I do actually think it’s very useful for developers to pick the version of ammo.js that they want to use. Because it is possible to build your own version of ammo.js from the source and expose and much or as little of the API as you want.