// calculates and adds forces triggered by holding the movement keys down.
// it also has to stop the forces applied by the prev call to this function
void blastengines(struct objnode *player)
{
struct movement *thrust;
cpFloat force, tforce;
struct forces newf;
cpVect rotv;
cpFloat angvel;
thrust = &player->pinfo->thrust;
rotv = cpBodyGetRot(player->b);
force = 0;
// these test cases are to enforce soft limits on the rate of movement
if (thrust->up && !thrust->down) {
if (cpvunrotate(cpBodyGetVel(player->b), rotv).y < MAXVEL)
force = FORCE;
} else if (!thrust->up && thrust->down) {
if (cpvunrotate(cpBodyGetVel(player->b), rotv).y > -MAXVEL)
force = -FORCE;
}
tforce = 0;
angvel = cpBodyGetAngVel(player->b);
if (thrust->ccw && !thrust->cw) {
if (angvel < MAXANGVEL)
tforce += TFORCE;
} else if (thrust->cw && !thrust->ccw) {
if (angvel > -MAXANGVEL)
tforce += -TFORCE;
}
newf.force = cpvrotate(cpv(0, force), rotv);
newf.tforce = cpv(0, tforce);
applyforces(player, thrust->prevf);
applyforces(player, newf);
thrust->prevf.force = cpvneg(newf.force);
thrust->prevf.tforce = cpvneg(newf.tforce);
}
static void
update(int ticks)
{
int steps = 1;
cpFloat dt = 1.0f/60.0f/(cpFloat)steps;
for(int i=0; i<steps; i++){
// turn the control body based on the angle relative to the actual body
cpVect mouseDelta = cpvsub(mousePoint, tankBody->p);
cpFloat turn = cpvtoangle(cpvunrotate(tankBody->rot, mouseDelta));
cpBodySetAngle(tankControlBody, tankBody->a - turn);
// drive the tank towards the mouse
if(cpvnear(mousePoint, tankBody->p, 30.0)){
tankControlBody->v = cpvzero; // stop
} else {
cpFloat direction = (cpvdot(mouseDelta, tankBody->rot) > 0.0 ? 1.0 : -1.0);
tankControlBody->v = cpvrotate(tankBody->rot, cpv(30.0f*direction, 0.0f));
}
cpSpaceStep(space, dt);
}
}
cpVect * bmx_cpvect_unrotate(cpVect * vec, cpVect * vec1) {
return bmx_cpvect_new(cpvunrotate(*vec, *vec1));
}
