void weapon_update(Entity *ent) {
cpBody *body = entity_body(ent);
WeaponEntityData *data = entity_data(ent);
if (data->owner && !data->player_joint) {
cvar_setd_player(entity_owner(ent), "weapon_id", entity_id(ent));
data->player_joint = cpSpaceAddConstraint(game.space, cpPivotJointNew2(
body,
entity_body(data->owner),
cpv(0, -WEAPON_HEIGHT / 2), cpv(1, 0)
));
cpConstraintSetErrorBias(data->player_joint, 0);
}
int mult = 0;
if (keymap_is_held("mouse1")) mult++;
if (keymap_is_held("mouse2")) mult--;
if (mult) {
cpVect force_pos = cpv(0, WEAPON_HEIGHT);
cpVect weapon_pos = cpBodyGetPosition(body);
cpVect world_force_pos = cpvadd(weapon_pos, cpvrotate(cpBodyGetRotation(body), force_pos));
cpVect mouse_delta = cpvsub(keymap_mouse_world(), world_force_pos);
cpVect force = cpvmult(cpvnormalize(mouse_delta), mult * WEAPON_SWING_FORCE);
cpBodyApplyForceAtWorldPoint(body, force, world_force_pos);
}
}
/*
* Chipmunk2d::Constraint#error_bias=(error_bias)
* @param [Float] error_bias
*/
static mrb_value
constraint_set_error_bias(mrb_state *mrb, mrb_value self)
{
cpConstraint *constraint;
mrb_float error_bias;
mrb_get_args(mrb, "f", &error_bias);
constraint = mrb_data_get_ptr(mrb, self, &mrb_cp_constraint_type);
cpConstraintSetErrorBias(constraint, (cpFloat)error_bias);
return mrb_nil_value();
}
/* Mouse handling is a bit tricky. We want the user to move
* tiles using the mouse but because tiles are dynamic bodies
* managed by Chipmunk2D, we cannot directly control them.
* This is resolved by creating a pivot joint between an
* invisible mouse body that we can control and the tile body
* that we cannot directly control.
*/
static void apply_mouse_motion(struct state* state)
{
struct mouse m;
update_mouse(&m);
int w, h;
get_screen_size(&w, &h);
int x = m.x_position * w;
int y = m.y_position * h;
cpVect mouse_pos = cpv(x, y);
cpVect new_point =
cpvlerp(cpBodyGetPosition(state->mouse_body), mouse_pos, 0.25f);
cpBodySetVelocity(
state->mouse_body,
cpvmult(cpvsub(new_point, cpBodyGetPosition(state->mouse_body)),
60.0f));
cpBodySetPosition(state->mouse_body, new_point);
if (m.left_click && state->mouse_joint == NULL) {
cpFloat radius = 5.0;
cpPointQueryInfo info = { 0 };
cpShape* shape = cpSpacePointQueryNearest(state->space, mouse_pos,
radius, GRAB_FILTER, &info);
if (shape && cpBodyGetMass(cpShapeGetBody(shape)) < INFINITY) {
cpVect nearest = (info.distance > 0.0f ? info.point : mouse_pos);
cpBody* body = cpShapeGetBody(shape);
state->mouse_joint =
cpPivotJointNew2(state->mouse_body, body, cpvzero,
cpBodyWorldToLocal(body, nearest));
cpConstraintSetMaxForce(state->mouse_joint, 5000000.0f);
cpConstraintSetErrorBias(state->mouse_joint,
cpfpow(1.0f - 0.15f, 60.0f));
cpSpaceAddConstraint(state->space, state->mouse_joint);
}
}
if (m.left_click == false && state->mouse_joint != NULL) {
cpSpaceRemoveConstraint(state->space, state->mouse_joint);
cpConstraintFree(state->mouse_joint);
state->mouse_joint = NULL;
}
}
void physics_add_top_down_friction(cpBody *body, cpBody *control, float friction, cpConstraint **out_pivot, cpConstraint **out_gear) {
//emulates linear friction
cpConstraint *pivot = cpSpaceAddConstraint(game.space, cpPivotJointNew2(
control,
body,
cpvzero,
cpvzero
));
cpConstraintSetErrorBias(pivot, cpBodyGetMass(body) * friction);
cpConstraintSetMaxForce(pivot, cpBodyGetMass(body) * friction);
//emulates angular friction
cpConstraint *gear = cpSpaceAddConstraint(game.space, cpGearJointNew(
control,
body,
0, 1
));
cpConstraintSetMaxBias(gear, 0);
cpConstraintSetMaxForce(gear, friction / cpBodyGetMass(body) / 10);
if (out_pivot) *out_pivot = pivot;
if (out_gear) *out_gear = gear;
}
// float SG_CALL sgPhysicsConstraintGetMaxForce(SGPhysicsConstraint* constr);
void SG_CALL sgPhysicsConstraintSetErrorBias(SGPhysicsConstraint* constr, float bias)
{
cpConstraintSetErrorBias(constr->handle, bias);
}
void CCJoint::setErrorBias(cpFloat errorBias)
{
cpConstraintSetErrorBias(this->m_constraint, errorBias);
}
