29 lines
1.5 KiB
Text
29 lines
1.5 KiB
Text
# hull.ludic - a boat: a buoyant box floated by PhysWater, rowed along its bow and turned about its
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# middle. Its bow is -z at yaw 0, the way the valley faces (forward is (-sin yaw, -cos yaw)).
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# hx, hy, hz its half width, depth and length; buoyancy over 1 floats it (4: a quarter under)
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@creates(PhysBody)
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export function phys_hull_add(physics_st: mut PhysicsState, x: float, y: float, z: float, yaw: float, hx: float, hy: float, hz: float, mass: float, buoyancy: float, drag: float) -> int {
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let s = phys_box(physics_st, hx, hy, hz)
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let id = phys_body_add(physics_st, s, x, y, z, yaw, mass)
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if id < 0 { return -1 }
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phys_own(physics_st, id, s)
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phys_float(physics_st, id, buoyancy, drag, drag * 1.5)
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return id
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}
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# a stroke of `forward` newtons along the bow and a turn of `turn` newton-metres about y, over the
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# next step
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export function phys_row(physics_st: mut PhysicsState, id: int, forward: float, turn: float) -> void {
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if physics_st.ph_world == null or jph_body_read(physics_st.ph_world, id, physics_st.ph_vals) != 0 { return }
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let v = physics_st.ph_vals
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let yaw = Math.atan2(2.0 * (v[6] * v[4] + v[3] * v[5]), 1.0 - 2.0 * (v[4] * v[4] + v[3] * v[3]))
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phys_force(physics_st, id, -Math.sin(yaw) * forward, 0.0, -Math.cos(yaw) * forward)
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phys_torque(physics_st, id, 0.0, turn, 0.0)
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}
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# how fast it goes along its bow (backwards is negative)
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export function phys_bow_speed(p: PhysPose) -> float {
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let yaw = phys_yaw_of(p)
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return -Math.sin(yaw) * p.vx - Math.cos(yaw) * p.vz
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}
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