boxdd 0.4.0

Safe, ergonomic Rust bindings for Box2D v3
Documentation 
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use super::*;

fn joint_base_from_world_points_impl<VA: Into<Vec2>, VB: Into<Vec2>>(
    body_a: BodyId,
    body_b: BodyId,
    anchor_a_world: VA,
    anchor_b_world: VB,
) -> crate::joints::JointBase {
    crate::core::debug_checks::assert_body_valid(body_a);
    crate::core::debug_checks::assert_body_valid(body_b);
    let ta = unsafe { ffi::b2Body_GetTransform(raw_body_id(body_a)) };
    let tb = unsafe { ffi::b2Body_GetTransform(raw_body_id(body_b)) };
    let wa: ffi::b2Vec2 = anchor_a_world.into().into_raw();
    let wb: ffi::b2Vec2 = anchor_b_world.into().into_raw();
    let la = crate::core::math::world_to_local_point(ta, wa);
    let lb = crate::core::math::world_to_local_point(tb, wb);
    crate::joints::JointBaseBuilder::new()
        .bodies_by_id(body_a, body_b)
        .local_frames_raw(
            ffi::b2Transform {
                p: la,
                q: ffi::b2Rot { c: 1.0, s: 0.0 },
            },
            ffi::b2Transform {
                p: lb,
                q: ffi::b2Rot { c: 1.0, s: 0.0 },
            },
        )
        .build()
}

fn joint_base_from_world_with_axis_impl<VA: Into<Vec2>, VB: Into<Vec2>, AX: Into<Vec2>>(
    body_a: BodyId,
    body_b: BodyId,
    anchor_a_world: VA,
    anchor_b_world: VB,
    axis_world: AX,
) -> crate::joints::JointBase {
    crate::core::debug_checks::assert_body_valid(body_a);
    crate::core::debug_checks::assert_body_valid(body_b);
    let ta = unsafe { ffi::b2Body_GetTransform(raw_body_id(body_a)) };
    let tb = unsafe { ffi::b2Body_GetTransform(raw_body_id(body_b)) };
    let wa: ffi::b2Vec2 = anchor_a_world.into().into_raw();
    let wb: ffi::b2Vec2 = anchor_b_world.into().into_raw();
    let axis: ffi::b2Vec2 = axis_world.into().into_raw();
    let la = crate::core::math::world_to_local_point(ta, wa);
    let lb = crate::core::math::world_to_local_point(tb, wb);
    let ra = crate::core::math::world_axis_to_local_rot(ta, axis);
    let rb = crate::core::math::world_axis_to_local_rot(tb, axis);
    crate::joints::JointBaseBuilder::new()
        .bodies_by_id(body_a, body_b)
        .local_frames_raw(
            ffi::b2Transform { p: la, q: ra },
            ffi::b2Transform { p: lb, q: rb },
        )
        .build()
}

impl World {
    // Convenience joints built from world anchors and axis using body ids
    pub fn create_revolute_joint_world<VA: Into<Vec2>>(
        &mut self,
        body_a: BodyId,
        body_b: BodyId,
        anchor_world: VA,
    ) -> crate::joints::Joint<'_> {
        let aw = anchor_world.into();
        let def = crate::joints::RevoluteJointDef::new(joint_base_from_world_points_impl(
            body_a, body_b, aw, aw,
        ));
        self.create_revolute_joint(&def)
    }

    pub fn create_revolute_joint_world_id<VA: Into<Vec2>>(
        &mut self,
        body_a: BodyId,
        body_b: BodyId,
        anchor_world: VA,
    ) -> JointId {
        let aw = anchor_world.into();
        let def = crate::joints::RevoluteJointDef::new(joint_base_from_world_points_impl(
            body_a, body_b, aw, aw,
        ));
        self.create_revolute_joint_id(&def)
    }

    pub fn create_prismatic_joint_world<VA: Into<Vec2>, VB: Into<Vec2>, AX: Into<Vec2>>(
        &mut self,
        body_a: BodyId,
        body_b: BodyId,
        anchor_a_world: VA,
        anchor_b_world: VB,
        axis_world: AX,
    ) -> crate::joints::Joint<'_> {
        let def = crate::joints::PrismaticJointDef::new(joint_base_from_world_with_axis_impl(
            body_a,
            body_b,
            anchor_a_world,
            anchor_b_world,
            axis_world,
        ));
        self.create_prismatic_joint(&def)
    }

    pub fn create_prismatic_joint_world_id<VA: Into<Vec2>, VB: Into<Vec2>, AX: Into<Vec2>>(
        &mut self,
        body_a: BodyId,
        body_b: BodyId,
        anchor_a_world: VA,
        anchor_b_world: VB,
        axis_world: AX,
    ) -> JointId {
        let def = crate::joints::PrismaticJointDef::new(joint_base_from_world_with_axis_impl(
            body_a,
            body_b,
            anchor_a_world,
            anchor_b_world,
            axis_world,
        ));
        self.create_prismatic_joint_id(&def)
    }

    pub fn create_wheel_joint_world<VA: Into<Vec2>, VB: Into<Vec2>, AX: Into<Vec2>>(
        &mut self,
        body_a: BodyId,
        body_b: BodyId,
        anchor_a_world: VA,
        anchor_b_world: VB,
        axis_world: AX,
    ) -> crate::joints::Joint<'_> {
        let def = crate::joints::WheelJointDef::new(joint_base_from_world_with_axis_impl(
            body_a,
            body_b,
            anchor_a_world,
            anchor_b_world,
            axis_world,
        ));
        self.create_wheel_joint(&def)
    }

    pub fn create_wheel_joint_world_id<VA: Into<Vec2>, VB: Into<Vec2>, AX: Into<Vec2>>(
        &mut self,
        body_a: BodyId,
        body_b: BodyId,
        anchor_a_world: VA,
        anchor_b_world: VB,
        axis_world: AX,
    ) -> JointId {
        let def = crate::joints::WheelJointDef::new(joint_base_from_world_with_axis_impl(
            body_a,
            body_b,
            anchor_a_world,
            anchor_b_world,
            axis_world,
        ));
        self.create_wheel_joint_id(&def)
    }

    /// Helper: build a joint base from two world anchor points.
    /// Build `JointBase` from two world anchor points.
    ///
    /// Example
    /// ```no_run
    /// use boxdd::{World, WorldDef, BodyBuilder, ShapeDef, shapes, Vec2};
    /// let mut world = World::new(WorldDef::builder().gravity([0.0,-9.8]).build()).unwrap();
    /// let a = world.create_body_id(BodyBuilder::new().position([-1.0,2.0]).build());
    /// let b = world.create_body_id(BodyBuilder::new().position([ 1.0,2.0]).build());
    /// let sdef = ShapeDef::builder().density(1.0).build();
    /// world.create_polygon_shape_for(a, &sdef, &shapes::box_polygon(0.5,0.5));
    /// world.create_polygon_shape_for(b, &sdef, &shapes::box_polygon(0.5,0.5));
    /// let base = world.joint_base_from_world_points(a, b, world.body_position(a), world.body_position(b));
    /// # let _ = base;
    /// ```
    pub fn joint_base_from_world_points<VA: Into<Vec2>, VB: Into<Vec2>>(
        &self,
        body_a: BodyId,
        body_b: BodyId,
        anchor_a_world: VA,
        anchor_b_world: VB,
    ) -> crate::joints::JointBase {
        joint_base_from_world_points_impl(body_a, body_b, anchor_a_world, anchor_b_world)
    }

    /// Helper: build a joint base from two world anchors and a shared world axis (X-axis of joint frames).
    /// Build `JointBase` from world anchors and a shared world axis (X-axis of local frames).
    ///
    /// Example
    /// ```no_run
    /// use boxdd::{World, WorldDef, BodyBuilder, ShapeDef, shapes, Vec2};
    /// let mut world = World::new(WorldDef::builder().gravity([0.0,-9.8]).build()).unwrap();
    /// let a = world.create_body_id(BodyBuilder::new().position([0.0,2.0]).build());
    /// let b = world.create_body_id(BodyBuilder::new().position([1.0,2.0]).build());
    /// let sdef = ShapeDef::builder().density(1.0).build();
    /// world.create_polygon_shape_for(a, &sdef, &shapes::box_polygon(0.5,0.5));
    /// world.create_polygon_shape_for(b, &sdef, &shapes::box_polygon(0.5,0.5));
    /// let axis = Vec2::new(1.0, 0.0);
    /// let base = world.joint_base_from_world_with_axis(a, b, world.body_position(a), world.body_position(b), axis);
    /// # let _ = base;
    /// ```
    pub fn joint_base_from_world_with_axis<VA: Into<Vec2>, VB: Into<Vec2>, AX: Into<Vec2>>(
        &self,
        body_a: BodyId,
        body_b: BodyId,
        anchor_a_world: VA,
        anchor_b_world: VB,
        axis_world: AX,
    ) -> crate::joints::JointBase {
        joint_base_from_world_with_axis_impl(
            body_a,
            body_b,
            anchor_a_world,
            anchor_b_world,
            axis_world,
        )
    }
}