jolt_custom_motion_shape.cpp

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/*  jolt_custom_motion_shape.cpp                                          */
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/* Copyright (c) 2007-2014 Juan Linietsky, Ariel Manzur.                  */
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#include "jolt_custom_motion_shape.h"

namespace {

class JoltMotionConvexSupport final : public JPH::ConvexShape::Support {
public:
	JoltMotionConvexSupport(JPH::Vec3Arg p_motion, const JPH::ConvexShape::Support *p_inner_support) :
			motion(p_motion),
			inner_support(p_inner_support) {}

	virtual JPH::Vec3 GetSupport(JPH::Vec3Arg p_direction) const override {
		JPH::Vec3 support = inner_support->GetSupport(p_direction);

		if (p_direction.Dot(motion) > 0) {
			support += motion;
		}

		return support;
	}

	virtual float GetConvexRadius() const override { return inner_support->GetConvexRadius(); }

private:
	JPH::Vec3 motion = JPH::Vec3::sZero();

	const JPH::ConvexShape::Support *inner_support = nullptr;
};

} // namespace

JPH::AABox JoltCustomMotionShape::GetLocalBounds() const {
	JPH::AABox aabb = inner_shape.GetLocalBounds();
	JPH::AABox aabb_translated = aabb;
	aabb_translated.Translate(motion);
	aabb.Encapsulate(aabb_translated);

	return aabb;
}

void JoltCustomMotionShape::GetSupportingFace(const JPH::SubShapeID &p_sub_shape_id, JPH::Vec3Arg p_direction, JPH::Vec3Arg p_scale, JPH::Mat44Arg p_center_of_mass_transform, JPH::Shape::SupportingFace &p_vertices) const {
	// This is technically called when using the enhanced internal edge removal, but `JPH::InternalEdgeRemovingCollector` will
	// only ever use the faces of the second shape in the collision pair, and this shape will always be the first in the pair, so
	// we can safely skip this.
}

const JPH::ConvexShape::Support *JoltCustomMotionShape::GetSupportFunction(JPH::ConvexShape::ESupportMode p_mode, JPH::ConvexShape::SupportBuffer &p_buffer, JPH::Vec3Arg p_scale) const {
	return new (&p_buffer) JoltMotionConvexSupport(motion, inner_shape.GetSupportFunction(p_mode, inner_support_buffer, p_scale));
}