love2d.love/src/modules/physics/box2d/Shape.cpp

/**
* Copyright (c) 2006-2012 LOVE Development Team
*
* This software is provided 'as-is', without any express or implied
* warranty.  In no event will the authors be held liable for any damages
* arising from the use of this software.
*
* Permission is granted to anyone to use this software for any purpose,
* including commercial applications, and to alter it and redistribute it
* freely, subject to the following restrictions:
*
* 1. The origin of this software must not be misrepresented; you must not
*    claim that you wrote the original software. If you use this software
*    in a product, an acknowledgment in the product documentation would be
*    appreciated but is not required.
* 2. Altered source versions must be plainly marked as such, and must not be
*    misrepresented as being the original software.
* 3. This notice may not be removed or altered from any source distribution.
**/

#include "Shape.h"

// Module
#include "Body.h"
#include "World.h"
#include "Physics.h"

#include <common/Memoizer.h>

// STD
#include <bitset>

namespace love
{
namespace physics
{
namespace box2d
{
	Shape::Shape()
		: shape(NULL)
	{
	}
	Shape::Shape(b2Shape * shape)
		: shape(shape)
	{
		Memoizer::add(shape, this);
	}

	Shape::~Shape()
	{
		if (shape)
		{
			Memoizer::remove(shape);
			delete shape;
		}
		shape = 0;
	}

	Shape::Type Shape::getType() const
	{
		switch(shape->GetType())
		{
		case b2Shape::e_circle:
			return SHAPE_CIRCLE;
		case b2Shape::e_polygon:
			return SHAPE_POLYGON;
		case b2Shape::e_edge:
			return SHAPE_EDGE;
		case b2Shape::e_chain:
			return SHAPE_CHAIN;
		default:
			return SHAPE_INVALID;
		}
	}

	float Shape::getRadius() const
	{
		return Physics::scaleUp(shape->m_radius);
	}

	int Shape::getChildCount() const
	{
		return shape->GetChildCount();
	}

	bool Shape::testPoint(float x, float y, float r, float px, float py) const
	{
		b2Vec2 point(px, py);
		b2Transform transform(Physics::scaleDown(b2Vec2(x, y)), b2Rot(r));
		return shape->TestPoint(transform, Physics::scaleDown(point));
	}

	int Shape::rayCast(lua_State * L) const
	{
		float p1x = Physics::scaleDown((float)luaL_checknumber(L, 1));
		float p1y = Physics::scaleDown((float)luaL_checknumber(L, 2));
		float p2x = Physics::scaleDown((float)luaL_checknumber(L, 3));
		float p2y = Physics::scaleDown((float)luaL_checknumber(L, 4));
		float maxFraction = (float)luaL_checknumber(L, 5);
		float x = Physics::scaleDown((float)luaL_checknumber(L, 6));
		float y = Physics::scaleDown((float)luaL_checknumber(L, 7));
		float r = (float)luaL_checknumber(L, 8);
		int childIndex = (int)luaL_optint(L, 9, 1) - 1; // Convert from 1-based index
		b2RayCastInput input;
		input.p1.Set(p1x, p1y);
		input.p2.Set(p2x, p2y);
		input.maxFraction = maxFraction;
		b2Transform transform(b2Vec2(x, y), b2Rot(r));
		b2RayCastOutput output;
		if (!shape->RayCast(&output, input, transform, childIndex))
			return 0; // No hit.
		lua_pushnumber(L, Physics::scaleUp(output.normal.x));
		lua_pushnumber(L, Physics::scaleUp(output.normal.y));
		lua_pushnumber(L, output.fraction);
		return 3;
	}

	int Shape::computeAABB(lua_State * L) const
	{
		float x = Physics::scaleDown((float)luaL_checknumber(L, 1));
		float y = Physics::scaleDown((float)luaL_checknumber(L, 2));
		float r = (float)luaL_checknumber(L, 3);
		int childIndex = (int)luaL_optint(L, 4, 1) - 1; // Convert from 1-based index
		b2Transform transform(b2Vec2(x, y), b2Rot(r));
		b2AABB box;
		shape->ComputeAABB(&box, transform, childIndex);
		box = Physics::scaleUp(box);
		lua_pushnumber(L, box.lowerBound.x);
		lua_pushnumber(L, box.lowerBound.y);
		lua_pushnumber(L, box.upperBound.x);
		lua_pushnumber(L, box.upperBound.y);
		return 4;
	}

	int Shape::computeMass(lua_State * L) const
	{
		float density = (float)luaL_checknumber(L, 1);
		b2MassData data;
		shape->ComputeMass(&data, density);
		b2Vec2 center = Physics::scaleUp(data.center);
		lua_pushnumber(L, center.x);
		lua_pushnumber(L, center.y);
		lua_pushnumber(L, data.mass);
		lua_pushnumber(L, Physics::scaleUp(Physics::scaleUp(data.I)));
		return 4;
	}

} // box2d
} // physics
} // love