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

/**
 * Copyright (c) 2006-2016 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)
	, own(false)
{
}

Shape::Shape(b2Shape *shape, bool own)
	: shape(shape)
	, own(own)
{
	if (own)
		Memoizer::add(shape, this);
}

Shape::~Shape()
{
	if (shape && own)
	{
		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_optnumber(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, output.normal.x);
	lua_pushnumber(L, 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_optnumber(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