irrlicht/source/Irrlicht/CSceneCollisionManager.cpp

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// Copyright (C) 2002-2012 Nikolaus Gebhardt
// This file is part of the "Irrlicht Engine".
// For conditions of distribution and use, see copyright notice in irrlicht.h
#include "CSceneCollisionManager.h"
#include "ICameraSceneNode.h"
#include "SViewFrustum.h"
#include "os.h"
#include "irrMath.h"
namespace irr
{
namespace scene
{
//! constructor
CSceneCollisionManager::CSceneCollisionManager(ISceneManager *smanager, video::IVideoDriver *driver) :
SceneManager(smanager), Driver(driver)
{
#ifdef _DEBUG
setDebugName("CSceneCollisionManager");
#endif
if (Driver)
Driver->grab();
}
//! destructor
CSceneCollisionManager::~CSceneCollisionManager()
{
if (Driver)
Driver->drop();
}
//! Returns a 3d ray which would go through the 2d screen coordinates.
core::line3d<f32> CSceneCollisionManager::getRayFromScreenCoordinates(
const core::position2d<s32> &pos, const ICameraSceneNode *camera)
{
core::line3d<f32> ln(0, 0, 0, 0, 0, 0);
if (!SceneManager)
return ln;
if (!camera)
camera = SceneManager->getActiveCamera();
if (!camera)
return ln;
const scene::SViewFrustum *f = camera->getViewFrustum();
core::vector3df farLeftUp = f->getFarLeftUp();
core::vector3df lefttoright = f->getFarRightUp() - farLeftUp;
core::vector3df uptodown = f->getFarLeftDown() - farLeftUp;
const core::rect<s32> &viewPort = Driver->getViewPort();
core::dimension2d<u32> screenSize(viewPort.getWidth(), viewPort.getHeight());
f32 dx = pos.X / (f32)screenSize.Width;
f32 dy = pos.Y / (f32)screenSize.Height;
if (camera->isOrthogonal())
ln.start = f->cameraPosition + (lefttoright * (dx - 0.5f)) + (uptodown * (dy - 0.5f));
else
ln.start = f->cameraPosition;
ln.end = farLeftUp + (lefttoright * dx) + (uptodown * dy);
return ln;
}
} // end namespace scene
} // end namespace irr