blender/source/gameengine/VideoTexture/ImageRender.cpp

/*
-----------------------------------------------------------------------------
This source file is part of VideoTexture library

Copyright (c) 2007 The Zdeno Ash Miklas

This program is free software; you can redistribute it and/or modify it under
the terms of the GNU Lesser General Public License as published by the Free Software
Foundation; either version 2 of the License, or (at your option) any later
version.

This program is distributed in the hope that it will be useful, but WITHOUT
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public License along with
this program; if not, write to the Free Software Foundation, Inc., 59 Temple
Place - Suite 330, Boston, MA 02111-1307, USA, or go to
http://www.gnu.org/copyleft/lesser.txt.
-----------------------------------------------------------------------------
*/

/** \file gameengine/VideoTexture/ImageRender.cpp
 *  \ingroup bgevideotex
 */

// implementation

#include "PyObjectPlus.h"
#include <structmember.h>
#include <float.h>
#include <math.h>


#include "GL/glew.h"

#include "KX_PythonInit.h"
#include "DNA_scene_types.h"
#include "RAS_CameraData.h"
#include "RAS_MeshObject.h"
#include "BLI_math.h"

#include "ImageRender.h"
#include "ImageBase.h"
#include "BlendType.h"
#include "Exception.h"
#include "Texture.h"

ExceptionID SceneInvalid, CameraInvalid, ObserverInvalid;
ExceptionID MirrorInvalid, MirrorSizeInvalid, MirrorNormalInvalid, MirrorHorizontal, MirrorTooSmall;
ExpDesc SceneInvalidDesc (SceneInvalid, "Scene object is invalid");
ExpDesc CameraInvalidDesc (CameraInvalid, "Camera object is invalid");
ExpDesc ObserverInvalidDesc (ObserverInvalid, "Observer object is invalid");
ExpDesc MirrorInvalidDesc (MirrorInvalid, "Mirror object is invalid");
ExpDesc MirrorSizeInvalidDesc (MirrorSizeInvalid, "Mirror has no vertex or no size");
ExpDesc MirrorNormalInvalidDesc (MirrorNormalInvalid, "Cannot determine mirror plane");
ExpDesc MirrorHorizontalDesc (MirrorHorizontal, "Mirror is horizontal in local space");
ExpDesc MirrorTooSmallDesc (MirrorTooSmall, "Mirror is too small");

// constructor
ImageRender::ImageRender (KX_Scene * scene, KX_Camera * camera) : 
    ImageViewport(),
    m_render(true),
    m_scene(scene),
    m_camera(camera),
    m_owncamera(false),
    m_observer(NULL),
    m_mirror(NULL),
    m_clip(100.f)
{
	// initialize background color
	setBackground(0, 0, 255, 255);
	// retrieve rendering objects
	m_engine = KX_GetActiveEngine();
	m_rasterizer = m_engine->GetRasterizer();
	m_canvas = m_engine->GetCanvas();
	m_rendertools = m_engine->GetRenderTools();
}

// destructor
ImageRender::~ImageRender (void)
{
	if (m_owncamera)
		m_camera->Release();
}


// set background color
void ImageRender::setBackground (int red, int green, int blue, int alpha)
{
	m_background[0] = (red < 0) ? 0.f : (red > 255) ? 1.f : float(red)/255.f;
	m_background[1] = (green < 0) ? 0.f : (green > 255) ? 1.f : float(green)/255.f;
	m_background[2] = (blue < 0) ? 0.f : (blue > 255) ? 1.f : float(blue)/255.f;
	m_background[3] = (alpha < 0) ? 0.f : (alpha > 255) ? 1.f : float(alpha)/255.f;
}


// capture image from viewport
void ImageRender::calcImage (unsigned int texId, double ts)
{
	if (m_rasterizer->GetDrawingMode() != RAS_IRasterizer::KX_TEXTURED ||   // no need for texture
	        m_camera->GetViewport() ||        // camera must be inactive
	        m_camera == m_scene->GetActiveCamera())
	{
		// no need to compute texture in non texture rendering
		m_avail = false;
		return;
	}
	// render the scene from the camera
	Render();
	// get image from viewport
	ImageViewport::calcImage(texId, ts);
	// restore OpenGL state
	m_canvas->EndFrame();
}

void ImageRender::Render()
{
	RAS_FrameFrustum frustrum;

	if (!m_render)
		return;

	if (m_mirror)
	{
		// mirror mode, compute camera frustrum, position and orientation
		// convert mirror position and normal in world space
		const MT_Matrix3x3 & mirrorObjWorldOri = m_mirror->GetSGNode()->GetWorldOrientation();
		const MT_Point3 & mirrorObjWorldPos = m_mirror->GetSGNode()->GetWorldPosition();
		const MT_Vector3 & mirrorObjWorldScale = m_mirror->GetSGNode()->GetWorldScaling();
		MT_Point3 mirrorWorldPos =
		        mirrorObjWorldPos + mirrorObjWorldScale * (mirrorObjWorldOri * m_mirrorPos);
		MT_Vector3 mirrorWorldZ = mirrorObjWorldOri * m_mirrorZ;
		// get observer world position
		const MT_Point3 & observerWorldPos = m_observer->GetSGNode()->GetWorldPosition();
		// get plane D term = mirrorPos . normal
		MT_Scalar mirrorPlaneDTerm = mirrorWorldPos.dot(mirrorWorldZ);
		// compute distance of observer to mirror = D - observerPos . normal
		MT_Scalar observerDistance = mirrorPlaneDTerm - observerWorldPos.dot(mirrorWorldZ);
		// if distance < 0.01 => observer is on wrong side of mirror, don't render
		if (observerDistance < 0.01f)
			return;
		// set camera world position = observerPos + normal * 2 * distance
		MT_Point3 cameraWorldPos = observerWorldPos + (MT_Scalar(2.0)*observerDistance)*mirrorWorldZ;
		m_camera->GetSGNode()->SetLocalPosition(cameraWorldPos);
		// set camera orientation: z=normal, y=mirror_up in world space, x= y x z
		MT_Vector3 mirrorWorldY = mirrorObjWorldOri * m_mirrorY;
		MT_Vector3 mirrorWorldX = mirrorObjWorldOri * m_mirrorX;
		MT_Matrix3x3 cameraWorldOri(
		            mirrorWorldX[0], mirrorWorldY[0], mirrorWorldZ[0],
		            mirrorWorldX[1], mirrorWorldY[1], mirrorWorldZ[1],
		            mirrorWorldX[2], mirrorWorldY[2], mirrorWorldZ[2]);
		m_camera->GetSGNode()->SetLocalOrientation(cameraWorldOri);
		m_camera->GetSGNode()->UpdateWorldData(0.0);
		// compute camera frustrum:
		//   get position of mirror relative to camera: offset = mirrorPos-cameraPos
		MT_Vector3 mirrorOffset = mirrorWorldPos - cameraWorldPos;
		//   convert to camera orientation
		mirrorOffset = mirrorOffset * cameraWorldOri;
		//   scale mirror size to world scale:
		//     get closest local axis for mirror Y and X axis and scale height and width by local axis scale
		MT_Scalar x, y;
		x = fabs(m_mirrorY[0]);
		y = fabs(m_mirrorY[1]);
		float height = (x > y) ?
		            ((x > fabs(m_mirrorY[2])) ? mirrorObjWorldScale[0] : mirrorObjWorldScale[2]):
		            ((y > fabs(m_mirrorY[2])) ? mirrorObjWorldScale[1] : mirrorObjWorldScale[2]);
		x = fabs(m_mirrorX[0]);
		y = fabs(m_mirrorX[1]);
		float width = (x > y) ?
		            ((x > fabs(m_mirrorX[2])) ? mirrorObjWorldScale[0] : mirrorObjWorldScale[2]):
		            ((y > fabs(m_mirrorX[2])) ? mirrorObjWorldScale[1] : mirrorObjWorldScale[2]);
		width *= m_mirrorHalfWidth;
		height *= m_mirrorHalfHeight;
		//   left = offsetx-width
		//   right = offsetx+width
		//   top = offsety+height
		//   bottom = offsety-height
		//   near = -offsetz
		//   far = near+100
		frustrum.x1 = mirrorOffset[0]-width;
		frustrum.x2 = mirrorOffset[0]+width;
		frustrum.y1 = mirrorOffset[1]-height;
		frustrum.y2 = mirrorOffset[1]+height;
		frustrum.camnear = -mirrorOffset[2];
		frustrum.camfar = -mirrorOffset[2]+m_clip;
	}
	// Store settings to be restored later
	const RAS_IRasterizer::StereoMode stereomode = m_rasterizer->GetStereoMode();
	RAS_Rect area = m_canvas->GetWindowArea();

	// The screen area that ImageViewport will copy is also the rendering zone
	m_canvas->SetViewPort(m_position[0], m_position[1], m_position[0]+m_capSize[0]-1, m_position[1]+m_capSize[1]-1);
	m_canvas->ClearColor(m_background[0], m_background[1], m_background[2], m_background[3]);
	m_canvas->ClearBuffer(RAS_ICanvas::COLOR_BUFFER|RAS_ICanvas::DEPTH_BUFFER);
	m_rasterizer->BeginFrame(RAS_IRasterizer::KX_TEXTURED,m_engine->GetClockTime());
	m_rendertools->BeginFrame(m_rasterizer);
	m_engine->SetWorldSettings(m_scene->GetWorldInfo());
	m_rendertools->SetAuxilaryClientInfo(m_scene);
	m_rasterizer->DisplayFog();
	// matrix calculation, don't apply any of the stereo mode
	m_rasterizer->SetStereoMode(RAS_IRasterizer::RAS_STEREO_NOSTEREO);
	if (m_mirror)
	{
		// frustrum was computed above
		// get frustrum matrix and set projection matrix
		MT_Matrix4x4 projmat = m_rasterizer->GetFrustumMatrix(
		            frustrum.x1, frustrum.x2, frustrum.y1, frustrum.y2, frustrum.camnear, frustrum.camfar);

		m_camera->SetProjectionMatrix(projmat);
	} else if (m_camera->hasValidProjectionMatrix())
	{
		m_rasterizer->SetProjectionMatrix(m_camera->GetProjectionMatrix());
	} else
	{
		float lens = m_camera->GetLens();
		float sensor_x = m_camera->GetSensorWidth();
		float sensor_y = m_camera->GetSensorHeight();
		bool orthographic = !m_camera->GetCameraData()->m_perspective;
		float nearfrust = m_camera->GetCameraNear();
		float farfrust = m_camera->GetCameraFar();
		float aspect_ratio = 1.0f;
		Scene *blenderScene = m_scene->GetBlenderScene();
		MT_Matrix4x4 projmat;

		// compute the aspect ratio from frame blender scene settings so that render to texture
		// works the same in Blender and in Blender player
		if (blenderScene->r.ysch != 0)
			aspect_ratio = float(blenderScene->r.xsch*blenderScene->r.xasp) / float(blenderScene->r.ysch*blenderScene->r.yasp);

		if (orthographic) {

			RAS_FramingManager::ComputeDefaultOrtho(
			            nearfrust,
			            farfrust,
			            m_camera->GetScale(),
			            aspect_ratio,
						m_camera->GetSensorFit(),
			            frustrum
			            );

			projmat = m_rasterizer->GetOrthoMatrix(
			            frustrum.x1, frustrum.x2, frustrum.y1, frustrum.y2, frustrum.camnear, frustrum.camfar);
		} else
		{
			RAS_FramingManager::ComputeDefaultFrustum(
			            nearfrust,
			            farfrust,
			            lens,
			            sensor_x,
			            sensor_y,
			            RAS_SENSORFIT_AUTO,
			            aspect_ratio,
			            frustrum);
			
			projmat = m_rasterizer->GetFrustumMatrix(
			            frustrum.x1, frustrum.x2, frustrum.y1, frustrum.y2, frustrum.camnear, frustrum.camfar);
		}
		m_camera->SetProjectionMatrix(projmat);
	}

	MT_Transform camtrans(m_camera->GetWorldToCamera());
	MT_Matrix4x4 viewmat(camtrans);
	
	m_rasterizer->SetViewMatrix(viewmat, m_camera->NodeGetWorldOrientation(), m_camera->NodeGetWorldPosition(), m_camera->GetCameraData()->m_perspective);
	m_camera->SetModelviewMatrix(viewmat);
	// restore the stereo mode now that the matrix is computed
	m_rasterizer->SetStereoMode(stereomode);

	m_scene->CalculateVisibleMeshes(m_rasterizer,m_camera);

	m_scene->RenderBuckets(camtrans, m_rasterizer, m_rendertools);

	// restore the canvas area now that the render is completed
	m_canvas->GetWindowArea() = area;
}


// cast Image pointer to ImageRender
inline ImageRender * getImageRender (PyImage * self)
{ return static_cast<ImageRender*>(self->m_image); }


// python methods

// Blender Scene type
BlendType<KX_Scene> sceneType ("KX_Scene");
// Blender Camera type
BlendType<KX_Camera> cameraType ("KX_Camera");


// object initialization
static int ImageRender_init (PyObject * pySelf, PyObject * args, PyObject * kwds)
{
	// parameters - scene object
	PyObject * scene;
	// camera object
	PyObject * camera;
	// parameter keywords
	static const char *kwlist[] = {"sceneObj", "cameraObj", NULL};
	// get parameters
	if (!PyArg_ParseTupleAndKeywords(args, kwds, "OO",
		const_cast<char**>(kwlist), &scene, &camera))
		return -1;
	try
	{
		// get scene pointer
		KX_Scene * scenePtr (NULL);
		if (scene != NULL) scenePtr = sceneType.checkType(scene);
		// throw exception if scene is not available
		if (scenePtr == NULL) THRWEXCP(SceneInvalid, S_OK);

		// get camera pointer
		KX_Camera * cameraPtr (NULL);
		if (camera != NULL) cameraPtr = cameraType.checkType(camera);
		// throw exception if camera is not available
		if (cameraPtr == NULL) THRWEXCP(CameraInvalid, S_OK);

		// get pointer to image structure
		PyImage * self = reinterpret_cast<PyImage*>(pySelf);
		// create source object
		if (self->m_image != NULL) delete self->m_image;
		self->m_image = new ImageRender(scenePtr, cameraPtr);
	}
	catch (Exception & exp)
	{
		exp.report();
		return -1;
	}
	// initialization succeded
	return 0;
}


// get background color
PyObject * getBackground (PyImage * self, void * closure)
{
	return Py_BuildValue("[BBBB]",
	                     getImageRender(self)->getBackground(0),
	                     getImageRender(self)->getBackground(1),
	                     getImageRender(self)->getBackground(2),
	                     getImageRender(self)->getBackground(3));
}

// set color
static int setBackground (PyImage * self, PyObject * value, void * closure)
{
	// check validity of parameter
	if (value == NULL || !PySequence_Check(value) || PySequence_Size(value) != 4
		|| !PyLong_Check(PySequence_Fast_GET_ITEM(value, 0))
		|| !PyLong_Check(PySequence_Fast_GET_ITEM(value, 1))
		|| !PyLong_Check(PySequence_Fast_GET_ITEM(value, 2))
		|| !PyLong_Check(PySequence_Fast_GET_ITEM(value, 3)))
	{
		PyErr_SetString(PyExc_TypeError, "The value must be a sequence of 4 integer between 0 and 255");
		return -1;
	}
	// set background color
	getImageRender(self)->setBackground((unsigned char)(PyLong_AsSsize_t(PySequence_Fast_GET_ITEM(value, 0))),
		(unsigned char)(PyLong_AsSsize_t(PySequence_Fast_GET_ITEM(value, 1))),
		(unsigned char)(PyLong_AsSsize_t(PySequence_Fast_GET_ITEM(value, 2))),
		(unsigned char)(PyLong_AsSsize_t(PySequence_Fast_GET_ITEM(value, 3))));
	// success
	return 0;
}


// methods structure
static PyMethodDef imageRenderMethods[] =
{ // methods from ImageBase class
	{"refresh", (PyCFunction)Image_refresh, METH_NOARGS, "Refresh image - invalidate its current content"},
	{NULL}
};
// attributes structure
static PyGetSetDef imageRenderGetSets[] =
{ 
	{(char*)"background", (getter)getBackground, (setter)setBackground, (char*)"background color", NULL},
    // attribute from ImageViewport
	{(char*)"capsize", (getter)ImageViewport_getCaptureSize, (setter)ImageViewport_setCaptureSize, (char*)"size of render area", NULL},
	{(char*)"alpha", (getter)ImageViewport_getAlpha, (setter)ImageViewport_setAlpha, (char*)"use alpha in texture", NULL},
	{(char*)"whole", (getter)ImageViewport_getWhole, (setter)ImageViewport_setWhole, (char*)"use whole viewport to render", NULL},
	// attributes from ImageBase class
	{(char*)"valid", (getter)Image_valid, NULL, (char*)"bool to tell if an image is available", NULL},
	{(char*)"image", (getter)Image_getImage, NULL, (char*)"image data", NULL},
	{(char*)"size", (getter)Image_getSize, NULL, (char*)"image size", NULL},
	{(char*)"scale", (getter)Image_getScale, (setter)Image_setScale, (char*)"fast scale of image (near neighbor)",	NULL},
	{(char*)"flip", (getter)Image_getFlip, (setter)Image_setFlip, (char*)"flip image vertically", NULL},
	{(char*)"filter", (getter)Image_getFilter, (setter)Image_setFilter, (char*)"pixel filter", NULL},
	{NULL}
};


// define python type
PyTypeObject ImageRenderType =
{ 
	PyVarObject_HEAD_INIT(NULL, 0)
	"VideoTexture.ImageRender",   /*tp_name*/
	sizeof(PyImage),          /*tp_basicsize*/
	0,                         /*tp_itemsize*/
	(destructor)Image_dealloc, /*tp_dealloc*/
	0,                         /*tp_print*/
	0,                         /*tp_getattr*/
	0,                         /*tp_setattr*/
	0,                         /*tp_compare*/
	0,                         /*tp_repr*/
	0,                         /*tp_as_number*/
	0,                         /*tp_as_sequence*/
	0,                         /*tp_as_mapping*/
	0,                         /*tp_hash */
	0,                         /*tp_call*/
	0,                         /*tp_str*/
	0,                         /*tp_getattro*/
	0,                         /*tp_setattro*/
	&imageBufferProcs,         /*tp_as_buffer*/
	Py_TPFLAGS_DEFAULT,        /*tp_flags*/
	"Image source from render",       /* tp_doc */
	0,		               /* tp_traverse */
	0,		               /* tp_clear */
	0,		               /* tp_richcompare */
	0,		               /* tp_weaklistoffset */
	0,		               /* tp_iter */
	0,		               /* tp_iternext */
	imageRenderMethods,    /* tp_methods */
	0,                   /* tp_members */
	imageRenderGetSets,          /* tp_getset */
	0,                         /* tp_base */
	0,                         /* tp_dict */
	0,                         /* tp_descr_get */
	0,                         /* tp_descr_set */
	0,                         /* tp_dictoffset */
	(initproc)ImageRender_init,     /* tp_init */
	0,                         /* tp_alloc */
	Image_allocNew,           /* tp_new */
};

// object initialization
static int ImageMirror_init (PyObject * pySelf, PyObject * args, PyObject * kwds)
{
	// parameters - scene object
	PyObject * scene;
	// reference object for mirror
	PyObject * observer;
	// object holding the mirror
	PyObject * mirror;
	// material of the mirror
	short materialID = 0;
	// parameter keywords
	static const char *kwlist[] = {"scene", "observer", "mirror", "material", NULL};
	// get parameters
	if (!PyArg_ParseTupleAndKeywords(args, kwds, "OOO|h",
	                                 const_cast<char**>(kwlist), &scene, &observer, &mirror, &materialID))
		return -1;
	try
	{
		// get scene pointer
		KX_Scene * scenePtr (NULL);
		if (scene != NULL && PyObject_TypeCheck(scene, &KX_Scene::Type))
			scenePtr = static_cast<KX_Scene*>BGE_PROXY_REF(scene);
		else
			THRWEXCP(SceneInvalid, S_OK);
		
		if (scenePtr==NULL) /* in case the python proxy reference is invalid */
			THRWEXCP(SceneInvalid, S_OK);
		
		// get observer pointer
		KX_GameObject * observerPtr (NULL);
		if (observer != NULL && PyObject_TypeCheck(observer, &KX_GameObject::Type))
			observerPtr = static_cast<KX_GameObject*>BGE_PROXY_REF(observer);
		else if (observer != NULL && PyObject_TypeCheck(observer, &KX_Camera::Type))
			observerPtr = static_cast<KX_Camera*>BGE_PROXY_REF(observer);
		else
			THRWEXCP(ObserverInvalid, S_OK);
		
		if (observerPtr==NULL) /* in case the python proxy reference is invalid */
			THRWEXCP(ObserverInvalid, S_OK);

		// get mirror pointer
		KX_GameObject * mirrorPtr (NULL);
		if (mirror != NULL && PyObject_TypeCheck(mirror, &KX_GameObject::Type))
			mirrorPtr = static_cast<KX_GameObject*>BGE_PROXY_REF(mirror);
		else
			THRWEXCP(MirrorInvalid, S_OK);
		
		if (mirrorPtr==NULL) /* in case the python proxy reference is invalid */
			THRWEXCP(MirrorInvalid, S_OK);

		// locate the material in the mirror
		RAS_IPolyMaterial * material = getMaterial(mirror, materialID);
		if (material == NULL)
			THRWEXCP(MaterialNotAvail, S_OK);

		// get pointer to image structure
		PyImage * self = reinterpret_cast<PyImage*>(pySelf);

		// create source object
		if (self->m_image != NULL)
		{
			delete self->m_image;
			self->m_image = NULL;
		}
		self->m_image = new ImageRender(scenePtr, observerPtr, mirrorPtr, material);
	}
	catch (Exception & exp)
	{
		exp.report();
		return -1;
	}
	// initialization succeded
	return 0;
}

// get background color
PyObject * getClip (PyImage * self, void * closure)
{
	return PyFloat_FromDouble(getImageRender(self)->getClip());
}

// set clip
static int setClip (PyImage * self, PyObject * value, void * closure)
{
	// check validity of parameter
	double clip;
	if (value == NULL || !PyFloat_Check(value) || (clip = PyFloat_AsDouble(value)) < 0.01 || clip > 5000.0)
	{
		PyErr_SetString(PyExc_TypeError, "The value must be an float between 0.01 and 5000");
		return -1;
	}
	// set background color
	getImageRender(self)->setClip(float(clip));
	// success
	return 0;
}

// attributes structure
static PyGetSetDef imageMirrorGetSets[] =
{ 
	{(char*)"clip", (getter)getClip, (setter)setClip, (char*)"clipping distance", NULL},
	// attribute from ImageRender
	{(char*)"background", (getter)getBackground, (setter)setBackground, (char*)"background color", NULL},
	// attribute from ImageViewport
	{(char*)"capsize", (getter)ImageViewport_getCaptureSize, (setter)ImageViewport_setCaptureSize, (char*)"size of render area", NULL},
	{(char*)"alpha", (getter)ImageViewport_getAlpha, (setter)ImageViewport_setAlpha, (char*)"use alpha in texture", NULL},
	{(char*)"whole", (getter)ImageViewport_getWhole, (setter)ImageViewport_setWhole, (char*)"use whole viewport to render", NULL},
	// attributes from ImageBase class
	{(char*)"valid", (getter)Image_valid, NULL, (char*)"bool to tell if an image is available", NULL},
	{(char*)"image", (getter)Image_getImage, NULL, (char*)"image data", NULL},
	{(char*)"size", (getter)Image_getSize, NULL, (char*)"image size", NULL},
	{(char*)"scale", (getter)Image_getScale, (setter)Image_setScale, (char*)"fast scale of image (near neighbor)",	NULL},
	{(char*)"flip", (getter)Image_getFlip, (setter)Image_setFlip, (char*)"flip image vertically", NULL},
	{(char*)"filter", (getter)Image_getFilter, (setter)Image_setFilter, (char*)"pixel filter", NULL},
	{NULL}
};


// constructor
ImageRender::ImageRender (KX_Scene * scene, KX_GameObject * observer, KX_GameObject * mirror, RAS_IPolyMaterial * mat) :
    ImageViewport(),
    m_render(false),
    m_scene(scene),
    m_observer(observer),
    m_mirror(mirror),
    m_clip(100.f)
{
	// this constructor is used for automatic planar mirror
	// create a camera, take all data by default, in any case we will recompute the frustrum on each frame
	RAS_CameraData camdata;
	vector<RAS_TexVert*> mirrorVerts;
	vector<RAS_TexVert*>::iterator it;
	float mirrorArea = 0.f;
	float mirrorNormal[3] = {0.f, 0.f, 0.f};
	float mirrorUp[3];
	float dist, vec[3], axis[3];
	float zaxis[3] = {0.f, 0.f, 1.f};
	float yaxis[3] = {0.f, 1.f, 0.f};
	float mirrorMat[3][3];
	float left, right, top, bottom, back;
	// make sure this camera will delete its node
	m_camera= new KX_Camera(scene, KX_Scene::m_callbacks, camdata, true, true);
	m_camera->SetName("__mirror__cam__");
	// don't add the camera to the scene object list, it doesn't need to be accessible
	m_owncamera = true;
	// retrieve rendering objects
	m_engine = KX_GetActiveEngine();
	m_rasterizer = m_engine->GetRasterizer();
	m_canvas = m_engine->GetCanvas();
	m_rendertools = m_engine->GetRenderTools();
	// locate the vertex assigned to mat and do following calculation in mesh coordinates
	for (int meshIndex = 0; meshIndex < mirror->GetMeshCount(); meshIndex++)
	{
		RAS_MeshObject*	mesh = mirror->GetMesh(meshIndex);
		int numPolygons = mesh->NumPolygons();
		for (int polygonIndex=0; polygonIndex < numPolygons; polygonIndex++)
		{
			RAS_Polygon* polygon = mesh->GetPolygon(polygonIndex);
			if (polygon->GetMaterial()->GetPolyMaterial() == mat)
			{
				RAS_TexVert *v1, *v2, *v3, *v4;
				float normal[3];
				float area;
				// this polygon is part of the mirror,
				v1 = polygon->GetVertex(0);
				v2 = polygon->GetVertex(1);
				v3 = polygon->GetVertex(2);
				mirrorVerts.push_back(v1);
				mirrorVerts.push_back(v2);
				mirrorVerts.push_back(v3);
				if (polygon->VertexCount() == 4)
				{
					v4 = polygon->GetVertex(3);
					mirrorVerts.push_back(v4);
					area = normal_quad_v3(normal,(float*)v1->getXYZ(), (float*)v2->getXYZ(), (float*)v3->getXYZ(), (float*)v4->getXYZ());
				} else
				{
					area = normal_tri_v3(normal,(float*)v1->getXYZ(), (float*)v2->getXYZ(), (float*)v3->getXYZ());
				}
				area = fabs(area);
				mirrorArea += area;
				mul_v3_fl(normal, area);
				add_v3_v3v3(mirrorNormal, mirrorNormal, normal);
			}
		}
	}
	if (mirrorVerts.size() == 0 || mirrorArea < FLT_EPSILON)
	{
		// no vertex or zero size mirror
		THRWEXCP(MirrorSizeInvalid, S_OK);
	}
	// compute average normal of mirror faces
	mul_v3_fl(mirrorNormal, 1.0f/mirrorArea);
	if (normalize_v3(mirrorNormal) == 0.f)
	{
		// no normal
		THRWEXCP(MirrorNormalInvalid, S_OK);
	}
	// the mirror plane has an equation of the type ax+by+cz = d where (a,b,c) is the normal vector
	// if the mirror is more vertical then horizontal, the Z axis is the up direction.
	// otherwise the Y axis is the up direction.
	// If the mirror is not perfectly vertical(horizontal), the Z(Y) axis projection on the mirror
	// plan by the normal will be the up direction.
	if (fabs(mirrorNormal[2]) > fabs(mirrorNormal[1]) &&
	        fabs(mirrorNormal[2]) > fabs(mirrorNormal[0]))
	{
		// the mirror is more horizontal than vertical
		copy_v3_v3(axis, yaxis);
	}
	else
	{
		// the mirror is more vertical than horizontal
		copy_v3_v3(axis, zaxis);
	}
	dist = dot_v3v3(mirrorNormal, axis);
	if (fabs(dist) < FLT_EPSILON)
	{
		// the mirror is already fully aligned with up axis
		copy_v3_v3(mirrorUp, axis);
	}
	else
	{
		// projection of axis to mirror plane through normal
		copy_v3_v3(vec, mirrorNormal);
		mul_v3_fl(vec, dist);
		sub_v3_v3v3(mirrorUp, axis, vec);
		if (normalize_v3(mirrorUp) == 0.f)
		{
			// should not happen
			THRWEXCP(MirrorHorizontal, S_OK);
			return;
		}
	}
	// compute rotation matrix between local coord and mirror coord
	// to match camera orientation, we select mirror z = -normal, y = up, x = y x z
	negate_v3_v3(mirrorMat[2], mirrorNormal);
	copy_v3_v3(mirrorMat[1], mirrorUp);
	cross_v3_v3v3(mirrorMat[0], mirrorMat[1], mirrorMat[2]);
	// transpose to make it a orientation matrix from local space to mirror space
	transpose_m3(mirrorMat);
	// transform all vertex to plane coordinates and determine mirror position
	left = FLT_MAX;
	right = -FLT_MAX;
	bottom = FLT_MAX;
	top = -FLT_MAX;
	back = -FLT_MAX; // most backward vertex (=highest Z coord in mirror space)
	for (it = mirrorVerts.begin(); it != mirrorVerts.end(); it++)
	{
		copy_v3_v3(vec, (float*)(*it)->getXYZ());
		mul_m3_v3(mirrorMat, vec);
		if (vec[0] < left)
			left = vec[0];
		if (vec[0] > right)
			right = vec[0];
		if (vec[1] < bottom)
			bottom = vec[1];
		if (vec[1] > top)
			top = vec[1];
		if (vec[2] > back)
			back = vec[2];
	}
	// now store this information in the object for later rendering
	m_mirrorHalfWidth = (right-left)*0.5f;
	m_mirrorHalfHeight = (top-bottom)*0.5f;
	if (m_mirrorHalfWidth < 0.01f || m_mirrorHalfHeight < 0.01f)
	{
		// mirror too small
		THRWEXCP(MirrorTooSmall, S_OK);
	}
	// mirror position in mirror coord
	vec[0] = (left+right)*0.5f;
	vec[1] = (top+bottom)*0.5f;
	vec[2] = back;
	// convert it in local space: transpose again the matrix to get back to mirror to local transform
	transpose_m3(mirrorMat);
	mul_m3_v3(mirrorMat, vec);
	// mirror position in local space
	m_mirrorPos.setValue(vec[0], vec[1], vec[2]);
	// mirror normal vector (pointed towards the back of the mirror) in local space
	m_mirrorZ.setValue(-mirrorNormal[0], -mirrorNormal[1], -mirrorNormal[2]);
	m_mirrorY.setValue(mirrorUp[0], mirrorUp[1], mirrorUp[2]);
	m_mirrorX = m_mirrorY.cross(m_mirrorZ);
	m_render = true;

	setBackground(0, 0, 255, 255);
}




// define python type
PyTypeObject ImageMirrorType =
{ 
	PyVarObject_HEAD_INIT(NULL, 0)
	"VideoTexture.ImageMirror",   /*tp_name*/
	sizeof(PyImage),          /*tp_basicsize*/
	0,                         /*tp_itemsize*/
	(destructor)Image_dealloc, /*tp_dealloc*/
	0,                         /*tp_print*/
	0,                         /*tp_getattr*/
	0,                         /*tp_setattr*/
	0,                         /*tp_compare*/
	0,                         /*tp_repr*/
	0,                         /*tp_as_number*/
	0,                         /*tp_as_sequence*/
	0,                         /*tp_as_mapping*/
	0,                         /*tp_hash */
	0,                         /*tp_call*/
	0,                         /*tp_str*/
	0,                         /*tp_getattro*/
	0,                         /*tp_setattro*/
	&imageBufferProcs,         /*tp_as_buffer*/
	Py_TPFLAGS_DEFAULT,        /*tp_flags*/
	"Image source from mirror",       /* tp_doc */
	0,		               /* tp_traverse */
	0,		               /* tp_clear */
	0,		               /* tp_richcompare */
	0,		               /* tp_weaklistoffset */
	0,		               /* tp_iter */
	0,		               /* tp_iternext */
	imageRenderMethods,    /* tp_methods */
	0,                   /* tp_members */
	imageMirrorGetSets,          /* tp_getset */
	0,                         /* tp_base */
	0,                         /* tp_dict */
	0,                         /* tp_descr_get */
	0,                         /* tp_descr_set */
	0,                         /* tp_dictoffset */
	(initproc)ImageMirror_init,     /* tp_init */
	0,                         /* tp_alloc */
	Image_allocNew,           /* tp_new */
};