btVector3 PhysicsServerExample::getRayTo(int x,int y)
{
CommonRenderInterface* renderer = m_guiHelper->getRenderInterface();
if (!renderer)
{
btAssert(0);
return btVector3(0,0,0);
}
float top = 1.f;
float bottom = -1.f;
float nearPlane = 1.f;
float tanFov = (top-bottom)*0.5f / nearPlane;
float fov = btScalar(2.0) * btAtan(tanFov);
btVector3 camPos,camTarget;
renderer->getActiveCamera()->getCameraPosition(camPos);
renderer->getActiveCamera()->getCameraTargetPosition(camTarget);
btVector3 rayFrom = camPos;
btVector3 rayForward = (camTarget-camPos);
rayForward.normalize();
float farPlane = 10000.f;
rayForward*= farPlane;
btVector3 rightOffset;
btVector3 cameraUp=btVector3(0,0,0);
cameraUp[m_guiHelper->getAppInterface()->getUpAxis()]=1;
btVector3 vertical = cameraUp;
btVector3 hor;
hor = rayForward.cross(vertical);
hor.normalize();
vertical = hor.cross(rayForward);
vertical.normalize();
float tanfov = tanf(0.5f*fov);
hor *= 2.f * farPlane * tanfov;
vertical *= 2.f * farPlane * tanfov;
btScalar aspect;
float width = float(renderer->getScreenWidth());
float height = float (renderer->getScreenHeight());
aspect = width / height;
hor*=aspect;
btVector3 rayToCenter = rayFrom + rayForward;
btVector3 dHor = hor * 1.f/width;
btVector3 dVert = vertical * 1.f/height;
btVector3 rayTo = rayToCenter - 0.5f * hor + 0.5f * vertical;
rayTo += btScalar(x) * dHor;
rayTo -= btScalar(y) * dVert;
return rayTo;
}
