///////////////////////////////////////////////////////////////////////////////////
// Render the camera's frustum
void CCamera::Render(int intermediates) const
{
CVector3D nearPoints[4];
CVector3D farPoints[4];
GetCameraPlanePoints(m_NearPlane, nearPoints);
GetCameraPlanePoints(m_FarPlane, farPoints);
for(int i = 0; i < 4; i++)
{
nearPoints[i] = m_Orientation.Transform(nearPoints[i]);
farPoints[i] = m_Orientation.Transform(farPoints[i]);
}
// near plane
glBegin(GL_POLYGON);
glVertex3fv(&nearPoints[0].X);
glVertex3fv(&nearPoints[1].X);
glVertex3fv(&nearPoints[2].X);
glVertex3fv(&nearPoints[3].X);
glEnd();
// far plane
glBegin(GL_POLYGON);
glVertex3fv(&farPoints[0].X);
glVertex3fv(&farPoints[1].X);
glVertex3fv(&farPoints[2].X);
glVertex3fv(&farPoints[3].X);
glEnd();
// connection lines
glBegin(GL_QUAD_STRIP);
glVertex3fv(&nearPoints[0].X);
glVertex3fv(&farPoints[0].X);
glVertex3fv(&nearPoints[1].X);
glVertex3fv(&farPoints[1].X);
glVertex3fv(&nearPoints[2].X);
glVertex3fv(&farPoints[2].X);
glVertex3fv(&nearPoints[3].X);
glVertex3fv(&farPoints[3].X);
glVertex3fv(&nearPoints[0].X);
glVertex3fv(&farPoints[0].X);
glEnd();
// intermediate planes
CVector3D intermediatePoints[4];
for(int i = 0; i < intermediates; ++i)
{
float t = (i+1.0)/(intermediates+1.0);
for(int j = 0; j < 4; ++j)
intermediatePoints[j] = nearPoints[j]*t + farPoints[j]*(1.0-t);
glBegin(GL_POLYGON);
glVertex3fv(&intermediatePoints[0].X);
glVertex3fv(&intermediatePoints[1].X);
glVertex3fv(&intermediatePoints[2].X);
glVertex3fv(&intermediatePoints[3].X);
glEnd();
}
}
void CCamera::BuildCameraRay(int px, int py, CVector3D& origin, CVector3D& dir) const
{
CVector3D cPts[4];
GetCameraPlanePoints(m_FarPlane, cPts);
// transform to world space
CVector3D wPts[4];
for (int i = 0; i < 4; i++)
wPts[i] = m_Orientation.Transform(cPts[i]);
// get world space position of mouse point
float dx = (float)px / (float)g_Renderer.GetWidth();
float dz = 1 - (float)py / (float)g_Renderer.GetHeight();
CVector3D vdx = wPts[1] - wPts[0];
CVector3D vdz = wPts[3] - wPts[0];
CVector3D pt = wPts[0] + (vdx * dx) + (vdz * dz);
// copy origin
origin = m_Orientation.GetTranslation();
// build direction
dir = pt - origin;
dir.Normalize();
}
