Everyframe light position updation

Graphics and GPU Programming Programming

Started by nail85 March 30, 2003 09:27 AM

2 comments, last by nail85 21 years ago

nail85

122

Author

March 30, 2003 09:27 AM

In my engine i have camera and light classes. Light class has function like this

  
void Light::SetPosition(Vector3& v)
{
  mPosition = v;
  
  if (mbEnabled)
    glLightfv(GL_LIGHT0 + mID, GL_POSITION, v);
}

And I have function Camera::UpdateView, wich loads view matrix to OpenGL. Well, I change position of my camera every frame - it moves, but all light are also moves with the camera. Heh, this is itresting effect, but I don''t want to get it. So I need update my Camera::UpdateView and add lines like this

  
for each light in scene
  if it enabled
    UpdatePositionOfThisLight;

I think that this is not fastest and optimal way. Have anybody any ideas?

Cifko

138

March 31, 2003 02:28 AM

When you use glLightfv(GL_LIGHT0 + mID, GL_POSITION, v);
the lights position is calculated with actual modelview matrix.
I wonder of useing only vector3 for light pos. What is 4. corrdinate?

nail85

122

Author

March 31, 2003 08:14 AM

This was sample, actualy I use 4D vectors with w=1 (point light).
And I want OpenGL automaticly multiplies light''s position with modelview matrix every frame. This was my question.