Greetings. The direction of DirectionalLights is opposite to what I expected, and opposite to the behavior of SpotLights -- at least in OpenSG 1.8. I've been tracing through the logic, and here's what I've figured out:
>From the OpenGL documentation: http://www.opengl.org/sdk/docs/man/ "If the w component of the position is 0, the light is treated as a directional source ... The initial position is (0, 0, 1, 0); thus, the initial light source is directional, parallel to, and in the direction of the -z axis." So the direction is opposite to the GL_POSITION, and conversely, the GL_POSITION is opposite to the direction, and the GL_SPOT_DIRECTION is ignored. But in OpenSG 1.8 DirectionalLight::drawEnter(Action *action) I see: Vec4f dir(_sfDirection.getValue()); dir[3] = 0; glLightfv(light, GL_POSITION , dir.getValues()); glLightf (light, GL_SPOT_CUTOFF, 180.f ); So it's setting the GL_POSITION from the specified direction, instead of its opposite. The direction is pointing toward the light, instead of away from it as with the SpotLight. I suppose it would break a lot of client code, but I would change one line: glLightfv(light, GL_POSITION , (-dir).getValues()); Thoughts? Does OpenSG 2.0 follow the same logic? Thanks for your attention. -- Ted ------------------------------------------------------------------------------ _______________________________________________ Opensg-users mailing list Opensg-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/opensg-users
