i have a model that is composed of a parent-child relation ship, to draw this model i use several glpop/push commands as well as several glrotate/translate command, the drawing occurs fine, when i rotate one limb of the figure all it’s children will rotate also. But for lighting purposes, i need to calculate the transformed vertices( their new position ) in order to calculate the new normals. How to do this?
tia
Paul
You can specify normals with respect to the untransformed vertices. Normals are transformed by the model view matrix as well. As long as you’re not performing any scaling everything should be fine. If you do perform scaling, the normals will also get scaled, which affects the results of the lighting calculations (normals will no longer have unit length; direction may change in case of non uniform scaling).
you may try glEnable(GL.GL_NORMALIZE) …