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lunes, 7 de junio de 2010

Blinn-Phong Halfway vector and the parallelogram rule / Blinn-Phong vector a "Mediocamino" y la regla del paralelogramo

Studying for the Computer Graphics final exam I bumped into a simple, but important fact about adding vectors. Is stated everywhere that in the Blinn-Phong reflection model, the angle spanned by the Halfway vector and the normal to the surface (where the reflection is taking place) is the half of the angle spanned by the Viewer (or Eye) vector and the Reflected vector ... English Version

Preparando el examen final de la materia Computer Graphics, me topé con una propiedad relacionada a la suma de vectores que, si bien es básica, no deja de ser importante. En muchos sitos de internet (link? no he visto muchos en Español...habrá que poner en wikipedia...tendré tiempo?) se dice que el vector de "Mediocamino" en el modelo de iluminación Blinn-Phong sustiende un ángulo con la normal de la superfice (donde la reflexión ocurre) que es la mitad del ángulo entre el vector que apunta al observador y el vector que indica la dirección de reflexión de la luz ... versión en Español



Figure 1: Light incident from direction L on a surface with normal N. The light is reflected in direction R and the viewer is pointed by V. H is the Halfway vector.


Figure 2: Addition of vectors using the parallelogram rule. The addition of vectors of arbitrary length does not yields the bisector of the angle. The addition of the normalized vectors produces the angle bisector.

4 comentarios:

  1. Hmmm for some reason only half the post can be seen. I tried reloading but still same.

    clomid

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  2. So what happens with your latex?
    Let me test
    $a^2+b^2+\int_a^b f(x)\,dx$

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  3. If you still want to keep your blogger, you may install the new script for your latex on http://www.watchmath.com/vlog

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  4. gracias por el aporte, si deberias colocarlo en wikipedia! saludos

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