mi_blinn_specular built in function 2004-06-19 - By Nick
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I'm trying to get the built in function mi_blinn_specular to work but I'm
having some troubles with it. I want to retrieve the specular strength and
although I've managed to do it with the built in mi_phong_specular somehow this
one is escaping me...
from shader.h:
/* evalution of reflection models */
miScalar mi_blinn_specular(
miVector *di, /* incident direction */
miVector *dr, /* direction of reflection */
miVector *n, /* surface normal */
miScalar roughness, /* average microfacet slope */
miScalar ior); /* index of refraction */
I've declared my variables:
miColor spec = *mi_eval_color(&in_pParams->m_spec);
miScalar roughness = *mi_eval_scalar(&in_pParams->m_roughness);
miScalar ior = *mi_eval_scalar(&in_pParams->m_ior);
miScalar spec_strength;
miVector di;
miVector dr;
miVector n;
miVector dir;
and am implementing it (while sampling the light shader) by using:
spec_strength = mi_blinn_specular(&di, &dr, &n, roughness, ior);
I've tried replacing it with
spec_strength = mi_blinn_specular(&state->dir, &dr, &state->normal, roughness,
ior);
which I got from looking at the baseblinn.c file included in the base shaders
zip file from the MR ftp site. It's returning something, I'm now getting a
result in the renderregion however it's not what I was expecting...
Cheers,
Nick.
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<DIV><FONT face=Arial size=2>I'm trying to get the built in function
</FONT><FONT face=Arial size=2>mi_blinn_specular to work but I'm having some
troubles with it. I want to retrieve the specular strength and although I've
managed to do it with the built in mi_phong_specular somehow this one is
escaping me...</FONT></DIV>
<DIV><FONT face=Arial size=2>from shader.h:</FONT></DIV>
<DIV><FONT face=Arial size=2><FONT color=#008000>/* evalution of reflection
models */</FONT><BR>miScalar
mi_blinn_specular(<BR> miVector *di, <FONT
color=#008000>/* incident direction
*/</FONT><BR> miVector *dr, <FONT color=#008000>/*
direction of reflection
*/</FONT><BR> miVector *n, <FONT color=#008000>/*
surface normal */</FONT><BR> miScalar roughness, <FONT
color=#008000>/* average microfacet slope
*/<BR></FONT> miScalar ior); <FONT color=#008000>/*
index of refraction */</FONT></FONT></DIV>
<DIV><FONT face=Arial color=#008000 size=2></FONT> </DIV>
<DIV><FONT face=Arial color=#008000 size=2><FONT color=#000000>I've
declared</FONT> <FONT color=#000000>my variables:</FONT></FONT></DIV>
<DIV><FONT face=Arial size=2>miColor spec =
*mi_eval_color(&in_pParams->m_spec);<BR>miScalar roughness =
*mi_eval_scalar(&in_pParams->m_roughness);<BR>miScalar ior =
*mi_eval_scalar(&in_pParams->m_ior); <BR> miScalar spec_strength;
</FONT></DIV>
<DIV><FONT face=Arial size=2>miVector di;<BR>miVector dr;<BR>miVector
n;<BR>miVector dir;</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>and am implementing it (while sampling the light
shader) by using:</FONT></DIV>
<DIV><FONT face=Arial size=2>spec_strength = mi_blinn_specular(&di, &dr
,
&n, roughness, ior);</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>I've tried replacing it with</FONT></DIV>
<DIV><FONT face=Arial size=2>spec_strength =
mi_blinn_specular(&state->dir, &dr, &state->normal, roughness
,
ior);</FONT></DIV>
<DIV><FONT face=Arial size=2>which I got from looking at the baseblinn.c file
included in the base shaders zip file from the MR ftp site. It's returning
something, I'm now getting a result in the renderregion however it's
not what I was expecting... </FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Cheers,</FONT></DIV>
<DIV><FONT face=Arial size=2>Nick.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV> </DIV></BODY></HTML>
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