发信人: yahoo(乡巴佬)
整理人: avexdesign(2003-11-11 20:18:20), 站内信件
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视乎你用什么渲染器，就用什么语言。
MAX的默认渲染器我就不知道可不可以编程，
但mental ray和renderman就肯定可以。
还有bmrt也可以，语言是类似C++的。
以下的就是bmrt渲染器的brick（砖墙）材质的程序，稍作修改应该也可在
renderman下编译通过。
我就看不明白了，希望mayaX能尽快写出编shade的教程。
/*
* brick.sl -- Surface shader for a bricks.
*
* DESCRIPTION:
* Makes a wall of bricks. Need more be said? OK. It makes a good
* looking staggered brick masonry. It is especially convincing when
* used in conjunction with the "brickbump" displacement shader (and
* identical parameters). Every other row of bricks is staggered.
* The staggering isn't exact, however, and this variance is controlled
* by the "rowvary" parameter.
*
* PARAMETERS:
* Ka, Kd The usual
* brickcolor, mortarcolor Pretty obvious (default is red bricks)
* brickvary How much does the brick color vary from
* brick to brick?
* brickwidth Width of a brick (in st space)
* brickheight Height of a brick (in st space)
* mortarthickness Thickness of the mortar (in st space)
* rowvary How much does each row shift?
* jagged How much do bricks deviate from squares?
*
* The Blue Moon Rendering Tools (BMRT) are:
* (c) Copyright 1990-2000 Exluna, Inc. and Larry Gritz. All rights reserved.
*/
#include "noises.h"
#include "patterns.h"
surface
brick ( float Ka = 1, Kd = 1;
color brickcolor = color "rgb" (.6,.1,.1);
color mortarcolor = color "rgb" (.6,.6,.6);
float raggedamp = 0.04, raggedfreq = 12;
float jagged = 0.006, brickvary = 0.3;
float brickwidth = .28, brickheight = .07;
float mortarthickness = .014;
float rowvary = .5;
float pitting = 0.01;
float pockfrequency = 10, groovedepth = 0.01;
)
{
#define sqr(x) ((x)*(x))
color bcolor, Ct;
normal Nf;
float sbrick, tbrick, w, h;
float ss, tt;
float swidth, twidth;
uniform float BMWIDTH = (brickwidth+mortarthickness);
uniform float BMHEIGHT = (brickheight+mortarthickness);
uniform float MWF = (mortarthickness*0.5/BMWIDTH);
uniform float MHF = (mortarthickness*0.5/BMHEIGHT);
float whichbrick;
float fact, disp;
/* Determine how wide in s-t space one pixel projects to, relative
* the the width and height of a brick. Overestimate the filter
* size by a bit -- it makes the transitions between brick and mortar
* a bit smoother.
*/
swidth = 1.5 * max (filterwidth(s), MINFILTWIDTH) / BMWIDTH;
twidth = 1.5 * max (filterwidth(t), MINFILTWIDTH) / BMHEIGHT;
basicbrick (s, t, BMWIDTH, BMHEIGHT, 0.5, 0.2, 1, jagged,
sbrick, tbrick, ss, tt);
/* Make the edges ragged, but different for each brick */
whichbrick = 103*sbrick + tbrick;
ss += raggedamp * snoisexy ((s+tbrick*5.15)*raggedfreq,
(t+sbrick*23.8)*raggedfreq);
tt += raggedamp * snoisexy ((s+tbrick*11.4)*raggedfreq,
(t+sbrick*7.2)*raggedfreq);
ss += raggedamp/2 * snoisexy ((s+tbrick*5.15)*raggedfreq*2,
(t+sbrick*23.8)*raggedfreq*2);
tt += raggedamp/2 * snoisexy ((s+tbrick*11.4)*raggedfreq*2,
(t+sbrick*7.2)*raggedfreq*2);
/* Choose a color for the surface */
if (swidth >= 1)
w = 1 - 2*MWF;
else w = clamp (filteredpulse (MWF, 1-MWF, ss, swidth), max(1-MWF/swidth,0), 1);
if (twidth >= 1)
h = 1 - 2*MHF;
else h = clamp (filteredpulse (MHF, 1-MHF, tt, twidth), max(1-MHF/twidth,0), 1);
fact = 1;
disp = 0;
if (tt < MHF) {
/* We're in the top horizontal groove */
disp = groovedepth * (sqr((tt)/MHF) - 1);
}
else if (tt > (1.0-MHF)) {
/* Bottom horizontal groove */
disp = groovedepth * (sqr((1-tt)/MHF) - 1);
}
if (ss < MWF) {
disp = min (disp, 0.85 * groovedepth * (sqr(ss/MWF) - 1));
}
else if (ss > (1.0-MWF)) {
disp = min (disp, 0.85 * groovedepth * (sqr((1-ss)/MWF) - 1));
}
fact = smoothstep (0, 1.3*MHF, tt) - smoothstep (1.0-1.3*MHF, 1, tt);
fact *= (smoothstep (0, 1.3*MWF, ss) - smoothstep (1.0-1.3*MWF, 1, ss));
fact = pitting * (0.5 * fact + 0.5);
disp -= fact * pow(noise ((ss+sbrick)*pockfrequency/BMHEIGHT,
(tt+tbrick)*pockfrequency/BMWIDTH), 0.25);
P += disp * normalize(N);
N = calculatenormal (P);
Nf = faceforward (normalize(N),I);
/* Choose a brick color that varies from brick to brick */
bcolor = brickcolor * (1 + (brickvary * snoise (whichbrick+0.5)));
Ct = mix (mortarcolor, bcolor, w*h);
Oi = Os;
Ci = Os * Ct * (Ka * ambient() + Kd*diffuse(Nf));
}
【 在 zyg 的大作中提到：】
:我记得你好像是说过这么回事吧？说国外的高手都是通过编程制作材质的，你能介绍一下那编程吗？是用什么语言写的？
:......
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