improved indentation and whitespace for markdown code blocks
All code blocks in markdown have been intended by at least 4 spaces. We add `--tab-stop=8` to all `pandoc(1)` executions in order to set a better tab stop indentation, especially for tab intended code blocks. Changed `bin/pandoc-wrapper.sh` VERSION from "1.5.3 2024-03-26" to "1.6 2024-03-31". Fixed `1991/brnstnd/sorta.README.md` so that the sorta code is code blocks. Removed unneeded paragraph group in copyright in `inc/footer.default.html`. Fixed excess whitespace after list Author on entry `index.html` page. Changed `bin/output-index-author.sh` VERSION from "1.5.2 2024-03-26" to "1.6 2024-03-31". Performed `make www` to perform the above and test under macOS. TODO: Fix the problem of the initial line of code being extra intended. TODO: Fix excess whitespace around code that is inline.
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@@ -125,38 +125,38 @@
|
||||
<h1 id="scene-format-documentation">Scene format documentation</h1>
|
||||
<p>The file must be encoded in UTF-8 as the BOF marker indicates.</p>
|
||||
<p>You can directly feed it to the renderer. If you’re wondering about what the following code block does, that’s why:)</p>
|
||||
<pre><code>@|?|?z#
|
||||
@|||?z&
|
||||
>?Sedvf
|
||||
??Tdeu#
|
||||
>>Tdeui
|
||||
??Tdmmf
|
||||
??[[euf
|
||||
?}?Oq}e
|
||||
?}?Oqqf
|
||||
v}?|q}e
|
||||
v}?|qqf
|
||||
?Sj|?{f
|
||||
?Tjk?{e
|
||||
FF?Oqq$
|
||||
RR?Oqq$
|
||||
^^?Oqq$
|
||||
jj?Oqq$
|
||||
vv?|qq$
|
||||
IOBMqqe
|
||||
U]BMqqe
|
||||
aiBMqqe
|
||||
muBMqqe
|
||||
EEEJpp%
|
||||
QQEJpp%
|
||||
]]EJpp%
|
||||
iiEJpp%
|
||||
uuEJpp%
|
||||
ZnY|{|e
|
||||
[mZ|\{\{#
|
||||
[mZ|||f
|
||||
kkdr\{\{\%
|
||||
lkdr\{\{></code></pre>
|
||||
<pre><code> @|?|?z#
|
||||
@|||?z&
|
||||
>?Sedvf
|
||||
??Tdeu#
|
||||
>>Tdeui
|
||||
??Tdmmf
|
||||
??[[euf
|
||||
?}?Oq}e
|
||||
?}?Oqqf
|
||||
v}?|q}e
|
||||
v}?|qqf
|
||||
?Sj|?{f
|
||||
?Tjk?{e
|
||||
FF?Oqq$
|
||||
RR?Oqq$
|
||||
^^?Oqq$
|
||||
jj?Oqq$
|
||||
vv?|qq$
|
||||
IOBMqqe
|
||||
U]BMqqe
|
||||
aiBMqqe
|
||||
muBMqqe
|
||||
EEEJpp%
|
||||
QQEJpp%
|
||||
]]EJpp%
|
||||
iiEJpp%
|
||||
uuEJpp%
|
||||
ZnY|{|e
|
||||
[mZ|\{\{#
|
||||
[mZ|||f
|
||||
kkdr\{\{\%
|
||||
lkdr\{\{></code></pre>
|
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<h2 id="basic-structure">Basic structure</h2>
|
||||
<p>A scene file begins with arbitrary binary data, followed by several shader
|
||||
functions.</p>
|
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@@ -164,33 +164,33 @@ functions.</p>
|
||||
character. There are some special function names, which will be explained below.</p>
|
||||
<p>The language used to write shader functions is very simple. Basically, you write
|
||||
a sequence of assignment statements like this:</p>
|
||||
<pre><code>A=A+D
|
||||
B=B+E</code></pre>
|
||||
<pre><code> A=A+D
|
||||
B=B+E</code></pre>
|
||||
<p>Namely, you write a one-character variable name, an equal sign (<code>=</code>), followed
|
||||
by an expression (made of operators and one-character variable names, of
|
||||
course).</p>
|
||||
<h2 id="expressions">Expressions</h2>
|
||||
<p>The shader language supports seven operators, listed highest priority first:</p>
|
||||
<pre><code>*/+-<#:</code></pre>
|
||||
<pre><code> */+-<#:</code></pre>
|
||||
<p><code>*/+-<</code> each mean what they mean in C, but the priority part is a bit different.
|
||||
Basically, <code>*</code> has higher priority than <code>/</code>, so <code>A/4*4</code> actually computes
|
||||
<code>A/(4*4)</code>. And you can’t write <code>(A/4)*4</code> – brackets are not supported. As an
|
||||
advice, keep your expressions simple :) If you really needs to write something
|
||||
like <code>C=(A/4)*4</code>, write instead:</p>
|
||||
<pre><code>B=A/4+
|
||||
C=B*4</code></pre>
|
||||
<pre><code> B=A/4+
|
||||
C=B*4</code></pre>
|
||||
<p>The <code>#</code> operator acts somewhat like the C <code>?:</code>. It returns one of its two
|
||||
operands based on, what else, the value of variable <code>#</code>. When <code>#</code> is true, <code>#</code>
|
||||
returns its second operand.</p>
|
||||
<p>The <code>:</code> operator calls built-in functions. The first operand is the function id and the second is the parameter. Here is a list of functions:</p>
|
||||
<pre><code>0:x = the x-th byte of the scene file
|
||||
1:x = sin(x*PI)
|
||||
2:x = atan2(x,#)/PI
|
||||
3:x = sqrt(max(x,0))
|
||||
4:x = floor(x)
|
||||
5:x = the next number in the (allegedly random) number sequence, can't be called in volume shaders
|
||||
6:x = value of the variable (char)(120+x)
|
||||
7:x = write #'s value to the variable (char)(120+x)</code></pre>
|
||||
<pre><code> 0:x = the x-th byte of the scene file
|
||||
1:x = sin(x*PI)
|
||||
2:x = atan2(x,#)/PI
|
||||
3:x = sqrt(max(x,0))
|
||||
4:x = floor(x)
|
||||
5:x = the next number in the (allegedly random) number sequence, can't be called in volume shaders
|
||||
6:x = value of the variable (char)(120+x)
|
||||
7:x = write #'s value to the variable (char)(120+x)</code></pre>
|
||||
<p>Contrary to popular belief, the language itself doesn’t support numerical
|
||||
constants. Any character sitting between operators is a variable. When you see
|
||||
1/2, it’s in fact dividing the variable 1’s value by the variable 2’s value. For
|
||||
@@ -208,7 +208,7 @@ the Windows <code>\r\n</code>), and it terminates your function. Also, the first
|
||||
must begin immediately after <code>]</code>.</p>
|
||||
<p>When a function terminates, the interpreter calls the next function specified by
|
||||
variable <code>R</code>. If you want to call function <code>n</code>, just write somewhere:</p>
|
||||
<pre><code>R=n</code></pre>
|
||||
<pre><code> R=n</code></pre>
|
||||
<p>providing you have left <code>n</code> at its initial value. If you want to actually return
|
||||
to the renderer, put in <code>R=0</code>.</p>
|
||||
<p>As you may have noticed, you can put in all kinds of stuff between functions,
|
||||
@@ -224,28 +224,28 @@ material shaders.</p>
|
||||
</tr>
|
||||
</tbody>
|
||||
</table>
|
||||
<pre><code>//As an (optional) assignment, figure out what function 'n' does. And why there is a plus sign at every EOL except the last.
|
||||
n]#=1+
|
||||
x=X+1/2+
|
||||
d=0:U;d=d-n;U=U+1;A=d<x;#=#*A+
|
||||
d=0:U;d=d-n;U=U+1;A=x<d+1;#=#*A+
|
||||
x=Y+1/2+
|
||||
d=0:U;d=d-n;U=U+1;A=d<x;#=#*A+
|
||||
d=0:U;d=d-n;U=U+1;A=x<d+1;#=#*A+
|
||||
x=Z+1/2+
|
||||
d=0:U;d=d-n;U=U+1;A=d<x;#=#*A+
|
||||
d=0:U;d=d-n;U=U+1;A=x<d+1;#=#*A+
|
||||
d=0:U;d=d-n;U=U+1+
|
||||
U=U+2+
|
||||
C=C#d+3*9+
|
||||
#=d+
|
||||
R=0#n</code></pre>
|
||||
<pre><code> //As an (optional) assignment, figure out what function 'n' does. And why there is a plus sign at every EOL except the last.
|
||||
n]#=1+
|
||||
x=X+1/2+
|
||||
d=0:U;d=d-n;U=U+1;A=d<x;#=#*A+
|
||||
d=0:U;d=d-n;U=U+1;A=x<d+1;#=#*A+
|
||||
x=Y+1/2+
|
||||
d=0:U;d=d-n;U=U+1;A=d<x;#=#*A+
|
||||
d=0:U;d=d-n;U=U+1;A=x<d+1;#=#*A+
|
||||
x=Z+1/2+
|
||||
d=0:U;d=d-n;U=U+1;A=d<x;#=#*A+
|
||||
d=0:U;d=d-n;U=U+1;A=x<d+1;#=#*A+
|
||||
d=0:U;d=d-n;U=U+1+
|
||||
U=U+2+
|
||||
C=C#d+3*9+
|
||||
#=d+
|
||||
R=0#n</code></pre>
|
||||
<hr />
|
||||
<p>The function <code>A</code> initializes global settings:</p>
|
||||
<pre><code>G -- Image width, in pixels
|
||||
H -- Image height, in pixels
|
||||
I -- Perturbation probability
|
||||
J -- Camera ray stratification probability</code></pre>
|
||||
<pre><code> G -- Image width, in pixels
|
||||
H -- Image height, in pixels
|
||||
I -- Perturbation probability
|
||||
J -- Camera ray stratification probability</code></pre>
|
||||
<p>If you have used a MLT renderer before, you probably know what <code>I</code> and <code>J</code> does.
|
||||
If you don’t, well, use the same value as the default scene. Everything
|
||||
converges just fine under suboptimal settings, just a little slower. Generally,
|
||||
@@ -280,17 +280,17 @@ the one facing my bed, to thank me for the effort.</p>
|
||||
</tr>
|
||||
</tbody>
|
||||
</table>
|
||||
<pre><code>//As a bonus, find out what the first line does
|
||||
A]#=#-#;"=7:0-p+^;#="+
|
||||
R=n+
|
||||
G=p*:+
|
||||
#=0<B+
|
||||
G=G*2#G+
|
||||
H=G*3/4+
|
||||
I=4/5+
|
||||
J=1/2+
|
||||
C=p+1+
|
||||
U=w+w+w</code></pre>
|
||||
<pre><code> //As a bonus, find out what the first line does
|
||||
A]#=#-#;"=7:0-p+^;#="+
|
||||
R=n+
|
||||
G=p*:+
|
||||
#=0<B+
|
||||
G=G*2#G+
|
||||
H=G*3/4+
|
||||
I=4/5+
|
||||
J=1/2+
|
||||
C=p+1+
|
||||
U=w+w+w</code></pre>
|
||||
<hr />
|
||||
<p>The function <code>a</code> is the camera shader, which, well, generates the camera ray.
|
||||
It’s supposed to return the ray in variables <code>UVWXYZ</code> and <code>ABCDEF</code> (that may
|
||||
@@ -312,8 +312,8 @@ coordinate space, volume 0 is scaled up 64x here to <code>(0,0,0)-(4096,4096,409
|
||||
happen. Wall up everything.</p>
|
||||
<p>Variables <code>ABCDEF</code> control the color returned from the ray. They will be
|
||||
explained in the material shaders part. For now, just put in:</p>
|
||||
<pre><code>A=0;B=0;C=0
|
||||
D=1;E=1;F=1</code></pre>
|
||||
<pre><code> A=0;B=0;C=0
|
||||
D=1;E=1;F=1</code></pre>
|
||||
<table>
|
||||
<tbody>
|
||||
<tr class="odd">
|
||||
@@ -321,29 +321,29 @@ D=1;E=1;F=1</code></pre>
|
||||
</tr>
|
||||
</tbody>
|
||||
</table>
|
||||
<pre><code>a]R=0+
|
||||
X=5:5+
|
||||
Y=5:5+
|
||||
X=X-1/2+
|
||||
Y=Y-1/2+
|
||||
x=5:5+
|
||||
y=5:5+
|
||||
x=x-1/2+
|
||||
y=y-1/2+
|
||||
x=x*8*7;y=y*8*7+
|
||||
X=X*G+
|
||||
Y=Y*H+
|
||||
Z=H*2/3+
|
||||
d=4*;+
|
||||
d=d*p/Z+
|
||||
X=x+X*d+
|
||||
Y=y+Y*d+
|
||||
Z=Z*d+
|
||||
U=p*p/2-p*2+x+
|
||||
V=p*p/2+p*1-y+
|
||||
W=p*8+
|
||||
A=0;B=0;C=0+
|
||||
D=1;E=1;F=1</code></pre>
|
||||
<pre><code> a]R=0+
|
||||
X=5:5+
|
||||
Y=5:5+
|
||||
X=X-1/2+
|
||||
Y=Y-1/2+
|
||||
x=5:5+
|
||||
y=5:5+
|
||||
x=x-1/2+
|
||||
y=y-1/2+
|
||||
x=x*8*7;y=y*8*7+
|
||||
X=X*G+
|
||||
Y=Y*H+
|
||||
Z=H*2/3+
|
||||
d=4*;+
|
||||
d=d*p/Z+
|
||||
X=x+X*d+
|
||||
Y=y+Y*d+
|
||||
Z=Z*d+
|
||||
U=p*p/2-p*2+x+
|
||||
V=p*p/2+p*1-y+
|
||||
W=p*8+
|
||||
A=0;B=0;C=0+
|
||||
D=1;E=1;F=1</code></pre>
|
||||
<hr />
|
||||
<p>The numbered functions define materials, i.e., surface reflectance properties.
|
||||
As the name suggests, the shader simulates ray-surface interaction. It’s done by
|
||||
@@ -374,32 +374,32 @@ Function) importance sampling. Let’s continue to function <code>o</code>.</p>
|
||||
</tr>
|
||||
</tbody>
|
||||
</table>
|
||||
<pre><code>//This function computes the starred wallpaper
|
||||
//Original color: 0.36 0.714285 0.8
|
||||
1]R=o+
|
||||
d=p*6+
|
||||
x=U+W+
|
||||
x=4:x/d+
|
||||
z=4:V/d+
|
||||
#=3*x-4*z+
|
||||
y=4:#/5+
|
||||
#=#-y*5+
|
||||
y=1#0+
|
||||
x=x*d+d/2-U+W+
|
||||
z=z*d+d/2-V+
|
||||
r=3:x*x+z*z+
|
||||
#=z+
|
||||
u=2:x+
|
||||
d=1:u*5+
|
||||
d=d*d*d+3/2+
|
||||
d=d*p+
|
||||
#=r<d+
|
||||
#=#*y+
|
||||
d=2/5#I+
|
||||
D=D*d+
|
||||
E=E*4/7+
|
||||
d=I#2/5+
|
||||
F=F*d</code></pre>
|
||||
<pre><code> //This function computes the starred wallpaper
|
||||
//Original color: 0.36 0.714285 0.8
|
||||
1]R=o+
|
||||
d=p*6+
|
||||
x=U+W+
|
||||
x=4:x/d+
|
||||
z=4:V/d+
|
||||
#=3*x-4*z+
|
||||
y=4:#/5+
|
||||
#=#-y*5+
|
||||
y=1#0+
|
||||
x=x*d+d/2-U+W+
|
||||
z=z*d+d/2-V+
|
||||
r=3:x*x+z*z+
|
||||
#=z+
|
||||
u=2:x+
|
||||
d=1:u*5+
|
||||
d=d*d*d+3/2+
|
||||
d=d*p+
|
||||
#=r<d+
|
||||
#=#*y+
|
||||
d=2/5#I+
|
||||
D=D*d+
|
||||
E=E*4/7+
|
||||
d=I#2/5+
|
||||
F=F*d</code></pre>
|
||||
<hr />
|
||||
<p>Function <code>o</code> defines a diffuse (that is, dull) surface. To define reflectance
|
||||
properties like this, one needs to sample an outgoing ray direction, based on
|
||||
@@ -415,9 +415,9 @@ defined as a bunch of cube-shaped cells, there are only 6 possible normals:
|
||||
<code>(±1,0,0) (0,±1,0) (0,0,±1)</code>. Here <code>S</code> is the sign and <code>T</code> is the dimension. If
|
||||
you get <code>S=-1</code> and <code>T=1</code>, the normal is <code>(0,-1,0)</code>.</p>
|
||||
<p>If you don’t want to redo all the math yourself… this file provides a few simple shader functions:</p>
|
||||
<pre><code>o -- Diffuse surface. Do the color thing your self and call R=o
|
||||
5 -- Perfect mirror.
|
||||
f -- Surface with a Fresnel term. Basically, it resembles a polished surface made from a dielectric material.</code></pre>
|
||||
<pre><code> o -- Diffuse surface. Do the color thing your self and call R=o
|
||||
5 -- Perfect mirror.
|
||||
f -- Surface with a Fresnel term. Basically, it resembles a polished surface made from a dielectric material.</code></pre>
|
||||
<p>For something more complex like a fluffy carpet, well, you could use a volume to
|
||||
directly model the
|
||||
<a href="https://en.wikipedia.org/wiki/Mesoscopic_physics">mesoscopic</a> detail. Shader
|
||||
@@ -430,107 +430,107 @@ appearance.</p>
|
||||
</tr>
|
||||
</tbody>
|
||||
</table>
|
||||
<pre><code>//diffuse ray generation
|
||||
o]R=0+
|
||||
u=5:5+
|
||||
v=5:5+
|
||||
v=v*2+
|
||||
r=3:u+
|
||||
z=1:v+
|
||||
y=1:1/2+v+
|
||||
z=z*r+
|
||||
y=y*r+
|
||||
x=3:1-u+
|
||||
x=0-x*S+
|
||||
X=6:T+
|
||||
w=x;x=z;z=y;y=w+
|
||||
Y=6:T+
|
||||
w=x;x=z;z=y;y=w+
|
||||
Z=6:T
|
||||
<pre><code> //diffuse ray generation
|
||||
o]R=0+
|
||||
u=5:5+
|
||||
v=5:5+
|
||||
v=v*2+
|
||||
r=3:u+
|
||||
z=1:v+
|
||||
y=1:1/2+v+
|
||||
z=z*r+
|
||||
y=y*r+
|
||||
x=3:1-u+
|
||||
x=0-x*S+
|
||||
X=6:T+
|
||||
w=x;x=z;z=y;y=w+
|
||||
Y=6:T+
|
||||
w=x;x=z;z=y;y=w+
|
||||
Z=6:T
|
||||
|
||||
//reflector
|
||||
5]R=0+
|
||||
x=1;y=1;z=1+
|
||||
#=0-1+
|
||||
#=7:T+
|
||||
X=x*X;Y=y*Y;Z=z*Z
|
||||
//reflector
|
||||
5]R=0+
|
||||
x=1;y=1;z=1+
|
||||
#=0-1+
|
||||
#=7:T+
|
||||
X=x*X;Y=y*Y;Z=z*Z
|
||||
|
||||
//approximate Fresnel, works better than the real thing when you don't want to tweak the IOR
|
||||
f]x=X;y=Y;z=Z+
|
||||
r=3:x*x+z*z+y*y+
|
||||
d=6:T+
|
||||
d=1-d*S/r+
|
||||
d=d*d*d+
|
||||
#=5:5+
|
||||
#=d<#+
|
||||
R=5#o+
|
||||
d=d#1-d+
|
||||
u=1#u+
|
||||
v=1#v+
|
||||
w=1#w+
|
||||
D=D*d*u+
|
||||
E=E*d*v+
|
||||
F=F*d*w
|
||||
//approximate Fresnel, works better than the real thing when you don't want to tweak the IOR
|
||||
f]x=X;y=Y;z=Z+
|
||||
r=3:x*x+z*z+y*y+
|
||||
d=6:T+
|
||||
d=1-d*S/r+
|
||||
d=d*d*d+
|
||||
#=5:5+
|
||||
#=d<#+
|
||||
R=5#o+
|
||||
d=d#1-d+
|
||||
u=1#u+
|
||||
v=1#v+
|
||||
w=1#w+
|
||||
D=D*d*u+
|
||||
E=E*d*v+
|
||||
F=F*d*w
|
||||
|
||||
//the handles
|
||||
B]R=0+
|
||||
#=X<8*3+
|
||||
C=3#0
|
||||
//the handles
|
||||
B]R=0+
|
||||
#=X<8*3+
|
||||
C=3#0
|
||||
|
||||
C]R=0+
|
||||
#=X<8*4+
|
||||
C=0#4
|
||||
C]R=0+
|
||||
#=X<8*4+
|
||||
C=0#4
|
||||
|
||||
//red-Fresnel
|
||||
2]R=f+
|
||||
u=1/2;v=1/9;w=v
|
||||
//red-Fresnel
|
||||
2]R=f+
|
||||
u=1/2;v=1/9;w=v
|
||||
|
||||
//white-Fresnel and the full moon
|
||||
3]R=f+
|
||||
u=7*9/p;v=u;w=v+
|
||||
x=3*:+8+
|
||||
z=U-x*p+p/2+
|
||||
x=V-x*p-p/2+
|
||||
r=3:x*x+z*z+
|
||||
#=4<r/p+
|
||||
D=D*I#D+
|
||||
E=E*4/7#E+
|
||||
F=F*2/5#F+
|
||||
d=1/5#0+
|
||||
A=A+D*d+
|
||||
B=B+E*d+
|
||||
C=C+F*d
|
||||
//white-Fresnel and the full moon
|
||||
3]R=f+
|
||||
u=7*9/p;v=u;w=v+
|
||||
x=3*:+8+
|
||||
z=U-x*p+p/2+
|
||||
x=V-x*p-p/2+
|
||||
r=3:x*x+z*z+
|
||||
#=4<r/p+
|
||||
D=D*I#D+
|
||||
E=E*4/7#E+
|
||||
F=F*2/5#F+
|
||||
d=1/5#0+
|
||||
A=A+D*d+
|
||||
B=B+E*d+
|
||||
C=C+F*d
|
||||
|
||||
//handle
|
||||
4]R=5+
|
||||
D=D*I;E=E*4/7;F=F*2/5
|
||||
//handle
|
||||
4]R=5+
|
||||
D=D*I;E=E*4/7;F=F*2/5
|
||||
|
||||
//light from the window
|
||||
6]R=0+
|
||||
#=P+
|
||||
d=2#8*2+
|
||||
A=A+D*d+
|
||||
B=B+E*d+
|
||||
C=C+F*d*I+
|
||||
P=9
|
||||
//light from the window
|
||||
6]R=0+
|
||||
#=P+
|
||||
d=2#8*2+
|
||||
A=A+D*d+
|
||||
B=B+E*d+
|
||||
C=C+F*d*I+
|
||||
P=9
|
||||
|
||||
//carpet
|
||||
7]R=o+
|
||||
D=D/7+
|
||||
E=E/3+
|
||||
F=F/7
|
||||
//carpet
|
||||
7]R=o+
|
||||
D=D/7+
|
||||
E=E/3+
|
||||
F=F/7
|
||||
|
||||
D]R=0+
|
||||
#=8<Y+
|
||||
C=0#3+
|
||||
#=4:3*X-4*Z+
|
||||
y=4:#/7+
|
||||
#=#-y*7+
|
||||
C=7#C</code></pre>
|
||||
D]R=0+
|
||||
#=8<Y+
|
||||
C=0#3+
|
||||
#=4:3*X-4*Z+
|
||||
y=4:#/7+
|
||||
#=#-y*7+
|
||||
C=7#C</code></pre>
|
||||
<hr />
|
||||
<p>The last line, well, is the output filename. Just remember to throw in two <code>]</code>s
|
||||
and don’t put a newline after it.</p>
|
||||
<pre><code>]]example.ppm</code></pre>
|
||||
<pre><code> ]]example.ppm</code></pre>
|
||||
<!--
|
||||
|
||||
Copyright © 1984-2024 by Landon Curt Noll. All Rights Reserved.
|
||||
|
||||
Reference in new issue
Block a user