Mark Henne
RenderMan Team
Pixar
9/13/89
Errata Sheet version 1
"The RenderMan Companion" 1st Edition
by Steve Upstill
INTRODUCTION:
The corrections presented in this document point out mistakes in the
book,
such as syntax errors. These mistakes make the code listings incorrect as
they appear in the RenderMan Companion. Extra code required to make the
examples run, such as camera setup for the geometry chapters, is not
discussed
here.
CORRECTIONS:
Chapter 2
p. 25 - Listing 2.3
There are two problems with the initialization of the array
Cube[6][4]. First, commas are missing between the second and
third points and also between the third and fourth points in
the bottom face definition. Second, the polygons' normals all
face towards the center of the cube. This is a somewhat subtle
error, but an error nonetheless. Note that the second and
fourth
columns of data are switched.
The cube's definition should be as follows:
static RtPoint Cube[6][4] = , , , }, /* Bottom face
*/
, , , }, /* Left face
*/
, , , }, /* Top face
*/
, , , }, /* Right face */
{ , , , }, /* Far face
*/
{ , , , } /* Near face
*/
};
p. 34 - Listing 2.8
The picture files produced by the animation sequence have
names which are too long for MS-DOS filenames. These should
be changed to "anim#.pic" where # is a number from 1 to 10.
Do this by changing the call to sprintf() to read:
sprintf( filename, "anim%d.pic", frame);
Chapter 4
p. 62 - "parameters to RiSphere() are illustrated at left"
should read
"... illustrated at right".
p. 64 - "... points in the x,z plane of three-dimensional gspace,
then
calls RiHyperboloid() ..."
should read
"... three-dimensional space, ...".
p. 67 - Listing 4.3
The call to RiSphere() in the middle of TorusWave() has an
incorrect argument 10310t199k list. As the comment indicates, a
downward-opening hemisphere is desired, but downward-opening
from the perspective of the viewer, not the object coordinate
space. Because of the 90 degree rotation about the X axis, an
upward-opening is needed for the hemisphere's creation. The
comment and code should read as follows:
/* Create the cap for the center of the wave */
RiSphere( innerrad, -innerrad, 0.0, thetamax, RI_NULL);
Chapter 5
p. 76 - Listing 5.2
The #include reference to surfor.h should not be there.
Note that the other #include file pin.hyper.h is not presented.
The /* comment */ in PolySurfOR() refers to "the goblet
description". This should read "the surface
profile".
PolyBoid() is supposed to be provided as a triangular
polygon approximation to hyperboloids, with the addition of
suitable surface normals. It is meant as an improvement to
the PolyBoid() function in Listing 5.1.
What is provided instead is a function called PolyBand(),
which is semantically identical to the PolyBoid() function
presented in Listing 5.3. This function illustrates the
RiPointsPolygons() interface call. Replace PolyBand() with
the PolyBoid() function shown below:
/* ================================================================ */
#define SWAP(a,b,temp) temp = a; a = b; b = temp;
#define COPY_POINT(d, s)
PolyBoid(point0, point1, normal0, normal1, ndivs, parity)
RtFloat *point0, *point1, *normal0, *normal1; int ndivs, parity;
}
/* ================================================================ */
Chapter 6
p. 94 - Listing 6.2
The call to RiBasis() is missing a comma after the first
RI_CATMULLROMSTEP argument. It should read:
RiBasis( RiCatmullRomBasis, RI_CATMULLROMSTEP,
RiCatmullRomBasis, RI_CATMULLROMSTEP);
p. 101 - Listing 6.3
There is a problem in consistency between this listing and the
other surface of revolution listings; this listing revolves about
the y-axis, everything else revolves about the z-axis. To make
this example also revolve about the z-axis, change the assignments
of the mesh[][][] to read as follows:
mesh[v][u][0] = points[v].x * coeff[u][0];
mesh[v][u][1] = points[v].x * coeff[u][1];
mesh[v][u][2] = points[v].y;
The comments refering to "XY plane" and "Y axis"
should also be
changed to "XZ plane" and "Z axis",
respectively.
All references to wrap and surfaces should be changed
to periodic and nonperiodic. The text in this section of the
book should be updated to reflect this fact: the term RI_NOWRAP
should be changed to RI_NONPERIODIC, and RI_WRAP should be
changed to RI_PERIODIC.
p. 102 - Listing 6.4
All references to wrap and surfaces should be changed
to periodic and nonperiodic. The text in this section of the
book should be updated to reflect this fact: the term RI_NOWRAP
should be changed to RI_NONPERIODIC, and RI_WRAP should be
changed to RI_PERIODIC.
Chapter 7
p. 128 - Listing 7.2
#include <math.h> should be at the top of this listing to
support
the calls to sqrt().
p. 135 - Listing 7.4
The parameter list to PlacePins() should be changed so that the
first parameter reads "xseparation", rather than
"separation".
Of course the following RtFloat declaration should also be updated.
Chapter 8
p. 154 - Listing 8.4
The function min() does not exist in the math library, but can
be #defined with:
#define min(a,b) ((a)<(b)?(a):(b))
The fov parameter in RiProjection() should be in degrees,
not radians. This can be done with the following change:
fov = 2 * atan((min(framewidth,frameheight)*.5)/focallength);
should read
fov = 2 * atan((min(framewidth,frameheight)*.5)/focallength)
*180.0/3.14159;
p. 168 - Listing 8.5
The call to RiProjection() should not be done; it is being
done in the call to FrameCamera().
Casting PICXRES and PICYRES to RtInt in the #define section
causes parameter passing problems when calling FrameCamera().
To fix this, change the call to FrameCamera() to read:
FrameCamera((float)PICXRES*CAMZOOM, (float)PICXRES,
(float)PICYRES);
Chapter 10
p. 205 - Listing 10.3
In addition to <ri.h>, <math.h> and <stdio.h>
should be
#included.
There is no presentation of RiProcedural() in this example.
The following code should be inserted between the typedef
of FractalTriangle and the #definition of MOVEPT.
/* ================================================================ */
Go()
/* ================================================================ */
The call to RiProcedural() in TriangleSplit() is missing a
semicolon (;) at the end of the line. Also, "data" should
be
of type "RtPointer", not "char *". Actually,
this doesn't
matter much, because TriangleSplit() needs to be fixed, as
noted below.
FractalDiv() does not correctly split a triangle and render its
children; FractalDiv() and TriangleSplit() should be modified
to read as follows:
/* ================================================================ */
#define MAXLEVELS 5
/*
* FractalDiv(): RenderMan refinement procedure for subdividing a fractal
* triangle.
*/
FractalDiv( data, levelofdetail )
RtPointer data;
RtFloat levelofdetail;
else
}
}
TriangleSplit( pFT )
FractalTriangle *pFT;
for( childnum = 0; childnum < 3; childnum++ )
for( childnum = 0; childnum < 3; childnum++ )
}
/* ================================================================ */
A FractalFree() function is not provided in the RenderMan
Companion. Append the following code to Listing 10.3.
/* ================================================================ */
FractalFree( data )
RtPointer data;
FreeChildren( pFTChildren )
FractalTriangle *pFTChildren;
}
/* ================================================================ */
Chapter 11
p. 216 - RiMatte() has a boolean flag which enables/disables
(RI_TRUE/RI_FALSE) the matte attribute.
RiMatte(onoff)
RtBoolean onoff;
p. 222 - "It (Fconeangle) decays from 1 in the spotlight direction
(to-from) to 0 coneangle radians away, and so is nonzero only
inside a cone 2*coneangle degrees wide". According to the
RMIS, p. 25, coneangle is in radians, thus this passage should
read "... 2*coneangle radians wide".
p. 228 - Listing 11.2
The order of the frames goes 3, 1, 2, 4. It seems reasonable
to
change this to 1, 2, 3, 4.
Chapter 12
p. 253 - Listing 12.1
The order of the points in textcoords[] does not agree with
corners[]. The line:
textcoords[] = , , , };
should read:
textcoords[] = , , , };
p. 254 - Listing 12.2
In addition to <ri.h>, <math.h> should be #included
because of
the call to sqrt().
In MapSurfOR(), "npts" is an input parameter, but is later
referred to as "npoints"; the same thing happens with
"pts" and
"points". The declaration should be changed to:
MapSurfOR(points, npoints)
Point2D points;
int npoints;
Also, MAXNPOINTS is not defined. NPOINTS can be used instead.
In TextSurfOR(), "tmap" is used as an interface variable,
but
it is not declared. The call to RiSurface() must be prefaced
by the RiDeclare() call:
RtToken RI_TMAP;
...
RI_TMAP = RiDeclare("tmap", "uniform
string");
RiSurface("mytexture", RT_TMAP, (RtPointer)&tmap,
RI_NULL);
p. 270 - Listing 12.5
A new RiDisplay() call must be made inside frame 2, to change
to
rgba rendering rather than z rendering. The new call to
RiDisplay() in frame 2 should be:
RiFrameBegin(2);
RiDisplay("ri.pic", RI_FILE, RI_RGBA, RI_NULL);
"shadowfile" is not declared as an interface variable. The
following line should appear next to the char declaration at
the top of the listing:
RtToken RI_SHADOWFILE;
and the call to "RiLightsource" should have
"source" capitalized
and be preceded by RiDeclare():
RI_SHADOWFILE = RiDeclare("shadowfile", "uniform
string");
RiLightSource("shadowspot", RI_SHADOWSPOT,
(RtPointer)&shadowfile, RI_NULL);
Chapter 13
p. 282 - Listing 13.1
An alternate "clouds" shader is presented than that
in
The RenderMan Companion. The book's listing results in a
dark image because the sum of the noise rarely exceeds 0.1.
Although lighting can be used here, a more effective looking
shader ignores the lights and scales the sum somewhat. The
color computation used is:
1. Substitute line 9, the declaration of "refl", with the
declaration of white:
color white = color(1.0, 1.0, 1.0);
2. Delete line 17, the assignment of "refl".
3. Replace line 18, the assignment of "Ci" with:
Ci = mix(Cs, white, sum*4.0);
Notice that there is a numbering error in the book; 19 is applied
to two lines in the listing.
Chapter 14
p. 298 - Table 14.4
Logical AND is presented as "&". It should be
"&&", as
presented on RMIS p. 94.
Chapter 15
p. 312 - Table 15.1
The "Returns" colums for step() and smoothstep() is
incorrect.
They should both say:
0 if val < min; 1 if val => max
^^^
Chapter 16
p. 335 - Listing 16.2:
The normal, N, must be normalized in its use for light
components.
point Nf = faceforward(N, I);
should read
point Nf = faceforward( normalize(N), I);
p. 336 - Listing 16.3:
The normal must be normalized, as in Listing 16.2 above. Also,
the vector "-I" in the specular() call should be
normalized.
This is commonly done by adding the following line just after
the declaration of Nf:
point V = normalize(-I);
Then use V in the specular() call instead of -I.
p. 337 - Listing 16.4:
The normal (N) and incident (I) vectors must be normalized,
as in Listing 16.3 above.
p. 338 - Listing 16.6:
To mimic the standard shader, the default position should be in
camera space. Also, the shader parameter list has a semicolon
(;)
instead of a comma (,).
point from = point(0,0,0); /* light position */
to = point(0,0,1))
should read
point from = point "camera" (0,0,0), /* light position
*/
to = point "camera" (0,0,1))
p. 339 - Listing 16.7:
To mimic the standard shader, the default position should be in
camera space. Also, the shader parameter list has an extra
semicolon (;).
point from = point(0,0,0)); /* light position */
should read
point from = point "camera" (0,0,0)) /* light position
*/
p. 340 - Listing 16.8:
To mimic the standard shader, the default position should be in
camera space.
point from = point(0,0,0), /* light position */
to = point(0,0,1); /* light direction */
should read
point from = point "camera" (0,0,0), /* light position
*/
to = point "camera" (0,0,1); /* light
direction */
The coneangle and conedeltaangle declarations have semicolons
where there should be commas.
float coneangle = radians(30);
conedeltaangle = radians(5);
should read
float coneangle = radians(30),
conedeltaangle = radians(5),
p. 345 - Listing 16.12:
The comment above the code says the shader is checker(), but
it is declared as checks(). checker() seems more appropriate.
N should be normalized inside the faceforward call.
Kd*diffuse(faceforward(N,I)));
should read
Kd*diffuse(faceforward(normalize(N),I)));
p. 349 - Listing 16.14:
The normal (N) and incident (I) vectors must be normalized,
as in Listing 16.3 above.
p. 351 - Listing 16.15:
This texture tends to alias near the quick jump from darkwood
back to lightwood. To fix this, change the 0.86 argument in the
smoothstep() function should be changed to 1.0. Also, the "* (1
-"
stuff is not necessary.
r = smoothstep(0, 0.8, r) - smoothstep(0.83, 1.0, r);
p. 353 - Listing 16.17:
The normal (N) and incident (I) vectors must be normalized,
as in Listing 16.3 above.
p. 354 - Listing 16.18:
The normal (N) and incident (I) vectors must be normalized,
as in Listing 16.3 above.
p. 355 - Listing 16.19:
The normal (N) and incident (I) vectors must be normalized,
as in Listing 16.3 above.
p. 357 - Listing 16.20:
The normal, N, must be normalized in its use for light
components.
point Nf = faceforward(N, I);
should read
point Nf = faceforward( normalize(N), I);
p. 363 - Listing 16.22:
The "I" and "N" vectors must be normalized, as
shown below:
point II = normalize(I);
point NN = normalize(N);
diffuse = II.NN / (II.II * NN.NN);
p. 365 - Listing 16.23:
The last line in this shader, the assignment of N, should not
be in the "if" block.
P = center + radius*normalize(P-center);
N = calculatenormal(P);
}
}
should read
P = center + radius*normalize(P-center);
}
N = calculatenormal(P);
}
p. 373 - Listing 16.28:
"spread" should be a uniform float, not a uniform point.
p. 376 - Listing 16.31:
There are some syntax errors in the parameter list. The
semicolons
after each of the float values (Ka, Kd, etc.) should be commas,
as
shown below:
float Ka = .5,
Kd = .5,
Ks = .8,
roughness = .1,
spin = 0;
In the assignment of Nf, N must be normalized. It's also
helpful
to assign V = normalize(-I), for use in the specular call.
The formulas for the red crown should use "u" instead of
"v":
else
All the texture names should be consistent in using the
extension
"txt", not "tx". Thus "coated.tx"
should be "coated.txt",
"circle.tx" should be "circle.txt", and
"b.tx" should be "b.txt".
The formulas for the dirt and gouge texture are wrong. Replace
strength = 1 - float texture(texturename, t+spin, y);
with the following:
strength = 1 - float texture(texturename, s+spin, y/15.0);
The specular() call at the end of the shader should use
"V"
instead of "-I" in its parameter list.
p. 379 - Listing 16.32:
The formulas for accessing the texture are wrong. Replace
P += (-Km * texture(texturename, t+spin, y))*normalize(N);
with the following:
P += (-Km * texture(texturename, s+spin,
y/15.0))*normalize(N);
p. 380 - Listing 16.33:
Semicolon (;) should be a comma (,) in the declaration of
coneangle, ie:
float coneangle = radians(30),
Declaration of string shadowname should be string shadowfile,
as
should the call inside the shadow() function. Also, shadow()
returns 1.0 for 100% shadow, so its inverse is needed. The
lines
should read:
string shadowfile = "";)
...
attenuation *= (1.0 - shadow( shadowfile, Ps));
p. 383 - Listing 16.36:
There is a syntax error in the declaration of Km at the top of
the shader. The comma at the end of the line should be a
semicolon.
p. 384 - Listing 16.37:
The normal (N) and incident (I) vectors must be normalized,
as in Listing 16.3 above.
p. 384 - Listing 16.38:
The normal must be normalized, as in Listing 16.2 above.
Appendix D
p. 412 - RiMatte() has a boolean flag.
RiMatte(onoff)
RtBoolean onoff;
