Metaprogramming GPUs with Sh Errata

From ShWiki

Here are the errors/typos we are aware of from the first edition of the book. Please comment on this page if you have found something that isn't listed yet.

Contents

Page 18: missing word

The first sentence on the page is missing a word: 

"Basically, sequences of calls into an API can be interpreted as a ..."

Page 28: wrong z convention noted

Second paragraph from the bottom: 

"Values of z at the near plane are mapped to 0, those close to the far plane are mapped to 1. This follows OpenGL conventions."

should be 

"Values of z at the near plane are mapped to -1, those close to the far plane are mapped to 1. This follows OpenGL conventions."

Page 29: our->are

In middle of first full paragraph on page: 

"Therefore, some simplifications to our shaders our possible in the ..."

should be 

"Therefore, some simplifications to our shaders are possible in the ..."

Listing 5.3: p -> update

The last line of the listing, 

ShProgram update_state = p << state;

should be 

ShProgram update_state = update << state;

Table 8.9: atan2

The definition of atan2() should be 

arctangent of a / b

instead of 

arctangent of b / a

In order words, atan2(y, x) = atan(y / x) just like in C++ and Python.

Table 8.11: bezier

The r in the formula should have a subscript of i

Page 168: faceforward

The math should be 

     /  b if dot(a, b) > 0,
r <- |
     \ -b otherwise

Rather than 

     /  a if dot(a, b) > 0,
r <- |
     \ -a otherwise

(ie. return b instead of a).

Page 181: load_PNG

load_PNG is a free function inside the ShUtil namespace, not a member of ShImage.

Therefore the example should read: 

ShImage image;
ShUtil::load_PNG(image, "monalisa.png");
ShTexture2D<ShColor3f> texture(image.width(), image.height());
texture.memory(image.memory());

instead of: 

ShImage image;
image.load_PNG("monalisa.png");
ShTexture2D<ShColor3f> texture(image.width(), image.height());
texture.memory(image.memory());

Table 10.1: iterators

The table is missing the following type: 

 typedef std::list<ShPaletteNodePtr> PaletteList;

and the following methods: 

 VarList::iterator begin_constants()
 VarList::iterator end_constants()
 VarList::iterator begin_all_parameters()
 VarList::iterator end_all_parameters()
 PaletteList::iterator begin_palettes()
 PaletteList::iterator end_palettes()

Page 191: ShPosition

The first definition is the one that dominates, not the last one. Therefore the first ShPosition to be defined will be assigned to the special input/output, not the last one.

Page 219: result.depth

result.depth is mapped to SH_POSITION, not SH_ATTRIB.

Index

"ShInterpolate modifier" should be "ShInterp modifier"

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