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Errata
"Fundamentals
of Vertex Shaders"
by Wolfgang F. Engel
page 35 - The following
paragraph is misleading:
"Vertex Shaders are executed with SetVertexShader() as many times
as there are vertices. For example if you try to visualize a rotating
quad with four vertices implemented as an indexed triangle list, you will
see in the NVIDIA Shader Debugger, that the vertex shader runs four times,
before the DrawPrimitive*() function is called. "
The correct paragraph
is:
"Vertex Shaders
are set with SetVertexShader() and executed with a call to DrawPrimitive*()
function as often as there are vertices. For example if you try to visualize
a rotating quad with four vertices implemented as an indexed triangle
list, you will see in the NVIDIA Shader Debugger, that the vertex shader
runs four times.
"Fundamentals
of Vertex Shaders"
by Wolfgang F. Engel
Tip from Markus Kobler:
I have just purchased
your very good shader book, and have just came up against a very small
problem which I'm embarrassed to say took me about an hour to figure out
what was wrong.
On page 50 you explain how to run NVASM internally from Visual Studio
and it was complaining that I was supplying too many variables. Anyway
it turns out I had to change the line:
nvasm.exe $(InputPath) shaders\$(InputName).vso
to
nvasm.exe "$(InputPath)"
"shaders\$(InputName).vso"
The problem by missing the
" it was sending file strings from C:\Documents and Settings\etc\...
and the spaces were cocking it up. I'm using visual studio .net so it
may just be a problem with this version of the MS complier but I thought
it was worth mentioning to save some other half awake people some grief.
Anyway
Keep up the good work
Markus
"Lighting
A Single-Surface Object"
by Greg James
page 211 - Code fragment
missing minus sign on last V_NORMAL -- ie it should be -V_NORMAL.
This is the correct code to put in:
sub INV_MASK, c[ONE], MASK
mul COR_NORMAL, MASK, V_NORMAL
mad COR_NORMAL, INV_MASK, -V_NORMAL, COR_NORMAL
"A Non-Integer
Power Function on the Pixel Shader"
by Philippe Beaudoin and Juan Guardado
Here are better images for this article:
 
Figure 1. Gouraud shading (left) and Phong shading (right)
 
Figure 12. Per pixel Phong shading
on spheres. Clockwise from upper left, uniform normal and exponent maps,
uniform normal map and faceted exponent map, noisy normal and exponent
maps with uniform orange specular material, and noisy normal and exponent
maps with uniform white specular material.
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