Index_A

A

Abrash, Mike, 23

abs macro, 205, 288-289

_abs modifier (absolute modifier), 270

absolute value

computing for the input register, 205

of the input register, 288

notation for, 11

ACM (Association for Computing Machinery), 146

add instruction, 206, 288-289

addition, notation for, 11

address register (a0.x), allowing a programmable index into constant registers, 197-198

address register assignment, pseudocode used in the emulation of, 201

address registers (an), 200-202, 271

moving data from a floating point register into, 251-252

affine transformation, 103, 104

air-glass interface

averaged reflectance and transmittance values for, 69

values for the Fresnel equation for, 67-70

alpha component, representing the opacity of color, 22

alpha mask, 364

alpha operations

pairing color operations with, 370

performing simultaneously with color operations, 93-94

alpha pipe, 93

alpha reference value, 178

ambient color, 34

ambient illumination

generating the effect of, 155-157

scene with, 40, 41

ambient light, 39-41, 43, 44

ambient light equation, compared to the diffuse lighting equation, 42

ambient light shader, 155-157

ambient lighting, 34

ambient shading, 155-157

an. See address registers

angle, between two vectors, 15

angle of incidence

Fresnel value as a function of, 71

of incoming light, 59, 60

anisotropic BRDFs, 80

anisotropic reflection, 78-80

antisymmetric, cross product as, 18

Arago, Francois, 67

arbitrary mask, 365

arithmetic instructions, for pixel shaders, 108, 274

arithmetic operations, of pixel shaders, 94

array of structures, 123

artistic screening, 82

ASCII shader program, 130

"asm" style comments, 193

ATI, RenderMonkey shader tool, 139-140

ATI session on hardware programming, 146

ATI Web site, 145

attenuated lighting calculations, 216

attenuation factor, equation for, 51

attenuation of lights, 33