Index_L

L

label instruction, 226-227

Lagrange's identity, 20

Lambertian diffuse lighting

with an infinite light, 157-158, 159

with a positional light, 158-161

Lambertian shading, 41

Lambert's cosine law, 41

length, of a vector, 14

Less-Than, setting, 265

light attenuation, 51-53

light diffuse color, passing as a constant, 157, 160

light-material surface interactions, 34

light sources. See also lights

interaction with a surface, 25

light from a, 44

light specular color, passing as a constant, 162

light-surface boundary interactions, 34

light wave

perpendicular nature of the magnetic and electrical fields of, 64, 65

reflection of, 59

refraction of, 59

lighting, calculating at a vertex, 38-39

lighting calculations, using m3x3 macro for normal transformations, 239

lighting equation, 50-51

with the attenuation factor, 51

refinements and alternative ways of calculating coefficients of, 51-58

lighting models, traditional 3D hardware-accelerated, 38-58

lights, 33. See also light sources

angle of incidence of incoming, 59

attenuation of, 33

interaction with surfaces, 36-38

line art style, 81-82

linear interpolation, between two registers, 236-237, 304-305

lit function, calculating the lighting term, 162

lit instruction, 173, 227-229

local light. See also positional light compared to "local viewer", 152

local lighting model, 39

local model space, transforming into the global world space coordinate system, 98

"local viewer", code for, 152

log instruction, 303-304

log macro, 230-231

log₂ of the input argument, computing, 230

logp instruction, 231-234

compared to the log macro, 230

loop blocks, scalar register added for control, 202

loop counter, 202, 219

loop-endloop block

starting point for, 234-236

termination point for, 218-219

loop instruction, 234-236, 258

loops, nesting not allowed, 235

lrp macro, 236-237, 304-305

luminance correction, 2D bump/environment mapping with, 329-330