| 1 |
greg |
1.1 |
RADIANCE Scene Description Language |
| 2 |
|
|
|
| 3 |
|
|
Altogether there are at least 4 "languages" involved with Radiance |
| 4 |
|
|
scene descriptions: the basic scene input language, the function file |
| 5 |
|
|
language, the data file language and the font language. |
| 6 |
|
|
|
| 7 |
|
|
Scene Input |
| 8 |
|
|
=========== |
| 9 |
|
|
|
| 10 |
|
|
scenefile: /* nothing */ |
| 11 |
|
|
| statement scenefile |
| 12 |
|
|
|
| 13 |
|
|
statement: primitive |
| 14 |
|
|
| alias |
| 15 |
|
|
| command |
| 16 |
|
|
| comment |
| 17 |
|
|
|
| 18 |
|
|
primitive: modifier type STRING |
| 19 |
|
|
INTEGER string_args |
| 20 |
|
|
INTEGER integer_args |
| 21 |
|
|
INTEGER real_args |
| 22 |
|
|
|
| 23 |
|
|
alias: modifier alias STRING STRING |
| 24 |
|
|
|
| 25 |
|
|
modifier: "void" |
| 26 |
|
|
| "inherit" |
| 27 |
|
|
| STRING |
| 28 |
|
|
|
| 29 |
|
|
command: '!' STRING string_args command_end |
| 30 |
|
|
|
| 31 |
|
|
command_end: '\n' |
| 32 |
|
|
| '\\' '\n' string_args command_end |
| 33 |
|
|
|
| 34 |
|
|
comment: '#' string_args '\n' |
| 35 |
|
|
|
| 36 |
|
|
string_args: /* nothing */ |
| 37 |
|
|
| STRING string_args |
| 38 |
|
|
|
| 39 |
|
|
integer_args: /* nothing */ |
| 40 |
|
|
| INTEGER integer_args |
| 41 |
|
|
|
| 42 |
|
|
real_args: /* nothing */ |
| 43 |
|
|
| REAL real_args |
| 44 |
|
|
|
| 45 |
|
|
type: "polygon" |
| 46 |
|
|
| "cone" |
| 47 |
|
|
| "sphere" |
| 48 |
|
|
| "texfunc" |
| 49 |
|
|
| "ring" |
| 50 |
|
|
| "cylinder" |
| 51 |
|
|
| "instance" |
| 52 |
|
|
| "cup" |
| 53 |
|
|
| "bubble" |
| 54 |
|
|
| "tube" |
| 55 |
|
|
| "mesh" |
| 56 |
|
|
| "plastic" |
| 57 |
|
|
| "metal" |
| 58 |
|
|
| "glass" |
| 59 |
|
|
| "trans" |
| 60 |
|
|
| "dielectric" |
| 61 |
|
|
| "plastic2" |
| 62 |
|
|
| "metal2" |
| 63 |
|
|
| "trans2" |
| 64 |
|
|
| "interface" |
| 65 |
|
|
| "plasfunc" |
| 66 |
|
|
| "metfunc" |
| 67 |
|
|
| "brightfunc" |
| 68 |
|
|
| "brightdata" |
| 69 |
|
|
| "brighttext" |
| 70 |
|
|
| "colorpict" |
| 71 |
|
|
| "glow" |
| 72 |
|
|
| "source" |
| 73 |
|
|
| "light" |
| 74 |
|
|
| "illum" |
| 75 |
|
|
| "spotlight" |
| 76 |
|
|
| "mist" |
| 77 |
|
|
| "mirror" |
| 78 |
|
|
| "transfunc" |
| 79 |
|
|
| "BRTDfunc" |
| 80 |
|
|
| "plasdata" |
| 81 |
|
|
| "metdata" |
| 82 |
|
|
| "transdata" |
| 83 |
|
|
| "colorfunc" |
| 84 |
|
|
| "antimatter" |
| 85 |
|
|
| "colordata" |
| 86 |
|
|
| "colortext" |
| 87 |
|
|
| "texdata" |
| 88 |
|
|
| "mixfunc" |
| 89 |
|
|
| "mixdata" |
| 90 |
|
|
| "mixtext" |
| 91 |
|
|
| "prism1" |
| 92 |
|
|
| "prism2" |
| 93 |
|
|
|
| 94 |
|
|
Function File |
| 95 |
|
|
============= |
| 96 |
|
|
|
| 97 |
|
|
funcfile: /* nothing */ |
| 98 |
|
|
| decl funcfile |
| 99 |
|
|
|
| 100 |
|
|
decl: ';' |
| 101 |
|
|
| function_decl ';' |
| 102 |
|
|
| variable_decl ';' |
| 103 |
|
|
|
| 104 |
|
|
function_decl: ID '(' id_list ')' assign_op e1 |
| 105 |
|
|
|
| 106 |
|
|
variable_decl: ID assign_op e1 |
| 107 |
|
|
|
| 108 |
|
|
id_list: ID |
| 109 |
|
|
| ID ',' id_list |
| 110 |
|
|
|
| 111 |
|
|
assign_op: '=' |
| 112 |
|
|
| ':' |
| 113 |
|
|
|
| 114 |
|
|
e1: e1 '+' e2 |
| 115 |
|
|
| e1 '-' e2 |
| 116 |
|
|
| e2 |
| 117 |
|
|
|
| 118 |
|
|
e2: e2 '*' e3 |
| 119 |
|
|
| e2 '/' e3 |
| 120 |
|
|
| e3 |
| 121 |
|
|
|
| 122 |
|
|
e3: e4 '^' e3 |
| 123 |
|
|
| e4 |
| 124 |
|
|
|
| 125 |
|
|
e4: '+' e5 |
| 126 |
|
|
| '-' e5 |
| 127 |
|
|
| e5 |
| 128 |
|
|
|
| 129 |
|
|
e5: '(' e1 ')' |
| 130 |
|
|
| ID |
| 131 |
|
|
| ID '(' id_list ')' |
| 132 |
|
|
| REAL |
| 133 |
|
|
| '$' INTEGER |
| 134 |
|
|
|
| 135 |
|
|
Comments may appear between any two tokens set off by curly braces {}, |
| 136 |
|
|
and may be nested to any level. |
| 137 |
|
|
|
| 138 |
|
|
Data File |
| 139 |
|
|
========= |
| 140 |
|
|
|
| 141 |
|
|
data: dimensions value_list |
| 142 |
|
|
|
| 143 |
|
|
dimensions: INTEGER dim_list |
| 144 |
|
|
|
| 145 |
|
|
dim_list: dim |
| 146 |
|
|
| dim dim_list |
| 147 |
|
|
|
| 148 |
|
|
dim: REAL REAL INTEGER |
| 149 |
|
|
| '0' '0' INTEGER indep_list |
| 150 |
|
|
|
| 151 |
|
|
indep_list: REAL |
| 152 |
|
|
| REAL indep_list |
| 153 |
|
|
|
| 154 |
|
|
value_list: /* nothing */ |
| 155 |
|
|
| REAL value_list |
| 156 |
|
|
|
| 157 |
|
|
Comments begin with a pound sign ('#') and continue to the end of line. |
| 158 |
|
|
|
| 159 |
|
|
Font File |
| 160 |
|
|
========= |
| 161 |
|
|
|
| 162 |
|
|
glyph_list: /* nothing */ |
| 163 |
|
|
| glyph glyph_list |
| 164 |
|
|
|
| 165 |
|
|
glyph: INTEGER INTEGER coord_list |
| 166 |
|
|
|
| 167 |
|
|
coord_list: /* nothing */ |
| 168 |
|
|
| INTEGER INTEGER coord_list |
| 169 |
|
|
|
| 170 |
|
|
Comments begin with a pound sign ('#') and continue to the end of line. |
| 171 |
|
|
|
| 172 |
|
|
-------------------------------------------------------------- |
| 173 |
|
|
|
| 174 |
|
|
With regards to your topics, I have the following comments. |
| 175 |
|
|
|
| 176 |
|
|
Specification of scene parameters: |
| 177 |
|
|
- Radiance uses a right-hand coordinate system |
| 178 |
|
|
- The eyepoint and view direction are given as options |
| 179 |
|
|
to the renderers, and can be stored in a separate file |
| 180 |
|
|
|
| 181 |
|
|
Supported primitives: |
| 182 |
|
|
- N-sided polygons |
| 183 |
|
|
- spheres |
| 184 |
|
|
- cones, cylinders, rings |
| 185 |
|
|
- hierarchical instancing for very complex geometries |
| 186 |
|
|
|
| 187 |
|
|
Lighting models: |
| 188 |
|
|
- Completely general |
| 189 |
|
|
- Converter provided for IES luminaire specification |
| 190 |
|
|
|
| 191 |
|
|
Participating media: |
| 192 |
|
|
- Single-scatter approximation |
| 193 |
|
|
- Mist zones may have different scattering/absorption properties |
| 194 |
|
|
|
| 195 |
|
|
Textures: |
| 196 |
|
|
- I break "textures" into two kinds, patterns and textures |
| 197 |
|
|
- Patterns are variation in color, and can be specified as |
| 198 |
|
|
pictures, data or functions in any combination |
| 199 |
|
|
- Textures are perturbations in surface normal, and can |
| 200 |
|
|
be specified in the same ways as patterns |
| 201 |
|
|
- A light source distribution is a pattern |
| 202 |
|
|
|
| 203 |
|
|
Bit Mapping: |
| 204 |
|
|
- Usually given as a picture-type pattern (ie. "colorpict" type) |
| 205 |
|
|
- True bit-maps (ie. 1-bit depth images) may also be produced |
| 206 |
|
|
using a special bit font |
| 207 |
|
|
|
| 208 |
|
|
CSG: |
| 209 |
|
|
- Radiance has an "antimatter" type which supports some rudimentary |
| 210 |
|
|
CSG subtraction, but otherwise we are strictly B-rep |
| 211 |
|
|
|
| 212 |
|
|
Looping constructs or Recursion: |
| 213 |
|
|
- The function file language supports recursion |
| 214 |
|
|
- The "xform" program provides iteration for repeated objects |
| 215 |
|
|
|
| 216 |
|
|
Functions or Procedures: |
| 217 |
|
|
- The function file language supports functions without side effects |
| 218 |
|
|
|
| 219 |
|
|
User extensibility: |
| 220 |
|
|
- The user may create function files, data files and font files, |
| 221 |
|
|
or provide his/her own images for patterns |
| 222 |
|
|
- General bidirectional reflection distribution functions may |
| 223 |
|
|
also be specified in the same way as patterns and textures |
| 224 |
|
|
|
