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be read by the program getinfo. |
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2. Scene Description |
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A scene description file represents a three-dimensional |
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physical environment in Cartesian (rectilinear) world coor- |
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dinates. It is stored as ascii text, with the following |
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basic format: |
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# comment |
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modifier type identifier |
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n S1 S2 S3 ... Sn |
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0 |
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m R1 R2 R3 ... Rm |
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! command |
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... |
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A comment line begins with a pound sign, `#'. |
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The scene description primitives all have the same gen- |
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eral format, and can be either surfaces or modifiers. A |
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primitive has a modifier, a type, and an identifier. A |
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modifier is either the identifier of a previously defined |
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primitive, or void. An identifier can be any string (ie. |
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sequence of non-blank characters). The arguments associated |
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with a primitive can be strings or real numbers. The first |
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integer following the identifier is the number of string |
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arguments, and it is followed by the arguments themselves. |
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The next integer is the number of integer arguments, and is |
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followed by the integer arguments. (There are currently no |
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primitives that use them, however.) The next integer is the |
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real argument count, and it is followed by the real argu- |
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ments. |
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A line beginning with an exclamation point, `!', is |
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interpreted as a command. It is executed by the shell, and |
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its output is read as input to the program. The command |
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must not try to read from its standard input, or confusion |
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will result. |
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Blank space is generally ignored, except as a separa- |
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tor. The exception is the newline character after a command |
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or comment. Commands, comments and primitives may appear in |
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any combination, so long as they are not intermingled. |
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2.1. Primitive Types |
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Primitives can be surfaces, materials, textures or pat- |
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terns. Materials modify surfaces, textures and patterns |
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modify textures, patterns and materials. |
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2.1.1. Surfaces |
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A scene description will consist mostly of surfaces. |
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The basic types are given below. |
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