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NAME - size 18
BYTE Name[18]; ; a name for the object.
Used for camera tracking, specifying story paths, etc.
SHAP - size 4
WORD Shape; ; number indicating object type
WORD Lamp; ; number indicating lamp type
Lamp numbers are composed of several bit fields:
Bits 0-1:
0 - not a lamp
1 - like sunlight
2 - like a lamp - intensity falls off with distance.
3 - unused/reserved
Bits 2:
0 - non-shadow-casting light
4 - shadow-casting light
Bits 3-4:
0 - Spherical light source
8 - Cylindrical light source.
16 - Conical light source.
24 - unused/reserved
Shape numbers are:
0 - Sphere
1 - Stencil ; not supported by Imagine
2 - Axis ; custom objects with points/triangles
3 - Facets ; illegal - for internal use only
4 - Surface ; not supported by Imagine
5 - Ground
Spheres have thier radius set by the X size parameter.
Stencils and surfaces are plane-parallelograms, with one
point at the object's position vector; one side lying along
the object's X axis with a length set by the X size; and
another side starting from the position vector and going
"Y size" units in the Y direction and "Z size" units in
the X direction. A ground object is an infinte plane
perpendicular to the world Z axis. Its Z coordinate sets
its height, and the X and Y coordinates are only relevant
to the position of the "hot point" used in selecting the
object in the editor. Custom objects have points, edges
and triangles associated with them. The size fields are
relevant only for drawing the object axes in the editor.
Shape number 3 is used internally for triangles of custom
objects, and should never appear in a data file.
POSI - size 12
VECTOR Position; ; the object's position.
Legal coordinates are in the range -32768 to 32767 and 65535/65536.
Currently, the ray-tracer only sees objects in the -1024 to 1024
range. Light sources, and the camera may be placed outside that
range, however.
AXIS - size 36
VECTOR XAxis;
VECTOR YAxis;
VECTOR ZAxis;
These are direction vectors for the object coordinate system.
They must be "orthogonal unit vectors" - i.e. the sum of the
squares of the vevtor components must equal one (or close to it),
and the vectors must be perpendicular.
SIZE - size 12
VECTOR Size;
See SHAP chunk above. The sizes are used in a variety of ways
depending on the object shape. For custom objects, they are
the lengths of the coordinate axes drawn in the editor. If the
object has its "Quickdraw" flag set, the axes lengths are also
used to set the size of a rectangular solid that is drawn rather
than drawing all the points and edges.
PNTS - size 2 + 12 * point count
UWORD PCount; ; point count
VECTOR Points[]; ; points
This chunk has all the points for custom objects. The are
refered to by thier position in the array.
EDGE - size 4 + 4 * edge cout
UWORD ECount; ; edge count
UWORD Edges[][2]; ; edges
This chunk contins the edge list for custom objects.
The Edges[][2] array is pairs of point numbers that
are connected by the edges. Edges are refered to by thier
position in the Edges[] array.
FACE - size 2 + 6 * face count
UWORD TCount; ; face count
UWORD Connects[][3]; ; faces
This chunk contains the triangle (face) list for custom objects.
The Connects[][3] array is triples of edge numbers that are
connected by triangles.
PTHD - size 2 + 6 * axis count - Imagine only
UWORD ACount; ; axis count
TFORM PData[][3]; ; axis data
This chunk contains the axis data for Imagine "path" objects.
The PData array contains a TFORM structure for each point along
the path. The "Y size" item for the last point on the path tells
whether the path is closed or not. Zero means closed, non-zero
means open. Otherwise the Y size field is the distance along
the path to the next path point/axis.
COLR - size 4
REFL - size 4
TRAN - size 4
SPC1 - size 4 - Imagine only
BYTE pad; ; pad byte - must be zero
COLOR col; ; RGB color
These are the main object RGB color, and reflection, transmission
and specularity coefficients.
CLST - size 2 + 3 * count
RLST - size 2 + 3 * count
TLST - size 2 + 3 * count
UWORD count; ; count of colors
COLOR colors[]; ; colors
These are the color, reflection and transmission coefficients
for each face in custom objects. The count should match the
face count in the FACE chunk. The ordering corresponds to the
face order.
TPAR - size 64 - not written by Imagine - see TXT1 below
FRACT Params[16]; ; texture parameters
This is the list of parameters for texture modules when
texture mapping is used.
TXT1 - variable size - Imagine only
This chunk contains texture data when texture mapping is used.
UWORD Flags; ; texture flags:
; 1 - TXTR_CHILDREN - apply to child objs
TFORM TForm; ; local coordinates of texture axes.
FRACT Params[16]; ; texture parameters
UBYTE PFlags[16]; ; parameter flags (currently unused)
UBYTE Length; ; length of texture file name
UBYTE Name[Length]; ; texture file name (not NULL terminated)
UBYTE pad; ; (if necessary to make an even length)
BRS1 - variable size - Imagine only (version 1.0)
BRS2 - variable size - Imagine only (version 1.1)
UWORD Flags; ; brush type:
; 0 - Color
; 1 - Reflection
; 2 - Filter
; 3 - Altitude
UWORD WFlags; ; brush wrapping flags:
; 1 WRAP_X - wrap type
; 2 WRAP_Z - wrap type
; 4 WRAP_CHILDREN - apply to children
; 8 WRAP_REPEAT - repeating brush
; 16 WRAP_FLIP - flip with repeats
TFORM TForm; ; local coordinates of brush axes.
(UWORD FullScale;) ; full scale value
(UWORD MaxSeq;) ; highest number for sequenced brushes
UBYTE Length; ; length of brush file name
UBYTE Name[Length]; ; brush file name (not NULL terminated)
UBYTE pad; ; (if necessary to make an even length)
The FullScale and MaxSeq items are in BRS2 chunks only.
SURF - size 5 - not written by Imagine
BYTE SProps[5]; ; object properties
This chunk contains object (surface) properties used by Turbo Silver.
SProps[0] - PRP_SURFACE ; surface type
; 0 - normal
; 4 - genlock
; 5 - IFF brush
SProps[1] - PRP_BRUSH ; brush number (if IFF mapped)
SProps[2] - PRP_WRAP ; IFF brush wrapping type
; 0 - no wrapping
; 1 - wrap X
; 2 - wrap Z
; 3 - wrap X and Z
SProps[3] - PRP_STENCIL ; stencil number for stencil objects
SProps[4] - PRP_TEXTURE ; texture number if texture mapped
MTTR - size 2 - not written by Imagine - see PRP1 chunk.
UBYTE Type; ; refraction type (0-4)
UBYTE Index; ; custom index of refraction
This chunk contains refraction data for transparent or glossy
objects. If the refraction type is 4, the object has a "custom"
refractive index stored in the Index field. The Index field is
100 * (true index of refraction - 1.00) -- so it must be in the
range of 1.00 to 3.55. The refraction types 0-3 specify 0) Air
- 1.00, 1) Water - 1.33, 2) Glass - 1.67 or 3) Crystal 2.00.
SPEC - size 2 - not written by Imagine - see SPC1 above.
UBYTE Specularity; ; range of 0-255
UBYTE Hardness; ; specular exponent (0-31)
This chunk contains specular information. The Specularity
field is the amount of specular reflection -- 0 is none,
255 is fully specular. The "specular exponent" controls
the "tightness" of the specular spots. A value of zero
gives broad specular spots and a value of 31 gives smaller
spots.
PRP0 - size 6 - not written by Imagine
UBYTE Props[6]; ; more object properties
This chunk contains object properties that programs other
than Turbo Silver might support.
Props[0] - PRP_BLEND ; blending factor (0-255)
Props[1] - PRP_SMOOTH ; roughness factor
Props[2] - PRP_SHADE ; shading on/off flag
Props[3] - PRP_PHONG ; phong shading on/off flag
Props[4] - PRP_GLOSSY ; glossy on/off flag
Props[5] - PRP_QUICK ; Quickdraw on/off flag
The blending factor controls the amount of dithering used
on the object - 255 is fully dithered. The roughness factor
controls how rough the object should appear - 0 is smooth, 255
is max roughness. The shading flag is interpreted differently
depending on whether the object is a light source or not. For
light sources, it sets the light to cast shadows or not. For
normal objects, if the flag is set, the object is always
considered as fully lit - i.e., it's color is read directly
from the object (or IFF brush), and is not affected by light
sources. The phong shading is on by default - a non-zero value
turns it off. The glossy flag sets the object to be glossy or
not. If the object is glossy, the "transmit" colors and the
index of refraction control the amount of "sheen". The glossy
feature is meant to simulate something like a wax coating
on the object with the specified index of refraction. The
trasmission coefficients control how much light from the
object makes it through the wax coating.
The Quickdraw flag, if set, tells the editor not to draw
all the points and edges for the object, but to draw a
rectanglular solid centered at the object position, and
with sizes detemined by the axis lengths.
PRP1 - size 8 - Imagine only
UBYTE IProps[8]; ; more object properties
This chunk contains object properties that programs other
than Imagine might support.
IProps[0] - IPRP_DITHER ; blending factor (0-255)
IProps[1] - IPRP_HARD ; hardness factor (0-255)
IProps[2] - IPRP_ROUGH ; roughness factor (0-255)
IProps[3] - IPRP_SHINY ; shinyness factor (0-255)
IProps[4] - IPRP_INDEX ; index of refraction
IProps[5] - IPRP_QUICK ; flag - Quickdraw on/off
IProps[6] - IPRP_PHONG ; flag - Phong shading on/off
IProps[7] - IPRP_GENLOCK ; flag - Genlock on/off
The blending factor controls the amount of dithering used
on the object - 255 is fully dithered.
The hardness factor controls how tight the specular spot
should be - 0 is a big soft spot, 255 is a tight hot spot
The roughness factor controls how rough the object should
appear - 0 is smooth, 255 is max roughness.
The shiny factor in interaction with the object's filter
values controls how shiny the object appears. Setting it
to anything but zero forces the object to be non-transparent
since then the filter values are used in the shiny (reflection)
calculations. A value of 255 means maximum shinyness.
INTS - size 4 - not written by Imagine
FRACT Intensity; ; light intensity
This is the intensity field for light source objects.
an intensity of 255 for a sun-like light fully lights
object surfaces which are perpendicular to the direction
to the light source. For lamp-like light sources, the
necessary intensity will depend on the distance to the light.
INT1 - size 12 - Imagine only
VECTOR Intensity; ; light intensity
This is like INTS above, but has seperate R, G & B intensities.
STRY - size 56 - not written by Imagine
STORY story; ; a story structure for the object.
The story structure is described above.
ANID - size 64 - Imagine only
LONG Cellno; ; cell number
TFORM TForm; ; object position/axes/size in that cell.
For Imagine's "Cycle" objects, within EACH DESC chunk in the
file - that is, for each object of the group, there will be
a series of ANID chunks. The cell number sequences of each
part of the must agree with the sequence for the head object,
and the first cell number must be zero.
FORD - size 56 + 12 * PC - Imagine only
WORD NumC; ; number of cross section points
WORD NumF; ; number of slices
WORD Flags; ; orientation flag
WORD pad; ; reserved
MATRIX TForm; ; object rotation/scaling transformation
VECTOR Shift; ; object translation
VECTOR Points[PC]; ; "Forms" editor points
For Imagine's "Forms" objects, the "PNTS" chunk above is not
written out, but this structure is written instead. The point
count is PC = NumC + 4 * NumF. The object's real points are
then calculated from these using a proprietary algorithm.
The tranformation parameters above allow the axes of the
real object be moved around relative to the "Forms" points.
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