DrawInfo allows clients to render the mesh object more efficiently through LODs (Levels of Detail). Many associate drawinfo with the ability to create moving objects in a map.
The code must be added to the mesh object.
drawInfo dlist # display list for all material sets decorative # older clients with not see this mesh angvel <degrees/sec> # rotation about initial Z axis extents <minX> <minY> <minZ> <maxX> <maxY> <maxZ> sphere <x> <y> <z> <radiusSquared> corner <v> <n> <t> (repeatable) vertex 0.0 0.0 0.0 (repeatable) normal 0.0 0.0 0.0 (repeatable) texcoord 0.0 0.0 (repeatable) lod (repeatable) lengthPerPixel <value> matref <name> (repeatable) dlist # display list for this material set sphere <x> <y> <z> <radiusSquared> points 0 (repeatable) lines 0 1 (repeatable) lineloop 0 1 (repeatable) linestrip 0 1 (repeatable) tris 0 1 2 (repeatable) tristrip 0 1 2 (repeatable) trifan 0 1 2 (repeatable) quads 0 1 2 3 (repeatable) quadstrip 0 1 2 3 (repeatable) polygon 0 1 2 (repeatable) end # matref end # lod end # drawInfo
Valid parameters for drawinfo are:
|dlist||requests that the client use display lists to render the object (recommended for meshes that are not overly complicated)|
|decorative||disables drawInfo in older clients|
|angvel||causes the mesh object to spin at the given rate in degrees per second|
|extents||the minimum and maximum x, y, and z point of the mesh to be drawn. This helps with rendering efficiency, meshes whose extents are outside of the point of view will not be drawn.|
|sphere||an imaginary sphere that encompasses all x, y, and z coordinates. Similar to extents, this helps increase rendering efficiency.|
|vertex||if defined within the drawInfo section, the vertices, normals, and texcoords will be used instead of those defined in the mesh|
|corner||(required)a point defined by a vertex, normal, and a texcoord|
|lod||(required)sections that determines which faces/points will be rendered from specific distances (lengthPerPixel)|
|lengthPerPixel||(required)distance from which the points will be rendered, 0 is close, .3 is about as far away as is needed|
|matref||(required)material to use for the faces that follow it.|
|tris||index numbers of corners that create triangles|
|tristrip||series of points that form a chain of triangles.|
|trifan||a series of points that create triangles that fan out from a single point. That point, usually in the center, is placed first in the series. Trifans are used only in pyramid and cone-shaped meshes.|
|quads||points that create 4-sided mesh planes|
|quadstrip||series of points that create a chain of 4-sided planes. Similarly to tristrips, the series zig-zags between the points, starting in the counter-clockwise direction.|
|polygon||same as quads except for planes of more than 4 sides.|
DrawInfo is only applied to existing mesh objects. These mesh objects will be altered by DrawInfo parameters.
A common example are spinning objects (angvel parameter in DrawInfo).
LODs can improve framerate as it features substitution of complex mesh objects at given lengthPerPixel steps with more simplistic objects. If the substitution is done decent then it'll be unobtrusive. LODs are used in Louman's Mystic Valley for instance: Shrubbery and trees will change in appearance slightly when viewed from about 200 units away.
DrawInfo was added (by trepan) in BZFlag version 2.0.4 and is rarely used for anything other than experimental and proof-of-concept maps. Notable exceptions to this are trees in Louman's "Mystic Valley" and "Churchyard" maps, and a more recent practical use of moving drawinfo in Planet MoFo's halloween passion map. Following the creation of tools to generate drawinfo from .obj files, it is getting more frequent use by more experienced map makers.