Globals: Fog Info

Fog Info

Availability  LightWave 6.0
Component  Layout
Header  lwrender.h

The fog info global returns information about the fog settings for the scene. The parameters are read-only, but you can set them using commands.

Global Call

   LWFogInfo *foginfo;
   foginfo = global( LWFOGINFO_GLOBAL, GFUSE_TRANSIENT );

The global function returns a pointer to an LWFogInfo.

   typedef struct st_LWFogInfo {
      int     type;
      int     flags;
      double (*minDist) (LWTime);
      double (*maxDist) (LWTime);
      double (*minAmt)  (LWTime);
      double (*maxAmt)  (LWTime);
      void   (*color)   (LWTime, double col[3]);
   } LWFogInfo;

type

The fog type. Generally this identifies the falloff function used to interpolate the fog level at distances between minDist and maxDist. Possible types are

LWFOG_NONE
LWFOG_LINEAR
LWFOG_NONLINEAR1
LWFOG_NONLINEAR2

flags

Fog-related flags. Currently the only flag defined for this field is LWFOGF_BACKGROUND, which indicates that fog will affect the backdrop.

amount = minDist( time )

Returns the distance from the viewer (typically the camera) at which the fog effect is at a minimum.

amount = maxDist( time )

Returns the distance at which the fog effect reaches its maximum.

amount = minAmt( time )

Returns the minimum amount of fog (the amount at the minimum distance). Fog amounts range from 0.0 to 1.0.

amount = maxAmt( time )

Returns the maximum amount of fog.

color( time, rgb )

The color of the fog.

Example

This code fragment uses Fog Info to determine whether a point at distance d is in fog at time t.

   #include <lwserver.h>
   #include <lwrender.h>

   LWFogInfo *foginfo;

   foginfo = global( LWFOGINFO_GLOBAL, GFUSE_TRANSIENT );
   if ( foginfo ) {
      if ( foginfo->type != LWFOG_NONE ) {
         if ( d >= foginfo->minDist( t )) {
            ...d is in fog