kmSetFogDensity
Specifies a coefficient (scale factor) to table fog.
Description:
This function assigns a coefficient (scale factor) to table fog.
PowerVR has a fog table containing 128 levels from 0 to 127.
FogDensity determines the depth range over which each of these 128 levels is effective.
If a low value is specified for FogDensity, the effect of fog appears from the polygon with the higher 1/w (Fog density increases).
If a high value is specified for FogDensity, the effect of fog can be seen only on the polygon with a low 1/w (Fog density decreases).
FogDensity consists of two bytes. The higher byte indicates the mantissa and the lower byte indicates the exponent (the nth power of 2).
Example: | 0x0100 | = 0.0000001(b) | = 0.015625 |
0x8000 | = 1.0(b) | = 1.0 | |
0xFF00 | = 1.1111111(b) | = 1.984375 | |
0xFF01 | = 11.111111(b) | = 3.96875 | |
0xFF06 | = 1111111.1(b) | = 128.5 | |
0xFF07 | = 11111111.0(b) | = 255 | |
0xFF08 | = 111111110.0(b) | = 510 | |
0xFF09 | = 1111111100.0(b) | = 1020 | |
0xFF0A | = 2040 | ||
0xFF0B | = 4080 | ||
0xFF0C | = 8160 |
Parameters:
FogDensity(input)
This parameter is a coefficient of table fog (scale factor).
Specify this parameter as "kmSetFogDensity(0xFF09)."
Return values:
Value | Explanation |
---|---|
KMSTATUS_SUCCESS | Success |
kmSetFogDensity