30 lines
867 B
HLSL
30 lines
867 B
HLSL
|
#ifndef VOLUMETRIC_FOG_2_PRIMITIVES
|
||
|
|
#define VOLUMETRIC_FOG_2_PRIMITIVES
|
||
|
|
|
||
|
|
float3 _BoundsCenter, _BoundsExtents;
|
||
|
|
|
||
|
|
float BoxIntersection(float3 origin, float3 viewDir) {
|
||
|
|
float3 ro = origin - _BoundsCenter;
|
||
|
|
float3 invR = 1.0.xxx / viewDir;
|
||
|
|
float3 tbot = invR * (-_BoundsExtents - ro);
|
||
|
|
float3 ttop = invR * (_BoundsExtents - ro);
|
||
|
|
float3 tmin = min (ttop, tbot);
|
||
|
|
float2 tt0 = max (tmin.xx, tmin.yz);
|
||
|
|
float t0 = max(tt0.x, tt0.y);
|
||
|
|
return max(t0, 0);
|
||
|
|
}
|
||
|
|
|
||
|
|
void SphereIntersection(float3 origin, float3 viewDir, out float t0, out float t1) {
|
||
|
|
float3 oc = origin - _BoundsCenter;
|
||
|
|
float b = dot(viewDir, oc);
|
||
|
|
float c = dot(oc,oc) - _BoundsExtents.x;
|
||
|
|
float t = b*b - c;
|
||
|
|
if (t>0) t = sqrt(t);
|
||
|
|
t0 = -b-t;
|
||
|
|
t1 = -b+t;
|
||
|
|
if (t1>t0) {
|
||
|
|
t0 = max(t0, 0);
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
#endif // VOLUMETRIC_FOG_2_PRIMITIVES
|