44 lines
1.1 KiB
HLSL
44 lines
1.1 KiB
HLSL
#ifndef VOLUMETRIC_FOG_2_PRIMITIVES
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#define VOLUMETRIC_FOG_2_PRIMITIVES
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float BoxIntersection(float3 origin, float3 viewDir) {
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float3 ro = origin - _BoundsCenter;
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float3 invR = 1.0.xxx / viewDir;
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float3 tbot = invR * (-_BoundsExtents - ro);
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float3 ttop = invR * (_BoundsExtents - ro);
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float3 tmin = min (ttop, tbot);
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float2 tt0 = max (tmin.xx, tmin.yz);
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float t0 = max(tt0.x, tt0.y);
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return max(t0, 0);
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}
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void SphereIntersection(float3 origin, float3 viewDir, out float t0, out float t1) {
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float3 oc = origin - _BoundsCenter;
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float b = dot(viewDir, oc);
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float c = dot(oc,oc) - _BoundsExtents.x;
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float t = b*b - c;
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if (t>0) t = sqrt(t);
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t0 = -b-t;
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t1 = -b+t;
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if (t1>t0) {
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t0 = max(t0, 0);
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}
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}
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inline float3 RotateInv(float3 wpos) {
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wpos -= _BoundsCenter.xyz;
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wpos = mul((float3x3)_InvRotMatrix, wpos);
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wpos += _BoundsCenter.xyz;
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return wpos;
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}
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inline float3 Rotate(float3 wpos) {
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wpos -= _BoundsCenter.xyz;
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wpos = mul((float3x3)_RotMatrix, wpos);
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wpos += _BoundsCenter.xyz;
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return wpos;
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}
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#endif // VOLUMETRIC_FOG_2_PRIMITIVES |