Modified source engine (2017) developed by valve and leaked in 2020. Not for commercial purporses
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//========= Copyright Valve Corporation, All rights reserved. ============//
// $Id$
#include "raytrace.h"
#include <mathlib/halton.h>
static uint32 MapDistanceToPixel(float t)
{
if (t<0) return 0xffff0000;
if (t>100) return 0xff000000;
int a=t*1000; a&=0xff;
int b=t*10; b &=0xff;
int c=t*.01; c &=0xff;
return 0xff000000+(a<<16)+(b<<8)+c;
}
#define IGAMMA (1.0/2.2)
#define MAGIC_NUMBER (1<<23)
static fltx4 Four_MagicNumbers={ MAGIC_NUMBER, MAGIC_NUMBER, MAGIC_NUMBER, MAGIC_NUMBER };
static ALIGN16 int32 Four_255s[4]= {0xff,0xff,0xff,0xff};
#define PIXMASK ( * ( reinterpret_cast< fltx4 *>( &Four_255s ) ) )
void MapLinearIntensities(FourVectors const &intens,uint32 *p1, uint32 *p2, uint32 *p3, uint32 *p4)
{
// convert four pixels worth of sse-style rgb into argb lwords
// NOTE the _mm_empty macro is voodoo. do not mess with this routine casually - simply throwing
// anything that ends up generating a fpu stack references in here would be bad news.
static fltx4 pixscale={255.0,255.0,255.0,255.0};
fltx4 r,g,b;
r=MinSIMD(pixscale,MulSIMD(pixscale,PowSIMD(intens.x,IGAMMA)));
g=MinSIMD(pixscale,MulSIMD(pixscale,PowSIMD(intens.y,IGAMMA)));
b=MinSIMD(pixscale,MulSIMD(pixscale,PowSIMD(intens.z,IGAMMA)));
// now, convert to integer
r=AndSIMD( AddSIMD( r, Four_MagicNumbers ), PIXMASK );
g=AndSIMD( AddSIMD( g, Four_MagicNumbers ), PIXMASK );
b=AndSIMD( AddSIMD( b, Four_MagicNumbers ), PIXMASK );
*(p1)=(SubInt(r, 0))|(SubInt(g, 0)<<8)|(SubInt(b, 0)<<16);
*(p2)=(SubInt(r, 1))|(SubInt(g, 1)<<8)|(SubInt(b, 1)<<16);
*(p3)=(SubInt(r, 2))|(SubInt(g, 2)<<8)|(SubInt(b, 2)<<16);
*(p4)=(SubInt(r, 3))|(SubInt(g, 3)<<8)|(SubInt(b, 3)<<16);
}
static ALIGN16 uint32 signmask[4]={0x80000000,0x80000000,0x80000000,0x80000000};
static ALIGN16 int32 all_ones[4]={-1,-1,-1,-1};
static fltx4 all_zeros={0,0,0,0};
static fltx4 TraceLimit={1.0e20,1.0e20,1.0e20,1.0e20};
void RayTracingEnvironment::RenderScene(
int width, int height, // width and height of desired rendering
int stride, // actual width in pixels of target buffer
uint32 *output_buffer, // pointer to destination
Vector CameraOrigin, // eye position
Vector ULCorner, // word space coordinates of upper left
// monitor corner
Vector URCorner, // top right corner
Vector LLCorner, // lower left
Vector LRCorner, // lower right
RayTraceLightingMode_t lmode)
{
// first, compute deltas
Vector dxvector=URCorner;
dxvector-=ULCorner;
dxvector*=(1.0/width);
Vector dxvectortimes2=dxvector;
dxvectortimes2+=dxvector;
Vector dyvector=LLCorner;
dyvector-=ULCorner;
dyvector*=(1.0/height);
// block_offsets-relative offsets for eahc of the 4 pixels in the block, in sse format
FourVectors block_offsets;
block_offsets.LoadAndSwizzle(Vector(0,0,0),dxvector,dyvector,dxvector+dyvector);
FourRays myrays;
myrays.origin.DuplicateVector(CameraOrigin);
// tmprays is used fo rthe case when we cannot trace 4 rays at once.
FourRays tmprays;
tmprays.origin.DuplicateVector(CameraOrigin);
// now, we will ray trace pixels. we will do the rays in a 2x2 pattern
for(int y=0;y<height;y+=2)
{
Vector SLoc=dyvector;
SLoc*=((float) y);
SLoc+=ULCorner;
uint32 *dest=output_buffer+y*stride;
for(int x=0;x<width;x+=2)
{
myrays.direction.DuplicateVector(SLoc);
myrays.direction+=block_offsets;
myrays.direction.VectorNormalize();
RayTracingResult rslt;
Trace4Rays(myrays,all_zeros,TraceLimit, &rslt);
if ((rslt.HitIds[0]==-1) && (rslt.HitIds[1]==-1) &&
(rslt.HitIds[2]==-1) && (rslt.HitIds[3]==-1))
MapLinearIntensities(BackgroundColor,dest,dest+1,dest+stride,dest+stride+1);
else
{
// make sure normal points back towards ray origin
fltx4 ndoti=rslt.surface_normal*myrays.direction;
fltx4 bad_dirs=AndSIMD(CmpGtSIMD(ndoti,Four_Zeros),
LoadAlignedSIMD((float *) signmask));
// flip signs of all "wrong" normals
rslt.surface_normal.x=XorSIMD(bad_dirs,rslt.surface_normal.x);
rslt.surface_normal.y=XorSIMD(bad_dirs,rslt.surface_normal.y);
rslt.surface_normal.z=XorSIMD(bad_dirs,rslt.surface_normal.z);
FourVectors intens;
intens.DuplicateVector(Vector(0,0,0));
// set up colors
FourVectors surf_colors;
surf_colors.DuplicateVector(Vector(0,0,0));
for(int i=0;i<4;i++)
{
if (rslt.HitIds[i]>=0)
{
surf_colors.X(i)=TriangleColors[rslt.HitIds[i]].x;
surf_colors.Y(i)=TriangleColors[rslt.HitIds[i]].y;
surf_colors.Z(i)=TriangleColors[rslt.HitIds[i]].z;
}
}
FourVectors surface_pos=myrays.direction;
surface_pos*=rslt.HitDistance;
surface_pos+=myrays.origin;
switch(lmode)
{
case DIRECT_LIGHTING:
{
// light all points
for(int l=0;l<LightList.Count();l++)
{
LightList[l].ComputeLightAtPoints(surface_pos,rslt.surface_normal,
intens);
}
}
break;
case DIRECT_LIGHTING_WITH_SHADOWS:
{
// light all points
for(int l=0;l<LightList.Count();l++)
{
FourVectors ldir;
ldir.DuplicateVector(LightList[l].m_Position);
ldir-=surface_pos;
fltx4 MaxT=ldir.length();
ldir.VectorNormalizeFast();
// now, compute shadow flag
//FourRays myrays;
myrays.origin=surface_pos;
FourVectors epsilon=ldir;
epsilon*=0.01;
myrays.origin+=epsilon;
myrays.direction=ldir;
RayTracingResult shadowtest;
Trace4Rays(myrays,Four_Zeros,MaxT, &shadowtest);
fltx4 unshadowed=CmpGtSIMD(shadowtest.HitDistance,MaxT);
if (! (IsAllZeros(unshadowed)))
{
FourVectors tmp;
tmp.DuplicateVector(Vector(0,0,0));
LightList[l].ComputeLightAtPoints(surface_pos,rslt.surface_normal,
tmp);
intens.x=AddSIMD(intens.x,AndSIMD(tmp.x,unshadowed));
intens.y=AddSIMD(intens.y,AndSIMD(tmp.y,unshadowed));
intens.z=AddSIMD(intens.z,AndSIMD(tmp.z,unshadowed));
}
}
}
break;
}
// now, mask off non-hitting pixels
intens.VProduct(surf_colors);
fltx4 no_hit_mask=CmpGtSIMD(rslt.HitDistance,TraceLimit);
intens.x=OrSIMD(AndSIMD(BackgroundColor.x,no_hit_mask),
AndNotSIMD(no_hit_mask,intens.x));
intens.y=OrSIMD(AndSIMD(BackgroundColor.y,no_hit_mask),
AndNotSIMD(no_hit_mask,intens.y));
intens.z=OrSIMD(AndSIMD(BackgroundColor.z,no_hit_mask),
AndNotSIMD(no_hit_mask,intens.z));
MapLinearIntensities(intens,dest,dest+1,dest+stride,dest+stride+1);
}
dest+=2;
SLoc+=dxvectortimes2;
}
}
}
#define SQ(x) ((x)*(x))
void RayTracingEnvironment::ComputeVirtualLightSources(void)
{
int start_pos=0;
for(int b=0;b<3;b++)
{
int nl=LightList.Count();
int where_to_start=start_pos;
start_pos=nl;
for(int l=where_to_start;l<nl;l++)
{
DirectionalSampler_t sample_generator;
int n_desired=1*LightList[l].m_Color.Length();
if (LightList[l].m_Type==MATERIAL_LIGHT_SPOT)
n_desired*=LightList[l].m_Phi/2;
for(int try1=0;try1<n_desired;try1++)
{
LightDesc_t const &li=LightList[l];
FourRays myrays;
myrays.origin.DuplicateVector(li.m_Position);
RayTracingResult rslt;
Vector trial_dir=sample_generator.NextValue();
if (li.IsDirectionWithinLightCone(trial_dir))
{
myrays.direction.DuplicateVector(trial_dir);
Trace4Rays(myrays,all_zeros,ReplicateX4(1000.0), &rslt);
if ((rslt.HitIds[0]!=-1))
{
// make sure normal points back towards ray origin
fltx4 ndoti=rslt.surface_normal*myrays.direction;
fltx4 bad_dirs=AndSIMD(CmpGtSIMD(ndoti,Four_Zeros),
LoadAlignedSIMD((float *) signmask));
// flip signs of all "wrong" normals
rslt.surface_normal.x=XorSIMD(bad_dirs,rslt.surface_normal.x);
rslt.surface_normal.y=XorSIMD(bad_dirs,rslt.surface_normal.y);
rslt.surface_normal.z=XorSIMD(bad_dirs,rslt.surface_normal.z);
// a hit! let's make a virtual light source
// treat the virtual light as a disk with its center at the hit position
// and its radius scaled by the amount of the solid angle this probe
// represents.
float area_of_virtual_light=
4.0*M_PI*SQ( SubFloat( rslt.HitDistance, 0 ) )*(1.0/n_desired);
FourVectors intens;
intens.DuplicateVector(Vector(0,0,0));
FourVectors surface_pos=myrays.direction;
surface_pos*=rslt.HitDistance;
surface_pos+=myrays.origin;
FourVectors delta=rslt.surface_normal;
delta*=0.1;
surface_pos+=delta;
LightList[l].ComputeLightAtPoints(surface_pos,rslt.surface_normal,
intens);
FourVectors surf_colors;
surf_colors.DuplicateVector(TriangleColors[rslt.HitIds[0]]);
intens*=surf_colors;
// see if significant
LightDesc_t l1;
l1.m_Type=MATERIAL_LIGHT_SPOT;
l1.m_Position=Vector(surface_pos.X(0),surface_pos.Y(0),surface_pos.Z(0));
l1.m_Direction=Vector(rslt.surface_normal.X(0),rslt.surface_normal.Y(0),
rslt.surface_normal.Z(0));
l1.m_Color=Vector(intens.X(0),intens.Y(0),intens.Z(0));
if (l1.m_Color.Length()>0)
{
l1.m_Color*=area_of_virtual_light/M_PI;
l1.m_Range=0.0;
l1.m_Falloff=1.0;
l1.m_Attenuation0=1.0;
l1.m_Attenuation1=0.0;
l1.m_Attenuation2=1.0; // intens falls off as 1/r^2
l1.m_Theta=0;
l1.m_Phi=M_PI;
l1.RecalculateDerivedValues();
LightList.AddToTail(l1);
}
}
}
}
}
}
}
static unsigned int GetSignMask(Vector const &v)
{
unsigned int ret=0;
if (v.x<0.0)
ret++;
if (v.y<0)
ret+=2;
if (v.z<0)
ret+=4;
return ret;
}
inline void RayTracingEnvironment::FlushStreamEntry(RayStream &s,int msk)
{
assert(msk>=0);
assert(msk<8);
fltx4 tmax=s.PendingRays[msk].direction.length();
fltx4 scl=ReciprocalSaturateSIMD(tmax);
s.PendingRays[msk].direction*=scl; // normalize
RayTracingResult tmpresult;
Trace4Rays(s.PendingRays[msk],Four_Zeros,tmax,msk,&tmpresult);
// now, write out results
for(int r=0;r<4;r++)
{
RayTracingSingleResult *out=s.PendingStreamOutputs[msk][r];
out->ray_length=SubFloat( tmax, r );
out->surface_normal.x=tmpresult.surface_normal.X(r);
out->surface_normal.y=tmpresult.surface_normal.Y(r);
out->surface_normal.z=tmpresult.surface_normal.Z(r);
out->HitID=tmpresult.HitIds[r];
out->HitDistance=SubFloat( tmpresult.HitDistance, r );
}
s.n_in_stream[msk]=0;
}
void RayTracingEnvironment::AddToRayStream(RayStream &s,
Vector const &start,Vector const &end,
RayTracingSingleResult *rslt_out)
{
Vector delta=end;
delta-=start;
int msk=GetSignMask(delta);
assert(msk>=0);
assert(msk<8);
int pos=s.n_in_stream[msk];
assert(pos<4);
s.PendingRays[msk].origin.X(pos)=start.x;
s.PendingRays[msk].origin.Y(pos)=start.y;
s.PendingRays[msk].origin.Z(pos)=start.z;
s.PendingRays[msk].direction.X(pos)=delta.x;
s.PendingRays[msk].direction.Y(pos)=delta.y;
s.PendingRays[msk].direction.Z(pos)=delta.z;
s.PendingStreamOutputs[msk][pos]=rslt_out;
if (pos==3)
{
FlushStreamEntry(s,msk);
}
else
s.n_in_stream[msk]++;
}
void RayTracingEnvironment::FinishRayStream(RayStream &s)
{
for(int msk=0;msk<8;msk++)
{
int cnt=s.n_in_stream[msk];
if (cnt)
{
// fill in unfilled entries with dups of first
for(int c=cnt;c<4;c++)
{
s.PendingRays[msk].origin.X(c) = s.PendingRays[msk].origin.X(0);
s.PendingRays[msk].origin.Y(c) = s.PendingRays[msk].origin.Y(0);
s.PendingRays[msk].origin.Z(c) = s.PendingRays[msk].origin.Z(0);
s.PendingRays[msk].direction.X(c) = s.PendingRays[msk].direction.X(0);
s.PendingRays[msk].direction.Y(c) = s.PendingRays[msk].direction.Y(0);
s.PendingRays[msk].direction.Z(c) = s.PendingRays[msk].direction.Z(0);
s.PendingStreamOutputs[msk][c]=s.PendingStreamOutputs[msk][0];
}
FlushStreamEntry(s,msk);
}
}
}