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. ============//
//
// Purpose:
//
//===========================================================================//
#include <tier0/platform.h>
#include <stdio.h>
#include <string.h>
#include <math.h>
#include <stdlib.h>
#include "bitmap/float_bm.h"
#include "vstdlib/vstdlib.h"
#include "raytrace.h"
#include "mathlib/bumpvects.h"
#include "mathlib/halton.h"
#include "tier0/threadtools.h"
#include "tier0/progressbar.h"
// In order to handle intersections with wrapped copies, we repeat the bitmap triangles this many
// times
#define NREPS_TILE 1
extern int n_intersection_calculations;
struct SSBumpCalculationContext // what each thread needs to see
{
RayTracingEnvironment *m_pRtEnv;
FloatBitMap_t *ret_bm; // the bitmnap we are building
FloatBitMap_t const *src_bm;
int nrays_to_trace_per_pixel;
float bump_scale;
Vector *trace_directions; // light source directions to trace
Vector *normals;
int min_y; // range of scanlines to computer for
int max_y;
uint32 m_nOptionFlags;
int thread_number;
};
static unsigned SSBumpCalculationThreadFN( void * ctx1 )
{
SSBumpCalculationContext *ctx = ( SSBumpCalculationContext * ) ctx1;
RayStream ray_trace_stream_ctx;
RayTracingSingleResult * rslts = new
RayTracingSingleResult[ctx->ret_bm->Width * ctx->nrays_to_trace_per_pixel];
for( int y = ctx->min_y; y <= ctx->max_y; y++ )
{
if ( ctx->thread_number == 0 )
ReportProgress("Computing output",(1+ctx->max_y-ctx->min_y),y-ctx->min_y);
for( int r = 0; r < ctx->nrays_to_trace_per_pixel; r++ )
{
for( int x = 0; x < ctx->ret_bm->Width; x++ )
{
Vector surf_pnt( x, y, ctx->bump_scale * ctx->src_bm->Pixel( x, y, 3 ) );
// move the ray origin up a hair
surf_pnt.z += 0.55;
Vector trace_end = surf_pnt;
Vector trace_dir = ctx->trace_directions[ r ];
trace_dir *= ( 1 + NREPS_TILE * 2 ) * max( ctx->src_bm->Width, ctx->src_bm->Height );
trace_end += trace_dir;
ctx->m_pRtEnv->AddToRayStream( ray_trace_stream_ctx, surf_pnt, trace_end,
& ( rslts[ r + ctx->nrays_to_trace_per_pixel * ( x )] ));
}
}
if ( ctx->nrays_to_trace_per_pixel )
ctx->m_pRtEnv->FinishRayStream( ray_trace_stream_ctx );
// now, all ray tracing results are in the results buffer. Determine the visible self-shadowed
// bump map lighting at each vertex in each basis direction
for( int x = 0; x < ctx->src_bm->Width; x++ )
{
int nNumChannels = ( ctx->m_nOptionFlags & SSBUMP_OPTION_NONDIRECTIONAL ) ? 1 : 3;
for( int c = 0; c < nNumChannels; c++ )
{
float sum_dots = 0;
float sum_possible_dots = 0;
Vector ldir = g_localBumpBasis[c];
float ndotl = DotProduct( ldir, ctx->normals[x + y * ctx->src_bm->Width] );
if ( ndotl < 0 )
ctx->ret_bm->Pixel( x, y, c ) = 0;
else
{
if ( ctx->nrays_to_trace_per_pixel )
{
RayTracingSingleResult *this_rslt =
rslts + ctx->nrays_to_trace_per_pixel * ( x );
for( int r = 0; r < ctx->nrays_to_trace_per_pixel; r++ )
{
float dot;
if ( ctx->m_nOptionFlags & SSBUMP_OPTION_NONDIRECTIONAL )
dot = ctx->trace_directions[r].z;
else
dot = DotProduct( ldir, ctx->trace_directions[r] );
if ( dot > 0 )
{
sum_possible_dots += dot;
if ( this_rslt[r].HitID == - 1 )
sum_dots += dot;
}
}
}
else
{
sum_dots = sum_possible_dots = 1.0;
}
ctx->ret_bm->Pixel( x, y, c ) = ( ndotl * sum_dots ) / sum_possible_dots;
}
}
if ( ctx->m_nOptionFlags & SSBUMP_OPTION_NONDIRECTIONAL )
{
ctx->ret_bm->Pixel( x, y, 1 ) = ctx->ret_bm->Pixel( x, y, 0 ); // copy height
ctx->ret_bm->Pixel( x, y, 2 ) = ctx->ret_bm->Pixel( x, y, 0 ); // copy height
ctx->ret_bm->Pixel( x, y, 3 ) = ctx->ret_bm->Pixel( x, y, 0 ); // copy height
}
else
{
ctx->ret_bm->Pixel( x, y, 3 ) = ctx->src_bm->Pixel( x, y, 3 ); // copy height
}
}
}
delete[] rslts;
return 0;
}
void FloatBitMap_t::ComputeVertexPositionsAndNormals( float flHeightScale, Vector **ppPosOut, Vector **ppNormalOut ) const
{
Vector *verts = new Vector[Width * Height];
// first, calculate vertex positions
for( int y = 0; y < Height; y++ )
for( int x = 0; x < Width; x++ )
{
Vector * out = verts + x + y * Width;
out->x = x;
out->y = y;
out->z = flHeightScale * Pixel( x, y, 3 );
}
Vector *normals = new Vector[Width * Height];
// now, calculate normals, smoothed
for( int y = 0; y < Height; y++ )
for( int x = 0; x < Width; x++ )
{
// now, calculcate average normal
Vector avg_normal( 0, 0, 0 );
for( int xofs =- 1;xofs <= 1;xofs++ )
for( int yofs =- 1;yofs <= 1;yofs++ )
{
int x0 = ( x + xofs );
if ( x0 < 0 )
x0 += Width;
int y0 = ( y + yofs );
if ( y0 < 0 )
y0 += Height;
x0 = x0 % Width;
y0 = y0 % Height;
int x1 = ( x0 + 1 ) % Width;
int y1 = ( y0 + 1 ) % Height;
// now, form the two triangles from this vertex
Vector p0 = verts[x0 + y0 * Width];
Vector e1 = verts[x1 + y0 * Width];
e1 -= p0;
Vector e2 = verts[x0 + y1 * Width];
e2 -= p0;
Vector n1;
CrossProduct( e1, e2, n1 );
if ( n1.z < 0 )
n1.Negate();
e1 = verts[x + y1 * Width];
e1 -= p0;
e2 = verts[x1 + y1 * Width];
e2 -= p0;
Vector n2;
CrossProduct( e1, e2, n2 );
if ( n2.z < 0 )
n2.Negate();
n1.NormalizeInPlace();
n2.NormalizeInPlace();
avg_normal += n1;
avg_normal += n2;
}
avg_normal.NormalizeInPlace();
normals[x + y * Width]= avg_normal;
}
*ppPosOut = verts;
*ppNormalOut = normals;
}
FloatBitMap_t *FloatBitMap_t::ComputeSelfShadowedBumpmapFromHeightInAlphaChannel(
float bump_scale, int nrays_to_trace_per_pixel,
uint32 nOptionFlags ) const
{
// first, add all the triangles from the height map to the "world".
// we will make multiple copies to handle wrapping
int tcnt = 1;
Vector * verts;
Vector * normals;
ComputeVertexPositionsAndNormals( bump_scale, & verts, & normals );
RayTracingEnvironment rtEnv;
rtEnv.Flags |= RTE_FLAGS_DONT_STORE_TRIANGLE_COLORS; // save some ram
if ( nrays_to_trace_per_pixel )
{
rtEnv.MakeRoomForTriangles( ( 1 + 2 * NREPS_TILE ) * ( 1 + 2 * NREPS_TILE ) * 2 * Height * Width );
// now, add a whole mess of triangles to trace against
for( int tilex =- NREPS_TILE; tilex <= NREPS_TILE; tilex++ )
for( int tiley =- NREPS_TILE; tiley <= NREPS_TILE; tiley++ )
{
int min_x = 0;
int max_x = Width - 1;
int min_y = 0;
int max_y = Height - 1;
if ( tilex < 0 )
min_x = Width / 2;
if ( tilex > 0 )
max_x = Width / 2;
if ( tiley < 0 )
min_y = Height / 2;
if ( tiley > 0 )
max_y = Height / 2;
for( int y = min_y; y <= max_y; y++ )
for( int x = min_x; x <= max_x; x++ )
{
Vector ofs( tilex * Width, tiley * Height, 0 );
int x1 = ( x + 1 ) % Width;
int y1 = ( y + 1 ) % Height;
Vector v0 = verts[x + y * Width];
Vector v1 = verts[x1 + y * Width];
Vector v2 = verts[x1 + y1 * Width];
Vector v3 = verts[x + y1 * Width];
v0.x = x; v0.y = y;
v1.x = x + 1; v1.y = y;
v2.x = x + 1; v2.y = y + 1;
v3.x = x; v3.y = y + 1;
v0 += ofs; v1 += ofs; v2 += ofs; v3 += ofs;
rtEnv.AddTriangle( tcnt++, v0, v1, v2, Vector( 1, 1, 1 ) );
rtEnv.AddTriangle( tcnt++, v0, v3, v2, Vector( 1, 1, 1 ) );
}
}
//printf("added %d triangles\n",tcnt-1);
ReportProgress("Creating kd-tree",0,0);
rtEnv.SetupAccelerationStructure();
// ok, now we have built a structure for ray intersection. we will take advantage
// of the SSE ray tracing code by intersecting rays as a batch.
}
// We need to calculate for each vertex (i.e. pixel) of the heightmap, how "much" of the world
// it can see in each basis direction. we will do this by sampling a sphere of rays around the
// vertex, and using dot-product weighting to measure the lighting contribution in each basis
// direction. note that the surface normal is not used here. The surface normal will end up
// being reflected in the result because of rays being blocked when they try to pass through
// the planes of the triangles touching the vertex.
// note that there is no reason inter-bounced lighting could not be folded into this
// calculation.
FloatBitMap_t * ret = new FloatBitMap_t( Width, Height );
Vector *trace_directions=new Vector[nrays_to_trace_per_pixel];
DirectionalSampler_t my_sphere_sampler;
for( int r=0; r < nrays_to_trace_per_pixel; r++)
{
Vector trace_dir=my_sphere_sampler.NextValue();
// trace_dir=Vector(1,0,0);
trace_dir.z=fabs(trace_dir.z); // upwards facing only
trace_directions[ r ]= trace_dir;
}
volatile SSBumpCalculationContext ctxs[32];
ctxs[0].m_pRtEnv =& rtEnv;
ctxs[0].ret_bm = ret;
ctxs[0].src_bm = this;
ctxs[0].nrays_to_trace_per_pixel = nrays_to_trace_per_pixel;
ctxs[0].bump_scale = bump_scale;
ctxs[0].trace_directions = trace_directions;
ctxs[0].normals = normals;
ctxs[0].min_y = 0;
ctxs[0].max_y = Height - 1;
ctxs[0].m_nOptionFlags = nOptionFlags;
int nthreads = min( 32, (int)GetCPUInformation()->m_nPhysicalProcessors );
ThreadHandle_t waithandles[32];
int starty = 0;
int ystep = Height / nthreads;
for( int t = 0;t < nthreads; t++ )
{
if ( t )
memcpy( (void * ) ( & ctxs[t] ), ( void * ) & ctxs[0], sizeof( ctxs[0] ));
ctxs[t].thread_number = t;
ctxs[t].min_y = starty;
if ( t != nthreads - 1 )
ctxs[t].max_y = min( Height - 1, starty + ystep - 1 );
else
ctxs[t].max_y = Height - 1;
waithandles[t]= CreateSimpleThread( SSBumpCalculationThreadFN, ( SSBumpCalculationContext * ) & ctxs[t] );
starty += ystep;
}
for(int t=0;t<nthreads;t++)
{
ThreadJoin( waithandles[t] );
}
if ( nOptionFlags & SSBUMP_MOD2X_DETAIL_TEXTURE )
{
const float flOutputScale = 0.5 * ( 1.0 / .57735026 ); // normalize so that a flat normal yields 0.5
// scale output weights by color channel
for( int nY = 0; nY < Height; nY++ )
for( int nX = 0; nX < Width; nX++ )
{
float flScale = flOutputScale * (2.0/3.0) * ( Pixel( nX, nY, 0 ) + Pixel( nX, nY, 1 ) + Pixel( nX, nY, 2 ) );
ret->Pixel( nX, nY, 0 ) *= flScale;
ret->Pixel( nX, nY, 1 ) *= flScale;
ret->Pixel( nX, nY, 2 ) *= flScale;
}
}
delete[] verts;
delete[] trace_directions;
delete[] normals;
return ret; // destructor will clean up rtenv
}
// generate a conventional normal map from a source with height stored in alpha.
FloatBitMap_t *FloatBitMap_t::ComputeBumpmapFromHeightInAlphaChannel( float bump_scale ) const
{
Vector *verts;
Vector *normals;
ComputeVertexPositionsAndNormals( bump_scale, &verts, &normals );
FloatBitMap_t *ret=new FloatBitMap_t( Width, Height );
for( int y = 0; y < Height; y++ )
for( int x = 0; x < Width; x++ )
{
Vector const & N = normals[ x + y * Width ];
ret->Pixel( x, y, 0 ) = 0.5+ 0.5 * N.x;
ret->Pixel( x, y, 1 ) = 0.5+ 0.5 * N.y;
ret->Pixel( x, y, 2 ) = 0.5+ 0.5 * N.z;
ret->Pixel( x, y, 3 ) = Pixel( x, y, 3 );
}
return ret;
}