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/*
===========================================================================
Doom 3 GPL Source Code
Copyright (C) 1999-2011 id Software LLC, a ZeniMax Media company.
This file is part of the Doom 3 GPL Source Code (?Doom 3 Source Code?).
Doom 3 Source Code is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
Doom 3 Source Code is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with Doom 3 Source Code. If not, see <http://www.gnu.org/licenses/>.
In addition, the Doom 3 Source Code is also subject to certain additional terms. You should have received a copy of these additional terms immediately following the terms and conditions of the GNU General Public License which accompanied the Doom 3 Source Code. If not, please request a copy in writing from id Software at the address below.
If you have questions concerning this license or the applicable additional terms, you may contact in writing id Software LLC, c/o ZeniMax Media Inc., Suite 120, Rockville, Maryland 20850 USA.
===========================================================================
*/
#include "../idlib/precompiled.h"
#pragma hdrstop
#include "tr_local.h"
// Compute conservative shadow bounds as the intersection
// of the object's bounds' shadow volume and the light's bounds.
//
// --cass
template <class T, int N>
struct MyArray
{
MyArray() : s(0) {}
MyArray( const MyArray<T,N> & cpy ) : s(cpy.s)
{
for(int i=0; i < s; i++)
v[i] = cpy.v[i];
}
void push_back(const T & i) {
v[s] = i;
s++;
//if(s > max_size)
// max_size = int(s);
}
T & operator[](int i) {
return v[i];
}
const T & operator[](int i) const {
return v[i];
}
unsigned int size() const {
return s;
}
void empty() {
s = 0;
}
T v[N];
int s;
// static int max_size;
};
typedef MyArray<int, 4> MyArrayInt;
//int MyArrayInt::max_size = 0;
typedef MyArray<idVec4, 16> MyArrayVec4;
//int MyArrayVec4::max_size = 0;
struct poly
{
MyArrayInt vi;
MyArrayInt ni;
idVec4 plane;
};
typedef MyArray<poly, 9> MyArrayPoly;
//int MyArrayPoly::max_size = 0;
struct edge
{
int vi[2];
int pi[2];
};
typedef MyArray<edge, 15> MyArrayEdge;
//int MyArrayEdge::max_size = 0;
MyArrayInt four_ints(int a, int b, int c, int d)
{
MyArrayInt vi;
vi.push_back(a);
vi.push_back(b);
vi.push_back(c);
vi.push_back(d);
return vi;
}
idVec3 homogeneous_difference(idVec4 a, idVec4 b)
{
idVec3 v;
v.x = b.x * a.w - a.x * b.w;
v.y = b.y * a.w - a.y * b.w;
v.z = b.z * a.w - a.z * b.w;
return v;
}
// handles positive w only
idVec4 compute_homogeneous_plane(idVec4 a, idVec4 b, idVec4 c)
{
idVec4 v, t;
if(a[3] == 0)
{ t = a; a = b; b = c; c = t; }
if(a[3] == 0)
{ t = a; a = b; b = c; c = t; }
// can't handle 3 infinite points
if( a[3] == 0 )
return v;
idVec3 vb = homogeneous_difference(a, b);
idVec3 vc = homogeneous_difference(a, c);
idVec3 n = vb.Cross(vc);
n.Normalize();
v.x = n.x;
v.y = n.y;
v.z = n.z;
v.w = - (n * idVec3(a.x, a.y, a.z)) / a.w ;
return v;
}
struct polyhedron
{
MyArrayVec4 v;
MyArrayPoly p;
MyArrayEdge e;
void add_quad( int va, int vb, int vc, int vd )
{
poly pg;
pg.vi = four_ints(va, vb, vc, vd);
pg.ni = four_ints(-1, -1, -1, -1);
pg.plane = compute_homogeneous_plane(v[va], v[vb], v[vc]);
p.push_back(pg);
}
void discard_neighbor_info()
{
for(unsigned int i = 0; i < p.size(); i++ )
{
MyArrayInt & ni = p[i].ni;
for(unsigned int j = 0; j < ni.size(); j++)
ni[j] = -1;
}
}
void compute_neighbors()
{
e.empty();
discard_neighbor_info();
bool found;
int P = p.size();
// for each polygon
for(int i = 0; i < P-1; i++ )
{
const MyArrayInt & vi = p[i].vi;
MyArrayInt & ni = p[i].ni;
int Si = vi.size();
// for each edge of that polygon
for(int ii=0; ii < Si; ii++)
{
int ii0 = ii;
int ii1 = (ii+1) % Si;
// continue if we've already found this neighbor
if(ni[ii] != -1)
continue;
found = false;
// check all remaining polygons
for(int j = i+1; j < P; j++ )
{
const MyArrayInt & vj = p[j].vi;
MyArrayInt & nj = p[j].ni;
int Sj = vj.size();
for( int jj = 0; jj < Sj; jj++ )
{
int jj0 = jj;
int jj1 = (jj+1) % Sj;
if(vi[ii0] == vj[jj1] && vi[ii1] == vj[jj0])
{
edge ed;
ed.vi[0] = vi[ii0];
ed.vi[1] = vi[ii1];
ed.pi[0] = i;
ed.pi[1] = j;
e.push_back(ed);
ni[ii] = j;
nj[jj] = i;
found = true;
break;
}
else if ( vi[ii0] == vj[jj0] && vi[ii1] == vj[jj1] )
{
fprintf(stderr,"why am I here?\n");
}
}
if( found )
break;
}
}
}
}
void recompute_planes()
{
// for each polygon
for(unsigned int i = 0; i < p.size(); i++ )
{
p[i].plane = compute_homogeneous_plane(v[p[i].vi[0]], v[p[i].vi[1]], v[p[i].vi[2]]);
}
}
void transform(const idMat4 & m)
{
for(unsigned int i=0; i < v.size(); i++ )
v[i] = m * v[i];
recompute_planes();
}
};
// make a unit cube
polyhedron PolyhedronFromBounds( const idBounds & b )
{
// 3----------2
// |\ /|
// | \ / |
// | 7--6 |
// | | | |
// | 4--5 |
// | / \ |
// | / \ |
// 0----------1
//
static polyhedron p;
if( p.e.size() == 0 ) {
p.v.push_back(idVec4( -1, -1, 1, 1));
p.v.push_back(idVec4( 1, -1, 1, 1));
p.v.push_back(idVec4( 1, 1, 1, 1));
p.v.push_back(idVec4( -1, 1, 1, 1));
p.v.push_back(idVec4( -1, -1, -1, 1));
p.v.push_back(idVec4( 1, -1, -1, 1));
p.v.push_back(idVec4( 1, 1, -1, 1));
p.v.push_back(idVec4( -1, 1, -1, 1));
p.add_quad( 0, 1, 2, 3 );
p.add_quad( 7, 6, 5, 4 );
p.add_quad( 1, 0, 4, 5 );
p.add_quad( 2, 1, 5, 6 );
p.add_quad( 3, 2, 6, 7 );
p.add_quad( 0, 3, 7, 4 );
p.compute_neighbors();
p.recompute_planes();
p.v.empty(); // no need to copy this data since it'll be replaced
}
polyhedron p2(p);
const idVec3 & min = b[0];
const idVec3 & max = b[1];
p2.v.empty();
p2.v.push_back(idVec4( min.x, min.y, max.z, 1));
p2.v.push_back(idVec4( max.x, min.y, max.z, 1));
p2.v.push_back(idVec4( max.x, max.y, max.z, 1));
p2.v.push_back(idVec4( min.x, max.y, max.z, 1));
p2.v.push_back(idVec4( min.x, min.y, min.z, 1));
p2.v.push_back(idVec4( max.x, min.y, min.z, 1));
p2.v.push_back(idVec4( max.x, max.y, min.z, 1));
p2.v.push_back(idVec4( min.x, max.y, min.z, 1));
p2.recompute_planes();
return p2;
}
polyhedron make_sv(const polyhedron & oc, idVec4 light)
{
static polyhedron lut[64];
int index = 0;
for(unsigned int i = 0; i < 6; i++) {
if( ( oc.p[i].plane * light ) > 0 )
index |= 1<<i;
}
if( lut[index].e.size() == 0 )
{
polyhedron & ph = lut[index];
ph = oc;
int V = ph.v.size();
for( int j = 0; j < V; j++ )
{
idVec3 proj = homogeneous_difference( light, ph.v[j] );
ph.v.push_back( idVec4(proj.x, proj.y, proj.z, 0) );
}
ph.p.empty();
for(unsigned int i=0; i < oc.p.size(); i++)
{
if( (oc.p[i].plane * light) > 0)
{
ph.p.push_back(oc.p[i]);
}
}
if(ph.p.size() == 0)
return ph = polyhedron();
ph.compute_neighbors();
MyArrayPoly vpg;
int I = ph.p.size();
for(int i=0; i < I; i++)
{
MyArrayInt & vi = ph.p[i].vi;
MyArrayInt & ni = ph.p[i].ni;
int S = vi.size();
for(int j = 0; j < S; j++)
{
if( ni[j] == -1 )
{
poly pg;
int a = vi[(j+1)%S];
int b = vi[j];
pg.vi = four_ints( a, b, b+V, a+V);
pg.ni = four_ints(-1, -1, -1, -1);
vpg.push_back(pg);
}
}
}
for(unsigned int i = 0; i < vpg.size(); i++)
ph.p.push_back(vpg[i]);
ph.compute_neighbors();
ph.v.empty(); // no need to copy this data since it'll be replaced
}
polyhedron ph2 = lut[index];
// initalize vertices
ph2.v = oc.v;
int V = ph2.v.size();
for( int j = 0; j < V; j++ )
{
idVec3 proj = homogeneous_difference( light, ph2.v[j] );
ph2.v.push_back( idVec4(proj.x, proj.y, proj.z, 0) );
}
// need to compute planes for the shadow volume (sv)
ph2.recompute_planes();
return ph2;
}
typedef MyArray<idVec4, 36> MySegments;
//int MySegments::max_size = 0;
void polyhedron_edges(polyhedron & a, MySegments & e)
{
e.empty();
if(a.e.size() == 0 && a.p.size() != 0)
a.compute_neighbors();
for(unsigned int i = 0; i < a.e.size(); i++)
{
e.push_back(a.v[a.e[i].vi[0]]);
e.push_back(a.v[a.e[i].vi[1]]);
}
}
// clip the segments of e by the planes of polyhedron a.
void clip_segments(const polyhedron & ph, MySegments & is, MySegments & os)
{
const MyArrayPoly & p = ph.p;
for(unsigned int i = 0; i < is.size(); i+=2 )
{
idVec4 a = is[i ];
idVec4 b = is[i+1];
idVec4 c;
bool discard = false;
for(unsigned int j = 0; j < p.size(); j++ )
{
float da = a * p[j].plane;
float db = b * p[j].plane;
float rdw = 1/(da - db);
int code = 0;
if( da > 0 )
code = 2;
if( db > 0 )
code |= 1;
switch ( code )
{
case 3:
discard = true;
break;
case 2:
c = -db * rdw * a + da * rdw * b;
a = c;
break;
case 1:
c = -db * rdw * a + da * rdw * b;
b = c;
break;
case 0:
break;
default:
common->Printf("bad clip code!\n");
break;
}
if( discard )
break;
}
if( ! discard )
{
os.push_back(a);
os.push_back(b);
}
}
}
idMat4 make_idMat4(const float * m)
{
return idMat4( m[ 0], m[ 4], m[ 8], m[12],
m[ 1], m[ 5], m[ 9], m[13],
m[ 2], m[ 6], m[10], m[14],
m[ 3], m[ 7], m[11], m[15] );
}
idVec3 v4to3(const idVec4 & v)
{
return idVec3(v.x/v.w, v.y/v.w, v.z/v.w);
}
void draw_polyhedron( const viewDef_t *viewDef, const polyhedron & p, idVec4 color )
{
for(unsigned int i = 0; i < p.e.size(); i++)
{
viewDef->renderWorld->DebugLine( color, v4to3(p.v[p.e[i].vi[0]]), v4to3(p.v[p.e[i].vi[1]]));
}
}
void draw_segments( const viewDef_t *viewDef, const MySegments & s, idVec4 color )
{
for(unsigned int i = 0; i < s.size(); i+=2)
{
viewDef->renderWorld->DebugLine( color, v4to3(s[i]), v4to3(s[i+1]));
}
}
void world_to_hclip( const viewDef_t *viewDef, const idVec4 &global, idVec4 &clip ) {
int i;
idVec4 view;
for ( i = 0 ; i < 4 ; i ++ ) {
view[i] =
global[0] * viewDef->worldSpace.modelViewMatrix[ i + 0 * 4 ] +
global[1] * viewDef->worldSpace.modelViewMatrix[ i + 1 * 4 ] +
global[2] * viewDef->worldSpace.modelViewMatrix[ i + 2 * 4 ] +
global[3] * viewDef->worldSpace.modelViewMatrix[ i + 3 * 4 ];
}
for ( i = 0 ; i < 4 ; i ++ ) {
clip[i] =
view[0] * viewDef->projectionMatrix[ i + 0 * 4 ] +
view[1] * viewDef->projectionMatrix[ i + 1 * 4 ] +
view[2] * viewDef->projectionMatrix[ i + 2 * 4 ] +
view[3] * viewDef->projectionMatrix[ i + 3 * 4 ];
}
}
idScreenRect R_CalcIntersectionScissor( const idRenderLightLocal * lightDef,
const idRenderEntityLocal * entityDef,
const viewDef_t * viewDef ) {
idMat4 omodel = make_idMat4( entityDef->modelMatrix );
idMat4 lmodel = make_idMat4( lightDef->modelMatrix );
// compute light polyhedron
polyhedron lvol = PolyhedronFromBounds( lightDef->frustumTris->bounds );
// transform it into world space
//lvol.transform( lmodel );
// debug //
if ( r_useInteractionScissors.GetInteger() == -2 ) {
draw_polyhedron( viewDef, lvol, colorRed );
}
// compute object polyhedron
polyhedron vol = PolyhedronFromBounds( entityDef->referenceBounds );
//viewDef->renderWorld->DebugBounds( colorRed, lightDef->frustumTris->bounds );
//viewDef->renderWorld->DebugBox( colorBlue, idBox( model->Bounds(), entityDef->parms.origin, entityDef->parms.axis ) );
// transform it into world space
vol.transform( omodel );
// debug //
if ( r_useInteractionScissors.GetInteger() == -2 ) {
draw_polyhedron( viewDef, vol, colorBlue );
}
// transform light position into world space
idVec4 lightpos = idVec4(lightDef->globalLightOrigin.x,
lightDef->globalLightOrigin.y,
lightDef->globalLightOrigin.z,
1.0f );
// generate shadow volume "polyhedron"
polyhedron sv = make_sv(vol, lightpos);
MySegments in_segs, out_segs;
// get shadow volume edges
polyhedron_edges(sv, in_segs);
// clip them against light bounds planes
clip_segments(lvol, in_segs, out_segs);
// get light bounds edges
polyhedron_edges(lvol, in_segs);
// clip them by the shadow volume
clip_segments(sv, in_segs, out_segs);
// debug //
if ( r_useInteractionScissors.GetInteger() == -2 ) {
draw_segments( viewDef, out_segs, colorGreen );
}
idBounds outbounds;
outbounds.Clear();
for( unsigned int i = 0; i < out_segs.size(); i++ ) {
idVec4 v;
world_to_hclip( viewDef, out_segs[i], v );
if( v.w <= 0.0f ) {
return lightDef->viewLight->scissorRect;
}
idVec3 rv(v.x, v.y, v.z);
rv /= v.w;
outbounds.AddPoint( rv );
}
// limit the bounds to avoid an inside out scissor rectangle due to floating point to short conversion
if ( outbounds[0].x < -1.0f ) {
outbounds[0].x = -1.0f;
}
if ( outbounds[1].x > 1.0f ) {
outbounds[1].x = 1.0f;
}
if ( outbounds[0].y < -1.0f ) {
outbounds[0].y = -1.0f;
}
if ( outbounds[1].y > 1.0f ) {
outbounds[1].y = 1.0f;
}
float w2 = ( viewDef->viewport.x2 - viewDef->viewport.x1 + 1 ) / 2.0f;
float x = viewDef->viewport.x1;
float h2 = ( viewDef->viewport.y2 - viewDef->viewport.y1 + 1 ) / 2.0f;
float y = viewDef->viewport.y1;
idScreenRect rect;
rect.x1 = outbounds[0].x * w2 + w2 + x;
rect.x2 = outbounds[1].x * w2 + w2 + x;
rect.y1 = outbounds[0].y * h2 + h2 + y;
rect.y2 = outbounds[1].y * h2 + h2 + y;
rect.Expand();
rect.Intersect( lightDef->viewLight->scissorRect );
// debug //
if ( r_useInteractionScissors.GetInteger() == -2 && !rect.IsEmpty() ) {
viewDef->renderWorld->DebugScreenRect( colorYellow, rect, viewDef );
}
return rect;
}