ref: 761946b93cf45a3b9e47868a704fb165af760333
dir: /code/renderer/tr_shadows.c/
/*
===========================================================================
Copyright (C) 1999-2005 Id Software, Inc.
This file is part of Quake III Arena source code.
Quake III Arena 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 2 of the License,
or (at your option) any later version.
Quake III Arena 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 Foobar; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
===========================================================================
*/
#include "tr_local.h"
/*
for a projection shadow:
point[x] += light vector * ( z - shadow plane )
point[y] +=
point[z] = shadow plane
1 0 light[x] / light[z]
*/
typedef struct {
int i2;
int facing;
} edgeDef_t;
#define MAX_EDGE_DEFS 32
static edgeDef_t edgeDefs[SHADER_MAX_VERTEXES][MAX_EDGE_DEFS];
static int numEdgeDefs[SHADER_MAX_VERTEXES];
static int facing[SHADER_MAX_INDEXES/3];
void R_AddEdgeDef( int i1, int i2, int facing ) {
int c;
c = numEdgeDefs[ i1 ];
if ( c == MAX_EDGE_DEFS ) {
return; // overflow
}
edgeDefs[ i1 ][ c ].i2 = i2;
edgeDefs[ i1 ][ c ].facing = facing;
numEdgeDefs[ i1 ]++;
}
void R_RenderShadowEdges( void ) {
int i;
#if 0
int numTris;
// dumb way -- render every triangle's edges
numTris = tess.numIndexes / 3;
for ( i = 0 ; i < numTris ; i++ ) {
int i1, i2, i3;
if ( !facing[i] ) {
continue;
}
i1 = tess.indexes[ i*3 + 0 ];
i2 = tess.indexes[ i*3 + 1 ];
i3 = tess.indexes[ i*3 + 2 ];
qglBegin( GL_TRIANGLE_STRIP );
qglVertex3fv( tess.xyz[ i1 ] );
qglVertex3fv( tess.xyz[ i1 + tess.numVertexes ] );
qglVertex3fv( tess.xyz[ i2 ] );
qglVertex3fv( tess.xyz[ i2 + tess.numVertexes ] );
qglVertex3fv( tess.xyz[ i3 ] );
qglVertex3fv( tess.xyz[ i3 + tess.numVertexes ] );
qglVertex3fv( tess.xyz[ i1 ] );
qglVertex3fv( tess.xyz[ i1 + tess.numVertexes ] );
qglEnd();
}
#else
int c, c2;
int j, k;
int i2;
int c_edges, c_rejected;
int hit[2];
// an edge is NOT a silhouette edge if its face doesn't face the light,
// or if it has a reverse paired edge that also faces the light.
// A well behaved polyhedron would have exactly two faces for each edge,
// but lots of models have dangling edges or overfanned edges
c_edges = 0;
c_rejected = 0;
for ( i = 0 ; i < tess.numVertexes ; i++ ) {
c = numEdgeDefs[ i ];
for ( j = 0 ; j < c ; j++ ) {
if ( !edgeDefs[ i ][ j ].facing ) {
continue;
}
hit[0] = 0;
hit[1] = 0;
i2 = edgeDefs[ i ][ j ].i2;
c2 = numEdgeDefs[ i2 ];
for ( k = 0 ; k < c2 ; k++ ) {
if ( edgeDefs[ i2 ][ k ].i2 == i ) {
hit[ edgeDefs[ i2 ][ k ].facing ]++;
}
}
// if it doesn't share the edge with another front facing
// triangle, it is a sil edge
if ( hit[ 1 ] == 0 ) {
qglBegin( GL_TRIANGLE_STRIP );
qglVertex3fv( tess.xyz[ i ] );
qglVertex3fv( tess.xyz[ i + tess.numVertexes ] );
qglVertex3fv( tess.xyz[ i2 ] );
qglVertex3fv( tess.xyz[ i2 + tess.numVertexes ] );
qglEnd();
c_edges++;
} else {
c_rejected++;
}
}
}
#endif
}
/*
=================
RB_ShadowTessEnd
triangleFromEdge[ v1 ][ v2 ]
set triangle from edge( v1, v2, tri )
if ( facing[ triangleFromEdge[ v1 ][ v2 ] ] && !facing[ triangleFromEdge[ v2 ][ v1 ] ) {
}
=================
*/
void RB_ShadowTessEnd( void ) {
int i;
int numTris;
vec3_t lightDir;
// we can only do this if we have enough space in the vertex buffers
if ( tess.numVertexes >= SHADER_MAX_VERTEXES / 2 ) {
return;
}
if ( glConfig.stencilBits < 4 ) {
return;
}
VectorCopy( backEnd.currentEntity->lightDir, lightDir );
// project vertexes away from light direction
for ( i = 0 ; i < tess.numVertexes ; i++ ) {
VectorMA( tess.xyz[i], -512, lightDir, tess.xyz[i+tess.numVertexes] );
}
// decide which triangles face the light
Com_Memset( numEdgeDefs, 0, 4 * tess.numVertexes );
numTris = tess.numIndexes / 3;
for ( i = 0 ; i < numTris ; i++ ) {
int i1, i2, i3;
vec3_t d1, d2, normal;
float *v1, *v2, *v3;
float d;
i1 = tess.indexes[ i*3 + 0 ];
i2 = tess.indexes[ i*3 + 1 ];
i3 = tess.indexes[ i*3 + 2 ];
v1 = tess.xyz[ i1 ];
v2 = tess.xyz[ i2 ];
v3 = tess.xyz[ i3 ];
VectorSubtract( v2, v1, d1 );
VectorSubtract( v3, v1, d2 );
CrossProduct( d1, d2, normal );
d = DotProduct( normal, lightDir );
if ( d > 0 ) {
facing[ i ] = 1;
} else {
facing[ i ] = 0;
}
// create the edges
R_AddEdgeDef( i1, i2, facing[ i ] );
R_AddEdgeDef( i2, i3, facing[ i ] );
R_AddEdgeDef( i3, i1, facing[ i ] );
}
// draw the silhouette edges
GL_Bind( tr.whiteImage );
qglEnable( GL_CULL_FACE );
GL_State( GLS_SRCBLEND_ONE | GLS_DSTBLEND_ZERO );
qglColor3f( 0.2f, 0.2f, 0.2f );
// don't write to the color buffer
qglColorMask( GL_FALSE, GL_FALSE, GL_FALSE, GL_FALSE );
qglEnable( GL_STENCIL_TEST );
qglStencilFunc( GL_ALWAYS, 1, 255 );
// mirrors have the culling order reversed
if ( backEnd.viewParms.isMirror ) {
qglCullFace( GL_FRONT );
qglStencilOp( GL_KEEP, GL_KEEP, GL_INCR );
R_RenderShadowEdges();
qglCullFace( GL_BACK );
qglStencilOp( GL_KEEP, GL_KEEP, GL_DECR );
R_RenderShadowEdges();
} else {
qglCullFace( GL_BACK );
qglStencilOp( GL_KEEP, GL_KEEP, GL_INCR );
R_RenderShadowEdges();
qglCullFace( GL_FRONT );
qglStencilOp( GL_KEEP, GL_KEEP, GL_DECR );
R_RenderShadowEdges();
}
// reenable writing to the color buffer
qglColorMask( GL_TRUE, GL_TRUE, GL_TRUE, GL_TRUE );
}
/*
=================
RB_ShadowFinish
Darken everything that is is a shadow volume.
We have to delay this until everything has been shadowed,
because otherwise shadows from different body parts would
overlap and double darken.
=================
*/
void RB_ShadowFinish( void ) {
if ( r_shadows->integer != 2 ) {
return;
}
if ( glConfig.stencilBits < 4 ) {
return;
}
qglEnable( GL_STENCIL_TEST );
qglStencilFunc( GL_NOTEQUAL, 0, 255 );
qglDisable (GL_CLIP_PLANE0);
qglDisable (GL_CULL_FACE);
GL_Bind( tr.whiteImage );
qglLoadIdentity ();
qglColor3f( 0.6f, 0.6f, 0.6f );
GL_State( GLS_DEPTHMASK_TRUE | GLS_SRCBLEND_DST_COLOR | GLS_DSTBLEND_ZERO );
// qglColor3f( 1, 0, 0 );
// GL_State( GLS_DEPTHMASK_TRUE | GLS_SRCBLEND_ONE | GLS_DSTBLEND_ZERO );
qglBegin( GL_QUADS );
qglVertex3f( -100, 100, -10 );
qglVertex3f( 100, 100, -10 );
qglVertex3f( 100, -100, -10 );
qglVertex3f( -100, -100, -10 );
qglEnd ();
qglColor4f(1,1,1,1);
qglDisable( GL_STENCIL_TEST );
}
/*
=================
RB_ProjectionShadowDeform
=================
*/
void RB_ProjectionShadowDeform( void ) {
float *xyz;
int i;
float h;
vec3_t ground;
vec3_t light;
float groundDist;
float d;
vec3_t lightDir;
xyz = ( float * ) tess.xyz;
ground[0] = backEnd.or.axis[0][2];
ground[1] = backEnd.or.axis[1][2];
ground[2] = backEnd.or.axis[2][2];
groundDist = backEnd.or.origin[2] - backEnd.currentEntity->e.shadowPlane;
VectorCopy( backEnd.currentEntity->lightDir, lightDir );
d = DotProduct( lightDir, ground );
// don't let the shadows get too long or go negative
if ( d < 0.5 ) {
VectorMA( lightDir, (0.5 - d), ground, lightDir );
d = DotProduct( lightDir, ground );
}
d = 1.0 / d;
light[0] = lightDir[0] * d;
light[1] = lightDir[1] * d;
light[2] = lightDir[2] * d;
for ( i = 0; i < tess.numVertexes; i++, xyz += 4 ) {
h = DotProduct( xyz, ground ) + groundDist;
xyz[0] -= light[0] * h;
xyz[1] -= light[1] * h;
xyz[2] -= light[2] * h;
}
}