Xash3D FWGS engine.
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/*
gl_frustum.cpp - frustum test implementation
Copyright (C) 2016 Uncle Mike
This program 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.
This program 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.
*/
#include "gl_local.h"
#include "xash3d_mathlib.h"
void GL_FrustumSetPlane( gl_frustum_t *out, int side, const vec3_t vecNormal, float flDist )
{
Assert( side >= 0 && side < FRUSTUM_PLANES );
out->planes[side].type = PlaneTypeForNormal( vecNormal );
out->planes[side].signbits = SignbitsForPlane( vecNormal );
VectorCopy( vecNormal, out->planes[side].normal );
out->planes[side].dist = flDist;
SetBits( out->clipFlags, BIT( side ));
}
void GL_FrustumInitProj( gl_frustum_t *out, float flZNear, float flZFar, float flFovX, float flFovY )
{
float xs, xc;
vec3_t farpoint, nearpoint;
vec3_t normal, iforward;
// horizontal fov used for left and right planes
SinCos( DEG2RAD( flFovX ) * 0.5f, &xs, &xc );
// setup left plane
VectorMAM( xs, RI.cull_vforward, -xc, RI.cull_vright, normal );
GL_FrustumSetPlane( out, FRUSTUM_LEFT, normal, DotProduct( RI.cullorigin, normal ));
// setup right plane
VectorMAM( xs, RI.cull_vforward, xc, RI.cull_vright, normal );
GL_FrustumSetPlane( out, FRUSTUM_RIGHT, normal, DotProduct( RI.cullorigin, normal ));
// vertical fov used for top and bottom planes
SinCos( DEG2RAD( flFovY ) * 0.5f, &xs, &xc );
VectorNegate( RI.cull_vforward, iforward );
// setup bottom plane
VectorMAM( xs, RI.cull_vforward, -xc, RI.cull_vup, normal );
GL_FrustumSetPlane( out, FRUSTUM_BOTTOM, normal, DotProduct( RI.cullorigin, normal ));
// setup top plane
VectorMAM( xs, RI.cull_vforward, xc, RI.cull_vup, normal );
GL_FrustumSetPlane( out, FRUSTUM_TOP, normal, DotProduct( RI.cullorigin, normal ));
// setup far plane
VectorMA( RI.cullorigin, flZFar, RI.cull_vforward, farpoint );
GL_FrustumSetPlane( out, FRUSTUM_FAR, iforward, DotProduct( iforward, farpoint ));
// no need to setup backplane for general view.
if( flZNear == 0.0f ) return;
// setup near plane
VectorMA( RI.cullorigin, flZNear, RI.cull_vforward, nearpoint );
GL_FrustumSetPlane( out, FRUSTUM_NEAR, RI.cull_vforward, DotProduct( RI.cull_vforward, nearpoint ));
}
void GL_FrustumInitOrtho( gl_frustum_t *out, float xLeft, float xRight, float yTop, float yBottom, float flZNear, float flZFar )
{
vec3_t iforward, iright, iup;
// setup the near and far planes
float orgOffset = DotProduct( RI.cullorigin, RI.cull_vforward );
VectorNegate( RI.cull_vforward, iforward );
// because quake ortho is inverted and far and near should be swaped
GL_FrustumSetPlane( out, FRUSTUM_FAR, iforward, -flZNear - orgOffset );
GL_FrustumSetPlane( out, FRUSTUM_NEAR, RI.cull_vforward, flZFar + orgOffset );
// setup left and right planes
orgOffset = DotProduct( RI.cullorigin, RI.cull_vright );
VectorNegate( RI.cull_vright, iright );
GL_FrustumSetPlane( out, FRUSTUM_LEFT, RI.cull_vright, xLeft + orgOffset );
GL_FrustumSetPlane( out, FRUSTUM_RIGHT, iright, -xRight - orgOffset );
// setup top and buttom planes
orgOffset = DotProduct( RI.cullorigin, RI.cull_vup );
VectorNegate( RI.cull_vup, iup );
GL_FrustumSetPlane( out, FRUSTUM_TOP, RI.cull_vup, yTop + orgOffset );
GL_FrustumSetPlane( out, FRUSTUM_BOTTOM, iup, -yBottom - orgOffset );
}
// cull methods
qboolean GL_FrustumCullBox( gl_frustum_t *out, const vec3_t mins, const vec3_t maxs, int userClipFlags )
{
int iClipFlags;
int i, bit;
if( r_nocull->value )
return false;
if( userClipFlags != 0 )
iClipFlags = userClipFlags;
else iClipFlags = out->clipFlags;
for( i = FRUSTUM_PLANES, bit = 1; i > 0; i--, bit <<= 1 )
{
const mplane_t *p = &out->planes[FRUSTUM_PLANES - i];
if( !FBitSet( iClipFlags, bit ))
continue;
switch( p->signbits )
{
case 0:
if( p->normal[0] * maxs[0] + p->normal[1] * maxs[1] + p->normal[2] * maxs[2] < p->dist )
return true;
break;
case 1:
if( p->normal[0] * mins[0] + p->normal[1] * maxs[1] + p->normal[2] * maxs[2] < p->dist )
return true;
break;
case 2:
if( p->normal[0] * maxs[0] + p->normal[1] * mins[1] + p->normal[2] * maxs[2] < p->dist )
return true;
break;
case 3:
if( p->normal[0] * mins[0] + p->normal[1] * mins[1] + p->normal[2] * maxs[2] < p->dist )
return true;
break;
case 4:
if( p->normal[0] * maxs[0] + p->normal[1] * maxs[1] + p->normal[2] * mins[2] < p->dist )
return true;
break;
case 5:
if( p->normal[0] * mins[0] + p->normal[1] * maxs[1] + p->normal[2] * mins[2] < p->dist )
return true;
break;
case 6:
if( p->normal[0] * maxs[0] + p->normal[1] * mins[1] + p->normal[2] * mins[2] < p->dist )
return true;
break;
case 7:
if( p->normal[0] * mins[0] + p->normal[1] * mins[1] + p->normal[2] * mins[2] < p->dist )
return true;
break;
default:
return false;
}
}
return false;
}
qboolean GL_FrustumCullSphere( gl_frustum_t *out, const vec3_t center, float radius, int userClipFlags )
{
int iClipFlags;
int i, bit;
if( r_nocull->value )
return false;
if( userClipFlags != 0 )
iClipFlags = userClipFlags;
else iClipFlags = out->clipFlags;
for( i = FRUSTUM_PLANES, bit = 1; i > 0; i--, bit <<= 1 )
{
const mplane_t *p = &out->planes[FRUSTUM_PLANES - i];
if( !FBitSet( iClipFlags, bit ))
continue;
if( DotProduct( center, p->normal ) - p->dist <= -radius )
return true;
}
return false;
}