tr_main.c

3D 游戏界的大牛人 John Carmack 终于放出了 Q3 的源代码

Setup that culling frustum planes for the current view
=================
*/
void R_SetupFrustum (void) {
	int		i;
	float	xs, xc;
	float	ang;

	ang = tr.viewParms.fovX / 180 * M_PI * 0.5f;
	xs = sin( ang );
	xc = cos( ang );

	VectorScale( tr.viewParms.or.axis[0], xs, tr.viewParms.frustum[0].normal );
	VectorMA( tr.viewParms.frustum[0].normal, xc, tr.viewParms.or.axis[1], tr.viewParms.frustum[0].normal );

	VectorScale( tr.viewParms.or.axis[0], xs, tr.viewParms.frustum[1].normal );
	VectorMA( tr.viewParms.frustum[1].normal, -xc, tr.viewParms.or.axis[1], tr.viewParms.frustum[1].normal );

	ang = tr.viewParms.fovY / 180 * M_PI * 0.5f;
	xs = sin( ang );
	xc = cos( ang );

	VectorScale( tr.viewParms.or.axis[0], xs, tr.viewParms.frustum[2].normal );
	VectorMA( tr.viewParms.frustum[2].normal, xc, tr.viewParms.or.axis[2], tr.viewParms.frustum[2].normal );

	VectorScale( tr.viewParms.or.axis[0], xs, tr.viewParms.frustum[3].normal );
	VectorMA( tr.viewParms.frustum[3].normal, -xc, tr.viewParms.or.axis[2], tr.viewParms.frustum[3].normal );

	for (i=0 ; i<4 ; i++) {
		tr.viewParms.frustum[i].type = PLANE_NON_AXIAL;
		tr.viewParms.frustum[i].dist = DotProduct (tr.viewParms.or.origin, tr.viewParms.frustum[i].normal);
		SetPlaneSignbits( &tr.viewParms.frustum[i] );
	}
}


/*
=================
R_MirrorPoint
=================
*/
void R_MirrorPoint (vec3_t in, orientation_t *surface, orientation_t *camera, vec3_t out) {
	int		i;
	vec3_t	local;
	vec3_t	transformed;
	float	d;

	VectorSubtract( in, surface->origin, local );

	VectorClear( transformed );
	for ( i = 0 ; i < 3 ; i++ ) {
		d = DotProduct(local, surface->axis[i]);
		VectorMA( transformed, d, camera->axis[i], transformed );
	}

	VectorAdd( transformed, camera->origin, out );
}

void R_MirrorVector (vec3_t in, orientation_t *surface, orientation_t *camera, vec3_t out) {
	int		i;
	float	d;

	VectorClear( out );
	for ( i = 0 ; i < 3 ; i++ ) {
		d = DotProduct(in, surface->axis[i]);
		VectorMA( out, d, camera->axis[i], out );
	}
}


/*
=============
R_PlaneForSurface
=============
*/
void R_PlaneForSurface (surfaceType_t *surfType, cplane_t *plane) {
	srfTriangles_t	*tri;
	srfPoly_t		*poly;
	drawVert_t		*v1, *v2, *v3;
	vec4_t			plane4;

	if (!surfType) {
		Com_Memset (plane, 0, sizeof(*plane));
		plane->normal[0] = 1;
		return;
	}
	switch (*surfType) {
	case SF_FACE:
		*plane = ((srfSurfaceFace_t *)surfType)->plane;
		return;
	case SF_TRIANGLES:
		tri = (srfTriangles_t *)surfType;
		v1 = tri->verts + tri->indexes[0];
		v2 = tri->verts + tri->indexes[1];
		v3 = tri->verts + tri->indexes[2];
		PlaneFromPoints( plane4, v1->xyz, v2->xyz, v3->xyz );
		VectorCopy( plane4, plane->normal ); 
		plane->dist = plane4[3];
		return;
	case SF_POLY:
		poly = (srfPoly_t *)surfType;
		PlaneFromPoints( plane4, poly->verts[0].xyz, poly->verts[1].xyz, poly->verts[2].xyz );
		VectorCopy( plane4, plane->normal ); 
		plane->dist = plane4[3];
		return;
	default:
		Com_Memset (plane, 0, sizeof(*plane));
		plane->normal[0] = 1;		
		return;
	}
}

/*
=================
R_GetPortalOrientation

entityNum is the entity that the portal surface is a part of, which may
be moving and rotating.

Returns qtrue if it should be mirrored
=================
*/
qboolean R_GetPortalOrientations( drawSurf_t *drawSurf, int entityNum, 
							 orientation_t *surface, orientation_t *camera,
							 vec3_t pvsOrigin, qboolean *mirror ) {
	int			i;
	cplane_t	originalPlane, plane;
	trRefEntity_t	*e;
	float		d;
	vec3_t		transformed;

	// create plane axis for the portal we are seeing
	R_PlaneForSurface( drawSurf->surface, &originalPlane );

	// rotate the plane if necessary
	if ( entityNum != ENTITYNUM_WORLD ) {
		tr.currentEntityNum = entityNum;
		tr.currentEntity = &tr.refdef.entities[entityNum];

		// get the orientation of the entity
		R_RotateForEntity( tr.currentEntity, &tr.viewParms, &tr.or );

		// rotate the plane, but keep the non-rotated version for matching
		// against the portalSurface entities
		R_LocalNormalToWorld( originalPlane.normal, plane.normal );
		plane.dist = originalPlane.dist + DotProduct( plane.normal, tr.or.origin );

		// translate the original plane
		originalPlane.dist = originalPlane.dist + DotProduct( originalPlane.normal, tr.or.origin );
	} else {
		plane = originalPlane;
	}

	VectorCopy( plane.normal, surface->axis[0] );
	PerpendicularVector( surface->axis[1], surface->axis[0] );
	CrossProduct( surface->axis[0], surface->axis[1], surface->axis[2] );

	// locate the portal entity closest to this plane.
	// origin will be the origin of the portal, origin2 will be
	// the origin of the camera
	for ( i = 0 ; i < tr.refdef.num_entities ; i++ ) {
		e = &tr.refdef.entities[i];
		if ( e->e.reType != RT_PORTALSURFACE ) {
			continue;
		}

		d = DotProduct( e->e.origin, originalPlane.normal ) - originalPlane.dist;
		if ( d > 64 || d < -64) {
			continue;
		}

		// get the pvsOrigin from the entity
		VectorCopy( e->e.oldorigin, pvsOrigin );

		// if the entity is just a mirror, don't use as a camera point
		if ( e->e.oldorigin[0] == e->e.origin[0] && 
			e->e.oldorigin[1] == e->e.origin[1] && 
			e->e.oldorigin[2] == e->e.origin[2] ) {
			VectorScale( plane.normal, plane.dist, surface->origin );
			VectorCopy( surface->origin, camera->origin );
			VectorSubtract( vec3_origin, surface->axis[0], camera->axis[0] );
			VectorCopy( surface->axis[1], camera->axis[1] );
			VectorCopy( surface->axis[2], camera->axis[2] );

			*mirror = qtrue;
			return qtrue;
		}

		// project the origin onto the surface plane to get
		// an origin point we can rotate around
		d = DotProduct( e->e.origin, plane.normal ) - plane.dist;
		VectorMA( e->e.origin, -d, surface->axis[0], surface->origin );
			
		// now get the camera origin and orientation
		VectorCopy( e->e.oldorigin, camera->origin );
		AxisCopy( e->e.axis, camera->axis );
		VectorSubtract( vec3_origin, camera->axis[0], camera->axis[0] );
		VectorSubtract( vec3_origin, camera->axis[1], camera->axis[1] );

		// optionally rotate
		if ( e->e.oldframe ) {
			// if a speed is specified
			if ( e->e.frame ) {
				// continuous rotate
				d = (tr.refdef.time/1000.0f) * e->e.frame;
				VectorCopy( camera->axis[1], transformed );
				RotatePointAroundVector( camera->axis[1], camera->axis[0], transformed, d );
				CrossProduct( camera->axis[0], camera->axis[1], camera->axis[2] );
			} else {
				// bobbing rotate, with skinNum being the rotation offset
				d = sin( tr.refdef.time * 0.003f );
				d = e->e.skinNum + d * 4;
				VectorCopy( camera->axis[1], transformed );
				RotatePointAroundVector( camera->axis[1], camera->axis[0], transformed, d );
				CrossProduct( camera->axis[0], camera->axis[1], camera->axis[2] );
			}
		}
		else if ( e->e.skinNum ) {
			d = e->e.skinNum;
			VectorCopy( camera->axis[1], transformed );
			RotatePointAroundVector( camera->axis[1], camera->axis[0], transformed, d );
			CrossProduct( camera->axis[0], camera->axis[1], camera->axis[2] );
		}
		*mirror = qfalse;
		return qtrue;
	}

	// if we didn't locate a portal entity, don't render anything.
	// We don't want to just treat it as a mirror, because without a
	// portal entity the server won't have communicated a proper entity set
	// in the snapshot

	// unfortunately, with local movement prediction it is easily possible
	// to see a surface before the server has communicated the matching
	// portal surface entity, so we don't want to print anything here...

	//ri.Printf( PRINT_ALL, "Portal surface without a portal entity\n" );

	return qfalse;
}

static qboolean IsMirror( const drawSurf_t *drawSurf, int entityNum )
{
	int			i;
	cplane_t	originalPlane, plane;
	trRefEntity_t	*e;
	float		d;

	// create plane axis for the portal we are seeing
	R_PlaneForSurface( drawSurf->surface, &originalPlane );

	// rotate the plane if necessary
	if ( entityNum != ENTITYNUM_WORLD ) 
	{
		tr.currentEntityNum = entityNum;
		tr.currentEntity = &tr.refdef.entities[entityNum];

		// get the orientation of the entity
		R_RotateForEntity( tr.currentEntity, &tr.viewParms, &tr.or );

		// rotate the plane, but keep the non-rotated version for matching
		// against the portalSurface entities
		R_LocalNormalToWorld( originalPlane.normal, plane.normal );
		plane.dist = originalPlane.dist + DotProduct( plane.normal, tr.or.origin );

		// translate the original plane
		originalPlane.dist = originalPlane.dist + DotProduct( originalPlane.normal, tr.or.origin );
	} 
	else 
	{
		plane = originalPlane;
	}

	// locate the portal entity closest to this plane.
	// origin will be the origin of the portal, origin2 will be
	// the origin of the camera
	for ( i = 0 ; i < tr.refdef.num_entities ; i++ ) 
	{
		e = &tr.refdef.entities[i];
		if ( e->e.reType != RT_PORTALSURFACE ) {
			continue;
		}

		d = DotProduct( e->e.origin, originalPlane.normal ) - originalPlane.dist;
		if ( d > 64 || d < -64) {
			continue;
		}

		// if the entity is just a mirror, don't use as a camera point
		if ( e->e.oldorigin[0] == e->e.origin[0] && 
			e->e.oldorigin[1] == e->e.origin[1] && 
			e->e.oldorigin[2] == e->e.origin[2] ) 
		{
			return qtrue;
		}

		return qfalse;
	}
	return qfalse;
}

/*
** SurfIsOffscreen
**
** Determines if a surface is completely offscreen.
*/
static qboolean SurfIsOffscreen( const drawSurf_t *drawSurf, vec4_t clipDest[128] ) {
	float shortest = 100000000;
	int entityNum;
	int numTriangles;
	shader_t *shader;
	int		fogNum;
	int dlighted;
	vec4_t clip, eye;
	int i;
	unsigned int pointOr = 0;
	unsigned int pointAnd = (unsigned int)~0;

	if ( glConfig.smpActive ) {		// FIXME!  we can't do RB_BeginSurface/RB_EndSurface stuff with smp!
		return qfalse;
	}

	R_RotateForViewer();

	R_DecomposeSort( drawSurf->sort, &entityNum, &shader, &fogNum, &dlighted );
	RB_BeginSurface( shader, fogNum );
	rb_surfaceTable[ *drawSurf->surface ]( drawSurf->surface );

	assert( tess.numVertexes < 128 );

	for ( i = 0; i < tess.numVertexes; i++ )
	{
		int j;
		unsigned int pointFlags = 0;

		R_TransformModelToClip( tess.xyz[i], tr.or.modelMatrix, tr.viewParms.projectionMatrix, eye, clip );

		for ( j = 0; j < 3; j++ )
		{
			if ( clip[j] >= clip[3] )
			{
				pointFlags |= (1 << (j*2));
			}
			else if ( clip[j] <= -clip[3] )
			{
				pointFlags |= ( 1 << (j*2+1));
			}
		}
		pointAnd &= pointFlags;
		pointOr |= pointFlags;
	}

	// trivially reject
	if ( pointAnd )
	{
		return qtrue;
	}

	// determine if this surface is backfaced and also determine the distance
	// to the nearest vertex so we can cull based on portal range.  Culling
	// based on vertex distance isn't 100% correct (we should be checking for
	// range to the surface), but it's good enough for the types of portals
	// we have in the game right now.
	numTriangles = tess.numIndexes / 3;

	for ( i = 0; i < tess.numIndexes; i += 3 )
	{
		vec3_t normal;
		float dot;
		float len;

		VectorSubtract( tess.xyz[tess.indexes[i]], tr.viewParms.or.origin, normal );

		len = VectorLengthSquared( normal );			// lose the sqrt
		if ( len < shortest )
		{
			shortest = len;
		}

		if ( ( dot = DotProduct( normal, tess.normal[tess.indexes[i]] ) ) >= 0 )
		{
			numTriangles--;
		}
	}
	if ( !numTriangles )
	{
		return qtrue;
	}

	// mirrors can early out at this point, since we don't do a fade over distance
	// with them (although we could)
	if ( IsMirror( drawSurf, entityNum ) )
	{
		return qfalse;
	}

	if ( shortest > (tess.shader->portalRange*tess.shader->portalRange) )
	{
		return qtrue;
	}

	return qfalse;
}

/*
========================
R_MirrorViewBySurface

Returns qtrue if another view has been rendered
========================
*/
qboolean R_MirrorViewBySurface (drawSurf_t *drawSurf, int entityNum) {
	vec4_t			clipDest[128];
	viewParms_t		newParms;
	viewParms_t		oldParms;
	orientation_t	surface, camera;

	// don't recursively mirror
	if (tr.viewParms.isPortal) {
		ri.Printf( PRINT_DEVELOPER, "WARNING: recursive mirror/portal found\n" );
		return qfalse;
	}

	if ( r_noportals->integer || (r_fastsky->integer == 1) ) {
		return qfalse;
	}

	// trivially reject portal/mirror
	if ( SurfIsOffscreen( drawSurf, clipDest ) ) {
		return qfalse;
	}

	// save old viewParms so we can return to it after the mirror view
	oldParms = tr.viewParms;

	newParms = tr.viewParms;
	newParms.isPortal = qtrue;
	if ( !R_GetPortalOrientations( drawSurf, entityNum, &surface, &camera, 
		newParms.pvsOrigin, &newParms.isMirror ) ) {
		return qfalse;		// bad portal, no portalentity
	}

	R_MirrorPoint (oldParms.or.origin, &surface, &camera, newParms.or.origin );

	VectorSubtract( vec3_origin, camera.axis[0], newParms.portalPlane.normal );
	newParms.portalPlane.dist = DotProduct( camera.origin, newParms.portalPlane.normal );
	
	R_MirrorVector (oldParms.or.axis[0], &surface, &camera, newParms.or.axis[0]);
	R_MirrorVector (oldParms.or.axis[1], &surface, &camera, newParms.or.axis[1]);
	R_MirrorVector (oldParms.or.axis[2], &surface, &camera, newParms.or.axis[2]);

	// OPTIMIZE: restrict the viewport on the mirrored view

	// render the mirror view
	R_RenderView (&newParms);

	tr.viewParms = oldParms;

	return qtrue;
}

/*
=================
R_SpriteFogNum

See if a sprite is inside a fog volume
=================
*/
int R_SpriteFogNum( trRefEntity_t *ent ) {
	int				i, j;
	fog_t			*fog;

	if ( tr.refdef.rdflags & RDF_NOWORLDMODEL ) {
		return 0;
	}

	for ( i = 1 ; i < tr.world->numfogs ; i++ ) {
		fog = &tr.world->fogs[i];
		for ( j = 0 ; j < 3 ; j++ ) {
			if ( ent->e.origin[j] - ent->e.radius >= fog->bounds[1][j] ) {
				break;
			}
			if ( ent->e.origin[j] + ent->e.radius <= fog->bounds[0][j] ) {
				break;
			}
		}
		if ( j == 3 ) {
			return i;
		}
	}

	return 0;
}

/*