/* -------------------------------------------------------------------------------

Copyright (C) 1999-2006 Id Software, Inc. and contributors.
For a list of contributors, see the accompanying CONTRIBUTORS file.

This file is part of GtkRadiant.

GtkRadiant 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.

GtkRadiant 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 GtkRadiant; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

----------------------------------------------------------------------------------

This code has been altered significantly from its original form, to support
several games based on the Quake III Arena engine, in the form of "Q3Map2."

------------------------------------------------------------------------------- */



/* marker */
#define PATCH_C



/* dependencies */
#include "q3map2.h"



/*
ExpandLongestCurve() - ydnar
finds length of quadratic curve specified and determines if length is longer than the supplied max
*/

#define APPROX_SUBDIVISION	8

static void ExpandLongestCurve( float *longestCurve, vec3_t a, vec3_t b, vec3_t c )
{
	int		i;
	float	t, len;
	vec3_t	ab, bc, ac, pt, last, delta;
	
	
	/* calc vectors */
	VectorSubtract( b, a, ab );
	if( VectorNormalize( ab, ab ) < 0.125f )
		return;
	VectorSubtract( c, b, bc );
	if( VectorNormalize( bc, bc ) < 0.125f )
		return;
	VectorSubtract( c, a, ac );
	if( VectorNormalize( ac, ac ) < 0.125f )
		return;
	
	/* if all 3 vectors are the same direction, then this edge is linear, so we ignore it */
	if( DotProduct( ab, bc ) > 0.99f && DotProduct( ab, ac ) > 0.99f )
		return;
	
	/* recalculate vectors */
	VectorSubtract( b, a, ab );
	VectorSubtract( c, b, bc );
	
	/* determine length */
	VectorCopy( a, last );
	for( i = 0, len = 0.0f, t = 0.0f; i < APPROX_SUBDIVISION; i++, t += (1.0f / APPROX_SUBDIVISION) )
	{
		/* calculate delta */
		delta[ 0 ] = ((1.0f - t) * ab[ 0 ]) + (t * bc[ 0 ]);
		delta[ 1 ] = ((1.0f - t) * ab[ 1 ]) + (t * bc[ 1 ]);
		delta[ 2 ] = ((1.0f - t) * ab[ 2 ]) + (t * bc[ 2 ]);
		
		/* add to first point and calculate pt-pt delta */
		VectorAdd( a, delta, pt );
		VectorSubtract( pt, last, delta );
		
		/* add it to length and store last point */
		len += VectorLength( delta );
		VectorCopy( pt, last );
	}
	
	/* longer? */
	if( len > *longestCurve )
		*longestCurve = len;
}



/*
ExpandMaxIterations() - ydnar
determines how many iterations a quadratic curve needs to be subdivided with to fit the specified error
*/

static void ExpandMaxIterations( int *maxIterations, int maxError, vec3_t a, vec3_t b, vec3_t c )
{
	int				i, j;
	vec3_t			prev, next, mid, delta, delta2;
	float			len, len2;
	int				numPoints, iterations;
	vec3_t			points[ MAX_EXPANDED_AXIS ];
	
	
	/* initial setup */
	numPoints = 3;
	VectorCopy( a, points[ 0 ] );
	VectorCopy( b, points[ 1 ] );
	VectorCopy( c, points[ 2 ] );

	/* subdivide */
	for( i = 0; i + 2 < numPoints; i += 2 )
	{
		/* check subdivision limit */
		if( numPoints + 2 >= MAX_EXPANDED_AXIS )
			break;
		
		/* calculate new curve deltas */
		for( j = 0; j < 3; j++ )
		{
			prev[ j ] = points[ i + 1 ][ j ] - points[ i ][ j ]; 
			next[ j ] = points[ i + 2 ][ j ] - points[ i + 1 ][ j ]; 
			mid[ j ] = (points[ i ][ j ] + points[ i + 1 ][ j ] * 2.0f + points[ i + 2 ][ j ]) * 0.25f;
		}
		
		/* see if this midpoint is off far enough to subdivide */
		VectorSubtract( points[ i + 1 ], mid, delta );
		len = VectorLength( delta );
		if( len < maxError )
			continue;
		
		/* subdivide */
		numPoints += 2;
		
		/* create new points */
		for( j = 0; j < 3; j++ )
		{
			prev[ j ] = 0.5f * (points[ i ][ j ] + points[ i + 1 ][ j ]);
			next[ j ] = 0.5f * (points[ i + 1 ][ j ] + points[ i + 2 ][ j ]);
			mid[ j ] = 0.5f * (prev[ j ] + next[ j ]);
		}
		
		/* push points out */
		for( j = numPoints - 1; j > i + 3; j-- )
			VectorCopy( points[ j - 2 ], points[ j ] );
		
		/* insert new points */
		VectorCopy( prev, points[ i + 1 ] );
		VectorCopy( mid, points[ i + 2 ] );
		VectorCopy( next, points[ i + 3 ] );

		/* back up and recheck this set again, it may need more subdivision */
		i -= 2;
	}
	
	/* put the line on the curve */
	for( i = 1; i < numPoints; i += 2 )
	{
		for( j = 0; j < 3; j++ )
		{
			prev[ j ] = 0.5f * (points[ i ][ j ] + points[ i + 1 ][ j ] );
			next[ j ] = 0.5f * (points[ i ][ j ] + points[ i - 1 ][ j ] );
			points[ i ][ j ] = 0.5f * (prev[ j ] + next[ j ]);
		}
	}
	
	/* eliminate linear sections */
	for( i = 0; i + 2 < numPoints; i++ )
	{
		/* create vectors */
		VectorSubtract( points[ i + 1 ], points[ i ], delta );
		len = VectorNormalize( delta, delta );
		VectorSubtract( points[ i + 2 ], points[ i + 1 ], delta2 );
		len2 = VectorNormalize( delta2, delta2 );
		
		/* if either edge is degenerate, then eliminate it */
		if( len < 0.0625f || len2 < 0.0625f || DotProduct( delta, delta2 ) >= 1.0f )
		{
			for( j = i + 1; j + 1 < numPoints; j++ )
				VectorCopy( points[ j + 1 ], points[ j ] );
			numPoints--;
			continue;
		}
	}
	
	/* the number of iterations is 2^(points - 1) - 1 */
	numPoints >>= 1;
	iterations = 0;
	while( numPoints > 1 )
	{
		numPoints >>= 1;
		iterations++;
	}
	
	/* more? */
	if( iterations > *maxIterations )
		*maxIterations = iterations;
}



/*
ParsePatch()
creates a mapDrawSurface_t from the patch text
*/

void ParsePatch( qboolean onlyLights )
{
	vec_t			info[ 5 ];
	int				i, j, k;
	parseMesh_t		*pm;
	char			texture[ MAX_QPATH ];
	char			shader[ MAX_QPATH ];
	mesh_t			m;
	bspDrawVert_t	*verts;
	epair_t			*ep;
	vec4_t			delta, delta2, delta3;
	qboolean		degenerate;
	float			longestCurve;
	int				maxIterations;
	
	
	MatchToken( "{" );
	
	/* get texture */
	GetToken( qtrue );
	strcpy( texture, token );
	
	Parse1DMatrix( 5, info );
	m.width = info[0];
	m.height = info[1];
	m.verts = verts = safe_malloc( m.width * m.height * sizeof( m.verts[0] ) );
	
	if( m.width < 0 || m.width > MAX_PATCH_SIZE || m.height < 0 || m.height > MAX_PATCH_SIZE )
		Error( "ParsePatch: bad size" );
	
	MatchToken( "(" );
	for( j = 0; j < m.width ; j++ )
	{
		MatchToken( "(" );
		for( i = 0; i < m.height ; i++ )
		{
			Parse1DMatrix( 5, verts[ i * m.width + j ].xyz );
			
			/* ydnar: fix colors */
			for( k = 0; k < MAX_LIGHTMAPS; k++ )
			{
				verts[ i * m.width + j ].color[ k ][ 0 ] = 255;
				verts[ i * m.width + j ].color[ k ][ 1 ] = 255;
				verts[ i * m.width + j ].color[ k ][ 2 ] = 255;
				verts[ i * m.width + j ].color[ k ][ 3 ] = 255;
			}
		}
		MatchToken( ")" );
	}
	MatchToken( ")" );

	// if brush primitives format, we may have some epairs to ignore here
	GetToken(qtrue);
	if (g_bBrushPrimit!=BPRIMIT_OLDBRUSHES && strcmp(token,"}"))
	{
		// NOTE: we leak that!
		ep = ParseEPair();
	}
	else
		UnGetToken();

	MatchToken( "}" );
	MatchToken( "}" );
	
	/* short circuit */
	if( noCurveBrushes || onlyLights )
		return;
	
	
	/* ydnar: delete and warn about degenerate patches */
	j = (m.width * m.height);
	VectorClear( delta );
	delta[ 3 ] = 0;
	degenerate = qtrue;
	
	/* find first valid vector */
	for( i = 1; i < j && delta[ 3 ] == 0; i++ )
	{
		VectorSubtract( m.verts[ 0 ].xyz, m.verts[ i ].xyz, delta );
		delta[ 3 ] = VectorNormalize( delta, delta );
	}
	
	/* secondary degenerate test */
	if( delta[ 3 ] == 0 )
		degenerate = qtrue;
	else
	{
		/* if all vectors match this or are zero, then this is a degenerate patch */
		for( i = 1; i < j && degenerate == qtrue; i++ )
		{
			VectorSubtract( m.verts[ 0 ].xyz, m.verts[ i ].xyz, delta2 );
			delta2[ 3 ] = VectorNormalize( delta2, delta2 );
			if( delta2[ 3 ] != 0 )
			{
				/* create inverse vector */
				VectorCopy( delta2, delta3 );
				delta3[ 3 ] = delta2[ 3 ];
				VectorInverse( delta3 );
				
				/* compare */
				if( VectorCompare( delta, delta2 ) == qfalse && VectorCompare( delta, delta3 ) == qfalse )
					degenerate = qfalse;
			}
		}
	}
	
	/* warn and select degenerate patch */
	if( degenerate )
	{
		xml_Select( "degenerate patch", mapEnt->mapEntityNum, entitySourceBrushes, qfalse );
		free( m.verts );
		return;
	}
	
	/* find longest curve on the mesh */
	longestCurve = 0.0f;
	maxIterations = 0;
	for( j = 0; j + 2 < m.width; j += 2 )
	{
		for( i = 0; i + 2 < m.height; i += 2 )
		{
			ExpandLongestCurve( &longestCurve, verts[ i * m.width + j ].xyz, verts[ i * m.width + (j + 1) ].xyz, verts[ i * m.width + (j + 2) ].xyz );		/* row */
			ExpandLongestCurve( &longestCurve, verts[ i * m.width + j ].xyz, verts[ (i + 1) * m.width + j ].xyz, verts[ (i + 2) * m.width + j ].xyz );		/* col */
			ExpandMaxIterations( &maxIterations, patchSubdivisions, verts[ i * m.width + j ].xyz, verts[ i * m.width + (j + 1) ].xyz, verts[ i * m.width + (j + 2) ].xyz );		/* row */
			ExpandMaxIterations( &maxIterations, patchSubdivisions, verts[ i * m.width + j ].xyz, verts[ (i + 1) * m.width + j ].xyz, verts[ (i + 2) * m.width + j ].xyz  );	/* col */
		}
	}
	
	/* allocate patch mesh */
	pm = safe_malloc( sizeof( *pm ) );
	memset( pm, 0, sizeof( *pm ) );
	
	/* ydnar: add entity/brush numbering */
	pm->entityNum = mapEnt->mapEntityNum;
	pm->brushNum = entitySourceBrushes;
	
	/* set shader */
	sprintf( shader, "textures/%s", texture );
	pm->shaderInfo = ShaderInfoForShader( shader );
	
	/* set mesh */
	pm->mesh = m;
	
	/* set longest curve */
	pm->longestCurve = longestCurve;
	pm->maxIterations = maxIterations;
	
	/* link to the entity */
	pm->next = mapEnt->patches;
	mapEnt->patches = pm;
}



/*
GrowGroup_r()
recursively adds patches to a lod group
*/

static void GrowGroup_r( parseMesh_t *pm, int patchNum, int patchCount, parseMesh_t **meshes, byte *bordering, byte *group )
{
	int			i;
	const byte	*row;
	
	
	/* early out check */
	if( group[ patchNum ] )
		return;
	
	
	/* set it */
	group[ patchNum ] = 1;
	row = bordering + patchNum * patchCount;
	
	/* check maximums */
	if( meshes[ patchNum ]->longestCurve > pm->longestCurve )
		pm->longestCurve = meshes[ patchNum ]->longestCurve;
	if( meshes[ patchNum ]->maxIterations > pm->maxIterations )
		pm->maxIterations = meshes[ patchNum ]->maxIterations;
	
	/* walk other patches */
	for( i = 0; i < patchCount; i++ )
	{
		if( row[ i ] )
			GrowGroup_r( pm, i, patchCount, meshes, bordering, group );
	}
}


/*
PatchMapDrawSurfs()
any patches that share an edge need to choose their
level of detail as a unit, otherwise the edges would
pull apart.
*/

void PatchMapDrawSurfs( entity_t *e )
{
	int						i, j, k, l, c1, c2;
	parseMesh_t				*pm;
	parseMesh_t				*check, *scan;
	mapDrawSurface_t		*ds;
	int						patchCount, groupCount;
	bspDrawVert_t			*v1, *v2;
	vec3_t					bounds[ 2 ];
	byte					*bordering;
	
	/* ydnar: mac os x fails with these if not static */
	MAC_STATIC parseMesh_t	*meshes[ MAX_MAP_DRAW_SURFS ];
	MAC_STATIC qb_t			grouped[ MAX_MAP_DRAW_SURFS ];
	MAC_STATIC byte			group[ MAX_MAP_DRAW_SURFS ];
	
	
	/* note it */
	Sys_FPrintf( SYS_VRB, "--- PatchMapDrawSurfs ---\n" );

	patchCount = 0;
	for ( pm = e->patches ; pm ; pm = pm->next  ) {
		meshes[patchCount] = pm;
		patchCount++;
	}

	if ( !patchCount ) {
		return;
	}
	bordering = safe_malloc( patchCount * patchCount );
	memset( bordering, 0, patchCount * patchCount );

	// build the bordering matrix
	for ( k = 0 ; k < patchCount ; k++ ) {
		bordering[k*patchCount+k] = 1;

		for ( l = k+1 ; l < patchCount ; l++ ) {
			check = meshes[k];
			scan = meshes[l];
			c1 = scan->mesh.width * scan->mesh.height;
			v1 = scan->mesh.verts;

			for ( i = 0 ; i < c1 ; i++, v1++ ) {
				c2 = check->mesh.width * check->mesh.height;
				v2 = check->mesh.verts;
				for ( j = 0 ; j < c2 ; j++, v2++ ) {
					if ( fabs( v1->xyz[0] - v2->xyz[0] ) < 1.0
						&& fabs( v1->xyz[1] - v2->xyz[1] ) < 1.0
						&& fabs( v1->xyz[2] - v2->xyz[2] ) < 1.0 ) {
						break;
					}
				}
				if ( j != c2 ) {
					break;
				}
			}
			if ( i != c1 ) {
				// we have a connection
				bordering[k*patchCount+l] =
				bordering[l*patchCount+k] = 1;
			} else {
				// no connection
				bordering[k*patchCount+l] =
				bordering[l*patchCount+k] = 0;
			}

		}
	}

	/* build groups */
	memset( grouped, 0, patchCount );
	groupCount = 0;
	for ( i = 0; i < patchCount; i++ )
	{
		/* get patch */
		scan = meshes[ i ];
		
		/* start a new group */
		if( !grouped[ i ] )
			groupCount++;
		
		/* recursively find all patches that belong in the same group */
		memset( group, 0, patchCount );
		GrowGroup_r( scan, i, patchCount, meshes, bordering, group );
		
		/* bound them */
		ClearBounds( bounds[ 0 ], bounds[ 1 ] );
		for( j = 0; j < patchCount; j++ )
		{
			if ( group[ j ] )
			{
				grouped[ j ] = qtrue;
				check = meshes[ j ];
				c1 = check->mesh.width * check->mesh.height;
				v1 = check->mesh.verts;
				for( k = 0; k < c1; k++, v1++ )
					AddPointToBounds( v1->xyz, bounds[ 0 ], bounds[ 1 ] );
			}
		}
		
		/* debug code */
		//%	Sys_Printf( "Longest curve: %f Iterations: %d\n", scan->longestCurve, scan->maxIterations );
		
		/* create drawsurf */
		scan->grouped = qtrue;
		ds = DrawSurfaceForMesh( e, scan, NULL );	/* ydnar */
		VectorCopy( bounds[ 0 ], ds->bounds[ 0 ] );
		VectorCopy( bounds[ 1 ], ds->bounds[ 1 ] );
	}
	
	/* emit some statistics */
	Sys_FPrintf( SYS_VRB, "%9d patches\n", patchCount );
	Sys_FPrintf( SYS_VRB, "%9d patch LOD groups\n", groupCount );
}