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

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

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

Foliage code for Wolfenstein: Enemy Territory by ydnar@splashdamage.com

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



/* marker */
#define SURFACE_FOLIAGE_C



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



#define MAX_FOLIAGE_INSTANCES	8192

static int						numFoliageInstances;
static foliageInstance_t		foliageInstances[ MAX_FOLIAGE_INSTANCES ];



/*
SubdivideFoliageTriangle_r()
recursively subdivides a triangle until the triangle is smaller than
the desired density, then pseudo-randomly sets a point
*/

static void SubdivideFoliageTriangle_r( mapDrawSurface_t *ds, foliage_t *foliage, bspDrawVert_t **tri )
{
	bspDrawVert_t	mid, *tri2[ 3 ];
	int				max;
	
	
	/* limit test */
	if( numFoliageInstances >= MAX_FOLIAGE_INSTANCES )
		return;
	
	/* plane test */
	{
		vec4_t		plane;
		
		
		/* make a plane */
		if( !PlaneFromPoints( plane, tri[ 0 ]->xyz, tri[ 1 ]->xyz, tri[ 2 ]->xyz ) )
			return;
		
		/* if normal is too far off vertical, then don't place an instance */
		if( plane[ 2 ] < 0.5f )
			return;
	}
	
	/* subdivide calc */
	{
		int					i;
		float				*a, *b, dx, dy, dz, dist, maxDist;
		foliageInstance_t	*fi;
		
		
		/* get instance */
		fi = &foliageInstances[ numFoliageInstances ];
		
		/* find the longest edge and split it */
		max = -1;
		maxDist = 0.0f;
		VectorClear( fi->xyz );
		VectorClear( fi->normal );
		for( i = 0; i < 3; i++ )
		{
			/* get verts */
			a = tri[ i ]->xyz;
			b = tri[ (i + 1) % 3 ]->xyz;
			
			/* get dists */
			dx = a[ 0 ] - b[ 0 ];
			dy = a[ 1 ] - b[ 1 ];
			dz = a[ 2 ] - b[ 2 ];
			dist = (dx * dx) + (dy * dy) + (dz * dz);
			
			/* longer? */
			if( dist > maxDist )
			{
				maxDist = dist;
				max = i;
			}
			
			/* add to centroid */
			VectorAdd( fi->xyz, tri[ i ]->xyz, fi->xyz );
			VectorAdd( fi->normal, tri[ i ]->normal, fi->normal );
		}
		
		/* is the triangle small enough? */
		if( maxDist <= (foliage->density * foliage->density) )
		{
			float	alpha, odds, r;
			
			
			/* get average alpha */
			if( foliage->inverseAlpha == 2 )
				alpha = 1.0f;
			else
			{
				alpha = ((float) tri[ 0 ]->color[ 0 ][ 3 ] + (float) tri[ 1 ]->color[ 0 ][ 3 ] + (float) tri[ 2 ]->color[ 0 ][ 3 ]) / 765.0f;
				if( foliage->inverseAlpha == 1 )
					alpha = 1.0f - alpha;
				if( alpha < 0.75f )
					return;
			}
			
			/* roll the dice */
			odds = foliage->odds * alpha;
			r = Random();
			if( r > odds )
				return;
			
			/* scale centroid */
			VectorScale( fi->xyz, 0.33333333f, fi->xyz );
			if( VectorNormalize( fi->normal, fi->normal ) == 0.0f )
				return;
			
			/* add to count and return */
			numFoliageInstances++;
			return;
		}
	}
	
	/* split the longest edge and map it */
	LerpDrawVert( tri[ max ], tri[ (max + 1) % 3 ], &mid );
	
	/* recurse to first triangle */
	VectorCopy( tri, tri2 );
	tri2[ max ] = &mid;
	SubdivideFoliageTriangle_r( ds, foliage, tri2 );
	
	/* recurse to second triangle */
	VectorCopy( tri, tri2 );
	tri2[ (max + 1) % 3 ] = &mid;
	SubdivideFoliageTriangle_r( ds, foliage, tri2 );
}



/*
GenFoliage()
generates a foliage file for a bsp
*/

void Foliage( mapDrawSurface_t *src )
{
	int					i, j, k, x, y, pw[ 5 ], r, oldNumMapDrawSurfs;
	mapDrawSurface_t	*ds;
	shaderInfo_t		*si;
	foliage_t			*foliage;
	mesh_t				srcMesh, *subdivided, *mesh;
	bspDrawVert_t		*verts, *dv[ 3 ], *fi;
	vec3_t				scale;
	m4x4_t				transform;
	
	
	/* get shader */
	si = src->shaderInfo;
	if( si == NULL || si->foliage == NULL )
		return;
	
	/* do every foliage */
	for( foliage = si->foliage; foliage != NULL; foliage = foliage->next )
	{
		/* zero out */
		numFoliageInstances = 0;
		
		/* map the surface onto the lightmap origin/cluster/normal buffers */
		switch( src->type )
		{
			case SURFACE_META:
			case SURFACE_FORCED_META:
			case SURFACE_TRIANGLES:
				/* get verts */
				verts = src->verts;
				
				/* map the triangles */
				for( i = 0; i < src->numIndexes; i += 3 )
				{
					dv[ 0 ] = &verts[ src->indexes[ i ] ];
					dv[ 1 ] = &verts[ src->indexes[ i + 1 ] ];
					dv[ 2 ] = &verts[ src->indexes[ i + 2 ] ];
					SubdivideFoliageTriangle_r( src, foliage, dv );
				}
				break;
			
			case SURFACE_PATCH:
				/* make a mesh from the drawsurf */ 
				srcMesh.width = src->patchWidth;
				srcMesh.height = src->patchHeight;
				srcMesh.verts = src->verts;
				subdivided = SubdivideMesh( srcMesh, 8, 512 );
				
				/* fit it to the curve and remove colinear verts on rows/columns */
				PutMeshOnCurve( *subdivided );
				mesh = RemoveLinearMeshColumnsRows( subdivided );
				FreeMesh( subdivided );
				
				/* get verts */
				verts = mesh->verts;
				
				/* map the mesh quads */
				for( y = 0; y < (mesh->height - 1); y++ )
				{
					for( x = 0; x < (mesh->width - 1); x++ )
					{
						/* set indexes */
						pw[ 0 ] = x + (y * mesh->width);
						pw[ 1 ] = x + ((y + 1) * mesh->width);
						pw[ 2 ] = x + 1 + ((y + 1) * mesh->width);
						pw[ 3 ] = x + 1 + (y * mesh->width);
						pw[ 4 ] = x + (y * mesh->width);	/* same as pw[ 0 ] */
						
						/* set radix */
						r = (x + y) & 1;
						
						/* get drawverts and map first triangle */
						dv[ 0 ] = &verts[ pw[ r + 0 ] ];
						dv[ 1 ] = &verts[ pw[ r + 1 ] ];
						dv[ 2 ] = &verts[ pw[ r + 2 ] ];
						SubdivideFoliageTriangle_r( src, foliage, dv );
						
						/* get drawverts and map second triangle */
						dv[ 0 ] = &verts[ pw[ r + 0 ] ];
						dv[ 1 ] = &verts[ pw[ r + 2 ] ];
						dv[ 2 ] = &verts[ pw[ r + 3 ] ];
						SubdivideFoliageTriangle_r( src, foliage, dv );
					}
				}
				
				/* free the mesh */
				FreeMesh( mesh );
				break;
			
			default:
				break;
		}
		
		/* any origins? */
		if( numFoliageInstances < 1 )
			continue;
		
		/* remember surface count */
		oldNumMapDrawSurfs = numMapDrawSurfs;
		
		/* set transform matrix */
		VectorSet( scale, foliage->scale, foliage->scale, foliage->scale );
		m4x4_scale_for_vec3( transform, scale );
		
		/* add the model to the bsp */
		InsertModel( foliage->model, 0, transform, NULL, NULL, src->entityNum, src->castShadows, src->recvShadows, 0, src->lightmapScale );
		
		/* walk each new surface */
		for( i = oldNumMapDrawSurfs; i < numMapDrawSurfs; i++ )
		{
			/* get surface */
			ds = &mapDrawSurfs[ i ];
			
			/* set up */
			ds->type = SURFACE_FOLIAGE;
			ds->numFoliageInstances = numFoliageInstances;
			
			/* a wee hack */
			ds->patchWidth = ds->numFoliageInstances;
			ds->patchHeight = ds->numVerts;
			
			/* set fog to be same as source surface */
			ds->fogNum = src->fogNum;
			
			/* add a drawvert for every instance */
			verts = safe_malloc( (ds->numVerts + ds->numFoliageInstances) * sizeof( *verts ) );
			memset( verts, 0, (ds->numVerts + ds->numFoliageInstances) * sizeof( *verts ) );
			memcpy( verts, ds->verts, ds->numVerts * sizeof( *verts ) );
			free( ds->verts );
			ds->verts = verts;
			
			/* copy the verts */
			for( j = 0; j < ds->numFoliageInstances; j++ )
			{
				/* get vert (foliage instance) */
				fi = &ds->verts[ ds->numVerts + j ];

				/* copy xyz and normal */
				VectorCopy( foliageInstances[ j ].xyz, fi->xyz );
				VectorCopy( foliageInstances[ j ].normal, fi->normal );

				/* ydnar: set color */
				for( k = 0; k < MAX_LIGHTMAPS; k++ )
				{
					fi->color[ k ][ 0 ] = 255;
					fi->color[ k ][ 1 ] = 255;
					fi->color[ k ][ 2 ] = 255;
					fi->color[ k ][ 3 ] = 255;
				}
			}
			
			/* increment */
			ds->numVerts += ds->numFoliageInstances;
		}
	}
}
