/*
===========================================================================
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 "qbsp.h"


/*
===============================================================

MESH SUBDIVISION

===============================================================
*/


int	originalWidths[MAX_EXPANDED_AXIS];
int	originalHeights[MAX_EXPANDED_AXIS];

int	neighbors[8][2] = {
	{0,1}, {1,1}, {1,0}, {1,-1}, {0,-1}, {-1,-1}, {-1,0}, {-1,1}
};

/*
============
LerpDrawVert
============
*/
void LerpDrawVert( drawVert_t *a, drawVert_t *b, drawVert_t *out ) {
	out->xyz[0] = 0.5 * (a->xyz[0] + b->xyz[0]);
	out->xyz[1] = 0.5 * (a->xyz[1] + b->xyz[1]);
	out->xyz[2] = 0.5 * (a->xyz[2] + b->xyz[2]);

	out->st[0] = 0.5 * (a->st[0] + b->st[0]);
	out->st[1] = 0.5 * (a->st[1] + b->st[1]);

	out->lightmap[0] = 0.5 * (a->lightmap[0] + b->lightmap[0]);
	out->lightmap[1] = 0.5 * (a->lightmap[1] + b->lightmap[1]);

	out->color[0] = (a->color[0] + b->color[0]) >> 1;
	out->color[1] = (a->color[1] + b->color[1]) >> 1;
	out->color[2] = (a->color[2] + b->color[2]) >> 1;
	out->color[3] = (a->color[3] + b->color[3]) >> 1;
}


void FreeMesh( mesh_t *m ) {
	free( m->verts );
	free( m );
}

void PrintMesh( mesh_t *m ) {
	int		i, j;

	for ( i = 0 ; i < m->height ; i++ ) {
		for ( j = 0 ; j < m->width ; j++ ) {
			_printf("(%5.2f %5.2f %5.2f) "
				, m->verts[i*m->width+j].xyz[0]
				, m->verts[i*m->width+j].xyz[1]
				, m->verts[i*m->width+j].xyz[2] );
		}
		_printf("\n");
	}
}


mesh_t *CopyMesh( mesh_t *mesh ) {
	mesh_t	*out;
	int		size;

	out = malloc( sizeof( *out ) );
	out->width = mesh->width;
	out->height = mesh->height;

	size = out->width * out->height * sizeof( *out->verts );
	out->verts = malloc( size );
	memcpy( out->verts, mesh->verts, size );

	return out;
}


/*
=================
TransposeMesh

Returns a transposed copy of the mesh, freeing the original
=================
*/
mesh_t *TransposeMesh( mesh_t *in ) {
	int			w, h;
	mesh_t		*out;

	out = malloc( sizeof( *out ) );
	out->width = in->height;
	out->height = in->width;
	out->verts = malloc( out->width * out->height * sizeof( drawVert_t ) );

	for ( h = 0 ; h < in->height ; h++ ) {
		for ( w = 0 ; w < in->width ; w++ ) {
			out->verts[ w * in->height + h ] = in->verts[ h * in->width + w ];
		}
	}

	FreeMesh( in );

	return out;
}

void InvertMesh( mesh_t *in ) {
	int			w, h;
	drawVert_t	temp;

	for ( h = 0 ; h < in->height ; h++ ) {
		for ( w = 0 ; w < in->width / 2 ; w++ ) {
			temp = in->verts[ h * in->width + w ];
			in->verts[ h * in->width + w ] = in->verts[ h * in->width + in->width - 1 - w ];
			in->verts[ h * in->width + in->width - 1 - w ] = temp;
		}
	}
}

/*
=================
MakeMeshNormals

=================
*/
void MakeMeshNormals( mesh_t in ) {
	int		i, j, k, dist;
	vec3_t	normal;
	vec3_t	sum;
	int		count;
	vec3_t	base;
	vec3_t	delta;
	int		x, y;
	drawVert_t	*dv;
	vec3_t		around[8], temp;
	qboolean	good[8];
	qboolean	wrapWidth, wrapHeight;
	float		len;

	wrapWidth = qfalse;
	for ( i = 0 ; i < in.height ; i++ ) {
		VectorSubtract( in.verts[i*in.width].xyz, 
			in.verts[i*in.width+in.width-1].xyz, delta );
		len = VectorLength( delta );
		if ( len > 1.0 ) {
			break;
		}
	}
	if ( i == in.height ) {
		wrapWidth = qtrue;
	}

	wrapHeight = qfalse;
	for ( i = 0 ; i < in.width ; i++ ) {
		VectorSubtract( in.verts[i].xyz, 
			in.verts[i + (in.height-1)*in.width].xyz, delta );
		len = VectorLength( delta );
		if ( len > 1.0 ) {
			break;
		}
	}
	if ( i == in.width) {
		wrapHeight = qtrue;
	}


	for ( i = 0 ; i < in.width ; i++ ) {
		for ( j = 0 ; j < in.height ; j++ ) {
			count = 0;
			dv = &in.verts[j*in.width+i];
			VectorCopy( dv->xyz, base );
			for ( k = 0 ; k < 8 ; k++ ) {
				VectorClear( around[k] );
				good[k] = qfalse;

				for ( dist = 1 ; dist <= 3 ; dist++ ) {
					x = i + neighbors[k][0] * dist;
					y = j + neighbors[k][1] * dist;
					if ( wrapWidth ) {
						if ( x < 0 ) {
							x = in.width - 1 + x;
						} else if ( x >= in.width ) {
							x = 1 + x - in.width;
						}
					}
					if ( wrapHeight ) {
						if ( y < 0 ) {
							y = in.height - 1 + y;
						} else if ( y >= in.height ) {
							y = 1 + y - in.height;
						}
					}

					if ( x < 0 || x >= in.width || y < 0 || y >= in.height ) {
						break;					// edge of patch
					}
					VectorSubtract( in.verts[y*in.width+x].xyz, base, temp );
					if ( VectorNormalize( temp, temp ) == 0 ) {
						continue;				// degenerate edge, get more dist
					} else {
						good[k] = qtrue;
						VectorCopy( temp, around[k] );
						break;					// good edge
					}
				}
			}

			VectorClear( sum );
			for ( k = 0 ; k < 8 ; k++ ) {
				if ( !good[k] || !good[(k+1)&7] ) {
					continue;	// didn't get two points
				}
				CrossProduct( around[(k+1)&7], around[k], normal );
				if ( VectorNormalize( normal, normal ) == 0 ) {
					continue;
				}
				VectorAdd( normal, sum, sum );
				count++;
			}
			if ( count == 0 ) {
//_printf("bad normal\n");
				count = 1;
			}
			VectorNormalize( sum, dv->normal );
		}
	}
}

/*
=================
PutMeshOnCurve

Drops the aproximating points onto the curve
=================
*/
void PutMeshOnCurve( mesh_t in ) {
	int		i, j, l;
	float	prev, next;

	// put all the aproximating points on the curve
	for ( i = 0 ; i < in.width ; i++ ) {
		for ( j = 1 ; j < in.height ; j += 2 ) {
			for ( l = 0 ; l < 3 ; l++ ) {
				prev = ( in.verts[j*in.width+i].xyz[l] + in.verts[(j+1)*in.width+i].xyz[l] ) * 0.5;
				next = ( in.verts[j*in.width+i].xyz[l] + in.verts[(j-1)*in.width+i].xyz[l] ) * 0.5;
				in.verts[j*in.width+i].xyz[l] = ( prev + next ) * 0.5;
			}
		}
	}

	for ( j = 0 ; j < in.height ; j++ ) {
		for ( i = 1 ; i < in.width ; i += 2 ) {
			for ( l = 0 ; l < 3 ; l++ ) {
				prev = ( in.verts[j*in.width+i].xyz[l] + in.verts[j*in.width+i+1].xyz[l] ) * 0.5;
				next = ( in.verts[j*in.width+i].xyz[l] + in.verts[j*in.width+i-1].xyz[l] ) * 0.5;
				in.verts[j*in.width+i].xyz[l] = ( prev + next ) * 0.5;
			}
		}
	}
}


/*
=================
SubdivideMesh

=================
*/
mesh_t *SubdivideMesh( mesh_t in, float maxError, float minLength ) {
	int			i, j, k, l;
	drawVert_t	prev, next, mid;
	vec3_t		prevxyz, nextxyz, midxyz;
	vec3_t		delta;
	float		len;
	mesh_t		out;
	drawVert_t	expand[MAX_EXPANDED_AXIS][MAX_EXPANDED_AXIS];

	out.width = in.width;
	out.height = in.height;

	for ( i = 0 ; i < in.width ; i++ ) {
		for ( j = 0 ; j < in.height ; j++ ) {
			expand[j][i] = in.verts[j*in.width+i];
		}
	}

	for ( i = 0 ; i < in.height ; i++ ) {
		originalHeights[i] = i;
	}
	for ( i = 0 ; i < in.width ; i++ ) {
		originalWidths[i] = i;
	}

	// horizontal subdivisions
	for ( j = 0 ; j + 2 < out.width ; j += 2 ) {
		// check subdivided midpoints against control points
		for ( i = 0 ; i < out.height ; i++ ) {
			for ( l = 0 ; l < 3 ; l++ ) {
				prevxyz[l] = expand[i][j+1].xyz[l] - expand[i][j].xyz[l]; 
				nextxyz[l] = expand[i][j+2].xyz[l] - expand[i][j+1].xyz[l]; 
				midxyz[l] = (expand[i][j].xyz[l] + expand[i][j+1].xyz[l] * 2
						+ expand[i][j+2].xyz[l] ) * 0.25;
			}

			// if the span length is too long, force a subdivision
			if ( VectorLength( prevxyz ) > minLength 
				|| VectorLength( nextxyz ) > minLength ) {
				break;
			}

			// see if this midpoint is off far enough to subdivide
			VectorSubtract( expand[i][j+1].xyz, midxyz, delta );
			len = VectorLength( delta );
			if ( len > maxError ) {
				break;
			}
		}

		if ( out.width + 2 >= MAX_EXPANDED_AXIS ) {
			break;	// can't subdivide any more
		}

		if ( i == out.height ) {
			continue;	// didn't need subdivision
		}

		// insert two columns and replace the peak
		out.width += 2;

		for ( k = out.width - 1 ; k > j + 3 ; k-- ) {
			originalWidths[k] = originalWidths[k-2];
		}
		originalWidths[j+3] = originalWidths[j+1];
		originalWidths[j+2] = originalWidths[j+1];
		originalWidths[j+1] = originalWidths[j];

		for ( i = 0 ; i < out.height ; i++ ) {
			LerpDrawVert( &expand[i][j], &expand[i][j+1], &prev );
			LerpDrawVert( &expand[i][j+1], &expand[i][j+2], &next );
			LerpDrawVert( &prev, &next, &mid );

			for ( k = out.width - 1 ; k > j + 3 ; k-- ) {
				expand[i][k] = expand[i][k-2];
			}
			expand[i][j + 1] = prev;
			expand[i][j + 2] = mid;
			expand[i][j + 3] = next;
		}

		// back up and recheck this set again, it may need more subdivision
		j -= 2;

	}

	// vertical subdivisions
	for ( j = 0 ; j + 2 < out.height ; j += 2 ) {
		// check subdivided midpoints against control points
		for ( i = 0 ; i < out.width ; i++ ) {
			for ( l = 0 ; l < 3 ; l++ ) {
				prevxyz[l] = expand[j+1][i].xyz[l] - expand[j][i].xyz[l]; 
				nextxyz[l] = expand[j+2][i].xyz[l] - expand[j+1][i].xyz[l]; 
				midxyz[l] = (expand[j][i].xyz[l] + expand[j+1][i].xyz[l] * 2
						+ expand[j+2][i].xyz[l] ) * 0.25;
			}

			// if the span length is too long, force a subdivision
			if ( VectorLength( prevxyz ) > minLength 
				|| VectorLength( nextxyz ) > minLength ) {
				break;
			}
			// see if this midpoint is off far enough to subdivide
			VectorSubtract( expand[j+1][i].xyz, midxyz, delta );
			len = VectorLength( delta );
			if ( len > maxError ) {
				break;
			}
		}

		if ( out.height + 2 >= MAX_EXPANDED_AXIS ) {
			break;	// can't subdivide any more
		}

		if ( i == out.width ) {
			continue;	// didn't need subdivision
		}

		// insert two columns and replace the peak
		out.height += 2;

		for ( k = out.height - 1 ; k > j + 3 ; k-- ) {
			originalHeights[k] = originalHeights[k-2];
		}
		originalHeights[j+3] = originalHeights[j+1];
		originalHeights[j+2] = originalHeights[j+1];
		originalHeights[j+1] = originalHeights[j];

		for ( i = 0 ; i < out.width ; i++ ) {
			LerpDrawVert( &expand[j][i], &expand[j+1][i], &prev );
			LerpDrawVert( &expand[j+1][i], &expand[j+2][i], &next );
			LerpDrawVert( &prev, &next, &mid );

			for ( k = out.height - 1 ; k > j + 3 ; k-- ) {
				expand[k][i] = expand[k-2][i];
			}
			expand[j+1][i] = prev;
			expand[j+2][i] = mid;
			expand[j+3][i] = next;
		}

		// back up and recheck this set again, it may need more subdivision
		j -= 2;

	}

	// collapse the verts

	out.verts = &expand[0][0];
	for ( i = 1 ; i < out.height ; i++ ) {
		memmove( &out.verts[i*out.width], expand[i], out.width * sizeof(drawVert_t) );
	}

	return CopyMesh(&out);
}

/*
================
ProjectPointOntoVector
================
*/
void ProjectPointOntoVector( vec3_t point, vec3_t vStart, vec3_t vEnd, vec3_t vProj )
{
	vec3_t pVec, vec;

	VectorSubtract( point, vStart, pVec );
	VectorSubtract( vEnd, vStart, vec );
	VectorNormalize( vec, vec );
	// project onto the directional vector for this segment
	VectorMA( vStart, DotProduct( pVec, vec ), vec, vProj );
}

/*
================
RemoveLinearMeshColumsRows
================
*/
mesh_t *RemoveLinearMeshColumnsRows( mesh_t *in ) {
	int i, j, k;
	float len, maxLength;
	vec3_t proj, dir;
	mesh_t out;
	drawVert_t	expand[MAX_EXPANDED_AXIS][MAX_EXPANDED_AXIS];

	out.width = in->width;
	out.height = in->height;

	for ( i = 0 ; i < in->width ; i++ ) {
		for ( j = 0 ; j < in->height ; j++ ) {
			expand[j][i] = in->verts[j*in->width+i];
		}
	}

	for ( j = 1 ; j < out.width - 1; j++ ) {
		maxLength = 0;
		for ( i = 0 ; i < out.height ; i++ ) {
			ProjectPointOntoVector(expand[i][j].xyz, expand[i][j-1].xyz, expand[i][j+1].xyz, proj);
			VectorSubtract(expand[i][j].xyz, proj, dir);
			len = VectorLength(dir);
			if (len > maxLength) {
				maxLength = len;
			}
		}
		if (maxLength < 0.1)
		{
			out.width--;
			for ( i = 0 ; i < out.height ; i++ ) {
				for (k = j; k < out.width; k++) {
					expand[i][k] = expand[i][k+1];
				}
			}
			for (k = j; k < out.width; k++) {
				originalWidths[k] = originalWidths[k+1];
			}
			j--;
		}
	}
	for ( j = 1 ; j < out.height - 1; j++ ) {
		maxLength = 0;
		for ( i = 0 ; i < out.width ; i++ ) {
			ProjectPointOntoVector(expand[j][i].xyz, expand[j-1][i].xyz, expand[j+1][i].xyz, proj);
			VectorSubtract(expand[j][i].xyz, proj, dir);
			len = VectorLength(dir);
			if (len > maxLength) {
				maxLength = len;
			}
		}
		if (maxLength < 0.1)
		{
			out.height--;
			for ( i = 0 ; i < out.width ; i++ ) {
				for (k = j; k < out.height; k++) {
					expand[k][i] = expand[k+1][i];
				}
			}
			for (k = j; k < out.height; k++) {
				originalHeights[k] = originalHeights[k+1];
			}
			j--;
		}
	}
	// collapse the verts
	out.verts = &expand[0][0];
	for ( i = 1 ; i < out.height ; i++ ) {
		memmove( &out.verts[i*out.width], expand[i], out.width * sizeof(drawVert_t) );
	}

	return CopyMesh(&out);
}

/*
============
LerpDrawVertAmount
============
*/
void LerpDrawVertAmount( drawVert_t *a, drawVert_t *b, float amount, drawVert_t *out ) {
	out->xyz[0] = a->xyz[0] + amount * (b->xyz[0] - a->xyz[0]);
	out->xyz[1] = a->xyz[1] + amount * (b->xyz[1] - a->xyz[1]);
	out->xyz[2] = a->xyz[2] + amount * (b->xyz[2] - a->xyz[2]);

	out->st[0] = a->st[0] + amount * (b->st[0] - a->st[0]);
	out->st[1] = a->st[1] + amount * (b->st[1] - a->st[1]);

	out->lightmap[0] = a->lightmap[0] + amount * (b->lightmap[0] - a->lightmap[0]);
	out->lightmap[1] = a->lightmap[1] + amount * (b->lightmap[1] - a->lightmap[1]);

	out->color[0] = a->color[0] + amount * (b->color[0] - a->color[0]);
	out->color[1] = a->color[1] + amount * (b->color[1] - a->color[1]);
	out->color[2] = a->color[2] + amount * (b->color[2] - a->color[2]);
	out->color[3] = a->color[3] + amount * (b->color[3] - a->color[3]);

	out->normal[0] = a->normal[0] + amount * (b->normal[0] - a->normal[0]);
	out->normal[1] = a->normal[1] + amount * (b->normal[1] - a->normal[1]);
	out->normal[2] = a->normal[2] + amount * (b->normal[2] - a->normal[2]);
	VectorNormalize(out->normal, out->normal);
}

/*
=================
SubdivideMeshQuads
=================
*/
mesh_t *SubdivideMeshQuads( mesh_t *in, float minLength, int maxsize, int widthtable[], int heighttable[]) {
	int			i, j, k, w, h, maxsubdivisions, subdivisions;
	vec3_t		dir;
	float		length, maxLength, amount;
	mesh_t		out;
	drawVert_t	expand[MAX_EXPANDED_AXIS][MAX_EXPANDED_AXIS];

	out.width = in->width;
	out.height = in->height;

	for ( i = 0 ; i < in->width ; i++ ) {
		for ( j = 0 ; j < in->height ; j++ ) {
			expand[j][i] = in->verts[j*in->width+i];
		}
	}

	if (maxsize > MAX_EXPANDED_AXIS)
		Error("SubdivideMeshQuads: maxsize > MAX_EXPANDED_AXIS");

	// horizontal subdivisions

	maxsubdivisions = (maxsize - in->width) / (in->width - 1);

	for ( w = 0, j = 0 ; w < in->width - 1; w++, j += subdivisions + 1) {
		maxLength = 0;
		for ( i = 0 ; i < out.height ; i++ ) {
			VectorSubtract(expand[i][j+1].xyz, expand[i][j].xyz, dir);
			length = VectorLength( dir );
			if (length > maxLength) {
				maxLength = length;
			}
		}
		
		subdivisions = (int) (maxLength / minLength);
		if (subdivisions > maxsubdivisions)
			subdivisions = maxsubdivisions;

		widthtable[w] = subdivisions + 1;
		if (subdivisions <= 0)
			continue;

		out.width += subdivisions;

		for ( k = out.width - 1; k >= j + subdivisions; k-- ) {
			originalWidths[k] = originalWidths[k-subdivisions];
		}
		for (k = 1; k <= subdivisions; k++) {
			originalWidths[j+k] = originalWidths[j];
		}

		for ( i = 0 ; i < out.height ; i++ ) {
			for ( k = out.width - 1 ; k > j + subdivisions; k-- ) {
				expand[i][k] = expand[i][k-subdivisions];
			}
			for (k = 1; k <= subdivisions; k++)
			{
				amount = (float) k / (subdivisions + 1);
				LerpDrawVertAmount(&expand[i][j], &expand[i][j+subdivisions+1], amount, &expand[i][j+k]);
			}
		}
	}

	maxsubdivisions = (maxsize - in->height) / (in->height - 1);

	for ( h = 0, j = 0 ; h < in->height - 1; h++, j += subdivisions + 1) {
		maxLength = 0;
		for ( i = 0 ; i < out.width ; i++ ) {
			VectorSubtract(expand[j+1][i].xyz, expand[j][i].xyz, dir);
			length = VectorLength( dir );
			if (length  > maxLength) {
				maxLength = length;
			}
		}
		
		subdivisions = (int) (maxLength / minLength);
		if (subdivisions > maxsubdivisions)
			subdivisions = maxsubdivisions;

		heighttable[h] = subdivisions + 1;
		if (subdivisions <= 0)
			continue;

		out.height += subdivisions;

		for ( k = out.height - 1; k >= j + subdivisions; k-- ) {
			originalHeights[k] = originalHeights[k-subdivisions];
		}
		for (k = 1; k <= subdivisions; k++) {
			originalHeights[j+k] = originalHeights[j];
		}

		for ( i = 0 ; i < out.width ; i++ ) {
			for ( k = out.height - 1 ; k > j + subdivisions; k-- ) {
				expand[k][i] = expand[k-subdivisions][i];
			}
			for (k = 1; k <= subdivisions; k++)
			{
				amount = (float) k / (subdivisions + 1);
				LerpDrawVertAmount(&expand[j][i], &expand[j+subdivisions+1][i], amount, &expand[j+k][i]);
			}
		}
	}

	// collapse the verts
	out.verts = &expand[0][0];
	for ( i = 1 ; i < out.height ; i++ ) {
		memmove( &out.verts[i*out.width], expand[i], out.width * sizeof(drawVert_t) );
	}

	return CopyMesh(&out);
}