//=======================================================================
//			Copyright XashXT Group 2010 ©
//		    gl_rsurf.c - surface-related refresh code
//=======================================================================

#include "common.h"
#include "client.h"
#include "gl_local.h"
#include "cm_local.h"

#define LIGHTMAP_BYTES	4
#define BLOCK_WIDTH		128
#define BLOCK_HEIGHT	128
#define MAX_LIGHTMAPS	128

#define SUBDIVIDE_SIZE	64
//#define	SUBDIVIDE_SIZE	1024

byte *Mod_GetCurrentVis( void )
{
//	return Mod_LeafPVS( r_viewleaf, r_worldmodel );
	return NULL;
}

static void BoundPoly( int numverts, float *verts, vec3_t mins, vec3_t maxs )
{
	int	i, j;
	float	*v;

	mins[0] = mins[1] = mins[2] = 9999;
	maxs[0] = maxs[1] = maxs[2] = -9999;

	for( i = 0, v = verts; i < numverts; i++ )
	{
		for( j = 0; j < 3; j++, v++ )
		{
			if( *v < mins[j] ) mins[j] = *v;
			if( *v > maxs[j] ) maxs[j] = *v;
		}
	}
}

static void SubdividePolygon_r( msurface_t *warpface, int numverts, float *verts )
{
	int	i, j, k, f, b;
	vec3_t	mins, maxs;
	float	m, frac, s, t, *v;
	vec3_t	front[SUBDIVIDE_SIZE], back[SUBDIVIDE_SIZE], total;
	float	dist[SUBDIVIDE_SIZE], total_s, total_t;
	glpoly_t	*poly;

	if( numverts > ( SUBDIVIDE_SIZE - 4 ))
		Host_Error( "Mod_SubdividePolygon: too many vertexes on face ( %i )\n", numverts );

	BoundPoly( numverts, verts, mins, maxs );

	for( i = 0; i < 3; i++ )
	{
		m = ( mins[i] + maxs[i] ) * 0.5f;
		m = SUBDIVIDE_SIZE * floor( m / SUBDIVIDE_SIZE + 0.5f );
		if( maxs[i] - m < 8 ) continue;
		if( m - mins[i] < 8 ) continue;

		// cut it
		v = verts + i;
		for( j = 0; j < numverts; j++, v += 3 )
			dist[j] = *v - m;

		// wrap cases
		dist[j] = dist[0];
		v -= i;
		VectorCopy( verts, v );

		f = b = 0;
		v = verts;
		for( j = 0; j < numverts; j++, v += 3 )
		{
			if( dist[j] >= 0 )
			{
				VectorCopy( v, front[f] );
				f++;
			}

			if( dist[j] <= 0 )
			{
				VectorCopy (v, back[b]);
				b++;
			}

			if( dist[j] == 0 || dist[j+1] == 0 )
				continue;

			if(( dist[j] > 0 ) != ( dist[j+1] > 0 ))
			{
				// clip point
				frac = dist[j] / ( dist[j] - dist[j+1] );
				for( k = 0; k < 3; k++ )
					front[f][k] = back[b][k] = v[k] + frac * (v[3+k] - v[k]);
				f++;
				b++;
			}
		}

		SubdividePolygon_r( warpface, f, front[0] );
		SubdividePolygon_r( warpface, b, back[0] );
		return;
	}

	// add a point in the center to help keep warp valid
	poly = Mem_Alloc( loadmodel->mempool, sizeof( glpoly_t ) + ((numverts-4)+2) * VERTEXSIZE * sizeof( float ));
	poly->next = warpface->polys;
	warpface->polys = poly;
	poly->numverts = numverts + 2;
	VectorClear( total );
	total_s = 0;
	total_t = 0;

	for( i = 0; i < numverts; i++, verts += 3 )
	{
		VectorCopy( verts, poly->verts[i+1] );
		s = DotProduct( verts, warpface->texinfo->vecs[0] );
		t = DotProduct( verts, warpface->texinfo->vecs[1] );

		total_s += s;
		total_t += t;
		VectorAdd( total, verts, total );

		poly->verts[i+1][3] = s;
		poly->verts[i+1][4] = t;
	}

	VectorScale( total, ( 1.0f / numverts ), poly->verts[0] );
	poly->verts[0][3] = total_s / numverts;
	poly->verts[0][4] = total_t / numverts;

	// copy first vertex to last
	Mem_Copy( poly->verts[i+1], poly->verts[1], sizeof( poly->verts[0] ));
}

/*
================
GL_SubdivideSurface

Breaks a polygon up along axial 64 unit
boundaries so that turbulent and sky warps
can be done reasonably.
================
*/
void GL_SubdivideSurface( msurface_t *fa )
{
	vec3_t	verts[SUBDIVIDE_SIZE];
	int	numverts;
	int	i, lindex;
	float	*vec;

	// convert edges back to a normal polygon
	numverts = 0;
	for( i = 0; i < fa->numedges; i++ )
	{
		lindex = loadmodel->surfedges[fa->firstedge + i];

		if( lindex > 0 ) vec = loadmodel->vertexes[loadmodel->edges[lindex].v[0]].position;
		else vec = loadmodel->vertexes[loadmodel->edges[-lindex].v[1]].position;
		VectorCopy (vec, verts[numverts]);
		numverts++;
	}

	// do subdivide
	SubdividePolygon_r( fa, numverts, verts[0] );
}

/*
================
GL_BuildPolygonFromSurface
================
*/
void GL_BuildPolygonFromSurface( msurface_t *fa )
{
	int		i, lindex, lnumverts;
	medge_t		*pedges, *r_pedge;
	int		vertpage;
	float		*vec;
	float		s, t;
	glpoly_t		*poly;
	vec3_t		total;

	// reconstruct the polygon
	pedges = loadmodel->edges;
	lnumverts = fa->numedges;
	vertpage = 0;

	VectorClear( total );

	// draw texture
	poly = Mem_Alloc( loadmodel->mempool, sizeof( glpoly_t ) + ( lnumverts - 4 ) * VERTEXSIZE * sizeof( float ));
	poly->next = fa->polys;
	poly->flags = fa->flags;
	fa->polys = poly;
	poly->numverts = lnumverts;

	for( i = 0; i < lnumverts; i++ )
	{
		lindex = loadmodel->surfedges[fa->firstedge + i];

		if( lindex > 0 )
		{
			r_pedge = &pedges[lindex];
			vec = loadmodel->vertexes[r_pedge->v[0]].position;
		}
		else
		{
			r_pedge = &pedges[-lindex];
			vec = loadmodel->vertexes[r_pedge->v[1]].position;
		}

		s = DotProduct( vec, fa->texinfo->vecs[0] ) + fa->texinfo->vecs[0][3];
		s /= fa->texinfo->texture->width;

		t = DotProduct( vec, fa->texinfo->vecs[1] ) + fa->texinfo->vecs[1][3];
		t /= fa->texinfo->texture->height;

		VectorAdd( total, vec, total );
		VectorCopy( vec, poly->verts[i] );
		poly->verts[i][3] = s;
		poly->verts[i][4] = t;

		// lightmap texture coordinates
		s = DotProduct( vec, fa->texinfo->vecs[0] ) + fa->texinfo->vecs[0][3];
		s -= fa->texturemins[0];
		s += fa->light_s * 16;
		s += 8;
		s /= BLOCK_WIDTH * 16; //fa->texinfo->texture->width;

		t = DotProduct( vec, fa->texinfo->vecs[1] ) + fa->texinfo->vecs[1][3];
		t -= fa->texturemins[1];
		t += fa->light_t * 16;
		t += 8;
		t /= BLOCK_HEIGHT * 16; //fa->texinfo->texture->height;

		poly->verts[i][5] = s;
		poly->verts[i][6] = t;
	}
	poly->numverts = lnumverts;
}