/**

 * $Id: rendsort.c,v 1.6 2007-10-08 11:52:13 nkeynes Exp $

 *

 * PVR2 renderer routines for depth sorted polygons

 *

 * Copyright (c) 2005 Nathan Keynes.

 *

 * This program 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.

 *

 * This program 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.

 */

#include <sys/time.h>

#include "pvr2/pvr2.h"

#include "asic.h"

extern char *video_base;

extern gboolean pvr2_force_fragment_alpha;

#define MIN3( a,b,c ) ((a) < (b) ? ( (a) < (c) ? (a) : (c) ) : ((b) < (c) ? (b) : (c)) )

#define MAX3( a,b,c ) ((a) > (b) ? ( (a) > (c) ? (a) : (c) ) : ((b) > (c) ? (b) : (c)) )

struct render_triangle {

    uint32_t *polygon;

    int vertex_length; /* Number of 32-bit words in vertex, or 0 for an unpacked vertex */

    float minx,miny,minz;

    float maxx,maxy,maxz;

    float *vertexes[3];

};

#define SENTINEL 0xDEADBEEF

/**

 * Count the number of triangles in the list starting at the given 

 * pvr memory address.

 */

int render_count_triangles( pvraddr_t tile_entry ) {

    uint32_t *tile_list = (uint32_t *)(video_base+tile_entry);

    int count = 0;

    while(1) {

	uint32_t entry = *tile_list++;

	if( entry >> 28 == 0x0F ) {

	    break;

	} else if( entry >> 28 == 0x0E ) {

	    tile_list = (uint32_t *)(video_base+(entry&0x007FFFFF));

	} else if( entry >> 29 == 0x04 ) { /* Triangle array */

	    count += ((entry >> 25) & 0x0F)+1;

	} else if( entry >> 29 == 0x05 ) { /* Quad array */

	    count += ((((entry >> 25) & 0x0F)+1)<<1);

	} else { /* Polygon */

	    int i;

	    for( i=0; i<6; i++ ) {

		if( entry & (0x40000000>>i) ) {

		    count++;

		}

	    }

	}

    }

    return count;

}

static void compute_triangle_boxes( struct render_triangle *triangle, int num_triangles )

{

    int i;

    for( i=0; i<num_triangles; i++ ) {

	triangle[i].minx = MIN3(triangle[i].vertexes[0][0],triangle[i].vertexes[1][0],triangle[i].vertexes[2][0]);

	triangle[i].maxx = MAX3(triangle[i].vertexes[0][0],triangle[i].vertexes[1][0],triangle[i].vertexes[2][0]);

	triangle[i].miny = MIN3(triangle[i].vertexes[0][1],triangle[i].vertexes[1][1],triangle[i].vertexes[2][1]);

	triangle[i].maxy = MAX3(triangle[i].vertexes[0][1],triangle[i].vertexes[1][1],triangle[i].vertexes[2][1]);

	float az = 1/triangle[i].vertexes[0][2];

	float bz = 1/triangle[i].vertexes[1][2];

	float cz = 1/triangle[i].vertexes[2][2];

	triangle[i].minz = MIN3(az,bz,cz);

	triangle[i].maxz = MAX3(az,bz,cz);

    }

}

void render_extract_triangles( pvraddr_t tile_entry, gboolean cheap_modifier_mode, 

			       struct render_triangle *triangles, int num_triangles,

			       struct vertex_unpacked *vertex_space, int render_mode )

{

    uint32_t poly_bank = MMIO_READ(PVR2,RENDER_POLYBASE);

    uint32_t *tile_list = (uint32_t *)(video_base+tile_entry);

    int count = 0;

    while(1) {

	uint32_t entry = *tile_list++;

	if( entry >> 28 == 0x0F ) {

	    break;

	} else if( entry >> 28 == 0x0E ) {

	    tile_list = (uint32_t *)(video_base+(entry&0x007FFFFF));

	} else {

	    uint32_t *polygon = (uint32_t *)(video_base + poly_bank + ((entry & 0x000FFFFF) << 2));

	    int is_modified = entry & 0x01000000;

	    int vertex_length = (entry >> 21) & 0x07;

	    int context_length = 3;

	    if( is_modified && !cheap_modifier_mode ) {

		context_length = 5;

		vertex_length *= 2 ;

	    }

	    vertex_length += 3;

	    if( (entry & 0xE0000000) == 0x80000000 ) {

		/* Triangle(s) */

		int strip_count = ((entry >> 25) & 0x0F)+1;

		int polygon_length = 3 * vertex_length + context_length;

		int i;

		for( i=0; i<strip_count; i++ ) {

		    float *vertex = (float *)(polygon+context_length);

		    triangles[count].polygon = polygon;

		    triangles[count].vertex_length = vertex_length;

		    triangles[count].vertexes[0] = vertex;

		    vertex+=vertex_length;

		    triangles[count].vertexes[1] = vertex;

		    vertex+=vertex_length;

		    triangles[count].vertexes[2] = vertex;

		    polygon += polygon_length;

		    count++;

		}

	    } else if( (entry & 0xE0000000) == 0xA0000000 ) {

		/* Quad(s) */

		int strip_count = ((entry >> 25) & 0x0F)+1;

		int polygon_length = 4 * vertex_length + context_length;

		int i;

		for( i=0; i<strip_count; i++ ) {

		    render_unpack_quad( vertex_space, *polygon, (polygon+context_length),

					vertex_length, render_mode );

		    triangles[count].polygon = polygon;

		    triangles[count].vertex_length = 0;

		    triangles[count].vertexes[0] = (float *)vertex_space;

		    triangles[count].vertexes[1] = (float *)(vertex_space + 1);

		    triangles[count].vertexes[2] = (float *)(vertex_space + 3);

		    count++;

		    /* Preserve face direction */

		    triangles[count].polygon = polygon;

		    triangles[count].vertex_length = 0;

		    triangles[count].vertexes[0] = (float *)(vertex_space + 1);

		    triangles[count].vertexes[1] = (float *)(vertex_space + 2);

		    triangles[count].vertexes[2] = (float *)(vertex_space + 3);

		    count++;

		    vertex_space += 4;

		    polygon += polygon_length;

		}

	    } else {

		/* Polygon */

		int i;

		float *vertex = (float *)polygon+context_length;

		for( i=0; i<6; i++ ) {

		    if( entry & (0x40000000>>i) ) {

			triangles[count].polygon = polygon;

			triangles[count].vertex_length = vertex_length;

			if( i&1 ) {

			    triangles[count].vertexes[0] = vertex + vertex_length;

			    triangles[count].vertexes[1] = vertex;

			    triangles[count].vertexes[2] = vertex + (vertex_length<<1);

			} else {

			    triangles[count].vertexes[0] = vertex;

			    triangles[count].vertexes[1] = vertex + vertex_length;

			    triangles[count].vertexes[2] = vertex + (vertex_length<<1);

			}

			count++;

		    }

		    vertex += vertex_length;

		}

	    }

	}

    }

    if( count != num_triangles ) {

	ERROR( "Extracted triangles do not match expected count!" );

    }

}

void render_triangles( struct render_triangle *triangles, int num_triangles,

		       int render_mode )

{

    int i;

    for( i=0; i<num_triangles; i++ ) {

	render_set_context( triangles[i].polygon, render_mode );

	glEnable(GL_DEPTH_TEST);

	glDepthFunc(GL_GEQUAL);

	if( triangles[i].vertex_length == 0 ) {

	    render_unpacked_vertex_array( *triangles[i].polygon, (struct vertex_unpacked **)triangles[i].vertexes, 3 );

	} else {

	    render_vertex_array( *triangles[i].polygon, (uint32_t **)triangles[i].vertexes, 3,

				 triangles[i].vertex_length, render_mode );

	}

    }

}

int compare_triangles( const void *a, const void *b ) 

{

    const struct render_triangle *tri1 = a;

    const struct render_triangle *tri2 = b;

    if( tri1->minz < tri2->minz ) {  

	return 1; // No these _aren't_ back to front...

    } else if( tri1->minz > tri2->minz ) {

	return -1;

    } else {

	return 0;

    }

}

void sort_triangles( struct render_triangle *triangles, int num_triangles )

{

    qsort( triangles, num_triangles, sizeof(struct render_triangle), compare_triangles );

} 

void render_autosort_tile( pvraddr_t tile_entry, int render_mode, gboolean cheap_modifier_mode ) 

{

    int num_triangles = render_count_triangles(tile_entry);

    if( num_triangles == 0 ) {

	return; /* nothing to do */

    } else if( num_triangles == 1 ) { /* Triangle can hardly overlap with itself */

	render_tile( tile_entry, render_mode, cheap_modifier_mode );

    } else { /* Ooh boy here we go... */

	struct render_triangle triangles[num_triangles+1];

	struct vertex_unpacked vertex_space[num_triangles << 1]; 

	// Reserve space for num_triangles / 2 * 4 vertexes (maximum possible number of

	// quad vertices)

	triangles[num_triangles].polygon = (void *)SENTINEL;

	render_extract_triangles(tile_entry, cheap_modifier_mode, triangles, num_triangles, vertex_space, render_mode);

	compute_triangle_boxes(triangles, num_triangles);

	sort_triangles( triangles, num_triangles );

	render_triangles(triangles, num_triangles, render_mode);

	if( triangles[num_triangles].polygon != (void *)SENTINEL ) {

	    fprintf( stderr, "Triangle overflow in render_autosort_tile!" );

	}

    }

}