/**

 * $Id: rendcore.c,v 1.2 2006-08-02 06:24:08 nkeynes Exp $

 *

 * PVR2 renderer core.

 *

 * 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 "pvr2/pvr2.h"

#include "asic.h"

static int pvr2_poly_depthmode[8] = { GL_NEVER, GL_LESS, GL_EQUAL, GL_LEQUAL,

				      GL_GREATER, GL_NOTEQUAL, GL_GEQUAL, 

				      GL_ALWAYS };

static int pvr2_poly_srcblend[8] = { 

    GL_ZERO, GL_ONE, GL_DST_COLOR, GL_ONE_MINUS_DST_COLOR,

    GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA, GL_DST_ALPHA, 

    GL_ONE_MINUS_DST_ALPHA };

static int pvr2_poly_dstblend[8] = {

    GL_ZERO, GL_ONE, GL_SRC_COLOR, GL_ONE_MINUS_SRC_COLOR,

    GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA, GL_DST_ALPHA,

    GL_ONE_MINUS_DST_ALPHA };

static int pvr2_poly_texblend[4] = {

    GL_REPLACE, GL_BLEND, GL_DECAL, GL_MODULATE };

static int pvr2_render_colour_format[8] = {

    COLFMT_ARGB1555, COLFMT_RGB565, COLFMT_ARGB4444, COLFMT_ARGB1555,

    COLFMT_RGB888, COLFMT_ARGB8888, COLFMT_ARGB8888, COLFMT_ARGB4444 };

#define POLY1_DEPTH_MODE(poly1) ( pvr2_poly_depthmode[(poly1)>>29] )

#define POLY1_DEPTH_ENABLE(poly1) (((poly1)&0x04000000) == 0 )

#define POLY1_CULL_MODE(poly1) (((poly1)>>27)&0x03)

#define POLY1_TEXTURED(poly1) (((poly1)&0x02000000))

#define POLY1_SPECULAR(poly1) (((poly1)&0x01000000))

#define POLY1_SHADE_MODEL(poly1) (((poly1)&0x00800000) ? GL_SMOOTH : GL_FLAT)

#define POLY1_UV16(poly1)   (((poly1)&0x00400000))

#define POLY1_SINGLE_TILE(poly1) (((poly1)&0x00200000))

#define POLY2_SRC_BLEND(poly2) ( pvr2_poly_srcblend[(poly2) >> 29] )

#define POLY2_DEST_BLEND(poly2) ( pvr2_poly_dstblend[((poly2)>>26)&0x07] )

#define POLY2_SRC_BLEND_ENABLE(poly2) ((poly2)&0x02000000)

#define POLY2_DEST_BLEND_ENABLE(poly2) ((poly2)&0x01000000)

#define POLY2_COLOUR_CLAMP_ENABLE(poly2) ((poly2)&0x00200000)

#define POLY2_ALPHA_ENABLE(poly2) ((poly2)&0x001000000)

#define POLY2_TEX_ALPHA_ENABLE(poly2) (((poly2)&0x00080000) == 0 )

#define POLY2_TEX_WIDTH(poly2) ( 1<< ((((poly2) >> 3) & 0x07 ) + 3) )

#define POLY2_TEX_HEIGHT(poly2) ( 1<< (((poly2) & 0x07 ) + 3) )

#define POLY2_TEX_BLEND(poly2) ( pvr2_poly_texblend[((poly2) >> 6)&0x03] )

#define RENDER_ZONLY  0

#define RENDER_NORMAL 1     /* Render non-modified polygons */

#define RENDER_CHEAPMOD 2   /* Render cheap-modified polygons */

#define RENDER_FULLMOD 3    /* Render the fully-modified version of the polygons */

#define CULL_NONE 0

#define CULL_SMALL 1

#define CULL_CCW 2

#define CULL_CW 3

#define SEGMENT_END         0x80000000

#define SEGMENT_SORT_TRANS  0x20000000

#define SEGMENT_START       0x10000000

#define SEGMENT_X(c)        (((c) >> 2) & 0x3F)

#define SEGMENT_Y(c)        (((c) >> 8) & 0x3F)

#define NO_POINTER          0x80000000

extern char *video_base;

struct tile_segment {

    uint32_t control;

    pvraddr_t opaque_ptr;

    pvraddr_t opaquemod_ptr;

    pvraddr_t trans_ptr;

    pvraddr_t transmod_ptr;

    pvraddr_t punchout_ptr;

};

/**

 * Convert a half-float (16-bit) FP number to a regular 32-bit float.

 * Source is 1-bit sign, 5-bit exponent, 10-bit mantissa.

 * TODO: Check the correctness of this.

 */

float halftofloat( uint16_t half )

{

    union {

        float f;

        uint32_t i;

    } temp;

    int e = ((half & 0x7C00) >> 10) - 15 + 127;

    temp.i = ((half & 0x8000) << 16) | (e << 23) |

             ((half & 0x03FF) << 13);

    return temp.f;

}

/**

 * Setup the GL context for the supplied polygon context.

 * @param context pointer to 3 or 5 words of polygon context

 * @param modified boolean flag indicating that the modified

 *  version should be used, rather than the normal version.

 */

void render_set_context( uint32_t *context, int render_mode )

{

    uint32_t poly1 = context[0], poly2, texture;

    if( render_mode == RENDER_FULLMOD ) {

	poly2 = context[3];

	texture = context[4];

    } else {

	poly2 = context[1];

	texture = context[2];

    }

    if( POLY1_DEPTH_ENABLE(poly1) ) {

	glEnable( GL_DEPTH_TEST );

	glDepthFunc( POLY1_DEPTH_MODE(poly1) );

    } else {

	glDisable( GL_DEPTH_TEST );

    }

    switch( POLY1_CULL_MODE(poly1) ) {

    case CULL_NONE:

    case CULL_SMALL:

	glDisable( GL_CULL_FACE );

	break;

    case CULL_CCW:

	glEnable( GL_CULL_FACE );

	glFrontFace( GL_CW );

	break;

    case CULL_CW:

	glEnable( GL_CULL_FACE );

	glFrontFace( GL_CCW );

	break;

    }

    if( POLY1_TEXTURED(poly1) ) {

	int width = POLY2_TEX_WIDTH(poly2);

	int height = POLY2_TEX_HEIGHT(poly2);

	glEnable(GL_TEXTURE_2D);

	texcache_get_texture( (texture&0x001FFFFF)<<3, width, height, texture );

	glTexEnvi( GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, POLY2_TEX_BLEND(poly2) );

    } else {

	glDisable( GL_TEXTURE_2D );

    }

    glShadeModel( POLY1_SHADE_MODEL(poly1) );

    glBlendFunc( POLY2_SRC_BLEND(poly2), POLY2_DEST_BLEND(poly2) );

    if( POLY2_TEX_ALPHA_ENABLE(poly2) ) {

	glEnable(GL_BLEND);

    } else {

	glDisable(GL_BLEND);

    }

}

void render_vertexes( uint32_t poly1, uint32_t *vertexes, int num_vertexes, int vertex_size,

		      int render_mode ) 

{

    int i, m=0;

    if( render_mode == RENDER_FULLMOD ) {

	m = (vertex_size - 3)/2;

    }

    glBegin( GL_TRIANGLE_STRIP );

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

	float *vertexf = (float *)vertexes;

	uint32_t argb;

	if( POLY1_TEXTURED(poly1) ) {

	    if( POLY1_UV16(poly1) ) {

		glTexCoord2f( halftofloat(vertexes[m+3]>>16),

			      halftofloat(vertexes[m+3]) );

		argb = vertexes[m+4];

	    } else {

		glTexCoord2f( vertexf[m+3], vertexf[m+4] );

		argb = vertexes[m+5];

	    }

	} else {

	    argb = vertexes[m+3];

	}

	glColor4ub( (GLubyte)(argb >> 16), (GLubyte)(argb >> 8), 

		    (GLubyte)argb, (GLubyte)(argb >> 24) );

	glVertex3f( vertexf[0], vertexf[1], vertexf[2] );

	vertexes += vertex_size;

    }

    glEnd();

}

/**

 * Render a simple (not auto-sorted) tile

 */

void render_tile( pvraddr_t tile_entry, int render_mode, gboolean cheap_modifier_mode ) {

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

    do {

	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 + ((entry & 0x001FFFFF) << 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++ ) {

		    render_set_context( polygon, render_mode );

		    render_vertexes( *polygon, polygon+context_length, 3, vertex_length,

				     render_mode );

		    polygon += polygon_length;

		}

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

		/* Sprite(s) */

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

		int polygon_length = 4 * vertex_length + context_length;

		int i;

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

		    render_set_context( polygon, render_mode );

		    render_vertexes( *polygon, polygon+context_length, 4, vertex_length,

				     render_mode );

		    polygon += polygon_length;

		}

	    } else {

		/* Polygon */

		int i, first=-1, last = -1;

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

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

			if( first == -1 ) first = i;

			last = i;

		    }

		}

		if( first != -1 ) {

		    first = 0;

		    render_set_context(polygon, render_mode);

		    render_vertexes( *polygon, polygon+context_length + (first*vertex_length),

				     (last-first+3), vertex_length, render_mode );

		}

	    }

	}

    } while( 1 );

}

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

    //WARN( "Autosort not implemented yet" );

    render_tile( tile_entry, render_mode, cheap_modifier_mode );

}

void pvr2_render_tilebuffer( int width, int height, int clipx1, int clipy1, 

			int clipx2, int clipy2 ) {

    pvraddr_t segmentbase = MMIO_READ( PVR2, RENDER_TILEBASE );

    int tile_sort;

    gboolean cheap_shadow;

    int obj_config = MMIO_READ( PVR2, RENDER_OBJCFG );

    int isp_config = MMIO_READ( PVR2, RENDER_ISPCFG );

    int shadow_cfg = MMIO_READ( PVR2, RENDER_SHADOW );

    if( obj_config & 0x00200000 ) {

	if( isp_config & 1 ) {

	    tile_sort = 0;

	} else {

	    tile_sort = 2;

	}

    } else {

	tile_sort = 1;

    }

    cheap_shadow = shadow_cfg & 0x100 ? TRUE : FALSE;

    struct tile_segment *segment = (struct tile_segment *)(video_base + segmentbase);

    glEnable( GL_SCISSOR_TEST );

    while( (segment->control & SEGMENT_END) == 0 ) {

	int tilex = SEGMENT_X(segment->control);

	int tiley = SEGMENT_Y(segment->control);

	int x1 = tilex << 5;

	int y1 = tiley << 5;

	if( x1 + 32 <= clipx1 ||

	    y1 + 32 <= clipy1 ||

	    x1 >= clipx2 ||

	    y1 >= clipy2 ) {

	    /* Tile completely clipped, skip */

	    segment++;

	    continue;

	}

	/* Set a scissor on the visible part of the tile */

	int w = MIN(x1+32, clipx2) - x1;

	int h = MIN(y1+32, clipy2) - y1;

	x1 = MAX(x1,clipx1);

	y1 = MAX(y1,clipy1);

	glScissor( x1, height-y1-h, w, h );

	if( (segment->opaque_ptr & NO_POINTER) == 0 ) {

	    if( (segment->opaquemod_ptr & NO_POINTER) == 0 ) {

		/* TODO */

	    }

	    render_tile( segment->opaque_ptr, RENDER_NORMAL, cheap_shadow );

	}

	if( (segment->trans_ptr & NO_POINTER) == 0 ) {

	    if( (segment->transmod_ptr & NO_POINTER) == 0 ) {

		/* TODO */

	    } 

	    if( tile_sort == 2 || (tile_sort == 1 && (segment->control & SEGMENT_SORT_TRANS)) ) {

		render_autosort_tile( segment->trans_ptr, RENDER_NORMAL, cheap_shadow );

	    } else {

		render_tile( segment->trans_ptr, RENDER_NORMAL, cheap_shadow );

	    }

	}

	if( (segment->punchout_ptr & NO_POINTER) == 0 ) {

	    render_tile( segment->punchout_ptr, RENDER_NORMAL, cheap_shadow );

	}

	segment++;

    }

    glDisable( GL_SCISSOR_TEST );

}