/**

  * $Id: render.c,v 1.10 2006-06-27 09:32:09 nkeynes Exp $

  *

  * PVR2 Renderer support. This is where the real work happens.

  *

  * 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"

 #define POLY_COLOUR_PACKED 0x00000000

 #define POLY_COLOUR_FLOAT 0x00000010

 #define POLY_COLOUR_INTENSITY 0x00000020

 #define POLY_COLOUR_INTENSITY_PREV 0x00000030

 static int pvr2_poly_vertexes[4] = { 3, 4, 6, 8 };

 static int pvr2_poly_type[4] = { GL_TRIANGLES, GL_QUADS, GL_TRIANGLE_STRIP, GL_TRIANGLE_STRIP };

 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 POLY_STRIP_TYPE(poly) ( pvr2_poly_type[((poly->command)>>18)&0x03] )

 #define POLY_STRIP_VERTEXES(poly) ( pvr2_poly_vertexes[((poly->command)>>18)&0x03] )

 #define POLY_DEPTH_MODE(poly) ( pvr2_poly_depthmode[poly->poly_cfg>>29] )

 #define POLY_DEPTH_WRITE(poly) ((poly->poly_cfg&0x04000000) == 0 )

 #define POLY_TEX_WIDTH(poly) ( 1<< (((poly->poly_mode >> 3) & 0x07 ) + 3) )

 #define POLY_TEX_HEIGHT(poly) ( 1<< (((poly->poly_mode) & 0x07 ) + 3) )

 #define POLY_BLEND_SRC(poly) ( pvr2_poly_srcblend[(poly->poly_mode) >> 29] )

 #define POLY_BLEND_DEST(poly) ( pvr2_poly_dstblend[((poly->poly_mode)>>26)&0x07] )

 #define POLY_TEX_BLEND(poly) ( pvr2_poly_texblend[((poly->poly_mode) >> 6)&0x03] )

 #define POLY_COLOUR_TYPE(poly) ( poly->command & 0x00000030 )

 /**

  * Describes a rendering buffer that's actually held in GL, for when we need

  * to fetch the bits back to vram.

  */

 typedef struct pvr2_render_buffer {

     sh4addr_t render_addr; /* The actual address rendered to in pvr ram */

     uint32_t size; /* Length of rendering region in bytes */

     int width, height;

     int colour_format;

 } *pvr2_render_buffer_t;

 struct pvr2_render_buffer front_buffer;

 struct pvr2_render_buffer back_buffer;

 struct tile_descriptor {

     uint32_t header[6];

     struct tile_pointers {

 	uint32_t tile_id;

 	uint32_t opaque_ptr;

 	uint32_t opaque_mod_ptr;

 	uint32_t trans_ptr;

 	uint32_t trans_mod_ptr;

 	uint32_t punchout_ptr;

     } tile[0];

 };

 /* Textured polygon */

 struct pvr2_poly {

     uint32_t command;

     uint32_t poly_cfg; /* Bitmask */

     uint32_t poly_mode; /* texture/blending mask */

     uint32_t texture; /* texture data */

     float alpha;

     float red;

     float green;

     float blue;

 };

 struct pvr2_specular_highlight {

     float base_alpha;

     float base_red;

     float base_green;

     float base_blue;

     float offset_alpha;

     float offset_red;

     float offset_green;

     float offset_blue;

 };

 struct pvr2_vertex_packed {

     uint32_t command;

     float x, y, z;

     float s,t;

     uint32_t colour;

     float f;

 };

 struct pvr2_vertex_float {

     uint32_t command;

     float x,y,z;

     float a, r, g, b;

 };

 union pvr2_vertex {

     struct pvr2_vertex_packed pack;

     struct pvr2_vertex_float flt;

 };

 typedef struct pvr2_bgplane_packed {

         uint32_t        poly_cfg, poly_mode;

         uint32_t        texture_mode;

         float           x1, y1, z1;

         uint32_t          colour1;

         float           x2, y2, z2;

         uint32_t          colour2;

         float           x3, y3, z3;

         uint32_t          colour3;

 } *pvr2_bgplane_packed_t;

 void pvr2_render_copy_to_sh4( pvr2_render_buffer_t buffer, 

 			      gboolean backBuffer );

 int pvr2_render_font_list = -1;

 int pvr2_render_trace = 0;

 int glPrintf( int x, int y, const char *fmt, ... )

 {

     va_list ap;     /* our argument pointer */

     char buf[256];

     int len;

     if (fmt == NULL)    /* if there is no string to draw do nothing */

         return;

     va_start(ap, fmt); 

     len = vsnprintf(buf, sizeof(buf), fmt, ap);

     va_end(ap);

     glPushAttrib(GL_LIST_BIT);

     glDisable( GL_DEPTH_TEST );

     glDisable( GL_BLEND );

     glDisable( GL_TEXTURE_2D );

     glDisable( GL_ALPHA_TEST );

     glListBase(pvr2_render_font_list - 32);

     glColor3f( 1.0, 1.0, 1.0 );

     glRasterPos2i( x, y );

     glCallLists(len, GL_UNSIGNED_BYTE, buf);

     glPopAttrib();

     return len;

 }

 gboolean pvr2_render_init( void )

 {

     front_buffer.render_addr = -1;

     back_buffer.render_addr = -1;

 }

 /**

  * Invalidate any caching on the supplied address. Specifically, if it falls

  * within either the front buffer or back buffer, flush the buffer back to

  * PVR2 ram (note that front buffer flush may be corrupt under some

  * circumstances).

  */

 gboolean pvr2_render_invalidate( sh4addr_t address )

 {

     address = address & 0x1FFFFFFF;

     if( front_buffer.render_addr != -1 &&

 	front_buffer.render_addr <= address &&

 	(front_buffer.render_addr + front_buffer.size) > address ) {

 	pvr2_render_copy_to_sh4( &front_buffer, FALSE );

 	front_buffer.render_addr = -1;

 	return TRUE;

     } else if( back_buffer.render_addr != -1 &&

 	       back_buffer.render_addr <= address &&

 	       (back_buffer.render_addr + back_buffer.size) > address ) {

 	pvr2_render_copy_to_sh4( &back_buffer, TRUE );

 	back_buffer.render_addr = -1;

 	return TRUE;

     }

     return FALSE;

 }

 /**

  * Display a rendered frame if one is available.

  * @param address An address in PVR ram (0500000 range).

  * @return TRUE if a frame was available to be displayed, otherwise false.

  */

 gboolean pvr2_render_display_frame( uint32_t address )

 {

     if( front_buffer.render_addr == address ) {

 	/* Current front buffer is already displayed, so do nothing

 	 * and tell the caller that all is well.

 	 */

 	return TRUE;

     }

     if( back_buffer.render_addr == address ) {

 	/* The more useful case - back buffer is to be displayed. Swap

 	 * the buffers 

 	 */

 	display_driver->display_back_buffer();

 	front_buffer = back_buffer;

 	back_buffer.render_addr = -1;

 	return TRUE;

     }

     return FALSE;

 }	

 /**

  * Prepare the OpenGL context to receive instructions for a new frame.

  */

 static void pvr2_render_prepare_context( sh4addr_t render_addr, 

 					 uint32_t width, uint32_t height,

 					 uint32_t colour_format, 

 					 float bgplanez,

 					 gboolean texture_target )

 {

     /* Select and initialize the render context */

     display_driver->set_render_format( width, height, colour_format, texture_target );

     if( pvr2_render_font_list == -1 ) {

 	pvr2_render_font_list = video_glx_load_font( "-*-helvetica-*-r-normal--16-*-*-*-p-*-iso8859-1");

     }

     if( back_buffer.render_addr != -1 && 

 	back_buffer.render_addr != render_addr ) {

 	/* There's a current back buffer, and we're rendering somewhere else -

 	 * flush the back buffer back to vram and start a new back buffer

 	 */

 	pvr2_render_copy_to_sh4( &back_buffer, TRUE );

     }

     if( front_buffer.render_addr == render_addr ) {

 	/* In case we've been asked to render to the current front buffer -

 	 * invalidate the front buffer and render to the back buffer, ensuring

 	 * we swap at the next frame display.

 	 */

 	front_buffer.render_addr = -1;

     }

     back_buffer.render_addr = render_addr;

     back_buffer.width = width;

     back_buffer.height = height;

     back_buffer.colour_format = colour_format;

     back_buffer.size = width * height * colour_format_bytes[colour_format];

     /* Setup the display model */

     glDrawBuffer(GL_BACK);

     glShadeModel(GL_SMOOTH);

     glHint(GL_PERSPECTIVE_CORRECTION_HINT, GL_NICEST);

     glViewport( 0, 0, width, height );

     glMatrixMode(GL_PROJECTION);

     glLoadIdentity();

     glOrtho( 0, width, height, 0, bgplanez, -4 );

     glMatrixMode(GL_MODELVIEW);

     glLoadIdentity();

     glCullFace( GL_BACK );

     /* Clear out the buffers */

     glClearColor(0.0f, 0.0f, 0.0f, 0.0f);

     glClearDepth(bgplanez);

     glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT );

 }

 static void pvr2_dump_display_list( uint32_t * display_list, uint32_t length )

 {

     uint32_t i;

     gboolean vertex = FALSE;

     for( i =0; i<length>>2; i++ ) {

 	if( (i % 8) == 0 ) {

 	    if( i != 0 )

 		fprintf( stderr, "\n" );

 	    fprintf( stderr, "%08X:", i*4 );

 	    if( display_list[i] == 0xE0000000 ||

 		display_list[i] == 0xF0000000 ) 

 		vertex = TRUE;

 	    else vertex = FALSE;

 	}

 	if( vertex && (i%8) > 0 && (i%8) < 4 )

 	    fprintf( stderr, " %f", ((float *)display_list)[i] );

 	else

 	    fprintf( stderr, " %08X", display_list[i] );

     }

     fprintf( stderr, "\n" );

 }

 static void pvr2_render_display_list( uint32_t *display_list, uint32_t length )

 {

     uint32_t *cmd_ptr = display_list;

     int strip_length = 0, vertex_count = 0;

     int colour_type;

     gboolean textured = FALSE;

     gboolean shaded = FALSE;

     struct pvr2_poly *poly;

     if( pvr2_render_trace ) {

 	fprintf( stderr, "-------- %d\n", pvr2_get_frame_count() );

 	pvr2_dump_display_list( display_list, length );

     }

     while( cmd_ptr < display_list+(length>>2) ) {

 	unsigned int cmd = *cmd_ptr >> 24;

 	switch( cmd ) {

 	case PVR2_CMD_POLY_OPAQUE:

 	case PVR2_CMD_POLY_TRANS:

 	case PVR2_CMD_POLY_PUNCHOUT:

 	    poly = (struct pvr2_poly *)cmd_ptr;

 	    if( poly->command & PVR2_POLY_TEXTURED ) {

 		uint32_t addr = PVR2_TEX_ADDR(poly->texture);

 		int width = POLY_TEX_WIDTH(poly);

 		int height = POLY_TEX_HEIGHT(poly);

 		glEnable( GL_TEXTURE_2D );

 		texcache_get_texture( addr, width, height, poly->texture );

 		textured = TRUE;

 		glTexEnvi( GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, POLY_TEX_BLEND(poly) );

 	    } else {

 		textured = FALSE;

 		glDisable( GL_TEXTURE_2D );

 	    }

 	    glBlendFunc( POLY_BLEND_SRC(poly), POLY_BLEND_DEST(poly) );

 	    if( poly->command & PVR2_POLY_SPECULAR ) {

 		/* Second block expected */

 	    }

 	    if( POLY_DEPTH_WRITE(poly) ) {

 		glEnable( GL_DEPTH_TEST );

 		glDepthFunc( POLY_DEPTH_MODE(poly) );

 	    } else {

 		glDisable( GL_DEPTH_TEST );

 	    }

 	    switch( (poly->poly_cfg >> 27) & 0x03 ) {

 	    case 0:

 	    case 1:

 		glDisable( GL_CULL_FACE );

 		break;

 	    case 2:

 		glEnable( GL_CULL_FACE );

 		glFrontFace( GL_CW );

 		break;

 	    case 3:

 		glEnable( GL_CULL_FACE );

 		glFrontFace( GL_CCW );

 	    }

 	    strip_length = POLY_STRIP_VERTEXES( poly );

 	    colour_type = POLY_COLOUR_TYPE( poly );

 	    vertex_count = 0;

 	    if( poly->command & PVR2_POLY_SHADED ) {

 		shaded = TRUE;

 	    } else {

 		shaded = FALSE;

 	    }

 	    if( poly->poly_mode & PVR2_POLY_MODE_TEXALPHA ) {

 		glDisable( GL_BLEND );

 	    } else {

 		glEnable( GL_BLEND );

 	    }

 	    break;

 	case PVR2_CMD_MOD_OPAQUE:

 	case PVR2_CMD_MOD_TRANS:

 	    /* TODO */

 	    break;

 	case PVR2_CMD_END_OF_LIST:

 	    break;

 	case PVR2_CMD_VERTEX_LAST:

 	case PVR2_CMD_VERTEX:

 	    if( vertex_count == 0 ) {

 		glBegin( GL_TRIANGLE_STRIP );

 	    }

 	    vertex_count++;

 	    struct pvr2_vertex_packed *vertex = (struct pvr2_vertex_packed *)cmd_ptr;

 	    if( textured ) {

 		glTexCoord2f( vertex->s, vertex->t );

 		if( shaded || vertex_count == 1) {

 		    switch( colour_type ) {

 		    case POLY_COLOUR_PACKED:

 			glColor4ub( vertex->colour >> 16, vertex->colour >> 8,

 				    vertex->colour, vertex->colour >> 24 );

 			break;

 		    }

 		}

 	    } else {

 		if( shaded || vertex_count == 1 ) {

 		    switch( colour_type ) {

 		    case POLY_COLOUR_PACKED:

 			glColor4ub( vertex->colour >> 16, vertex->colour >> 8,

 				    vertex->colour, vertex->colour >> 24 );

 			break;

 		    case POLY_COLOUR_FLOAT: 

 			{

 			    struct pvr2_vertex_float *v = (struct pvr2_vertex_float *)cmd_ptr;

 			    glColor4f( v->r, v->g, v->b, v->a );

 			}

 			break;

 		    }

 		}

 	    }

 	    glVertex3f( vertex->x, vertex->y, vertex->z );

 	    if( cmd == PVR2_CMD_VERTEX_LAST ) {

 		glEnd();

 		vertex_count = 0;

 	    }

 	    break;

 	default:

 	    ERROR( "Unhandled command %08X in display list", *cmd_ptr );

 	    pvr2_dump_display_list( display_list, length );

 	    return;

 	}

 	cmd_ptr += 8; /* Next record */

     }

 }

 #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)) )

 /**

  * Render the background plane as best we can. Unfortunately information

  * is a little scant, to say the least.

  */

 void pvr2_render_draw_backplane( uint32_t mode, uint32_t *poly )

 {

     if( (mode >> 24) == 0x01 ) {

 	/* Packed colour. I think */

 	pvr2_bgplane_packed_t bg = (pvr2_bgplane_packed_t)poly;

 	if( bg->colour1 != bg->colour2 || bg->colour2 != bg->colour3 ) {

 	    WARN( "Multiple background colours specified. Confused" );

 	}

 	float x1 = MIN3( bg->x1, bg->x2, bg->x3 );

 	float y1 = MIN3( bg->y1, bg->y2, bg->y3 );

 	float x2 = MAX3( bg->x1, bg->x2, bg->x3 );

 	float y2 = MAX3( bg->y1, bg->y2, bg->y3 );

 	float z = MIN3( bg->z1, bg->z2, bg->z3 );

 	glDisable( GL_TEXTURE_2D );

 	glDisable( GL_DEPTH_TEST );

 	glColor3ub( (uint8_t)(bg->colour1 >> 16), (uint8_t)(bg->colour1 >> 8), 

 		    (uint8_t)bg->colour1 );

 	glBegin( GL_QUADS );

 	glVertex3f( x1, y1, z );

 	glVertex3f( x2, y1, z );

 	glVertex3f( x2, y2, z );

 	glVertex3f( x1, y2, z );

 	glEnd();

     } else {

 	WARN( "Unknown bgplane mode: %08X", mode );

 	fwrite_dump( poly, 48, stderr );

     }

 }

 /**

  * Render a complete scene into the OpenGL back buffer.

  * Note: this will probably need to be broken up eventually once timings are

  * determined.

  */

 void pvr2_render_scene( )

 {

     struct tile_descriptor *tile_desc =

 	(struct tile_descriptor *)mem_get_region(PVR2_RAM_BASE + MMIO_READ( PVR2, TILEBASE ));

     uint32_t render_addr = MMIO_READ( PVR2, RENDADDR1 );

     gboolean render_to_tex;

     if( render_addr & 0x01000000 ) {

 	render_addr = (render_addr & 0x00FFFFFF) + PVR2_RAM_BASE_INT;

 	/* Heuristic - if we're rendering to the interlaced region we're

 	 * probably creating a texture rather than rendering actual output.

 	 * We can optimise for this case a little

 	 */

 	render_to_tex = TRUE;

 	WARN( "Render to texture not supported properly yet" );

     } else {

 	render_addr = (render_addr & 0x00FFFFFF) + PVR2_RAM_BASE;

 	render_to_tex = FALSE;

     }

     float bgplanez = MMIO_READF( PVR2, BGPLANEZ );

     uint32_t render_mode = MMIO_READ( PVR2, RENDMODE );

     int width = 640; /* FIXME - get this from the tile buffer */

     int height = 480;

     int colour_format = pvr2_render_colour_format[render_mode&0x07];

     pvr2_render_prepare_context( render_addr, width, height, colour_format, 

 				 bgplanez, render_to_tex );

     uint32_t *display_list = 

 	(uint32_t *)mem_get_region(PVR2_RAM_BASE + MMIO_READ( PVR2, OBJBASE ));

     uint32_t display_length = *display_list++;

     int clip_x = MMIO_READ( PVR2, HCLIP ) & 0x03FF;

     int clip_y = MMIO_READ( PVR2, VCLIP ) & 0x03FF;

     int clip_width = ((MMIO_READ( PVR2, HCLIP ) >> 16) & 0x03FF) - clip_x + 1;

     int clip_height= ((MMIO_READ( PVR2, VCLIP ) >> 16) & 0x03FF) - clip_y + 1;

     if( clip_x == 0 && clip_y == 0 && clip_width == width && clip_height == height ) {

 	glDisable( GL_SCISSOR_TEST );

     } else {

 	glEnable( GL_SCISSOR_TEST );

 	glScissor( clip_x, clip_y, clip_width, clip_height );

     }

     /* Fog setup goes here */

     /* Render the background plane */

     uint32_t bgplane_mode = MMIO_READ(PVR2, BGPLANE);

     uint32_t *bgplane = display_list + (((bgplane_mode & 0x00FFFFFF)) >> 3) - 1;

     pvr2_render_draw_backplane( bgplane_mode, bgplane );

     /* Render the display list */

     pvr2_render_display_list( display_list, display_length );

     /* Post-render cleanup and update */

     /* Add frame, fps, etc data */

     glPrintf( 4, 16, "Frame %d", pvr2_get_frame_count() );

     /* Generate end of render event */

     asic_event( EVENT_PVR_RENDER_DONE );

     DEBUG( "Rendered frame %d", pvr2_get_frame_count() );

 }

 /**

  * Flush the indicated render buffer back to PVR. Caller is responsible for

  * tracking whether there is actually anything in the buffer.

  *

  * @param buffer A render buffer indicating the address to store to, and the

  * format the data needs to be in.

  * @param backBuffer TRUE to flush the back buffer, FALSE for 

  * the front buffer.

  */

 void pvr2_render_copy_to_sh4( pvr2_render_buffer_t buffer, 

 			      gboolean backBuffer )

 {

     if( buffer->render_addr == -1 )

 	return;

     GLenum type, format = GL_RGBA;

     int size = buffer->width * buffer->height;

     switch( buffer->colour_format ) {

     case COLFMT_RGB565: 

 	type = GL_UNSIGNED_SHORT_5_6_5; 

 	format = GL_RGB; 

 	size <<= 1;

 	break;

     case COLFMT_RGB888: 

 	type = GL_UNSIGNED_INT; 

 	format = GL_RGB;

 	size = (size<<1)+size;

 	break;

     case COLFMT_ARGB1555: 

 	type = GL_UNSIGNED_SHORT_5_5_5_1; 

 	size <<= 1;

 	break;

     case COLFMT_ARGB4444: 

 	type = GL_UNSIGNED_SHORT_4_4_4_4; 

 	size <<= 1;

 	break;

     case COLFMT_ARGB8888: 

 	type = GL_UNSIGNED_INT_8_8_8_8; 

 	size <<= 2;

 	break;

     }

     if( backBuffer ) {

 	glFinish();

 	glReadBuffer( GL_BACK );

     } else {

 	glReadBuffer( GL_FRONT );

     }

     if( buffer->render_addr & 0xFF000000 == 0x04000000 ) {

 	/* Interlaced buffer. Go the double copy... :( */

 	char target[size];

 	glReadPixels( 0, 0, buffer->width, buffer->height, format, type, target );

 	pvr2_vram64_write( buffer->render_addr, target, size );

     } else {

 	/* Regular buffer - go direct */

 	char *target = mem_get_region( buffer->render_addr );

 	glReadPixels( 0, 0, buffer->width, buffer->height, format, type, target );

     }

 }

 /**

  * Copy data from PVR ram into the GL render buffer. 

  *

  * @param buffer A render buffer indicating the address to read from, and the

  * format the data is in.

  * @param backBuffer TRUE to write the back buffer, FALSE for 

  * the front buffer.

  */

 void pvr2_render_copy_from_sh4( pvr2_render_buffer_t buffer, 

 				gboolean backBuffer )

 {

     if( buffer->render_addr == -1 )

 	return;

     GLenum type, format = GL_RGBA;

     int size = buffer->width * buffer->height;

     switch( buffer->colour_format ) {

     case COLFMT_RGB565: 

 	type = GL_UNSIGNED_SHORT_5_6_5; 

 	format = GL_RGB; 

 	size <<= 1;

 	break;

     case COLFMT_RGB888: 

 	type = GL_UNSIGNED_INT; 

 	format = GL_RGB;

 	size = (size<<1)+size;

 	break;

     case COLFMT_ARGB1555: 

 	type = GL_UNSIGNED_SHORT_5_5_5_1; 

 	size <<= 1;

 	break;

     case COLFMT_ARGB4444: 

 	type = GL_UNSIGNED_SHORT_4_4_4_4; 

 	size <<= 1;

 	break;

     case COLFMT_ARGB8888: 

 	type = GL_UNSIGNED_INT_8_8_8_8; 

 	size <<= 2;

 	break;

     }

     if( backBuffer ) {

 	glDrawBuffer( GL_BACK );

     } else {

 	glDrawBuffer( GL_FRONT );

     }

     glRasterPos2i( 0, 0 );

     if( buffer->render_addr & 0xFF000000 == 0x04000000 ) {

 	/* Interlaced buffer. Go the double copy... :( */

 	char target[size];

 	pvr2_vram64_read( target, buffer->render_addr, size );

 	glDrawPixels( buffer->width, buffer->height, 

 		      format, type, target );

     } else {

 	/* Regular buffer - go direct */

 	char *target = mem_get_region( buffer->render_addr );

 	glDrawPixels( buffer->width, buffer->height, 

 		      format, type, target );

     }

 }