/**

 * $Id: render.c,v 1.19 2007-01-25 08:18:03 nkeynes Exp $

 *

 * PVR2 Renderer support. This part is primarily

 *

 * 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"

struct pvr2_render_buffer front_buffer;

struct pvr2_render_buffer back_buffer;

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;

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 );

    glDisable( GL_CULL_FACE );

    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;

}

void glDrawGrid( int width, int height )

{

    int i;

    glDisable( GL_DEPTH_TEST );

    glLineWidth(1);

    glBegin( GL_LINES );

    glColor4f( 1.0, 1.0, 1.0, 1.0 );

    for( i=32; i<width; i+=32 ) {

	glVertex3f( i, 0.0, 3.0 );

	glVertex3f( i,height-1, 3.0 );

    }

    for( i=32; i<height; i+=32 ) {

	glVertex3f( 0.0, i, 3.0 );

	glVertex3f( width, i, 3.0 );

    }

    glEnd();

}

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_buffer_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_buffer_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_buffer_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, float nearz,

					 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_buffer_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, -(nearz+1) );

    glMatrixMode(GL_MODELVIEW);

    glLoadIdentity();

    glCullFace( GL_BACK );

    glEnable( GL_BLEND );

    /* Clear out the buffers */

    glDisable( GL_SCISSOR_TEST );

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

    glClearDepth(0);

    glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT );

}

/**

 * 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, RENDER_TILEBASE ));

    uint32_t render_addr = MMIO_READ( PVR2, RENDER_ADDR1 );

    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, RENDER_FARCLIP );

    uint32_t render_mode = MMIO_READ( PVR2, RENDER_MODE );

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

    int height = 480;

    int colour_format = pvr2_render_colour_format[render_mode&0x07];

    float maxz = pvr2_render_find_maximum_z();

    pvr2_render_prepare_context( render_addr, width, height, colour_format, 

				 bgplanez, maxz, render_to_tex );

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

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

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

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

    /* Fog setup goes here */

    /* Render the background plane */

    uint32_t bgplane_mode = MMIO_READ(PVR2, RENDER_BGPLANE);

    uint32_t *display_list = 

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

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

    render_backplane( bgplane, width, height, bgplane_mode );

    pvr2_render_tilebuffer( width, height, clip_x, clip_y, 

			    clip_x + clip_width, clip_y + clip_height );

    /* Post-render cleanup and update */

    /* Add frame, fps, etc data */

    //glDrawGrid( width, height );

    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() );

}