/**

 * $Id: render.c,v 1.2 2006-03-13 12:39:07 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_ARGB8888 0x00000000

#define POLY_COLOUR_ARGBFLOAT 0x00000010

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_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)

#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] )

extern uint32_t pvr2_frame_counter;

/**

 * 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 {

    uint32_t render_addr; /* The actual address rendered to in pvr ram */

    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_basic {

    uint32_t command;

    float x, y, z;

    float s,t;

    uint32_t col;

    float f;

};

void pvr2_render_copy_to_sh4( pvr2_render_buffer_t buffer, 

			      gboolean backBuffer );

gboolean pvr2_render_init( void )

{

    front_buffer.render_addr = -1;

    back_buffer.render_addr = -1;

}

/**

 * 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 

	 */

	video_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, 

					 gboolean texture_target )

{

    /* Select and initialize the render context */

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

    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;

    /* 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, 0, 65535 );

    glMatrixMode(GL_MODELVIEW);

    glLoadIdentity();

    /* Clear out the buffers */

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

    glClearDepth(1.0f);

    glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT );

}

static void pvr2_render_display_list( uint32_t *display_list, uint32_t length )

{

    uint32_t *cmd_ptr = display_list;

    int expect_vertexes = 0;

    gboolean textured = FALSE;

    struct pvr2_poly *poly;

    while( cmd_ptr < display_list+length ) {

	switch( *cmd_ptr >> 24 ) {

	case PVR2_CMD_POLY_OPAQUE:

	    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);

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

		textured = TRUE;

		glEnable( GL_TEXTURE_2D );

	    } 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 );

	    }

	    expect_vertexes = POLY_STRIP_VERTEXES( poly );

	    if( expect_vertexes == 3 )

		glBegin( GL_TRIANGLES );

	    else if( expect_vertexes == 4 )

		glBegin( GL_QUADS );

	    else 

		glBegin( GL_TRIANGLE_STRIP );

	    break;

	case PVR2_CMD_VERTEX_LAST:

	case PVR2_CMD_VERTEX:

	    if( expect_vertexes == 0 ) {

		ERROR( "Unexpected vertex!" );

		return;

	    }

	    expect_vertexes--;

	    struct pvr2_vertex_basic *vertex = (struct pvr2_vertex_basic *)cmd_ptr;

	    if( textured ) {

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

	    }

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

	    if( expect_vertexes == 0 )

		glEnd();

	    break;

	}

	cmd_ptr += 8; /* Next record */

    }

}

/**

 * 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;

    } else {

	render_addr = (render_addr & 0x00FFFFFF) + PVR2_RAM_BASE;

	render_to_tex = FALSE;

    }

    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, 

				 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 display list */

    pvr2_render_display_list( display_list, display_length );

    /* Post-render cleanup and update */

    /* Generate end of render event */

    asic_event( EVENT_PVR_RENDER_DONE );

    DEBUG( "Rendered frame %d", pvr2_frame_counter );

}

/**

 * 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 );

    }

}