/**

 * $Id$

 *

 * Standard OpenGL rendering engine. 

 *

 * 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 <assert.h>

#include <sys/time.h>

#include "display.h"

#include "pvr2/pvr2.h"

#include "pvr2/scene.h"

#include "pvr2/glutil.h"

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

				      GL_GREATER, GL_NOTEQUAL, GL_GEQUAL, 

				      GL_ALWAYS };

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 };

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 };

int pvr2_poly_texblend[4] = {

    GL_REPLACE, 

    GL_MODULATE,  

    GL_DECAL, 

    GL_MODULATE 

};

int pvr2_render_colour_format[8] = {

    COLFMT_BGRA1555, COLFMT_RGB565, COLFMT_BGRA4444, COLFMT_BGRA1555,

    COLFMT_BGR888, COLFMT_BGRA8888, COLFMT_BGRA8888, COLFMT_BGRA4444 };

/**

 * Clip the tile bounds to the clipping plane. 

 * @return TRUE if the tile was not clipped completely.

 */

static gboolean clip_tile_bounds( uint32_t *tile, float *clip )

{

    if( tile[0] < clip[0] ) tile[0] = clip[0];

    if( tile[1] > clip[1] ) tile[1] = clip[1];

    if( tile[2] < clip[2] ) tile[2] = clip[2];

    if( tile[3] > clip[3] ) tile[3] = clip[3];

    return tile[0] < tile[1] && tile[2] < tile[3];

}

void pvr2_scene_load_textures()

{

    int i;

    for( i=0; i < pvr2_scene.poly_count; i++ ) {

	struct polygon_struct *poly = &pvr2_scene.poly_array[i];

	if( POLY1_TEXTURED(poly->context[0]) ) {

	    poly->tex_id = texcache_get_texture( poly->context[2],

						 POLY2_TEX_WIDTH(poly->context[1]),

						 POLY2_TEX_HEIGHT(poly->context[1]) );

	    if( poly->mod_vertex_index != -1 ) {

		poly->mod_tex_id = texcache_get_texture( poly->context[4],

							 POLY2_TEX_WIDTH(poly->context[3]),

							 POLY2_TEX_HEIGHT(poly->context[3]) );

	    }

	} else {

	    poly->tex_id = -1;

	    poly->mod_tex_id = -1;

	}

    }

}

/**

 * Once-off call to setup the OpenGL context.

 */

void pvr2_setup_gl_context()

{

    if( glsl_is_supported() ) {

    	if( !glsl_load_shaders( glsl_vertex_shader_src, NULL ) ) {

            WARN( "Unable to load GL shaders" );

        }

    }

    texcache_gl_init(); // Allocate texture IDs

    glCullFace( GL_BACK );

    glEnable( GL_BLEND );

    glEnable( GL_DEPTH_TEST );

    glHint(GL_PERSPECTIVE_CORRECTION_HINT, GL_NICEST);

    glMatrixMode(GL_MODELVIEW);

    glLoadIdentity();

    glEnableClientState( GL_COLOR_ARRAY );

    glEnableClientState( GL_VERTEX_ARRAY );

    glEnableClientState( GL_TEXTURE_COORD_ARRAY );

    glEnableClientState( GL_SECONDARY_COLOR_ARRAY );

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

    glClearDepth(0);

    glClearStencil(0);

}

/**

 * 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];

    }

    glDepthFunc( POLY1_DEPTH_MODE(poly1) );

    glDepthMask( POLY1_DEPTH_WRITE(poly1) ? GL_TRUE : GL_FALSE );

    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_SPECULAR(poly1) ) {

	glEnable(GL_COLOR_SUM);

    } else {

	glDisable(GL_COLOR_SUM);

    }

    if( POLY1_TEXTURED(poly1) ) {

	glEnable(GL_TEXTURE_2D);

	glTexEnvi( GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, pvr2_poly_texblend[POLY2_TEX_BLEND(poly2)] );

	if( POLY2_TEX_CLAMP_U(poly2) ) {

	    glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP );

	} else if( POLY2_TEX_MIRROR_U(poly2) ) {

	    glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_MIRRORED_REPEAT_ARB );

	} else {

	    glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT );

	}	    

	if( POLY2_TEX_CLAMP_V(poly2) ) {

	    glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP );

	} else if( POLY2_TEX_MIRROR_V(poly2) ) {

	    glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_MIRRORED_REPEAT_ARB );

	} else {

	    glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT );

	}

    } else {

	glDisable( GL_TEXTURE_2D );

    }

    glShadeModel( POLY1_SHADE_MODEL(poly1) );

    int srcblend = POLY2_SRC_BLEND(poly2);

    int destblend = POLY2_DEST_BLEND(poly2);

    glBlendFunc( srcblend, destblend );

    if( POLY2_SRC_BLEND_TARGET(poly2) || POLY2_DEST_BLEND_TARGET(poly2) ) {

	ERROR( "Accumulation buffer not supported" );

    }

}

static void gl_render_poly( struct polygon_struct *poly )

{

    if( poly->tex_id != -1 ) {

	glBindTexture(GL_TEXTURE_2D, poly->tex_id);

    }

    render_set_context( poly->context, RENDER_NORMAL );

    glDrawArrays(GL_TRIANGLE_STRIP, poly->vertex_index, poly->vertex_count );

}

void gl_render_tilelist( pvraddr_t tile_entry )

{

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

    int strip_count;

    struct polygon_struct *poly;

    while(1) {

	uint32_t entry = *tile_list++;

	switch( entry >> 28 ) {

	case 0x0F:

	    return; // End-of-list

	case 0x0E:

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

	    break;

	case 0x08: case 0x09: case 0x0A: case 0x0B:

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

	    poly = pvr2_scene.buf_to_poly_map[entry&0x000FFFFF];

	    while( strip_count > 0 ) {

		assert( poly != NULL );

		gl_render_poly( poly );

		poly = poly->next;

		strip_count--;

	    }

	    break;

	default:

	    if( entry & 0x7E000000 ) {

		poly = pvr2_scene.buf_to_poly_map[entry&0x000FFFFF];

		gl_render_poly( poly );

	    }

	}

    }	    

}

/**

 * Render the currently defined scene in pvr2_scene

 */

void pvr2_scene_render( render_buffer_t buffer )

{

    /* Scene setup */

    struct timeval start_tv, tex_tv, end_tv;

    gettimeofday(&start_tv, NULL);

    display_driver->set_render_target(buffer);

    pvr2_check_palette_changed();

    pvr2_scene_load_textures();

    gettimeofday( &tex_tv, NULL );

    uint32_t ms = (tex_tv.tv_sec - start_tv.tv_sec) * 1000 +

        (tex_tv.tv_usec - start_tv.tv_usec)/1000;

    DEBUG( "Scene setup in %dms", ms );

    /* Setup view projection matrix */

    glMatrixMode(GL_PROJECTION);

    glLoadIdentity();

    float nearz = pvr2_scene.bounds[4];

    float farz = pvr2_scene.bounds[5];

    if( nearz == farz ) {

	farz*= 2.0;

    }

    glOrtho( 0, pvr2_scene.buffer_width, pvr2_scene.buffer_height, 0, 

    	     -farz, -nearz );

    float alphaRef = ((float)(MMIO_READ(PVR2, RENDER_ALPHA_REF)&0xFF)+1)/256.0;

    glAlphaFunc( GL_GEQUAL, alphaRef );

    /* Clear the buffer (FIXME: May not want always want to do this) */

    glDisable( GL_SCISSOR_TEST );

    glDepthMask( GL_TRUE );

    glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT | GL_STENCIL_BUFFER_BIT );

    /* Setup vertex array pointers */

    glInterleavedArrays(GL_T2F_C4UB_V3F, sizeof(struct vertex_struct), pvr2_scene.vertex_array);

    glSecondaryColorPointerEXT(3, GL_UNSIGNED_BYTE, sizeof(struct vertex_struct), &pvr2_scene.vertex_array[0].offset_rgba );

    /* Turn on the shaders (if available) */

    glsl_enable_shaders(TRUE);

    uint32_t bgplane_mode = MMIO_READ(PVR2, RENDER_BGPLANE);

    uint32_t *bgplane = pvr2_scene.pvr2_pbuf + (((bgplane_mode & 0x00FFFFFF)) >> 3) ;

    render_backplane( bgplane, pvr2_scene.buffer_width, pvr2_scene.buffer_height, bgplane_mode );

    glEnable( GL_SCISSOR_TEST );

    /* Process the segment list */

    struct tile_segment *segment = pvr2_scene.segment_list;

    do {

	int tilex = SEGMENT_X(segment->control);

	int tiley = SEGMENT_Y(segment->control);

	uint32_t tile_bounds[4] = { tilex << 5, (tilex+1)<<5, tiley<<5, (tiley+1)<<5 };

	if( !clip_tile_bounds(tile_bounds, pvr2_scene.bounds) ) {

	    continue; // fully clipped, skip tile

	}

	/* Clip to the visible part of the tile */

	glScissor( tile_bounds[0], pvr2_scene.buffer_height-tile_bounds[3], 

		   tile_bounds[1]-tile_bounds[0], tile_bounds[3] - tile_bounds[2] );

	if( IS_TILE_PTR(segment->opaque_ptr) ) {

	    gl_render_tilelist(segment->opaque_ptr);

	}

	if( IS_TILE_PTR(segment->trans_ptr) ) {

	    if( pvr2_scene.sort_mode == SORT_NEVER || 

		(pvr2_scene.sort_mode == SORT_TILEFLAG && (segment->control&SEGMENT_SORT_TRANS))) {

		gl_render_tilelist(segment->trans_ptr);

	    } else {

		render_autosort_tile(segment->trans_ptr, RENDER_NORMAL );

	    }

	}

	if( IS_TILE_PTR(segment->punchout_ptr) ) {

	    glEnable(GL_ALPHA_TEST );

	    render_autosort_tile(segment->punchout_ptr, RENDER_NORMAL );

	    glDisable(GL_ALPHA_TEST );

	}

    } while( !IS_LAST_SEGMENT(segment++) );

    glDisable( GL_SCISSOR_TEST );

    glsl_enable_shaders(FALSE);

    gettimeofday( &end_tv, NULL );

    ms = (end_tv.tv_sec - tex_tv.tv_sec) * 1000 +

        (end_tv.tv_usec - tex_tv.tv_usec)/1000;

    DEBUG( "Scene render in %dms", ms );

}