/**

 * $Id$

 *

 * Common GL code that doesn't depend on a specific implementation

 *

 * 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 <sys/time.h>

#include "display.h"

#include "pvr2/pvr2.h"

#include "pvr2/glutil.h"

#include "pvr2/shaders.h"

#include "drivers/video_gl.h"

/* FIXME: Need to actually handle this case */

#ifndef GL_PACK_ROW_LENGTH

#define glPixelStorei(key,val)

#endif

uint32_t video_width, video_height;

struct video_vertex {

    float x,y;

    float u,v;

    float r,g,b,a;

};

static struct video_box_t {

    float viewMatrix[16];

    struct video_vertex gap1[4];

    struct video_vertex gap2[4];

    struct video_vertex video_view[4];

    struct video_vertex invert_view[4];

} video_box;

void gl_set_video_size( uint32_t width, uint32_t height, int flipped )

{

    video_width = width;

    video_height = height;

    int x1=0,y1=0,x2=video_width,y2=video_height;

    int top = 0, bottom = 1;

    if( flipped ) {

        top = 1;

        bottom = 0;

    }

    int ah = video_width * 0.75;

    if( ah > video_height ) {

        int w = (video_height/0.75);

        x1 = (video_width - w)/2;

        x2 -= x1;

        video_box.gap1[0].x = 0; video_box.gap1[0].y = 0;

        video_box.gap1[1].x = x1; video_box.gap1[1].y = 0;

        video_box.gap1[2].x = 0; video_box.gap1[2].y = video_height;

        video_box.gap1[3].x = x2; video_box.gap1[3].y = video_height;

        video_box.gap2[0].x = x2; video_box.gap2[0].y = 0;

        video_box.gap2[1].x = video_width; video_box.gap2[1].y = 0;

        video_box.gap2[2].x = x2; video_box.gap2[2].y = video_height;

        video_box.gap2[3].x = video_width; video_box.gap2[3].y = video_height;

    } else if( ah < video_height ) {

        y1 = (video_height - ah)/2;

        y2 -= y1;

        video_box.gap1[0].x = 0; video_box.gap1[0].y = 0;

        video_box.gap1[1].x = video_width; video_box.gap1[1].y = 0;

        video_box.gap1[2].x = 0; video_box.gap1[2].y = y1;

        video_box.gap1[3].x = video_width; video_box.gap1[3].y = y1;

        video_box.gap2[0].x = 0; video_box.gap2[0].y = y2;

        video_box.gap2[1].x = video_width; video_box.gap2[1].y = y2;

        video_box.gap2[2].x = 0; video_box.gap2[2].y = video_height;

        video_box.gap2[3].x = video_width; video_box.gap2[3].y = video_height;

    }

    video_box.video_view[0].x = x1; video_box.video_view[0].y = y1;

    video_box.video_view[0].u = top; video_box.video_view[0].v = top;

    video_box.video_view[1].x = x2; video_box.video_view[1].y = y1;

    video_box.video_view[1].u = bottom; video_box.video_view[1].v = top;

    video_box.video_view[2].x = x1; video_box.video_view[2].y = y2;

    video_box.video_view[2].u = top; video_box.video_view[2].v = bottom;

    video_box.video_view[3].x = x2; video_box.video_view[3].y = y2;

    video_box.video_view[3].u = bottom; video_box.video_view[3].v = bottom;

    memcpy( &video_box.invert_view, &video_box.video_view, sizeof(video_box.video_view) );

    video_box.invert_view[0].v = bottom; video_box.invert_view[1].v = bottom;

    video_box.invert_view[2].v = top; video_box.invert_view[3].v = top;

    defineOrthoMatrix(video_box.viewMatrix, video_width, video_height, 0, 65535);

}

#ifdef HAVE_OPENGL_FIXEDFUNC

/**

 * Setup the gl context for writes to the display output.

 */

void gl_framebuffer_setup()

{

    glViewport( 0, 0, video_width, video_height );

    glLoadMatrixf(video_box.viewMatrix);

    glBlendFunc( GL_ONE, GL_ZERO );

    glTexEnvi( GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_REPLACE );

    glVertexPointer(2, GL_FLOAT, sizeof(struct video_vertex), &video_box.gap1[0].x);

    glColorPointer(3, GL_FLOAT, sizeof(struct video_vertex), &video_box.gap1[0].r);

    glTexCoordPointer(2, GL_FLOAT, sizeof(struct video_vertex), &video_box.gap1[0].u);

    glEnableClientState( GL_VERTEX_ARRAY );

    glEnableClientState( GL_COLOR_ARRAY );

    glEnableClientState( GL_TEXTURE_COORD_ARRAY );

}

void gl_framebuffer_cleanup()

{

    glDisableClientState( GL_VERTEX_ARRAY );

    glDisableClientState( GL_COLOR_ARRAY );

    glDisableClientState( GL_TEXTURE_COORD_ARRAY );

}

#else

void gl_framebuffer_setup()

{

    glViewport( 0, 0, video_width, video_height );

    glBlendFunc( GL_ONE, GL_ZERO );

    glsl_use_basic_shader();

    glsl_set_basic_shader_view_matrix(video_box.viewMatrix);

    glsl_set_basic_shader_in_vertex_pointer(&video_box.gap1[0].x, sizeof(struct video_vertex));

    glsl_set_basic_shader_in_colour_pointer(&video_box.gap1[0].r, sizeof(struct video_vertex));

    glsl_set_basic_shader_in_texcoord_pointer(&video_box.gap1[0].u, sizeof(struct video_vertex));

    glsl_set_basic_shader_primary_texture(0);

}

void gl_framebuffer_cleanup()

{

    glsl_clear_shader();

}

#endif

void gl_display_render_buffer( render_buffer_t buffer )

{

    gl_texture_window( buffer->width, buffer->height, buffer->buf_id, buffer->inverted );

}

/**

 * Convert window coordinates to dreamcast device coords (640x480) using the 

 * same viewable area as gl_texture_window.

 * If the coordinates are outside the viewable area, the result is -1,-1.

 */ 

void gl_window_to_system_coords( int *x, int *y )

{

    int x1=0,y1=0,x2=video_width,y2=video_height;

    int ah = video_width * 0.75;

    if( ah > video_height ) {

        int w = (video_height/0.75);

        x1 = (video_width - w)/2;

        x2 -= x1;

    } else if( ah < video_height ) {

        y1 = (video_height - ah)/2;

        y2 -= y1;

    }

    if( *x < x1 || *x >= x2 || *y < y1 || *y >= y2 ) {

        *x = -1;

        *y = -1;

    } else {

        *x = (*x - x1) * DISPLAY_WIDTH / (x2-x1);

        *y = (*y - y1) * DISPLAY_HEIGHT / (y2-y1);

    }

}

void gl_texture_window( int width, int height, int tex_id, gboolean inverted )

{

    /* Set video box tex alpha to 1 */

    video_box.video_view[0].a = video_box.video_view[1].a = video_box.video_view[2].a = video_box.video_view[3].a = 1;

    video_box.invert_view[0].a = video_box.invert_view[1].a = video_box.invert_view[2].a = video_box.invert_view[3].a = 1;

    /* Reset display parameters */

    gl_framebuffer_setup();

    glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);

    glDrawArrays(GL_TRIANGLE_STRIP, 4, 4);

    glEnable(GL_TEXTURE_2D);

    glBindTexture(GL_TEXTURE_2D,tex_id);

    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);

    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);

    glDrawArrays(GL_TRIANGLE_STRIP, inverted ? 12 : 8, 4);

    glDisable(GL_TEXTURE_2D);

    gl_framebuffer_cleanup();

    glFlush();

}

gboolean gl_load_frame_buffer( frame_buffer_t frame, int tex_id )

{

    GLenum type = colour_formats[frame->colour_format].type;

    GLenum format = colour_formats[frame->colour_format].format;

    int bpp = colour_formats[frame->colour_format].bpp;

    int rowstride = (frame->rowstride / bpp) - frame->width;

    glPixelStorei( GL_UNPACK_ROW_LENGTH, rowstride );

    glBindTexture( GL_TEXTURE_2D, tex_id );

    glTexSubImage2D( GL_TEXTURE_2D, 0, 0,0,

                     frame->width, frame->height, format, type, frame->data );

    glPixelStorei( GL_UNPACK_ROW_LENGTH, 0 );

    return TRUE;

}

void gl_display_blank( uint32_t colour )

{

    /* Set the video_box background colour */

    video_box.video_view[0].r = ((float)(((colour >> 16) & 0xFF) + 1)) / 256.0;

    video_box.video_view[0].g = ((float)(((colour >> 8) & 0xFF) + 1)) / 256.0;

    video_box.video_view[0].b = ((float)((colour & 0xFF) + 1)) / 256.0;

    video_box.video_view[0].a = 0;

    memcpy( &video_box.video_view[1].r, &video_box.video_view[0].r, sizeof(float)*3 );

    memcpy( &video_box.video_view[2].r, &video_box.video_view[0].r, sizeof(float)*3 );

    memcpy( &video_box.video_view[3].r, &video_box.video_view[0].r, sizeof(float)*3 );

    /* And render */

    gl_framebuffer_setup();

    glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);

    glDrawArrays(GL_TRIANGLE_STRIP, 4, 4);

    glDrawArrays(GL_TRIANGLE_STRIP, 8, 4);

    gl_framebuffer_cleanup();

    glFlush();

}

/**

 * Generic GL read_render_buffer. This function assumes that the caller

 * has already set the appropriate glReadBuffer(); in other words, unless

 * there's only one buffer this needs to be wrapped.

 */

gboolean gl_read_render_buffer( unsigned char *target, render_buffer_t buffer, 

                                int rowstride, int colour_format ) 

{

    glFinish();

    GLenum type = colour_formats[colour_format].type;

    GLenum format = colour_formats[colour_format].format;

    // int line_size = buffer->width * colour_formats[colour_format].bpp;

    // int size = line_size * buffer->height;

    int glrowstride = (rowstride / colour_formats[colour_format].bpp) - buffer->width;

    glPixelStorei( GL_PACK_ROW_LENGTH, glrowstride );

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

    glPixelStorei( GL_PACK_ROW_LENGTH, 0 );

    return TRUE;

}

gboolean gl_init_driver( display_driver_t driver, gboolean need_fbo )

{

    /* Use framebuffer objects if available */

    if( gl_fbo_is_supported() ) {

        gl_fbo_init(driver);

    } else if( need_fbo ) {

        ERROR( "Framebuffer objects not supported - unable to construct an off-screen buffer" );

        return FALSE;

    }

    /* Use SL shaders if available */

    gboolean have_shaders = glsl_init(driver);

#ifndef HAVE_OPENGL_FIXEDFUNC

    if( !have_shaders ) { /* Shaders are required if we don't have fixed-functionality */

        gl_fbo_shutdown();

        return FALSE;

    }

#endif

    /* Use vertex arrays, VBOs, etc, if we have them */

    gl_vbo_init(driver);

    driver->capabilities.has_gl = TRUE;

    return TRUE;

}

static gboolean video_gl_init();

/**

 * Minimal GL driver (assuming that the GL context is already set up externally)

 * This requires FBO support (since otherwise we have no way to get a render buffer)

 */

struct display_driver display_gl_driver = {

        "gl", N_("OpenGL driver"), video_gl_init, NULL,

        NULL, NULL, NULL,

        NULL, NULL, NULL, NULL,

        gl_load_frame_buffer, gl_display_render_buffer, gl_display_blank,

        NULL, gl_read_render_buffer, NULL, NULL

};

static gboolean video_gl_init()

{

    return gl_init_driver(&display_gl_driver, TRUE);

}