/**

  * $Id$

  *

  * 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 = x1; video_box.gap1[2].y = video_height;

         video_box.gap1[3].x = 0; 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 = video_width; video_box.gap2[2].y = video_height;

         video_box.gap2[3].x = x2; 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 = video_width; video_box.gap1[2].y = y1;

         video_box.gap1[3].x = 0; 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 = video_width; video_box.gap2[2].y = video_height;

         video_box.gap2[3].x = 0; 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 = 0; 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 = 1; video_box.video_view[1].v = top;

     video_box.video_view[2].x = x2; video_box.video_view[2].y = y2;

     video_box.video_view[2].u = 1; video_box.video_view[2].v = bottom;

     video_box.video_view[3].x = x1; video_box.video_view[3].y = y2;

     video_box.video_view[3].u = 0; 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);

     }

 }

 /**

  * Use quads if we have them, otherwise tri-fans.

  */

 #ifndef GL_QUADS

 #define GL_QUADS GL_TRIANGLE_FAN

 #endif

 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_QUADS, 0, 4);

     glDrawArrays(GL_QUADS, 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_QUADS, 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_QUADS, 0, 4);

     glDrawArrays(GL_QUADS, 4, 4);

     glDrawArrays(GL_QUADS, 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);

 }