quakeforge/libs/video/renderer/glsl/glsl_fog.c

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/*
Copyright (C) 1996-2001 Id Software, Inc.
Copyright (C) 2002-2009 John Fitzgibbons and others
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.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/
//gl_fog.c -- global and volumetric fog
#ifdef HAVE_CONFIG_H
# include "config.h"
#endif
static __attribute__ ((used)) const char rcsid[] = "$Id$";
#ifdef HAVE_STRING_H
# include <string.h>
#endif
#ifdef HAVE_STRINGS_H
# include <strings.h>
#endif
#include "QF/cmd.h"
#include "QF/qfplist.h"
#include "QF/render.h"
#include "QF/sys.h"
#include "QF/GLSL/defines.h"
#include "QF/GLSL/funcs.h"
#include "compat.h"
#include "r_shared.h"
//==============================================================================
//
// GLOBAL FOG
//
//==============================================================================
static float fog_density;
static float fog_red;
static float fog_green;
static float fog_blue;
static float old_density;
static float old_red;
static float old_green;
static float old_blue;
static float fade_time; //duration of fade
static float fade_done; //time when fade will be done
/*
Fog_Update
update internal variables
*/
void
Fog_Update (float density, float red, float green, float blue, float time)
{
//save previous settings for fade
if (time > 0) {
//check for a fade in progress
if (fade_done > r_realtime) {
float f;
f = (fade_done - r_realtime) / fade_time;
old_density = f * old_density + (1.0 - f) * fog_density;
old_red = f * old_red + (1.0 - f) * fog_red;
old_green = f * old_green + (1.0 - f) * fog_green;
old_blue = f * old_blue + (1.0 - f) * fog_blue;
} else {
old_density = fog_density;
old_red = fog_red;
old_green = fog_green;
old_blue = fog_blue;
}
}
fog_density = density;
fog_red = red;
fog_green = green;
fog_blue = blue;
fade_time = time;
fade_done = r_realtime + time;
}
/*
Fog_FogCommand_f
handle the 'fog' console command
*/
static void
Fog_FogCommand_f (void)
{
switch (Cmd_Argc ()) {
default:
case 1:
Sys_Printf ("usage:\n");
Sys_Printf (" fog <density>\n");
Sys_Printf (" fog <red> <green> <blue>\n");
Sys_Printf (" fog <density> <red> <green> <blue>\n");
Sys_Printf ("current values:\n");
Sys_Printf (" \"density\" is \"%f\"\n", fog_density);
Sys_Printf (" \"red\" is \"%f\"\n", fog_red);
Sys_Printf (" \"green\" is \"%f\"\n", fog_green);
Sys_Printf (" \"blue\" is \"%f\"\n", fog_blue);
break;
case 2:
Fog_Update (max (0.0, atof (Cmd_Argv (1))),
fog_red, fog_green, fog_blue, 0.0);
break;
case 3: //TEST
Fog_Update (max (0.0, atof (Cmd_Argv (1))),
fog_red, fog_green, fog_blue, atof (Cmd_Argv (2)));
break;
case 4:
Fog_Update (fog_density,
bound (0.0, atof (Cmd_Argv (1)), 1.0),
bound (0.0, atof (Cmd_Argv (2)), 1.0),
bound (0.0, atof (Cmd_Argv (3)), 1.0),
0.0);
break;
case 5:
Fog_Update (max (0.0, atof (Cmd_Argv (1))),
bound (0.0, atof (Cmd_Argv (2)), 1.0),
bound (0.0, atof (Cmd_Argv (3)), 1.0),
bound (0.0, atof (Cmd_Argv (4)), 1.0),
0.0);
break;
case 6: //TEST
Fog_Update (max (0.0, atof (Cmd_Argv (1))),
bound (0.0, atof (Cmd_Argv (2)), 1.0),
bound (0.0, atof (Cmd_Argv (3)), 1.0),
bound (0.0, atof (Cmd_Argv (4)), 1.0),
atof (Cmd_Argv (5)));
break;
}
}
/*
Fog_ParseWorldspawn
called at map load
*/
void
Fog_ParseWorldspawn (plitem_t *worldspawn)
{
plitem_t *fog;
const char *value;
//initially no fog
fog_density = 0.0;
old_density = 0.0;
fade_time = 0.0;
fade_done = 0.0;
if (!worldspawn)
return; // error
if ((fog = PL_ObjectForKey (worldspawn, "fog"))
&& (value = PL_String (fog))) {
sscanf (value, "%f %f %f %f", &fog_density,
&fog_red, &fog_green, &fog_blue);
}
}
/*
Fog_GetColor
calculates fog color for this frame, taking into account fade times
*/
float *
Fog_GetColor (void)
{
static float c[4];
float f;
int i;
if (fade_done > r_realtime) {
f = (fade_done - r_realtime) / fade_time;
c[0] = f * old_red + (1.0 - f) * fog_red;
c[1] = f * old_green + (1.0 - f) * fog_green;
c[2] = f * old_blue + (1.0 - f) * fog_blue;
c[3] = 1.0;
} else {
c[0] = fog_red;
c[1] = fog_green;
c[2] = fog_blue;
c[3] = 1.0;
}
//find closest 24-bit RGB value, so solid-colored sky can match the fog
//perfectly
for (i = 0; i < 3; i++)
c[i] = (float) (rint (c[i] * 255)) / 255.0f;
return c;
}
/*
Fog_GetDensity
returns current density of fog
*/
float
Fog_GetDensity (void)
{
float f;
if (fade_done > r_realtime) {
f = (fade_done - r_realtime) / fade_time;
return f * old_density + (1.0 - f) * fog_density;
} else {
return fog_density;
}
}
/*
Fog_Init
called when quake initializes
*/
void
Fog_Init (void)
{
Cmd_AddCommand ("fog", Fog_FogCommand_f, "");
//Cvar_RegisterVariable (&r_vfog, NULL);
//set up global fog
fog_density = 0.0;
fog_red = 0.3;
fog_green = 0.3;
fog_blue = 0.3;
}