ref: c7dca7cbc24c38f3834713e1f62b953a97a137b3
dir: /src/i_video.c/
// Emacs style mode select -*- C++ -*-
//-----------------------------------------------------------------------------
//
// $Id: i_video.c 283 2006-01-12 01:34:48Z fraggle $
//
// Copyright(C) 1993-1996 Id Software, Inc.
// Copyright(C) 2005 Simon Howard
//
// 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.
//
// $Log$
// Revision 1.43 2006/01/12 01:34:48 fraggle
// Combine mouse motion for tics into single events.
//
// Revision 1.42 2006/01/02 20:27:45 fraggle
// Clear the screen AFTER initialising the loading disk buffer, so that
// bits of loading disk are not visible on the initial screen melt.
//
// Revision 1.41 2006/01/02 00:06:30 fraggle
// Make functions static. Remove unused variable.
//
// Revision 1.40 2005/10/17 19:46:22 fraggle
// Guard against multiple video shutdowns better. Fix crash due to improper
// screen clear at startup.
//
// Revision 1.39 2005/10/16 20:55:50 fraggle
// Fix the '-cdrom' command-line option.
//
// Revision 1.38 2005/10/15 22:50:57 fraggle
// Fix pink icon on startup
//
// Revision 1.37 2005/10/15 15:59:14 fraggle
// Map mouse buttons correctly.
//
// Revision 1.36 2005/10/15 15:45:03 fraggle
// Check the return code from SDL_LockSurface to ensure a surface has been
// properly locked. Fixes crash when switching applications while running
// fullscreen.
//
// Revision 1.35 2005/10/02 03:16:29 fraggle
// ENDOOM support using text mode emulation
//
// Revision 1.34 2005/10/02 03:03:40 fraggle
// Make sure loading disk is only shown if the display is initialised
//
// Revision 1.33 2005/09/27 22:33:42 fraggle
// Always use SDL_Flip to update the screen. Fixes problems in Windows when
// running fullscreen, introduced by fixes to the disk icon code.
//
// Revision 1.32 2005/09/26 21:44:30 fraggle
// Fix melting crap on startup - oops
//
// Revision 1.31 2005/09/25 00:31:32 fraggle
// Fix disk icon appearing before palette is set (pink disk!)
// Cleanup and commenting
//
// Revision 1.30 2005/09/24 23:44:49 fraggle
// Enforce sane screenmultiply values
//
// Revision 1.29 2005/09/24 23:41:07 fraggle
// Fix "loading" icon for all video modes
//
// Revision 1.28 2005/09/24 22:04:03 fraggle
// Add application icon to running program
//
// Revision 1.27 2005/09/17 20:50:46 fraggle
// Mouse acceleration code to emulate old DOS drivers
//
// Revision 1.26 2005/09/14 21:55:47 fraggle
// Lock surfaces properly when we have to (fixes crash under Windows 98)
//
// Revision 1.25 2005/09/11 20:25:56 fraggle
// Second configuration file to allow chocolate doom-specific settings.
// Adjust some existing command line logic (for graphics settings and
// novert) to adjust for this.
//
// Revision 1.24 2005/09/08 22:05:17 fraggle
// Allow alt-tab away while running fullscreen
//
// Revision 1.23 2005/09/07 20:44:23 fraggle
// Fix up names of functions
// Make the quit button work (pops up the "quit doom?" prompt).
// Fix focus detection to release the mouse and ignore mouse events
// when window is not focused.
//
// Revision 1.22 2005/09/04 23:18:30 fraggle
// Remove dead code. Cope with the screen not having width == pitch. Lock
// the SDL screen surface properly. Rewrite 2x scaling code.
//
// Revision 1.21 2005/09/01 00:01:36 fraggle
// -nograbmouse option
//
// Revision 1.20 2005/08/31 23:58:28 fraggle
// smarter mouse grabbing for windowed mode
//
// Revision 1.19 2005/08/31 21:35:42 fraggle
// Display the game name in the title bar. Move game start code to later
// in initialisation because of the IWAD detection changes.
//
// Revision 1.18 2005/08/10 08:45:35 fraggle
// Remove "if (french)" stuff, FRENCH define, detect french wad automatically
//
// Revision 1.17 2005/08/07 20:01:00 fraggle
// Clear the screen on startup
//
// Revision 1.16 2005/08/07 03:09:33 fraggle
// Fix gamma correction
//
// Revision 1.15 2005/08/07 02:59:23 fraggle
// Clear disk image when loading at startup
//
// Revision 1.14 2005/08/06 17:30:30 fraggle
// Only change palette on screen updates
//
// Revision 1.13 2005/08/04 22:23:07 fraggle
// Use zone memory function. Add command line options
//
// Revision 1.12 2005/08/04 19:54:56 fraggle
// Use keysym value rather than unicode value (fixes problems with shift
// key)
//
// Revision 1.11 2005/08/04 18:42:15 fraggle
// Silence compiler warnings
//
// Revision 1.10 2005/08/04 01:13:46 fraggle
// Loading disk
//
// Revision 1.9 2005/08/03 22:19:52 fraggle
// Set some flags to fix palette and improve performance
//
// Revision 1.8 2005/08/03 21:58:02 fraggle
// Working scale*2
//
// Revision 1.7 2005/07/25 20:50:55 fraggle
// mouse
//
// Revision 1.6 2005/07/24 02:14:04 fraggle
// Move to SDL for graphics.
// Translate key scancodes to correct internal format when reading
// settings from config file - backwards compatible with config files
// for original exes
//
// Revision 1.5 2005/07/23 21:32:47 fraggle
// Add missing errno.h, fix crash on startup when no IWAD present
//
// Revision 1.4 2005/07/23 19:17:11 fraggle
// Use ANSI-standard limit constants. Remove LINUX define.
//
// Revision 1.3 2005/07/23 17:27:04 fraggle
// Stop crash on shutdown
//
// Revision 1.2 2005/07/23 16:44:55 fraggle
// Update copyright to GNU GPL
//
// Revision 1.1.1.1 2005/07/23 16:19:58 fraggle
// Initial import
//
//
// DESCRIPTION:
// DOOM graphics stuff for X11, UNIX.
//
//-----------------------------------------------------------------------------
static const char
rcsid[] = "$Id: i_video.c 283 2006-01-12 01:34:48Z fraggle $";
#include <SDL.h>
#include <ctype.h>
#include <math.h>
#include "chocolate_doom_icon.c"
#include "config.h"
#include "doomdef.h"
#include "doomstat.h"
#include "d_main.h"
#include "i_system.h"
#include "m_argv.h"
#include "m_swap.h"
#include "s_sound.h"
#include "sounds.h"
#include "v_video.h"
#include "w_wad.h"
#include "z_zone.h"
extern void M_QuitDOOM();
static SDL_Surface *screen;
// palette
static SDL_Color palette[256];
static boolean palette_to_set;
static int windowwidth, windowheight;
// display has been set up?
static boolean initialised = false;
// if true, screens[0] is screen->pixel
static boolean native_surface;
// Run in full screen mode? (int type for config code)
int fullscreen = true;
// Grab the mouse? (int type for config code)
int grabmouse = true;
// Flag indicating whether the screen is currently visible:
// when the screen isnt visible, don't render the screen
boolean screenvisible;
// Blocky mode,
// replace each 320x200 pixel with screenmultiply*screenmultiply pixels.
// According to Dave Taylor, it still is a bonehead thing
// to use ....
int screenmultiply = 1;
// disk image data and background overwritten by the disk to be
// restored by EndRead
static byte *disk_image = NULL;
static int disk_image_w, disk_image_h;
static byte *saved_background;
static boolean window_focused;
// mouse acceleration
// We accelerate the mouse by raising the mouse movement values to
// the power of this value, to simulate the acceleration in DOS
// mouse drivers
//
// TODO: See what is a sensible default value for this
float mouse_acceleration = 1.5;
static boolean MouseShouldBeGrabbed()
{
// if the window doesnt have focus, never grab it
if (!window_focused)
return false;
// always grab the mouse when full screen (dont want to
// see the mouse pointer)
if (fullscreen)
return true;
// if we specify not to grab the mouse, never grab
if (!grabmouse)
return false;
// when menu is active or game is paused, release the mouse
if (menuactive || paused)
return false;
// only grab mouse when playing levels (but not demos)
return (gamestate == GS_LEVEL) && !demoplayback;
}
// Update the value of window_focused when we get a focus event
//
// We try to make ourselves be well-behaved: the grab on the mouse
// is removed if we lose focus (such as a popup window appearing),
// and we dont move the mouse around if we aren't focused either.
static void UpdateFocus(void)
{
Uint8 state;
state = SDL_GetAppState();
// We should have input (keyboard) focus and be visible
// (not minimised)
window_focused = (state & SDL_APPINPUTFOCUS) && (state & SDL_APPACTIVE);
// Should the screen be grabbed?
screenvisible = (state & SDL_APPACTIVE) != 0;
}
static void LoadDiskImage(void)
{
patch_t *disk;
int y;
if (M_CheckParm("-cdrom") > 0)
disk = (patch_t *) W_CacheLumpName("STCDROM", PU_STATIC);
else
disk = (patch_t *) W_CacheLumpName("STDISK", PU_STATIC);
V_DrawPatch(0, 0, 0, disk);
disk_image_w = SHORT(disk->width);
disk_image_h = SHORT(disk->height);
disk_image = Z_Malloc(disk_image_w * disk_image_h, PU_STATIC, NULL);
saved_background = Z_Malloc(disk_image_w * disk_image_h, PU_STATIC, NULL);
for (y=0; y<disk_image_h; ++y)
{
memcpy(disk_image + disk_image_w * y,
screens[0] + SCREENWIDTH * y,
disk_image_w);
memset(screens[0] + SCREENWIDTH * y, 0, disk_image_w);
}
Z_Free(disk);
}
//
// Translates the SDL key
//
int TranslateKey(SDL_keysym *sym)
{
switch(sym->sym)
{
case SDLK_LEFT: return KEY_LEFTARROW;
case SDLK_RIGHT: return KEY_RIGHTARROW;
case SDLK_DOWN: return KEY_DOWNARROW;
case SDLK_UP: return KEY_UPARROW;
case SDLK_ESCAPE: return KEY_ESCAPE;
case SDLK_RETURN: return KEY_ENTER;
case SDLK_TAB: return KEY_TAB;
case SDLK_F1: return KEY_F1;
case SDLK_F2: return KEY_F2;
case SDLK_F3: return KEY_F3;
case SDLK_F4: return KEY_F4;
case SDLK_F5: return KEY_F5;
case SDLK_F6: return KEY_F6;
case SDLK_F7: return KEY_F7;
case SDLK_F8: return KEY_F8;
case SDLK_F9: return KEY_F9;
case SDLK_F10: return KEY_F10;
case SDLK_F11: return KEY_F11;
case SDLK_F12: return KEY_F12;
case SDLK_BACKSPACE: return KEY_BACKSPACE;
case SDLK_DELETE: return KEY_DEL;
case SDLK_PAUSE: return KEY_PAUSE;
case SDLK_EQUALS:
case SDLK_KP_EQUALS: return KEY_EQUALS;
case SDLK_MINUS: return KEY_MINUS;
case SDLK_LSHIFT:
case SDLK_RSHIFT:
return KEY_RSHIFT;
case SDLK_LCTRL:
case SDLK_RCTRL:
return KEY_RCTRL;
case SDLK_LALT:
case SDLK_LMETA:
case SDLK_RALT:
case SDLK_RMETA:
return KEY_RALT;
case SDLK_CAPSLOCK: return KEY_CAPSLOCK;
case SDLK_SCROLLOCK: return KEY_SCRLCK;
case SDLK_KP0: return KEYP_0;
case SDLK_KP1: return KEYP_1;
case SDLK_KP2: return KEYP_2;
case SDLK_KP3: return KEYP_3;
case SDLK_KP4: return KEYP_4;
case SDLK_KP5: return KEYP_5;
case SDLK_KP6: return KEYP_6;
case SDLK_KP7: return KEYP_7;
case SDLK_KP8: return KEYP_8;
case SDLK_KP9: return KEYP_9;
case SDLK_HOME: return KEY_HOME;
case SDLK_INSERT: return KEY_INS;
case SDLK_END: return KEY_END;
case SDLK_PAGEUP: return KEY_PGUP;
case SDLK_PAGEDOWN: return KEY_PGDN;
case SDLK_KP_MULTIPLY: return KEYP_MULTIPLY;
case SDLK_KP_PLUS: return KEYP_PLUS;
case SDLK_KP_MINUS: return KEYP_MINUS;
case SDLK_KP_DIVIDE: return KEYP_DIVIDE;
default:
return tolower(sym->sym);
}
}
void I_ShutdownGraphics(void)
{
if (initialised)
{
SDL_ShowCursor(1);
SDL_WM_GrabInput(SDL_GRAB_OFF);
SDL_QuitSubSystem(SDL_INIT_VIDEO);
initialised = false;
}
}
//
// I_StartFrame
//
void I_StartFrame (void)
{
// er?
}
static int MouseButtonState(void)
{
Uint8 state = SDL_GetMouseState(NULL, NULL);
int result = 0;
// Note: button "0" is left, button "1" is right,
// button "2" is middle for Doom. This is different
// to how SDL sees things.
if (state & SDL_BUTTON(1))
result |= 1;
if (state & SDL_BUTTON(3))
result |= 2;
if (state & SDL_BUTTON(2))
result |= 4;
return result;
}
static int AccelerateMouse(int val)
{
if (val < 0)
return -AccelerateMouse(-val);
return (int) pow(val, mouse_acceleration) / 5;
}
void I_GetEvent(void)
{
SDL_Event sdlevent;
event_t event;
// put event-grabbing stuff in here
while (SDL_PollEvent(&sdlevent))
{
// ignore mouse events when the window is not focused
if (!window_focused
&& (sdlevent.type == SDL_MOUSEMOTION
|| sdlevent.type == SDL_MOUSEBUTTONDOWN
|| sdlevent.type == SDL_MOUSEBUTTONUP))
{
continue;
}
// process event
switch (sdlevent.type)
{
case SDL_KEYDOWN:
event.type = ev_keydown;
event.data1 = TranslateKey(&sdlevent.key.keysym);
event.data2 = sdlevent.key.keysym.unicode;
D_PostEvent(&event);
break;
case SDL_KEYUP:
event.type = ev_keyup;
event.data1 = TranslateKey(&sdlevent.key.keysym);
D_PostEvent(&event);
break;
/*
case SDL_MOUSEMOTION:
event.type = ev_mouse;
event.data1 = MouseButtonState();
event.data2 = AccelerateMouse(sdlevent.motion.xrel);
event.data3 = -AccelerateMouse(sdlevent.motion.yrel);
D_PostEvent(&event);
break;
*/
case SDL_MOUSEBUTTONDOWN:
event.type = ev_mouse;
event.data1 = MouseButtonState();
event.data2 = event.data3 = 0;
D_PostEvent(&event);
break;
case SDL_MOUSEBUTTONUP:
event.type = ev_mouse;
event.data1 = MouseButtonState();
event.data2 = event.data3 = 0;
D_PostEvent(&event);
break;
case SDL_QUIT:
// bring up the "quit doom?" prompt
S_StartSound(NULL,sfx_swtchn);
M_QuitDOOM(0);
break;
case SDL_ACTIVEEVENT:
// need to update our focus state
UpdateFocus();
break;
default:
break;
}
}
}
//
// Read the change in mouse state to generate mouse motion events
//
// This is to combine all mouse movement for a tic into one mouse
// motion event.
static void I_ReadMouse(void)
{
int x, y;
event_t ev;
SDL_GetRelativeMouseState(&x, &y);
if (x != 0 || y != 0)
{
ev.type = ev_mouse;
ev.data1 = MouseButtonState();
ev.data2 = AccelerateMouse(x);
ev.data3 = -AccelerateMouse(y);
D_PostEvent(&ev);
}
}
//
// I_StartTic
//
void I_StartTic (void)
{
I_GetEvent();
I_ReadMouse();
}
//
// I_UpdateNoBlit
//
void I_UpdateNoBlit (void)
{
// what is this?
}
static void UpdateGrab(void)
{
static boolean currently_grabbed = false;
boolean grab;
grab = MouseShouldBeGrabbed();
if (grab && !currently_grabbed)
{
SDL_ShowCursor(0);
SDL_WM_GrabInput(SDL_GRAB_ON);
}
if (!grab && currently_grabbed)
{
SDL_ShowCursor(1);
SDL_WM_GrabInput(SDL_GRAB_OFF);
}
currently_grabbed = grab;
}
// Update a small portion of the screen
//
// Does 2x stretching and buffer blitting if neccessary
static void BlitArea(int x1, int y1, int x2, int y2)
{
int w = x2 - x1;
if (screenmultiply == 1 && !native_surface)
{
byte *bufp, *screenp;
int y;
int pitch;
if (SDL_LockSurface(screen) >= 0)
{
pitch = screen->pitch;
bufp = screens[0] + y1 * SCREENWIDTH + x1;
screenp = (byte *) screen->pixels + y1 * pitch + x1;
for (y=y1; y<y2; ++y)
{
memcpy(screenp, bufp, w);
screenp += pitch;
bufp += SCREENWIDTH;
}
SDL_UnlockSurface(screen);
}
}
// scales the screen size before blitting it
if (screenmultiply == 2)
{
byte *bufp, *screenp, *screenp2;
int x, y;
int pitch;
if (SDL_LockSurface(screen) >= 0)
{
pitch = screen->pitch * 2;
bufp = screens[0] + y1 * SCREENWIDTH + x1;
screenp = (byte *) screen->pixels + (y1 * pitch) + (x1 * 2);
screenp2 = screenp + screen->pitch;
for (y=y1; y<y2; ++y)
{
byte *sp, *sp2, *bp;
sp = screenp;
sp2 = screenp2;
bp = bufp;
for (x=x1; x<x2; ++x)
{
*sp2++ = *bp;
*sp2++ = *bp;
*sp++ = *bp;
*sp++ = *bp++;
}
screenp += pitch;
screenp2 += pitch;
bufp += SCREENWIDTH;
}
SDL_UnlockSurface(screen);
}
}
}
static void UpdateRect(int x1, int y1, int x2, int y2)
{
// Do stretching and blitting
BlitArea(x1, y1, x2, y2);
// Update the area
SDL_UpdateRect(screen,
x1 * screenmultiply,
y1 * screenmultiply,
(x2-x1) * screenmultiply,
(y2-y1) * screenmultiply);
}
void I_BeginRead(void)
{
int y;
if (!initialised || disk_image == NULL)
return;
// save background and copy the disk image in
for (y=0; y<disk_image_h; ++y)
{
byte *screenloc =
screens[0]
+ (SCREENHEIGHT - 1 - disk_image_h + y) * SCREENWIDTH
+ (SCREENWIDTH - 1 - disk_image_w);
memcpy(saved_background + y * disk_image_w,
screenloc,
disk_image_w);
memcpy(screenloc, disk_image + y * disk_image_w, disk_image_w);
}
UpdateRect(SCREENWIDTH - disk_image_w, SCREENHEIGHT - disk_image_h,
SCREENWIDTH, SCREENHEIGHT);
}
void I_EndRead(void)
{
int y;
if (!initialised || disk_image == NULL)
return;
// save background and copy the disk image in
for (y=0; y<disk_image_h; ++y)
{
byte *screenloc =
screens[0]
+ (SCREENHEIGHT - 1 - disk_image_h + y) * SCREENWIDTH
+ (SCREENWIDTH - 1 - disk_image_w);
memcpy(screenloc, saved_background + y * disk_image_w, disk_image_w);
}
UpdateRect(SCREENWIDTH - disk_image_w, SCREENHEIGHT - disk_image_h,
SCREENWIDTH, SCREENHEIGHT);
}
//
// I_FinishUpdate
//
void I_FinishUpdate (void)
{
static int lasttic;
int tics;
int i;
// UNUSED static unsigned char *bigscreen=0;
if (!initialised)
return;
UpdateGrab();
// Don't update the screen if the window isn't visible.
// Not doing this breaks under Windows when we alt-tab away
// while fullscreen.
if (!(SDL_GetAppState() & SDL_APPACTIVE))
return;
// draws little dots on the bottom of the screen
if (devparm)
{
i = I_GetTime();
tics = i - lasttic;
lasttic = i;
if (tics > 20) tics = 20;
for (i=0 ; i<tics*2 ; i+=2)
screens[0][ (SCREENHEIGHT-1)*SCREENWIDTH + i] = 0xff;
for ( ; i<20*2 ; i+=2)
screens[0][ (SCREENHEIGHT-1)*SCREENWIDTH + i] = 0x0;
}
// draw to screen
BlitArea(0, 0, SCREENWIDTH, SCREENHEIGHT);
// If we have a palette to set, the act of setting the palette
// updates the screen
if (palette_to_set)
{
SDL_SetColors(screen, palette, 0, 256);
palette_to_set = 0;
}
else
{
SDL_Flip(screen);
}
}
//
// I_ReadScreen
//
void I_ReadScreen (byte* scr)
{
memcpy (scr, screens[0], SCREENWIDTH*SCREENHEIGHT);
}
//
// I_SetPalette
//
void I_SetPalette (byte *doompalette)
{
int i;
for (i=0; i<256; ++i)
{
palette[i].r = gammatable[usegamma][*doompalette++];
palette[i].g = gammatable[usegamma][*doompalette++];
palette[i].b = gammatable[usegamma][*doompalette++];
}
palette_to_set = 1;
}
//
// Set the window caption
//
void I_SetWindowCaption(void)
{
char *buf;
buf = Z_Malloc(strlen(gamedescription) + strlen(PACKAGE_STRING) + 10,
PU_STATIC, NULL);
sprintf(buf, "%s - %s", gamedescription, PACKAGE_STRING);
SDL_WM_SetCaption(buf, NULL);
Z_Free(buf);
}
// Set the application icon
void I_SetWindowIcon(void)
{
SDL_Surface *surface;
surface = SDL_CreateRGBSurfaceFrom(chocolate_doom_data,
chocolate_doom_w,
chocolate_doom_h,
24,
chocolate_doom_w * 3,
0xff << 0,
0xff << 8,
0xff << 16,
0);
SDL_WM_SetIcon(surface, NULL);
SDL_FreeSurface(surface);
}
void I_InitGraphics(void)
{
SDL_Event dummy;
int flags = 0;
SDL_Init(SDL_INIT_VIDEO);
flags |= SDL_SWSURFACE | SDL_HWPALETTE | SDL_DOUBLEBUF;
// mouse grabbing
if (M_CheckParm("-grabmouse"))
{
grabmouse = true;
}
else if (M_CheckParm("-nograbmouse"))
{
grabmouse = false;
}
// default to fullscreen mode, allow override with command line
// nofullscreen because we love prboom
if (M_CheckParm("-window") || M_CheckParm("-nofullscreen"))
{
fullscreen = false;
}
else if (M_CheckParm("-fullscreen"))
{
fullscreen = true;
}
if (fullscreen)
{
flags |= SDL_FULLSCREEN;
}
// scale-by-2 mode
if (M_CheckParm("-1"))
{
screenmultiply = 1;
}
else if (M_CheckParm("-2"))
{
screenmultiply = 2;
}
if (screenmultiply < 1)
screenmultiply = 1;
if (screenmultiply > 2)
screenmultiply = 2;
windowwidth = SCREENWIDTH * screenmultiply;
windowheight = SCREENHEIGHT * screenmultiply;
screen = SDL_SetVideoMode(windowwidth, windowheight, 8, flags);
if (screen == NULL)
{
I_Error("Error setting video mode: %s\n", SDL_GetError());
}
// Start with a clear black screen
// (screen will be flipped after we set the palette)
if (SDL_LockSurface(screen) >= 0)
{
byte *screenpixels;
int y;
screenpixels = (byte *) screen->pixels;
for (y=0; y<screen->h; ++y)
memset(screenpixels + screen->pitch * y, 0, screen->w);
SDL_UnlockSurface(screen);
}
// Set the palette
I_SetPalette (W_CacheLumpName ("PLAYPAL",PU_CACHE));
SDL_SetColors(screen, palette, 0, 256);
// Setup title and icon
I_SetWindowCaption();
I_SetWindowIcon();
UpdateFocus();
UpdateGrab();
// Check if we have a native surface we can use
// If we have to lock the screen, draw to a buffer and copy
// Likewise if the screen pitch is not the same as the width
// If we have to multiply, drawing is done to a separate 320x200 buf
native_surface = !SDL_MUSTLOCK(screen)
&& screenmultiply == 1
&& screen->pitch == SCREENWIDTH;
// If not, allocate a buffer and copy from that buffer to the
// screen when we do an update
if (native_surface)
screens[0] = (unsigned char *) (screen->pixels);
else
screens[0] = (unsigned char *) Z_Malloc (SCREENWIDTH * SCREENHEIGHT, PU_STATIC, NULL);
// Loading from disk icon
LoadDiskImage();
memset(screens[0], 0, SCREENWIDTH * SCREENHEIGHT);
// We need SDL to give us translated versions of keys as well
SDL_EnableUNICODE(1);
// clear out any events waiting at the start
while (SDL_PollEvent(&dummy));
initialised = true;
}