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Fixed bug #84
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Date: Sun, 23 Oct 2005 16:39:03 +0200
From: "A. Schmid" <sahib@phreaker.net>
Subject: [SDL] no software surfaces with svgalib driver?

Hi,

I noticed that the SDL (1.2.9) svgalib driver only makes use of linear
addressable (framebuffer) video modes. On older systems (like one of
mine), linear addressable modes are often not available.
Especially for cards with VESA VBE < 2.0 the svgalib vesa driver is
unusable, since VESA only supports framebuffering for VBE 2.0 and later.

The changes necessary to add support for software surfaces seem to be
relatively small. I only had to hack src/video/svga/SDL_svgavideo.c (see
attached patch). The code worked fine for me, but it is no more than a
proof of concept and should be reviewed (probably has a memory leak when
switching modes). It also uses the vgagl library (included in the
svgalib package) and needs to be linked against it.

-Alex
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@slouken
slouken committed Mar 19, 2006
1 parent 9bfc711 commit 79d1f3e
Showing 1 changed file with 73 additions and 16 deletions.
89 changes: 73 additions & 16 deletions src/video/svga/SDL_svgavideo.c
View file
Expand Up @@ -40,6 +40,7 @@
#include <vga.h>
#include <vgamouse.h>
#include <vgakeyboard.h>
#include <vgagl.h>

#include "SDL_video.h"
#include "SDL_mouse.h"
Expand All @@ -50,6 +51,8 @@
#include "SDL_svgaevents_c.h"
#include "SDL_svgamouse_c.h"

static GraphicsContext *realgc = NULL;
static GraphicsContext *virtgc = NULL;

/* Initialization/Query functions */
static int SVGA_VideoInit(_THIS, SDL_PixelFormat *vformat);
Expand Down Expand Up @@ -168,6 +171,9 @@ static int SVGA_AddMode(_THIS, int mode, int actually_add, int force)
int i, j;

i = modeinfo->bytesperpixel-1;
if ( i < 0 ) {
return 0;
}
if ( actually_add ) {
SDL_Rect saved_rect[2];
int saved_mode[2];
Expand Down Expand Up @@ -215,7 +221,7 @@ static void SVGA_UpdateVideoInfo(_THIS)
vga_modeinfo *modeinfo;

this->info.wm_available = 0;
this->info.hw_available = 1;
this->info.hw_available = (virtgc ? 0 : 1);
modeinfo = vga_getmodeinfo(vga_getcurrentmode());
this->info.video_mem = modeinfo->memory;
/* FIXME: Add hardware accelerated blit information */
Expand Down Expand Up @@ -268,7 +274,7 @@ int SVGA_VideoInit(_THIS, SDL_PixelFormat *vformat)
total_modes = 0;
for ( mode=vga_lastmodenumber(); mode; --mode ) {
if ( vga_hasmode(mode) ) {
if ( SVGA_AddMode(this, mode, 0, 0) ) {
if ( SVGA_AddMode(this, mode, 0, 1) ) {
++total_modes;
}
}
Expand Down Expand Up @@ -302,7 +308,7 @@ int SVGA_VideoInit(_THIS, SDL_PixelFormat *vformat)
}
for ( mode=vga_lastmodenumber(); mode; --mode ) {
if ( vga_hasmode(mode) ) {
SVGA_AddMode(this, mode, 1, 0);
SVGA_AddMode(this, mode, 1, 1);
}
}
SVGA_AddMode(this, G320x200x256, 1, 1);
Expand Down Expand Up @@ -344,6 +350,18 @@ SDL_Surface *SVGA_SetVideoMode(_THIS, SDL_Surface *current,
vga_modeinfo *modeinfo;
int screenpage_len;

/* Clean up old video mode data */
if ( realgc ) {
free(realgc);
realgc = NULL;
}
if ( virtgc ) {
/* FIXME: Why does this crash?
gl_freecontext(virtgc);*/
free(virtgc);
virtgc = NULL;
}

/* Try to set the requested linear video mode */
bpp = (bpp+7)/8-1;
for ( mode=0; SDL_modelist[bpp][mode]; ++mode ) {
Expand All @@ -356,14 +374,22 @@ SDL_Surface *SVGA_SetVideoMode(_THIS, SDL_Surface *current,
SDL_SetError("Couldn't find requested mode in list");
return(NULL);
}
vga_setmode(SDL_vgamode[bpp][mode]);
vgamode = SDL_vgamode[bpp][mode];
vga_setmode(vgamode);
vga_setpage(0);

vgamode=SDL_vgamode[bpp][mode];
if ((vga_setlinearaddressing()<0) && (vgamode!=G320x200x256)) {
SDL_SetError("Unable to set linear addressing");
return(NULL);
if ( (vga_setlinearaddressing() < 0) && (vgamode != G320x200x256) ) {
gl_setcontextvga(vgamode);
realgc = gl_allocatecontext();
gl_getcontext(realgc);

gl_setcontextvgavirtual(vgamode);
virtgc = gl_allocatecontext();
gl_getcontext(virtgc);

flags &= ~SDL_DOUBLEBUF;
}

modeinfo = vga_getmodeinfo(SDL_vgamode[bpp][mode]);

/* Update hardware acceleration info */
Expand All @@ -379,15 +405,24 @@ SDL_Surface *SVGA_SetVideoMode(_THIS, SDL_Surface *current,
}

/* Set up the new mode framebuffer */
current->flags = (SDL_FULLSCREEN|SDL_HWSURFACE);
current->flags = SDL_FULLSCREEN;
if ( virtgc ) {
current->flags |= SDL_SWSURFACE;
} else {
current->flags |= SDL_HWSURFACE;
}
if ( bpp == 8 ) {
/* FIXME: What about DirectColor? */
current->flags |= SDL_HWPALETTE;
}
current->w = width;
current->h = height;
current->pitch = modeinfo->linewidth;
current->pixels = vga_getgraphmem();
if ( virtgc ) {
current->pixels = virtgc->vbuf;
} else {
current->pixels = vga_getgraphmem();
}

/* set double-buffering */
if ( flags & SDL_DOUBLEBUF )
Expand Down Expand Up @@ -418,7 +453,11 @@ SDL_Surface *SVGA_SetVideoMode(_THIS, SDL_Surface *current,
}

/* Set the blit function */
this->UpdateRects = SVGA_DirectUpdate;
if ( virtgc ) {
this->UpdateRects = SVGA_BankedUpdate;
} else {
this->UpdateRects = SVGA_DirectUpdate;
}

/* Set up the mouse handler again (buggy SVGAlib 1.40) */
mouse_seteventhandler(SVGA_mousecallback);
Expand Down Expand Up @@ -450,10 +489,12 @@ static void SVGA_UnlockHWSurface(_THIS, SDL_Surface *surface)

static int SVGA_FlipHWSurface(_THIS, SDL_Surface *surface)
{
vga_setdisplaystart(flip_offset[flip_page]);
flip_page=!flip_page;
surface->pixels=flip_address[flip_page];
vga_waitretrace();
if ( !virtgc ) {
vga_setdisplaystart(flip_offset[flip_page]);
flip_page=!flip_page;
surface->pixels=flip_address[flip_page];
vga_waitretrace();
}
return(0);
}

Expand All @@ -462,9 +503,15 @@ static void SVGA_DirectUpdate(_THIS, int numrects, SDL_Rect *rects)
return;
}

/* FIXME: Can this be used under SVGAlib? */
static void SVGA_BankedUpdate(_THIS, int numrects, SDL_Rect *rects)
{
int i;
SDL_Rect *rect;

for ( i=0; i < numrects; ++i ) {
rect = &rects[i];
gl_copyboxtocontext(rect->x, rect->y, rect->w, rect->h, realgc, rect->x, rect->y);
}
return;
}

Expand All @@ -490,6 +537,16 @@ void SVGA_VideoQuit(_THIS)

/* Reset the console video mode */
if ( this->screen && (this->screen->w && this->screen->h) ) {
if ( realgc ) {
free(realgc);
realgc = NULL;
}
if ( virtgc ) {
/* FIXME: Why does this crash?
gl_freecontext(virtgc);*/
free(virtgc);
virtgc = NULL;
}
vga_setmode(TEXT);
}
keyboard_close();
Expand Down

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