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Date: Sat, 10 Apr 2004 02:25:33 -0400 From: Glenn Maynard To: sdl@libsdl.org Subject: [SDL] SDL_SetVideoMode() failing and not setting an error (patch) Running an OpenGL SDL application off 1.2.7, at SDL_InitSubSystem(SDL_INIT_VIDEO) time: Warning: Unable to initialize AAlib mouseUsing AAlib driver: Slang driver 1.0 (slang) SDL_SetVideoMode then fails; SDL_GetError() returns "". The installation problem is straightforward: X (the higher priority driver) isn't running, so SDL is falling back on aalib. However, no error is being set when aalib fails to initialize. This also happens with the svgalib driver. SDL_video.c line ~653 sets mode to NULL, since aalib didn't return an OpenGL surface. Line ~711 ("failed setting a video mode") returns NULL. The attached patch sets an error. It's a horrible, useless error message--it should really say eg. "aalib does not support OpenGL"; this should probably be done earlier in the individual drivers, too.
author Sam Lantinga <slouken@libsdl.org>
date Sun, 11 Apr 2004 19:54:40 +0000
parents 355632dca928
children
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<HTML
><HEAD
><TITLE
>SDL_CreateCursor</TITLE
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><H1
><A
NAME="SDLCREATECURSOR"
></A
>SDL_CreateCursor</H1
><DIV
CLASS="REFNAMEDIV"
><A
NAME="AEN2487"
></A
><H2
>Name</H2
>SDL_CreateCursor&nbsp;--&nbsp;Creates a new mouse cursor.</DIV
><DIV
CLASS="REFSYNOPSISDIV"
><A
NAME="AEN2490"
></A
><H2
>Synopsis</H2
><DIV
CLASS="FUNCSYNOPSIS"
><A
NAME="AEN2491"
></A
><P
></P
><PRE
CLASS="FUNCSYNOPSISINFO"
>#include "SDL.h"</PRE
><P
><CODE
><CODE
CLASS="FUNCDEF"
>SDL_Cursor *<B
CLASS="FSFUNC"
>SDL_CreateCursor</B
></CODE
>(Uint8 *data, Uint8 *mask, int w, int h, int hot_x, int hot_y);</CODE
></P
><P
></P
></DIV
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN2497"
></A
><H2
>Description</H2
><P
>Create a cursor using the specified <TT
CLASS="PARAMETER"
><I
>data</I
></TT
> and <TT
CLASS="PARAMETER"
><I
>mask</I
></TT
> (in MSB format).
The cursor width must be a multiple of 8 bits.</P
><P
>The cursor is created in black and white according to the following:
<DIV
CLASS="INFORMALTABLE"
><A
NAME="AEN2503"
></A
><P
></P
><TABLE
BORDER="1"
CLASS="CALSTABLE"
><THEAD
><TR
><TH
ALIGN="LEFT"
VALIGN="TOP"
>Data / Mask</TH
><TH
ALIGN="LEFT"
VALIGN="TOP"
>Resulting pixel on screen</TH
></TR
></THEAD
><TBODY
><TR
><TD
ALIGN="LEFT"
VALIGN="TOP"
>0 / 1</TD
><TD
ALIGN="LEFT"
VALIGN="TOP"
>White</TD
></TR
><TR
><TD
ALIGN="LEFT"
VALIGN="TOP"
>1 / 1</TD
><TD
ALIGN="LEFT"
VALIGN="TOP"
>Black</TD
></TR
><TR
><TD
ALIGN="LEFT"
VALIGN="TOP"
>0 / 0</TD
><TD
ALIGN="LEFT"
VALIGN="TOP"
>Transparent</TD
></TR
><TR
><TD
ALIGN="LEFT"
VALIGN="TOP"
>1 / 0</TD
><TD
ALIGN="LEFT"
VALIGN="TOP"
>Inverted color if possible, black if not.</TD
></TR
></TBODY
></TABLE
><P
></P
></DIV
></P
><P
>Cursors created with this function must be freed with
<A
HREF="sdlfreecursor.html"
>SDL_FreeCursor</A
>.</P
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN2524"
></A
><H2
>Example</H2
><PRE
CLASS="PROGRAMLISTING"
>/* Stolen from the mailing list */
/* Creates a new mouse cursor from an XPM */


/* XPM */
static const char *arrow[] = {
  /* width height num_colors chars_per_pixel */
  "    32    32        3            1",
  /* colors */
  "X c #000000",
  ". c #ffffff",
  "  c None",
  /* pixels */
  "X                               ",
  "XX                              ",
  "X.X                             ",
  "X..X                            ",
  "X...X                           ",
  "X....X                          ",
  "X.....X                         ",
  "X......X                        ",
  "X.......X                       ",
  "X........X                      ",
  "X.....XXXXX                     ",
  "X..X..X                         ",
  "X.X X..X                        ",
  "XX  X..X                        ",
  "X    X..X                       ",
  "     X..X                       ",
  "      X..X                      ",
  "      X..X                      ",
  "       XX                       ",
  "                                ",
  "                                ",
  "                                ",
  "                                ",
  "                                ",
  "                                ",
  "                                ",
  "                                ",
  "                                ",
  "                                ",
  "                                ",
  "                                ",
  "                                ",
  "0,0"
};

static SDL_Cursor *init_system_cursor(const char *image[])
{
  int i, row, col;
  Uint8 data[4*32];
  Uint8 mask[4*32];
  int hot_x, hot_y;

  i = -1;
  for ( row=0; row&#60;32; ++row ) {
    for ( col=0; col&#60;32; ++col ) {
      if ( col % 8 ) {
        data[i] &#60;&#60;= 1;
        mask[i] &#60;&#60;= 1;
      } else {
        ++i;
        data[i] = mask[i] = 0;
      }
      switch (image[4+row][col]) {
        case 'X':
          data[i] |= 0x01;
          mask[i] |= 0x01;
          break;
        case '.':
          mask[i] |= 0x01;
          break;
        case ' ':
          break;
      }
    }
  }
  sscanf(image[4+row], "%d,%d", &#38;hot_x, &#38;hot_y);
  return SDL_CreateCursor(data, mask, 32, 32, hot_x, hot_y);
}</PRE
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN2527"
></A
><H2
>See Also</H2
><P
><A
HREF="sdlfreecursor.html"
><TT
CLASS="FUNCTION"
>SDL_FreeCursor</TT
></A
>,
<A
HREF="sdlsetcursor.html"
><TT
CLASS="FUNCTION"
>SDL_SetCursor</TT
></A
>,
<A
HREF="sdlshowcursor.html"
><TT
CLASS="FUNCTION"
>SDL_ShowCursor</TT
></A
></P
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