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Fixed bug #33 Mike Frysinger wrote: > with libsdl-1.2.9, some games (like bomberclone) started > segfaulting in Gentoo [...snip...] > the last change in the last hunk: [...snip...] > if i change the statement to read: > (table[which].blit_features & GetBlitFeatures()) == GetBlitFeatures() > bomberclone no longer segfaults on my box Alex Volkov wrote: > The test "(table[which].blit_features & GetBlitFeatures()) == > table[which].blit_features)" is correct, and the previous > "(table[which].cpu_mmx == SDL_HasMMX())" was actually broken. I think there is potentially a slightly different cause of the above problem. During the introduction of the Altivec code, the blit_table struct field 'alpha' got changed from a straightforward enum to a bitmask, which makes perfect sense by itself. However, now the table driven blitter selection code in SDL_CalculateBlitN() can choose the wrong blitters when searching for a NO_ALPHA blitter because of the following code: int a_need = 0; ... (a_need & table[which].alpha) == a_need && When searching through the normal_blit_2[] table, a SET_ALPHA blitter (like Blit_RGB565_ARGB8888) can now be selected instead of a NO_ALPHA one, causing alpha channel bits to appear in a non-alpha destination surface. I suppose this could theoretically be an indirect cause of the segfault mentioned above. I *think* this can be fixed by changing to int a_need = NO_ALPHA;
author Sam Lantinga <slouken@libsdl.org>
date Wed, 15 Mar 2006 15:47:49 +0000
parents e5bc29de3f0a
children 546f7c1eb755
line wrap: on
line source

.TH "SDL_CreateCursor" "3" "Tue 11 Sep 2001, 23:01" "SDL" "SDL API Reference" 
.SH "NAME"
SDL_CreateCursor\- Creates a new mouse cursor\&.
.SH "SYNOPSIS"
.PP
\fB#include "SDL\&.h"
.sp
\fBSDL_Cursor *\fBSDL_CreateCursor\fP\fR(\fBUint8 *data, Uint8 *mask, int w, int h, int hot_x, int hot_y\fR);
.SH "DESCRIPTION"
.PP
Create a cursor using the specified \fBdata\fR and \fBmask\fR (in MSB format)\&. The cursor width must be a multiple of 8 bits\&.
.PP
The cursor is created in black and white according to the following: 
.TP 20
\fBData / Mask\fR
\fBResulting pixel on screen\fR
.TP 20
0 / 1
White
.TP 20
1 / 1
Black
.TP 20
0 / 0
Transparent
.TP 20
1 / 0
Inverted color if possible, black if not\&.
.PP
Cursors created with this function must be freed with \fISDL_FreeCursor\fR\&.
.SH "EXAMPLE"
.PP
.nf
\f(CW/* 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<32; ++row ) {
    for ( col=0; col<32; ++col ) {
      if ( col % 8 ) {
        data[i] <<= 1;
        mask[i] <<= 1;
      } else {
        ++i;
        data[i] = mask[i] = 0;
      }
      switch (image[4+row][col]) {
        case \&'X\&':
          data[i] |= 0x01;
          k[i] |= 0x01;
          break;
        case \&'\&.\&':
          mask[i] |= 0x01;
          break;
        case \&' \&':
          break;
      }
    }
  }
  sscanf(image[4+row], "%d,%d", &hot_x, &hot_y);
  return SDL_CreateCursor(data, mask, 32, 32, hot_x, hot_y);
}\fR
.fi
.PP
.SH "SEE ALSO"
.PP
\fI\fBSDL_FreeCursor\fP\fR, \fI\fBSDL_SetCursor\fP\fR, \fI\fBSDL_ShowCursor\fP\fR
...\" created by instant / docbook-to-man, Tue 11 Sep 2001, 23:01