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From Bug #36: There are a couple of issues with the selection of Altivec alpha-blitting routines in CalculateAlphaBlit() in src/video/SDL_Blit_A.c. 1) There's no check for the presence of Altivec when checking if the Blit32to565PixelAlphaAltivec() routine can be selected. 2) Altivec cannot be used in video memory, and there's no check if the destination surface is a hardware surface. (Alpha-blitting to a hardware surface with GPU support is a bad idea, but somebody's bound to do it anyway.) Patch to fix these attached.
author Ryan C. Gordon <icculus@icculus.org>
date Sun, 08 Jan 2006 21:18:15 +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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