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view docs/html/sdlcreatecursor.html @ 773:da0a2ad35bf4
Date: Sun, 4 Jan 2004 23:48:19 +0100
From: Max Horn
Subject: Re: Again Audio CD patch
Am 04.01.2004 um 22:38 schrieb Sam Lantinga:
>
> Okay, I fixed the buffering problems by simply using a 4 second buffer
> instead of a 1 second buffer. However, using your code I can't play an
> entire CD - the playback stops after the first song.
>
Found the problem: FSReadFork returns eofErr when the file is finished.
However, we check its return value for errors, and if anything but
noErr occurs, the reader thread aborts its current iteration. That is
bad, because it aborts before it can ever set the flag which tells that
the file is over (also, any remaining data which FSRead did return is
lost - so you'd not hear about to 4 seconds from the end of the file.
Furthermore, the computed data size was 8 bytes to high (I forgot to
account for the fact that the size of an (A)IFF chunk always contains
the chunk header & size fields, too). This is enough to make it work.
However, the end condition is rather fragile, so I tuned some other
things to be pessimistic (check for <= 0 instead of == 0, when eofErr
is encountered enforce mReadFilePosition == mFileLength). You never
know...
The attached patch fixes the issue for me.
author | Sam Lantinga <slouken@libsdl.org> |
---|---|
date | Mon, 05 Jan 2004 00:57:51 +0000 |
parents | e5bc29de3f0a |
children | 355632dca928 |
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<HTML ><HEAD ><TITLE >SDL_CreateCursor</TITLE ><META NAME="GENERATOR" CONTENT="Modular DocBook HTML Stylesheet Version 1.64 "><LINK REL="HOME" TITLE="SDL Library Documentation" HREF="index.html"><LINK REL="UP" TITLE="Video" HREF="video.html"><LINK REL="PREVIOUS" TITLE="SDL_WarpMouse" HREF="sdlwarpmouse.html"><LINK REL="NEXT" TITLE="SDL_FreeCursor" HREF="sdlfreecursor.html"></HEAD ><BODY CLASS="REFENTRY" BGCOLOR="#FFF8DC" TEXT="#000000" LINK="#0000ee" VLINK="#551a8b" ALINK="#ff0000" ><DIV CLASS="NAVHEADER" ><TABLE WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" ><TR ><TH COLSPAN="3" ALIGN="center" >SDL Library Documentation</TH ></TR ><TR ><TD WIDTH="10%" ALIGN="left" VALIGN="bottom" ><A HREF="sdlwarpmouse.html" >Prev</A ></TD ><TD WIDTH="80%" ALIGN="center" VALIGN="bottom" ></TD ><TD WIDTH="10%" ALIGN="right" VALIGN="bottom" ><A HREF="sdlfreecursor.html" >Next</A ></TD ></TR ></TABLE ><HR ALIGN="LEFT" WIDTH="100%"></DIV ><H1 ><A NAME="SDLCREATECURSOR" >SDL_CreateCursor</A ></H1 ><DIV CLASS="REFNAMEDIV" ><A NAME="AEN2103" ></A ><H2 >Name</H2 >SDL_CreateCursor -- Creates a new mouse cursor.</DIV ><DIV CLASS="REFSYNOPSISDIV" ><A NAME="AEN2106" ></A ><H2 >Synopsis</H2 ><DIV CLASS="FUNCSYNOPSIS" ><A NAME="AEN2107" ></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="AEN2113" ></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="AEN2119" ></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="AEN2140" ></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<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); }</PRE ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN2143" ></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 ></DIV ><DIV CLASS="NAVFOOTER" ><HR ALIGN="LEFT" WIDTH="100%"><TABLE WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" ><A HREF="sdlwarpmouse.html" >Prev</A ></TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="index.html" >Home</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" ><A HREF="sdlfreecursor.html" >Next</A ></TD ></TR ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" >SDL_WarpMouse</TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="video.html" >Up</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" >SDL_FreeCursor</TD ></TR ></TABLE ></DIV ></BODY ></HTML >