Mercurial > sdl-ios-xcode
annotate docs/html/guideeventexamples.html @ 765:4c2ba6161939
Editors Note: The original patch was modified to use SDL_Delay() instead of
nanosleep because nanosleep may not be portable to all systems
using SDL with the ALSA backend. This may be a moot point with
the switch to blocking writes anyway...
Date: Sat, 27 Dec 2003 21:47:36 +0100
From: Michel Daenzer
To: Debian Bug Tracking System
Subject: [SDL] Bug#225252: [PATCH] ALSA fixes
Package: libsdl1.2debian-all
Version: 1.2.6-2
Severity: normal
Tags: patch
For SDL 1.2.6, the ALSA backend was changed to call snd_pcm_open() with
SND_PCM_NONBLOCK. That's a good idea per se, however, it causes high CPU
usage, interrupted sound and stuttering in some games here. Taking a nanosleep
whenever snd_pcm_writei() returns -EAGAIN fixes this, but I think it's more
efficient to use blocking mode for the actual sound playback. Feedback from the
SDL and ALSA lists appreciated.
The patch also fixes the default ALSA device to be used.
| author | Sam Lantinga <slouken@libsdl.org> |
|---|---|
| date | Sun, 04 Jan 2004 15:40:50 +0000 |
| parents | 55f1f1b3e27d |
| children | 355632dca928 |
| rev | line source |
|---|---|
| 0 | 1 <HTML |
| 2 ><HEAD | |
| 3 ><TITLE | |
| 4 >Event Examples</TITLE | |
| 5 ><META | |
| 6 NAME="GENERATOR" | |
|
55
55f1f1b3e27d
Added new docs for SDL 1.2.1
Sam Lantinga <slouken@lokigames.com>
parents:
0
diff
changeset
|
7 CONTENT="Modular DocBook HTML Stylesheet Version 1.64 |
| 0 | 8 "><LINK |
| 9 REL="HOME" | |
| 10 TITLE="SDL Library Documentation" | |
| 11 HREF="index.html"><LINK | |
| 12 REL="UP" | |
| 13 TITLE="Examples" | |
| 14 HREF="guideexamples.html"><LINK | |
| 15 REL="PREVIOUS" | |
|
55
55f1f1b3e27d
Added new docs for SDL 1.2.1
Sam Lantinga <slouken@lokigames.com>
parents:
0
diff
changeset
|
16 TITLE="Examples" |
|
55f1f1b3e27d
Added new docs for SDL 1.2.1
Sam Lantinga <slouken@lokigames.com>
parents:
0
diff
changeset
|
17 HREF="guideexamples.html"><LINK |
| 0 | 18 REL="NEXT" |
| 19 TITLE="Audio Examples" | |
| 20 HREF="guideaudioexamples.html"></HEAD | |
| 21 ><BODY | |
| 22 CLASS="SECT1" | |
| 23 BGCOLOR="#FFF8DC" | |
| 24 TEXT="#000000" | |
| 25 LINK="#0000ee" | |
| 26 VLINK="#551a8b" | |
| 27 ALINK="#ff0000" | |
| 28 ><DIV | |
| 29 CLASS="NAVHEADER" | |
| 30 ><TABLE | |
| 31 WIDTH="100%" | |
| 32 BORDER="0" | |
| 33 CELLPADDING="0" | |
| 34 CELLSPACING="0" | |
| 35 ><TR | |
| 36 ><TH | |
| 37 COLSPAN="3" | |
| 38 ALIGN="center" | |
| 39 >SDL Library Documentation</TH | |
| 40 ></TR | |
| 41 ><TR | |
| 42 ><TD | |
| 43 WIDTH="10%" | |
| 44 ALIGN="left" | |
| 45 VALIGN="bottom" | |
| 46 ><A | |
|
55
55f1f1b3e27d
Added new docs for SDL 1.2.1
Sam Lantinga <slouken@lokigames.com>
parents:
0
diff
changeset
|
47 HREF="guideexamples.html" |
| 0 | 48 >Prev</A |
| 49 ></TD | |
| 50 ><TD | |
| 51 WIDTH="80%" | |
| 52 ALIGN="center" | |
| 53 VALIGN="bottom" | |
| 54 >Chapter 4. Examples</TD | |
| 55 ><TD | |
| 56 WIDTH="10%" | |
| 57 ALIGN="right" | |
| 58 VALIGN="bottom" | |
| 59 ><A | |
| 60 HREF="guideaudioexamples.html" | |
| 61 >Next</A | |
| 62 ></TD | |
| 63 ></TR | |
| 64 ></TABLE | |
| 65 ><HR | |
| 66 ALIGN="LEFT" | |
| 67 WIDTH="100%"></DIV | |
| 68 ><DIV | |
| 69 CLASS="SECT1" | |
| 70 ><H1 | |
| 71 CLASS="SECT1" | |
| 72 ><A | |
| 73 NAME="GUIDEEVENTEXAMPLES" | |
| 74 >Event Examples</A | |
| 75 ></H1 | |
| 76 ><P | |
| 77 ></P | |
| 78 ><DIV | |
| 79 CLASS="SECT2" | |
| 80 ><H2 | |
| 81 CLASS="SECT2" | |
| 82 ><A | |
|
55
55f1f1b3e27d
Added new docs for SDL 1.2.1
Sam Lantinga <slouken@lokigames.com>
parents:
0
diff
changeset
|
83 NAME="AEN375" |
| 0 | 84 >Filtering and Handling Events</A |
| 85 ></H2 | |
| 86 ><P | |
| 87 ><PRE | |
| 88 CLASS="PROGRAMLISTING" | |
| 89 >#include <stdio.h> | |
| 90 #include <stdlib.h> | |
| 91 | |
| 92 #include "SDL.h" | |
| 93 | |
| 94 /* This function may run in a separate event thread */ | |
| 95 int FilterEvents(const SDL_Event *event) { | |
| 96 static int boycott = 1; | |
| 97 | |
| 98 /* This quit event signals the closing of the window */ | |
| 99 if ( (event->type == SDL_QUIT) && boycott ) { | |
| 100 printf("Quit event filtered out -- try again.\n"); | |
| 101 boycott = 0; | |
| 102 return(0); | |
| 103 } | |
| 104 if ( event->type == SDL_MOUSEMOTION ) { | |
| 105 printf("Mouse moved to (%d,%d)\n", | |
| 106 event->motion.x, event->motion.y); | |
| 107 return(0); /* Drop it, we've handled it */ | |
| 108 } | |
| 109 return(1); | |
| 110 } | |
| 111 | |
| 112 int main(int argc, char *argv[]) | |
| 113 { | |
| 114 SDL_Event event; | |
| 115 | |
| 116 /* Initialize the SDL library (starts the event loop) */ | |
| 117 if ( SDL_Init(SDL_INIT_VIDEO) < 0 ) { | |
| 118 fprintf(stderr, | |
| 119 "Couldn't initialize SDL: %s\n", SDL_GetError()); | |
| 120 exit(1); | |
| 121 } | |
| 122 | |
| 123 /* Clean up on exit, exit on window close and interrupt */ | |
| 124 atexit(SDL_Quit); | |
| 125 | |
| 126 /* Ignore key events */ | |
| 127 SDL_EventState(SDL_KEYDOWN, SDL_IGNORE); | |
| 128 SDL_EventState(SDL_KEYUP, SDL_IGNORE); | |
| 129 | |
| 130 /* Filter quit and mouse motion events */ | |
| 131 SDL_SetEventFilter(FilterEvents); | |
| 132 | |
| 133 /* The mouse isn't much use unless we have a display for reference */ | |
| 134 if ( SDL_SetVideoMode(640, 480, 8, 0) == NULL ) { | |
| 135 fprintf(stderr, "Couldn't set 640x480x8 video mode: %s\n", | |
| 136 SDL_GetError()); | |
| 137 exit(1); | |
| 138 } | |
| 139 | |
| 140 /* Loop waiting for ESC+Mouse_Button */ | |
| 141 while ( SDL_WaitEvent(&event) >= 0 ) { | |
| 142 switch (event.type) { | |
| 143 case SDL_ACTIVEEVENT: { | |
| 144 if ( event.active.state & SDL_APPACTIVE ) { | |
| 145 if ( event.active.gain ) { | |
| 146 printf("App activated\n"); | |
| 147 } else { | |
| 148 printf("App iconified\n"); | |
| 149 } | |
| 150 } | |
| 151 } | |
| 152 break; | |
| 153 | |
| 154 case SDL_MOUSEBUTTONDOWN: { | |
| 155 Uint8 *keys; | |
| 156 | |
| 157 keys = SDL_GetKeyState(NULL); | |
| 158 if ( keys[SDLK_ESCAPE] == SDL_PRESSED ) { | |
| 159 printf("Bye bye...\n"); | |
| 160 exit(0); | |
| 161 } | |
| 162 printf("Mouse button pressed\n"); | |
| 163 } | |
| 164 break; | |
| 165 | |
| 166 case SDL_QUIT: { | |
| 167 printf("Quit requested, quitting.\n"); | |
| 168 exit(0); | |
| 169 } | |
| 170 break; | |
| 171 } | |
| 172 } | |
| 173 /* This should never happen */ | |
| 174 printf("SDL_WaitEvent error: %s\n", SDL_GetError()); | |
| 175 exit(1); | |
| 176 }</PRE | |
| 177 ></P | |
| 178 ></DIV | |
| 179 ></DIV | |
| 180 ><DIV | |
| 181 CLASS="NAVFOOTER" | |
| 182 ><HR | |
| 183 ALIGN="LEFT" | |
| 184 WIDTH="100%"><TABLE | |
| 185 WIDTH="100%" | |
| 186 BORDER="0" | |
| 187 CELLPADDING="0" | |
| 188 CELLSPACING="0" | |
| 189 ><TR | |
| 190 ><TD | |
| 191 WIDTH="33%" | |
| 192 ALIGN="left" | |
| 193 VALIGN="top" | |
| 194 ><A | |
|
55
55f1f1b3e27d
Added new docs for SDL 1.2.1
Sam Lantinga <slouken@lokigames.com>
parents:
0
diff
changeset
|
195 HREF="guideexamples.html" |
| 0 | 196 >Prev</A |
| 197 ></TD | |
| 198 ><TD | |
| 199 WIDTH="34%" | |
| 200 ALIGN="center" | |
| 201 VALIGN="top" | |
| 202 ><A | |
| 203 HREF="index.html" | |
| 204 >Home</A | |
| 205 ></TD | |
| 206 ><TD | |
| 207 WIDTH="33%" | |
| 208 ALIGN="right" | |
| 209 VALIGN="top" | |
| 210 ><A | |
| 211 HREF="guideaudioexamples.html" | |
| 212 >Next</A | |
| 213 ></TD | |
| 214 ></TR | |
| 215 ><TR | |
| 216 ><TD | |
| 217 WIDTH="33%" | |
| 218 ALIGN="left" | |
| 219 VALIGN="top" | |
|
55
55f1f1b3e27d
Added new docs for SDL 1.2.1
Sam Lantinga <slouken@lokigames.com>
parents:
0
diff
changeset
|
220 >Examples</TD |
| 0 | 221 ><TD |
| 222 WIDTH="34%" | |
| 223 ALIGN="center" | |
| 224 VALIGN="top" | |
| 225 ><A | |
| 226 HREF="guideexamples.html" | |
| 227 >Up</A | |
| 228 ></TD | |
| 229 ><TD | |
| 230 WIDTH="33%" | |
| 231 ALIGN="right" | |
| 232 VALIGN="top" | |
| 233 >Audio Examples</TD | |
| 234 ></TR | |
| 235 ></TABLE | |
| 236 ></DIV | |
| 237 ></BODY | |
| 238 ></HTML | |
| 239 > |