.\" .\" Copyright (c) 2009, Charles McGarvey .\" All rights reserved. .\" .\" Redistribution and use in source and binary forms, with or without .\" modification, are permitted provided that the following conditions are met: .\" .\" * Redistributions of source code must retain the above copyright notice, .\" this list of conditions and the following disclaimer. .\" * Redistributions in binary form must reproduce the above copyright .\" notice, this list of conditions and the following disclaimer in the .\" documentation and/or other materials provided with the distribution. .\" .\" THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS .\" IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED .\" TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR .\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR .\" CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, .\" EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, .\" PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR .\" PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF .\" LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING .\" NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, .\" EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. .\" .hy .TH YOINK 6 "July 24, 2009" .SH NAME Yoink \- An alien-smashing action game. .SH SYNOPSIS .B yoink [-h|--help] [OPTION=VALUE]... .br .SH DESCRIPTION .PP Leap tall buildings! Crush stupid robots beneath your feet! Wield your extra-terrestrial powers in the defence of humanity, and send those alien invaders back from whence they came! This is Yoink. .PP You play the part of a flying alien heroine who must defend her home on Earth from other airborne alien invaders. The game draws inspiration from classic arcade games like Joust, Bombjack, Rampage, and Defender--simple, fast-moving action. Basic arguments include: .TP .B -h, --help Display this help and exit. .br .SH TIPS .PP To attack, you must dive on the enemy at high speed. If you're going too slowly, you'll just drift harmlessly by. Diving from above gives different results from swooping in and hitting them from the side. If you're too close to attack, try to build up speed by running away and bouncing off a nearby building! .PP By charging your special alien powers, you can throw fireballs. The orange bar at the top of the screen represents your power level--at maximum, you can destroy almost anything. Aiming can be tricky, but with a little practice it's quite easy to launch them in the right direction. Try doing a little swoop or circle in the air to line yourself up before releasing your fireball. .PP The heroine has limited energy, measured by the blue bar at the top of the screen. When it runs out, it's game over! She can regain lost energy by picking up bonuses dropped by enemies. .PP To complete the current attack wave, you must destroy all the enemies. Hunt around, especially in the sky, if you can't find the last few. .br .SH OPTIONS .PP There are a plethora of options available for tweaking various aspects of the game. All options can be set either from a configuration file or by passing them as arguments. .PP A .B yoink configuration file ("yoinkrc") consists of key-value pairs. The format is not unlike that of other configuration files you are already familiar with. The syntax used is lua. .B yoink looks for configuration files and loads them in this order, the options from each subsequent configuration files taking precedence over the same options if they exist in previous files. .TP 1. @DATADIR@/yoinkrc This is the base configuration file which should be considered read-only. Look to this file as an example of the format used for configuration files. .TP 2. /etc/yoinkrc This is the system-wide configuration file. Not available on Windows. .TP 3. $HOME/.yoinkrc This is your own personal configuration file. .TP 4. $YOINKRC This is an optional environment variable you can set to point to a configuration file. .PP Options that are passed as arguments take precedence over options loaded from the configuration file(s). This mechanism can be used to play the game with temporary settings which you do not intend to retain. Here are some examples of passing options on the command-line: .PP .TP yoink fullscreen=true Run Yoink with the option .I fullscreen as true. This will run the game in full-screen mode. .TP yoink maxfps=60 Run Yoink with the option .I maxfps as 60. This will cap the display rate at 60Hz. .PP You can also set options with array values. Arrays can be passed on the command line by surrounding all the parts with curly brackets and separating each part by a comma. You may also have to quote the brackets so your shell doesn't parse them. For example: .TP yoink videomode=\\{1024,768\\} Run Yoink with the top .I videomode as the numbers 1024 and 768. The video size will be 1024x768. .PP Here is a list of some of the options available: .TP .B detail The level of detail. Possible values are 1, 2, or 3, 1 meaning the least amount of detail and 3 meaning the most. This effects the number of objects drawn to the screen. A high level of detail will draw everything but could cause poor frame rates if the graphics driver can't keep up with the load. Lower levels will omit certain details which aren't crucial for playing the game with the benefit of higher frame rates. See the Notes for more ways to increase the game's performance. The default value is 3. .TP .B doublebuffer If true, double-buffering will be used to help minimize distortion and artifacts caused by the animation of the game. Otherwise, a single buffer will be used. The default value is true. .TP .B fullscreen If true, the window will capture the display and render the game in full screen splendor. A value of false means the game will run in a window. The default value is false. .TP .B maxfps The maximum number of frames to be drawn per second. If your computer is really old, you can get away with decreasing this value and still have reasonably smooth animation. You can set this to a very high number to effectively render as many frames as is possible, but the actual rate could be limited by vertical display synchronization, depending on the X11 driver and settings used. You should not set this option higher than the point where the vertical synchronization effectively limits the draw rate or else the game may not be able to update the physics on schedule which could actually significantly lower the quality of the animation. The default value is 40. .TP .B printfps If true, the current number of frames being drawn per second will be printed to the console. The default value is false. .TP .B resizable If true, the window will be resizable by the window manager. This option is meaningless if the game is drawing to the full screen. The default option is true. .TP .B showcursor This option effects the visibility of the cursor while it is "hovering" over the display. If the value is true, the cursor will be visible. Otherwise, the cursor will be hidden. The default value is true. .TP .B timestep The number of times per second the simulation state will be updated. A value of 100 or higher is ideal for a better physical simulation. Values that are much lower cause the CPU to do less work, but accuracy will suffer. Errors could be introduced in the game with extremely low values. The default value is 80. .TP .B videomode The resolution or size of the window. The value is an array with three number elements representing the width, height, and bits per pixel that make up the video mode. The third number is optional. The default value is {800, 600}. .PP This is only a list of the more useful options. You'll have to use the source to find out about the more esoteric options, but you probably won't need to. .br .SH ENVIRONMENT .PP .B yoink responds to some variables in the environment: .TP HOME If set to a path of a valid directory (presumably a user's home directory), .B yoink will look for a file at .I $HOME/.yoinkrc and load it as a configuration file. .TP USER .B yoink uses this variable to guess the user's nickname, for a high score entry or whatever. .TP YOINK_DATADIR If set to a path of a valid directory, .B yoink will look in this directory first when it is loading game assets. Set this variable if you move the game's assets to another directory or perhaps want to load your own custom assets rather than the defaults. .TP YOINKRC If set to a path of a valid configuration file, .B yoink will load the options from that file, and those options will take precedence over options loaded from other configuration files. .br .SH NOTES .PP Yoink may or may not be playable with acceptable frame rates without a hardware accelerated OpenGL driver installed and working, depending on how fast your CPU is. Yoink is really not all that heavy on graphics, but it doesn't take much to overload a software implementation. If you're stuck without hardware acceleration, there are some things you can do to get better frame rates, in order of effectiveness: .TP 1. Decrease the resolution. Use the .I videomode option or just resize the window if the .I fullscreen option is false and the .I resizable option is true. This speeds up software renderers considerably. .TP 2. Decrease the timestep. Use the .I timestep option. You can set the timestep to be as low as the your .I maxfps option, but it is not recommended to set this lower than the target frame rate. Remember the trade-off here is decreased simulation accuracy. Try this to set your frame rate to 30Hz and your timestep to 60Hz: .PP yoink maxfps=30 timestep=maxfps\\*2 .TP 3. Decrease the level of rendering detail. Use the .I detail option. The game world may look sparse or incomplete, but that may be better than choppy animation. .br .SH BUGS .PP Although the pixelated graphics are intentional, there are some unintended artifacts which are more obvious on certain OpenGL implementations. .PP Send bug reports, patches, and love notes to: .br Charles McGarvey <@PACKAGE_BUGREPORT@> .SH AUTHOR .PP Neil Carter was the original creator of Yoink, his winning entry in the uDevGames 2003 Mac game development contest. Charles McGarvey restored the game and is the current maintainer.