| Common Production Tasks
| The Power Game Factory interface relies heavily on a few types of controls that are not seen frequently in other Mac OS applications. The usage of each of these controls is described below.
Using Image Wells | The pictures used by a game project's various animation sequences and interface elements are displayed in image wells. Moving a picture into an image well adds it to a game project. Image wells that contain sprite animation frames come in pairs, as shown above. The first well contains a color image, with pure white pixels (RGB value 255,255,255) representing the empty space surrounding the sprite. The second well contains a mask, which is a grayscale picture of the same dimensions as the image itself, used to determine the opacity of each pixel in a given frame. Any white pixels in a mask indicate full opacity, and darker colors represent varying levels of transparency, with black (RGB value 0,0,0) indicating complete transparency. Be sure to create images and masks that follow these specifications to ensure that they appear correctly in Power Game Factory and, more importantly, in the game itself. A button labeled Generate Mask appears near the Mask image well, and may be used to quickly create a simple mask for the associated image. More refined masks featuring soft edges and varying levels of transparency can not be created with the Generate Mask button; such masks must be painted in an image editing application and moved to the mask image well by hand. Most image wells contain images that are part of multi-frame animation sequences, much like the one shown above. In cases like these, an accompanying list box contains all of the images in the animation sequence, and whichever frame is selected in the list box is displayed in the image well. Before moving a picture into this type of image well, the animation frame that is to be updated must be selected in the list box. To quickly change the selection from one frame to another, use the up and down arrow keys. (This is a good way to preview an animation sequence when you want to make sure it is fluid.) The Add Frame button appends a new frame to the end of the animation sequence, and the Remove Frame button can be used to delete the selected frame. Animation sequences may be nearly any length. There are three ways to move a picture into an image well. The first is to drag an image file from the Finder into the well. Pictures may also be dragged directly from some image editing applications. If an image is dragged into a well from the Finder, it must be in one of the following image file formats:
Image File Format Name | File Name Extension
BMP | .bmp
GIF | .gif
PICT | .pct
PNG (Portable Network Graphics) | .png
Photoshop | .psd
Targa | .tga
TIFF (Tagged Imager File Format) | .tif*
* | When saving TIFF files, set the Image Compression to either None or LZW. Power Game Factory does not support other TIFF compression types, such as zip and jpeg.
The second way to move a picture to an image well is to copy the image in an image editing application and paste it into the well. control-click the well and select Paste Image from the contextual menu that appears. A third way to move a picture to an image well only applies to image wells that display animation sequence frames. Select a frame from the nearby animation frames list box and choose Paste from the Edit menu. Images must be created with a resolution of 72 pixels per inch. It is best to use a color depth of 24 bits per pixel. (Images are automatically converted to 24 bits per pixel when they are added to game projects.) A list of recommended image editing applications can be found in the Content Creation Applications section. Note that the Levels Window in Power Game Factory displays sprites using a graphics engine that differs somewhat from the engine used in finished games. Because of this, sprites that should be semitransparent may instead appear fully opaque in the Levels Window, where pixel opacity is either all or nothing (with white pixels appearing transparent.)
Object Type Management | A common set of controls is used to manage various game object types, such as character types, projectile types, and contrail types. On the left of each object type editing window is a list box containing the names of each object type. Below the list box are controls for renaming the selected object type, deleting the selected object type, and creating a new object type. When a new object type is created, it is usually based on the previously selected object type. The various editable properties of the selected object type appear to the right of these object type management controls.
Editing Property Lists | Some object types, particularly character types, have large numbers of properties that are arranged into property lists such as the one shown above. Property lists contain several rows, with property names usually appearing in alphabetical order in the left column, and with their values listed in the right column. Most property values are numbers, but some are checkboxes that may be checked or unchecked.
Editing Sound Collections | Most of the sound effects used by characters, weapons, projectiles, and other objects in a game are collected into sets of several sounds, only one of which is actually heard each time the sound is played. In an effort to prevent game audio from becoming repetitive, the exact sound that is heard is chosen at random. In Power Game Factory, list boxes contain each variation of a sound. Sound collections are managed with the nearby Remove Sound and Add New Sound buttons. To preview a sound, select it and click the Play Sound button. Sounds may be stopped by pressing Command-. (Command-Period) on the keyboard. When adding new sounds, the Open dialog box appears, prompting you to select a sound file. Power Game Factory supports sounds in the formats listed in the chart below. Note that the System 7 Sound format is recommended, because System 7 Sound files can be loaded very quickly. Very large sounds files and sound files that use sophisticated compression techniques, such as MP3, are not recommended, because they may take a long time to load.
Sound File Format Name | File Name Extension
Audio Interchange File Format | .aiff
MPEG Layer 3 | .mp3
MPEG 4 Audio | .mp4
System 7 Sound (recommended) | .sfil
WAVE | .wav
The Content Creation Applications section provides information on various audio editing applications that can be used to create sounds for games.