| Measurement Conventions
| Power Game Factory uses a variety of units of measurement with which you should be familiar when setting properties, particularly those relating to character behavior and the interaction of physical objects.
Distance | Distance is measured in pixels. Appropriate distance-related properties can often be determined by considering the dimensions of the screen. For example, if the screen width is 640 pixels, then a character's Maximum Viewing Distance would need to be about 320 in order for him to be able to see the player from halfway across the screen.
Time | Time is measured in units called ticks. There are normally 30 ticks per second. Accordingly, games created with Power Game Factory normally display 30 frames per second (though the frame rate may decrease on slower computers.) Ticks are often used to measure delays between events that occur repeatedly. For example, if a character's Delay Between Attacks property is set to 45, he will attack once every 45 ticks, or about once every second and a half. Note that although the number of ticks per second is assumed to be 30, this value can be changed by adjusting the Target Frame Rate, as described in the Specifying Basic Game Behavior part of the Interface Design section.
Speed | An object's speed is measured in pixels of movement per tick. Since there are normally 30 ticks per second, a projectile moving at a speed of 10 pixels per tick is able to travel 300 pixels per second, or nearly half the width of a 640-pixel screen.
Acceleration | Acceleration is an expression of the increase in an object's speed over time. If a character has a Horizontal Acceleration Rate of 1, then his speed will be increased by 1 pixel of movement per tick. After a second, he would be moving at a rate of 30 pixels per tick. (Most objects have a speed cap which eliminates acceleration after a certain point.)
Weight | Weight is measured in units similar to pounds. The weight of an object determines its ability to remain steady under physical pressure. For example, a heavier character will push a lighter character out of his way, and heavier particles sweep lighter particles along through the air. The weights of stacked objects are cumulative. For example, two characters standing on a particular bridge could cause the bridge to collapse, where a single character could not.
Object Display Order | The display order of objects determine which objects overlap others. Objects with higher display orders overlap objects with lower display orders. The display orders of characters and scenery may be edited, but most other objects are rendered at a fixed display order. When determining the display order of a particular character or scenery object, consider the display orders of the other objects with which it must interact in a level:
Object Type | Display Order
Level Background Layers | 0 thru 100
Switches | 115
Particle Projectiles | 550 thru 560
Standard Projectiles | 570 thru 580
Player | 600
Doors | 1125
Items | 1180
Sound Volume | The volume of most sounds is determined by the game engine, which compares the location of the sound's origin to the camera location. A sound being emitted by an object located at the center of the screen will be louder than one being produced by an object near the side of the screen. It is possible for a user-designed routine to change the volume of a level's background music. In that case, the sound's volume can be set to any value between 100 (loudest) and 0 (inaudible.)