摘要: The get_enable_state function checks the current status of a trigger; by passing the
trigger identification number, you get in return the state of the trigger. If a trigger
is disabled, a call to get_enable_state returns a value of false. If enabled, the return
value is true. To enable or disable a trigger, call on the enable function, using the
trigger's identification number as the only argument.
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摘要: get_trigger is the function in the trigger class that you call every time the player’s character
moves. get_trigger will take the coordinates of the character you are checking and
return the identification number of the first trigger found at that location (if any). If
no triggers are found at the specified location, get_trigger returns a value of zero.
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摘要: add_trigger is the heart of all the other functions that add a trigger. This function
allocates a sTrigger structure, sets its type, identification number, and enable flag,
and then links the structure into the linked list of triggers. Once you allocate your
program using the add_trigger function, the program can fill in the returned sTrigger
structure with the coordinates, radius, height, or whatever other information the
trigger needs to have defined.
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摘要: Just as does every C++ class, cTrigger has a constructor and a destructor that set up
and free the data contained within the class. The only data tracked by the trigger
class that is not contained with the linked list is the number of triggers currently
held in the linked list and a pointer to that linked list. The constructor and
destructor ensure that the class is prepared for using those two variables to free
the class's data when destroyed (by calling the free function).
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摘要: Adhering to object-oriented programming techniques, create a class that will handle
a list of triggers and determine which (if any) has been touched by a character. The
class uses a structure to store the information of each trigger—the coordinates, type,
and so on. Each trigger is also assigned an identification number that it uses to refer
back to itself. The entire list is maintained as a linked list of structure.
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摘要: You define sphere triggers (see Figure 17.1) by a set of coordinates and a radius.
Sphere triggers have two unique benefits:
■ Spheres are perfect for defining large areas of a map as a trigger, only using
the center coordinates and a radius to define the location of the sphere.
■ The sphere trigger is one of the fastest ways to check for character-to-trigger
collisions in the map trigger engine.
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摘要: Using character map lists is a quick way to place characters in a map. When you
load a map into memory, load the matching character map list and insert the characters.
Although this method of adding characters to a map seems desirable, you’ll
need a bit more flexibility at times, and that’s when using scripts comes into play.
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摘要: While going through the examples, I placed characters on the map in
a direct, hard-coded manner. However, remember that hard-coding game data is a
no-no. You need to have as much flexibility as possible when designing your maps,
and this includes placement of characters in a level.
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