Drawmethod

Drawmethod is a series of properties OpenBOR applies to almost every element it draws to the screen. For instance, an entity might be drawn with alpha transparency and at 50% of its normal size. Drawmethod is actually applied at the drawing level (hence the name), but many OpenBOR elements have their own set of drawmethod properties to control the final drawmethod.

Native Access

Under construction

Script Access

Getting Drawmethods

void drawmethod = get_entity_property(void <entity pointer>, "drawmethod"));

Before you can access drawmethod properties, you need the drawmethod pointer. There are different ways to get these depending on the object in question. See the individual objects for details on how to access their drawmethod pointers. As an example, you can get the drawmethod property of an entity using the get_entity_property() function.

Common Drawmethod

void drawmethod = openborvariant("drawmethod_common");

Most direct draw script functions rely on a global common drawmethod. The pointer location for this drawmethod is read only, but you may modify its properties at will. The common drawmethod applies to all of the following:

• Drawbox()
• Drawboxtoscreen()
• Drawdot()
• Drawdottoscreen()
• Drawline()
• Drawlinetoscreen()
• Drawscreen()
• Drawsprite()
• Drawspritetoscreen()

Default Drawmethod

void drawmethod = openborvariant("drawmethod_default");

In order to provide default drawmethod properties, OpenBOR includes a hard-coded default drawmethod. You cannot modify the pointer or properties of this drawmethod in any way. If you try, a warning will be sent to the log and your attempt is ignored. The default drawmethod is available as a read only system variant.

Copy Drawmethod

void source_drawmethod = <value>; 
void target_drawmethod = <value>;

copy_drawmethod(source_drawmethod , target_drawmethod);

For convenience, you can copy the values of one drawmethod structure directly to another.

Tip: Use the default drawmethod as a source to quickly reset all of a target drawmethod’s properties to their default values.

Allocate Drawmethod

void drawmethod = allocate_drawmethod();

OpenBOR script allows you to allocate your own drawmethod to memory, after which you may get and set its properties normally. This is especially useful for certain objects that do not normally have an independent drawmethod. For example, when any text is displayed it does not have its own drawmethod copy. Instead, its drawmethod pointer is set to the global drawmethod. This saves memory, but it also means you cannot normally modify the drawmethod properties of that text. But you can allocate a new drawmethod property and point the text’s drawmethod property to it, after which you are able to modify its properties at will.

Make sure you don’t lose the pointer so you can clear the allocated memory when you are finished, and only allocate drawmethods you need. Additionally, if the drawmethod pointer you replace DOES have its own independent drawmethod, you will need to be wary of its memory as well. Lastly, watch out for automated behaviors. For instance, if you allocate a new drawmethod and assign it to an entity, but that entity is then killed, OpenBOR will automatically destroy whatever drawmethod structure the entity’s drawmethod points to. If you aren’t paying attention, it’s possible to have odd situations such as an entity’s original drawmethod structure left floating around in memory while your created structure is gone!

Free (delete) Drawmethod

void drawmethod = <value>;

free(drawmethod);

As previously mentioned, always keep the pointer to drawmethods you allocate or detach, and free them when no longer needed. Otherwise the drawmethod structure stays in memory until the engine is shut down.

After the target drawmethod structure is deleted, its pointer is now “dangling”, meaning the part of memory it pointed to isn’t there any more, and the computer may allocate it to something else. Don’t try to use that pointer again, or you will get undefined behavior. Lastly, don’t try to free the global default drawmethod. At best, you will cause a shutdown.

Properties

Get a drawmethod property value.

mixed x = get_drawmethod_property(void <drawmethod pointer>, int <property>);

Modify a drawmethod property value.

mixed x = <value>;

set_drawmethod_property(void <drawmethod pointer>, int <property>, x);

Property List

• Constant: The property’s constant identifier.
• Type: The property value’s variable type.
• Description: A short description of what the property is and does.

Examples

Alpha

Clip

Rotate

Shift_x

Tint

Water Mode

Water Wave Amplitude

Legacy

Under construction