These are general interpreter functions and properties that relate to the background screen.

Properties

BackgroundImage BackgroundZBuffer TransitionEffect TransitionTime ScrollX ScrollY

Functions

BackgroundHeight BackgroundWidth StampZBufferRegion

property BackgroundImage = none

The current background image resource.

Example

BackgroundImage = MyPicture_image;

property BackgroundZBuffer = none

The current background zbuffer resource. This should always have the same height and width as the backgroundImage.

Example

BackgroundZBuffer = MyPicture_zbuffer;

property TransitionEffect = EFFECT_BLEND

This is the type of transition that is applied to the screen between scenes, when the enter-statement is executed. The game is not stopped during this transition, and objects still move and animate, events still get triggered, and scripts continue executing. The possible effects are listed below, and are defined in the standard script file Constants.s.
 

EFFECT_NONE	Has no special effect; the scene just blips from one to the next.
EFFECT_BLEND	Blends the scenes together smoothly over several frames.
EFFECT_FADE	Fades the old screen to black and the new screen from black.
EFFECT_FADE_IN	Fades the screen in from black, without fading out first.
EFFECT_FADE_OUT	Fades the screen out to black.
EFFECT_BLANK	Blanking is just like fading, except to white instead of black.
EFFECT_BLANK_IN
EFFECT_BLANK_OUT
EFFECT_BOX_IN	A shrinking-box effect starting from the edges of the screen, and moving inward to the middle.
EFFECT_WIPE_UP	Wipe effects wipe across the screen from old to new.
EFFECT_WIPE_DOWN
EFFECT_WIPE_LEFT
EFFECT_WIPE_RIGHT
EFFECT_SLIDE_UP	The old screen slides up, revealing the new.
EFFECT_SLIDE_DOWN
EFFECT_SLIDE_LEFT
EFFECT_SLIDE_RIGHT
EFFECT_ZOOM_OUT	The old screen shrinks inwards.

A related property, transitionTime, determines the number of cycles over which the effect is applied.

property TransitionTime = 24

This chooses the number of cycles in which the transition effect (decided by the transitionEffect property) is applied.

property ScrollX = 0

The offset of the background image from the right side of the screen. It is used to scroll the game space horizontally. ScrollX is reset to zero every time a new scene is entered.

Example

// pan from left to right
autoScroll = false;  // set manual scrolling
scrollX = bgWidth - 640;
while scrollX > 0
{
   scrollX = scrollX - 10;
     delay;
}

property ScrollY = 0

The offset of the background image from the top of the screen. It is used to scroll the game space vertically. ScrollY is reset to zero every time a new scene is entered.

function BackgroundHeight

Gets the height of the current background image.

Returns

Height in pixels, or 0 if none exists.

function BackgroundWidth

Gets the width of the current background image.

Returns

Width in pixels, or 0 if none exists.

function StampZBufferRegion (zbuffer, x, y, transparencyMode, left, top, right, bottom)

Copies a section of a zbuffer onto a dynamic zbuffer.

Parameters

zbuffer		The zbuffer to copy.
x		The x coordinate at which to stamp the zbuffer.
y		The y coordinate at which to stamp the zbuffer.
transparencyMode		Mode with which to stamp the zbuffer. (0: none, 1: all areas originally filled with black [priority 0] are transparent.)
left		Left x coordinate of the region of the zbuffer to stamp.
top		Top y coordinate of the region of the zbuffer to stamp.
right		Right x coordinate of the region of the zbuffer to stamp.
bottom		Bottom y coordinate of the region of the zbuffer to stamp.

See Also...