Flash AS3从顶部减小载物台高度

Question

I'm trying to reduce stage height from the top to get an item to spawn under a specific area. Where the HUD is.

I used to have my HUD on the bottom which caused no problem. Because my function has:

headY = Math.ceil((((stage.stageHeight - hudHeight)))/(headWidth))*Math.random())*headWidth;

This reduces stage.stageHeight with 80 so the head can spawn properly. However, this isn't the case when the HUD is at the top. What this line currently does is that it is making the head not able to spawn under stageheight - 80 pixels instead of the top.

My question is; how can I make the code reduce the stageheight from the top.

Thanks in advance,

Jordi

Extra info about my question: All I'm trying to do actually, is 'selecting' the bottom of the stage, leaving the stage out of the picture. I was just using stageheight as an indicator to control the 800 pixels. So when I manipulate the stageheight, I wouldn't have to change the code. But since this might not be possible. There should be a different way. I hope you understand my question now. If not, what I want to do is select everything from 80 pixels down and under. The stage's height is 800 pixels so I need to select 720 pixels. However, I can't find a way to select the bottom 720 pixels.. only the top 720 pixels.

Answer 1

Although your question is hard to understand, the answer is most likely that you cant . The stageHeight is read-only. You can set it in HTML, and even set it to a percentage. But you can't alter it in Actionscript.

Answer 2

The way your question is worded, makes it extremely hard to understand what you want.

I am guessing that what you want is to spawn a given object and ensure that it is not spawned in the same space as your HUD.

So if your screen is 800 x 800 , and your HUD takes up the full width of the screen and the top 80 pixels of the screen you might try this to get a valid y spawn location :

var headY:Number = Math.random() * (800 - 80) + 80;

That would give you a resulting value from 80 - 800;

Given your variables I would suggest this :

var headY:Number = Math.random() * (stage.stageHeight - hudHeight) + hudHeight; 

Now based on your code, it seems like you are also trying to ensure that whatever you are spawning is not partially off the top or bottom of the screen, so you need to factor in the height of the head. So consider this code :

var headY:Number = Math.random() * ((stage.stageHeight - headHeight) - (hudHeight + headHeight)) + (hudHeight + headHeight);

Not completely sure if this is what you are looking for, but it's the best I can do based on your question and trying to suppose what it is that you want.