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## Detecting Billboards

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9 replies to this topic

### #1Medo3337  Members

Posted 08 May 2013 - 04:17 PM

When the player shoot, I draw a bullet impact billboard, sometimes the player shoot at the same target multiple times, I don't want to place multiple billboards over each others.

How do I detect if a billboard already exists, so I only draw it if no billboards exists on the hit point?

D3DXVECTOR3 triangleP0, triangleP1, triangleP2; // Intersected triangle
D3DXVECTOR3 pHitPoint; // The hit point

// --> I want to use if () statement to check if a billboard already exists here...

// Code to draw billboard here...


Edited by Medo3337, 08 May 2013 - 05:11 PM.

### #2ankhd  Members

Posted 08 May 2013 - 09:12 PM

You would need to keep track of the hit spots on each object

### #3Medo3337  Members

Posted 09 May 2013 - 01:49 AM

@ankhd: The player could shoot at: 2.0f, 1.8f, 1.0f

Then shoot at: 2.0f, 1.4f, 1.0f

Notice, it's not the same hit spot but I shouldn't be drawing the billboard since it will still appear over another one.

See the sceenshot, two billboards appears over each others, I want to AVOID that:

Edited by Medo3337, 09 May 2013 - 05:10 AM.

### #4ankhd  Members

Posted 09 May 2013 - 08:27 AM

they both look ok. use a radius as well

### #5Medo3337  Members

Posted 09 May 2013 - 09:30 AM

They don't look ok, take a look at the following screenshot:

I want to avoid that.

### #6belfegor  Members

Posted 09 May 2013 - 09:57 AM

You could calculate the distance between position of "billboard" that you want to place against position of each existing "billboards" and if it is smaller then some value  do not add it to the world. Hint: D3DXVec3LengthSq

### #7Medo3337  Members

Posted 09 May 2013 - 06:42 PM

How do I get the position of the billboard if I have the position of the vertices v0, v1, v2. v3?

### #8unbird  Members

Posted 09 May 2013 - 07:37 PM

The average. Though, you probably had the quad created from some center point, which you could use as well.

### #9BornToCode  Members

Posted 09 May 2013 - 07:54 PM

use the average position of all 4 vertices as your position

### #10Medo3337  Members

Posted 09 May 2013 - 08:00 PM

In some games, I notice they place bullet impact billboards over each others, though they still look realistic.

In my case, If I draw multiple billboard over each others, they don't look realistic.

Do I only have to change the texture to another one that can appear realistic when placed over each others? Maybe there are some techniques like resizing existing billboard before drawing another one over it?

Edited by Medo3337, 09 May 2013 - 11:38 PM.

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