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Detecting Billboards

Started by Medo Mex May 8, 2013 at 10:17 PM 8 replies 2k views

Original Post

May 8, 2013 at 10:17 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...

ankhd

May 9, 2013 at 3:12 AM

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

Medo Mex

May 9, 2013 at 7:49 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:

[attachment=15634:bboard1.png]

[attachment=15635:bboard.png]

ankhd

May 9, 2013 at 2:27 PM

they both look ok. use a radius as well

Medo Mex

May 9, 2013 at 3:30 PM

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

[attachment=15638:bboard2.png]

I want to avoid that.

belfegor

May 9, 2013 at 3:57 PM

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

Medo Mex

May 10, 2013 at 12:42 AM

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

unbird

May 10, 2013 at 1:37 AM

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

BornToCode

May 10, 2013 at 1:54 AM

use the average position of all 4 vertices as your position

Medo Mex

May 10, 2013 at 2:00 AM

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?

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