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Jeason

Member Since 30 Nov 2011
Offline Last Active Sep 12 2012 12:35 AM

Posts I've Made

In Topic: Paste a new picture to mesh

18 May 2012 - 06:53 PM

Hi,

You may draw your decals in a separate pass using alpha blending. Drawing the decals in the same time as the base texture sounds overly complicated.

Technically drawing a decal isn't that difficult. It involves a little bit of matrix and vector math. I won't go into the math details since that isn't my field of expertise.

Roughly, however, you'll need a matrix which defines x and y rotation and scale of decal and a position of course. With matrix vector multiplication using this decal matrix and all vertex positions of your model you'll be able to calculate the texture coordinates for each vertex in your scene.

Redrawing the model using these texture coordinates and the decal texture allows you to project any texture on the model. Remember to set the texture address mode to clamp and blending mode to alpha blending (for example).

Obvious optimization is to not draw the faces which are totally outside of the decal area. Also, the projected texture coordinates may be calculated in a vertex shader.

Best regards!

Thank you, kauna.As you say, I have to recalculate the texture coordinates for the model, such as the wall. Is it right?By the way, do you have some simple sample or demo for me to learn? You know i can't work it out just with your reply. Thank you.

In Topic: Paste a new picture to mesh

20 April 2012 - 05:03 AM

You should look up decals or projected textures. There're many ways to do it and it depends on the engine you use.


I just want to implement it by only using DirectX. Any more information for me?

Is it that I have to find the the correct texture coordinates where the user-defined picture should resides in the corresponding texture, and then modulate the two texture to final texture for the mesh?

In Topic: Real-time collision

19 April 2012 - 03:43 AM

I will try it.

In Topic: Real-time collision

17 April 2012 - 09:22 AM

I am busy in building the scene and other simple effect, so i have almost forget thisPosted Image .

My meaning is that, supposing, i get a stair model, through it the character can walk up to another floor. So how can i do the collision between stair and character?

Is it that I get all triangles from the stair model and then use each of them to do collisionPosted Image ?

In Topic: Real-time collision

10 April 2012 - 06:31 AM

I want to implement it all by myself. So i think i need to get some information from some open source.
Any advice for the learning?

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