Per-vertex displacement for LE4?

[havenphillip]

Would it be difficult to do this for regular Leadwerks as well? It just looks really cool.
 

It

[Josh]

It would be possible to write a tessellation shader based on the content of the LE5 shaders.

[havenphillip]

I wish I knew shaders well enough to make something like that. I messed with the tesselation shader and found some geometry shaders but I can't see how to take care of those cracks in the seams. If you integrated this into Leadwerks 4 and sold it as an add-on I'd buy it. 20 bucks. These texture editors make your heightmaps look cool but then you bring it to Leadwerks and you lose a little bit in translation.

Then again, it  might serve better strictly as a selling point for LE5. Sounds like you got some ground-breaking stuff going on over there.

Either way Turbo look great. Two thumbs up.

[Josh]

The way I get rid of cracks is by disabling displacement along seams.

The new engine uses a per-vertex displacement value but you could use the vertex alpha to control the displacement amount.

[havenphillip]

Dude, how do I get the seams? and then use vertex alpha to control the displacement? What is it? Like length(texcoords) or something? Do you have a code example or even a shader you'd be wiliing to impart? Or a webpage or tutorial somewhere that shows an example? That would be awesome.

I learned how to displace but after reading your article I just assumed you needed "per-vertex" which I thought meant you have to subdivide. I've been scouring the internet for geometry shader examples for subdivision and tesselation shaders.

I imagine the new engine will be much faster, and therefore better for this kind of thing, but I'm still trying to wrap my head around LE4.

[havenphillip]

Hey Josh I know you're busy and I keep bugging you with this but could you explain real quick how I get the seams so I can disable displacement on them. I've been looking everywhere and can't seem to find the answer. This is my displacement code:

    //Vertex displacement
    //-----------------------------------------------------------------
    vec4 height = texture(texture3,ex_texcoords0);
    float offset = (height.r + height.g + height.b)*0.025;
    vec4 newPos = vec4(modelvertexposition.xyz + vNormal* offset,1.0);

    if (height.r > 0.5) {        
        gl_Position = projectioncameramatrix * newPos;
    }
    //-------------------------------------------------------------------

[Josh]

There is a Mesh::UpdateEdges() method (Leadwerks 5) that will attempt to find them and set vertex displacement based on that. I don't think you can do this in the vertex shader.