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eppo

Member Since 14 Mar 2008
Offline Last Active Yesterday, 04:46 AM

Posts I've Made

In Topic: How to draw [these kind of] splines?

16 May 2014 - 12:01 PM

I suspect you'll be able to draw such a spline as a Hermite curve using only an outgoing and an incoming set of positions and (flat/horizontal) tangents.

 

You can use the Hermite routines that come with the D3DX-library.

 

http://msdn.microsoft.com/en-us/library/windows/desktop/bb204998(v=vs.85).aspx

 

Or you can use the cubic equations mentioned there directly.


In Topic: High Speed Quadric Mesh Simplification without problems (Resolved)

10 May 2014 - 11:23 AM

Based on what criteria do you prioritize one contraction over the other? I don't see you (re-)sorting the list of triangles.


In Topic: Aligning a path, along a another dynamically

09 May 2014 - 07:47 AM

This is probably easiest when the underlying road structure is defined as a network of interconnected splines. That way the center of the road and its tangent/direction are exactly defined. Also, you can do distance tests between the (tessellated) curve and surrounding points to see whether such points lie on the road. Lastly, a user-defined route becomes a simple series of (spline-)key-points.


In Topic: Having trouble with my Vertex Element Class

03 May 2014 - 02:54 AM

What are the VertexElements you feed it with? Do elements that share the same semantic-name have individually unique indices? A name + index pair defines a unique semantic.

 

It would be less error sensitive if you don't have to specify a semanticIndex, but calculate it based on the number of previous occurrences of the same name.


In Topic: Alpha blending with a color that has no RGB components

27 April 2014 - 08:21 AM

You can make sure all pixels in a texture have a valid RGB value by setting the RGB value of zero-alpha pixels to the RGB value of the nearest pixel that has a non-zero alpha value.

 

One simple way is to do it during mipmap creation. At the pixel position, sample downwards to the lower detail maps until you find a sample that has some alpha value. Use the RGB value of that sample while leaving the alpha at zero.


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