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Member Since 14 Mar 2008
Online Last Active Today, 03:19 PM

Topics I've Started

Barycentric coordinates of circumcenter of tetrahedron

21 January 2014 - 09:40 AM

I'm looking for a way to express the center of a tetrahedron's circumcircle as a set of barycentric coordinates. The way I do it now is to first calculate the center coordinates and then in a second step convert those to their bc-equivalent.


On this blog the author seems to use a more efficient method: http://realtimecollisiondetection.net/blog/?p=20


I can't quite figure out how to translate that to the tetrahedral case though.



DrawIndexed : StartIndexLocation / IASetVertexBuffers : Offset

01 January 2013 - 01:43 PM



My renderer has this issue where I get an DEVICE_DRAW_INDEX_BUFFER_TOO_SMALL warning when using DrawIndexed(Instanced)().


I use 16 bit index buffers that refer to max 2^16 vertices chunks in a vertex buffer. Whenever I pass a BaseVertexLocation > 0 to DrawIndexed(), this warning is output. However, if I set StartIndexLocation to zero and instead pass an index buffer offset to IASetIndexBuffer(), the warning disappears. For both cases the rendered scene looks fine.


Any ideas what could be causing this?


Using environment variables in include directive

26 November 2012 - 01:18 PM


I'm trying to get the pre-Windows 8 XAudio2 headers from the DirectX SDK to work under VS2012.
At one point the documentation tells me to add the following line of code...

#include <%DXSDK_DIR%Include\xaudio2.h>

..., which doesn't work: cannot open include file.

I assume this is because it's not possible to literally specify environment variables this way?

Corrupt VS -> PS interpolants

29 October 2012 - 01:04 PM


I'm having this issue where artifacts show up around geometric edges (D3D10.1):

Posted Image

These blown-out pixels are caused by per-vertex occlusion values passed from a vertex shader. VS input values are all normalized values between 0.0 - 1.0. I perform no kind of processing on these values in the vertex shader, and they are used as simple multipliers in the PS, but for some reason these errors still occur. I'm writing these values out to a DXGI_FORMAT_R11G11B10_FLOAT render target, but any floating point rt shows the same symptoms.

Any ideas?

apps, tools and scripts

11 September 2012 - 03:25 PM


I've been bundling the tools I've written for various projects over the past few years together. Mostly geometric processing tools and procedural generators. They're part of a library which can be found:


All tools are console applications that can be called from within a scripting environment. A script feeds serialized data into an app via the standard streams and vice versa.

I've added a php setup and scripts for a handful of tools:

- the brancher (a tree generator)
- a poisson sampler (covers a mesh in sample points)
- a convex hull tool
- mesh reduction tool
- texture block compressor
- a shader compiler (wrapper for D3DCompiler)

Scripts and samples for remaining tools I'll add later.
Hope you find something useful in there...


In general, scripts look like this:
[source lang="java"] options["somevalue"] = 6; options["aspline"] = new Spline(0.3, 0.4, 0.7); options["andatexture"] = Texture2D::fromNormalMap("Replicator_Normal.png"); meshsaver(array("meshes" => replicator(options)));[/source]
Because of how multiple tools pipe into one another, I think a node editor would suit well as a GUI-frontend.
Is there an existing library that provides this sort of functionality? (...and perhaps a spline/curve editor as well?)

edit: can't get those = chars to line up