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About Theodoros

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  1. OpenGL OpenCL OpenGL interop

    1) clSetKernelArg(kernel, 0, sizeof(vbo), &vbo) should be: clSetKernelArg(kernel, 0, sizeof(cl_mem), &PositionArray) 2) remove clWaitForEvents(1, &wait) (it is not necessary) 3) clEnqueueNDRangeKernel can take NULL as a local size argument
  2. Parallel Octree Construction on GPU

    You usually convert the BVH construction problem to a sorting problem. This can be done with the use of morton codes, see for example this paper [url=""][/url] Bitonic sort and Radix sorts can be implemented very efficiently on modern GPUs, see here for example for an OpenCL implementation: [url=""][/url]
  3. Tessellation makes point

    Do you set the primitives to GL_PATCHES and set the glPatchParameteri ?
  4. Need help with reliable polygon triangulation

    Another vote for the Triangle program. In my experience it can easily handle cases like 2 and 3. Although the interface is a little cumbersome (especially if you try to specify internal holes), it is very robust and fast. To AvengerDr: yes the result can be index based.
  5. Water Ripples

    I am not familiar with the language you use, but I do not think that the casting from a float to a byte will work. You must find the maximum,minimun height and scale the values or do some clamping. Anyway, some blokiness is expected to that kind of approximation algorithms. Personally, I use a better approximation based on this paper.
  6. Water Ripples

    You need the damping, otherwise the waves will propagate forever. See link for more details.
  7. FFT water model

    The code seems fine, it is probably a parameter issue. Use a bigger grid (e.g. 256x256) and simulate a smaller area (e.g. 32mx32m) to increase the wave resolution. In addition, you can try changing the cutoff l and the alpha value.
  8. FFT water model

    Can you give more details about what you are doing at each step or post some code?
  9. FFT water model

    Inverse FFT is used to get the original wave height field expressed as the sum of complex time dependent amplitudes (eq. 19), so it is applied only on h~(K, t).
  10. FFT water model

    In step 2, you must calculate the h~(K,t) from the Tessendorf paper eq. 26 as h~(K,t) = h0(K)*exp(iwkt)) + conj(h0(K))*exp(-iwkt) and perform an inverse FFT on h~(K,t). The real part of the result is the wave height. In my experience ,the parameters values like the alpha value and the small-wave cutoff l in phillips spectrum calculation are also important to get a reasonable result.
  11. lighiting.. (PLZ its urgent)

    Do you provide correct normals for the geometry? Also since you use glScalef do you also enable GL_NORMALIZE?
  12. curve extraction

    In general, this is a difficult problem to tackle. You could look into least squares fitting. Although in the end you will probably have to solve a non linear minimization problem and resolve to Non Linear optimization with all sorts of problems such as selecting a good initial solution. Can you give more details about what are you trying to achieve ?
  13. OpenGL loading skeletal animated model

    You can use the md5 file format in Blender to support bone animation, for loading I use assimp.
  14. OpenGL OpenGL 3.2 and SDL 1.3

    Setting the glDrawElements pointer to 0 is fine as long as the vbo is active with glBindBufferARB, at least in OpenGL 2.1.
  15. GeoMipMapping - my approach

    I use a similar technique in my game with 3 level of details, I also suggest to take into account the terrain curvature in the boundaries to remove unnecessary vertices