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Type: Posts; User: StefanG

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  1. Replies
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    You seem to be activating your shader before you...

    You seem to be activating your shader before you try to set a uniform value,
    so that common mistake is not the cause of your problems.
    In some Nvidia drivers, I have experienced that glUniform1f...
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    Re: Cellular noise in GLSL

    I have not been keeping track of this thread for a while, so I am sorry for being so very late to respond. Your points are all very valid, and I think you should not use these new functions if you...
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    Re: color index with material properties

    > ,i want to know that how can we use text box,menubar,scroll bar

    Then please post that question in a separate thread.
    Also, consider posting it in the "OpenGL toolkits" section, as it is not...
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    Re: How to display a vertex with large values?

    You need to read up on view transformations.

    The relation between world space coordinates and screen space coordinates is determined by how you transform the vertices in your code. In classic...
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    Re: seamless tileable texture algorithm

    This is not an OpenGL question, although it is of course relevant to 3D graphics programming. It is a question on image processing, and you are unlikely to find good help here.
    All algorithms in...
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    Re: Cellular noise in GLSL

    The one on the floor ("flow noise") actually uses a previously unpublished version of 2D noise with rotating gradients and analytic derivatives. I ran into problems extending it nicely to 3D (I need...
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    Re: Cellular noise in GLSL

    Wow. 12,000 views and still ticking for this post. It will be fun to see what people make with this!

    I sent in a suggestion for a talk at Siggraph, but the reviewers rejected it, which I more or...
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    Re: A GLSL compiler problem?

    Loops with variable loop termination conditions
    were not supported in early versions of GLSL.
    Because you are not supplying a #version pragma
    to the compiler, you are implicitly asking for...
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    Re: GLSL UVW mapping

    What do you mean? Please be more specific!
    3D texture coordinate specification? 3D texture lookup?
    GLSL has support for 3D textures, and you can specify
    3D texture coordinates as vertex attributes...
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    Re: Draw circle in shader

    You could scale your vector from the midpoint to the fragment differently in x and y to adjust for the aspect ratio, but a cleaner way would be to do the computations in unscaled fragment...
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    Re: opengl es and multipass shader

    You need to render to a "framebuffer object" (FBO), and
    then change the role of that FBO and bind it as a texture
    in the next pass. It is done the same way in "proper"
    OpenGL, so apart from the...
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    Cellular noise in GLSL

    Just a quick update: yesterday I wrote some cellular noise functions ("Worley noise") of various flavors for GLSL, using the same pseudo-random permutation method as the Perlin noise implementations...
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    Re: GLSL noise fail? Not necessarily!

    The wiki on the Github repository now links to a rewritten cross platform benchmark with a side by side comparison of my old GLSL noise implementation (which was texture bandwidth limited and used...
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    Re: GLSL noise fail? Not necessarily!

    I was speaking of ATI drivers in particular, where constant expressions don't seem to be identified and collapsed properly. The other thing I noticed, that replacing a division by a constant with a...
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    Re: Problem with glsldevil

    What exactly do you mean by "runs infinitely"?
    Have you managed to get glsldevil to work for
    a simple demo program without bugs? It is a
    complex tool, and it might be a bit of an
    overkill for...
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    Re: GLSL noise fail? Not necessarily!

    The 2D simplex noise was just optimized some more. I replaced a division with a multiplication and removed one multiplication and one addition by introducing two more constants. The speedup I see on...
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    Re: GLSL noise fail? Not necessarily!

    The github repository has now been updated with some slight speedups, code cleanups and classic Perlin noise in regular and periodic versions.

    2D simplex noise is now only about 20 mult and add...
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    Re: Have problem to pass texture into shader.

    As Alfonse said, you really should do some texturing and shader tutorials and learn to walk before you run. We are happy to help, but your problems are many and concern things that are rather basic....
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    Re: GLSL noise fail? Not necessarily!

    That 0->0 mapping is not a problem. It is perfectly alright for a permutation to have one or even several fixed points that map to themselves, as long as they do not appear in a too regular pattern....
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    Re: GLSL noise fail? Not necessarily!

    For some reason, that "Fragment shader compile error:" shows up on many platforms, although the error message you get when you ask what went wrong is an empty string. On some systems I have tried,...
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    Re: GLSL noise fail? Not necessarily!

    Your benchmark is 25% lower than mine on the same hardware and software (MacBook Pro, GF9400M, MacOS X, 1280x800 fullscreen). Did you run the demo on a single screen? Mirroring, or just having a...
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    Re: GLSL noise fail? Not necessarily!

    Yes, of course. Good catch, thanks! It has only a minor effect
    on the final result, but it does make a difference. This change
    will be committed to the repository as soon as I have
    determined the...
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    Re: GLSL noise fail? Not necessarily!

    The code in the Github repository provided by Ian has now been updated rather a lot, and I no longer recommend using my pre-packaged zip archives posted above. They still work, but I will not be...
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    Re: GLSL noise fail? Not necessarily!

    Benchmark result for ATI Radeon HD 4850:
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    Re: GLSL noise fail? Not necessarily!

    Apart from editing the source and recompiling, not right now.
    I really should change that, but still, it's nice to see some benchmarks from high-end cards. The result from the MacBook Pro I am...
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