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Type: Posts; User: carsten neumann

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  1. Replies
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    374

    You are omitting one step from painter's...

    You are omitting one step from painter's algorithm: sorting of polygons by depth.
  2. Replies
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    374

    Hmm, are you describing reasons why the painter's...

    Hmm, are you describing reasons why the painter's algorithm is inefficient or reasons why the z-buffer algorithm is inefficient?
    Also, this does sound a bit like a homework question...
  3. Please use around source code snippets. I'm...

    Please use
    around source code snippets.

    I'm not sure I understand what your question is. Could you perhaps try again, stating clearly what you want the code to do and what it does instead,...
  4. AFAIK it does though - you can just create and...

    AFAIK it does though - you can just create and bind a VAO during initialization and then never touch it again.
  5. I don't think there is a way to answer your...

    I don't think there is a way to answer your question without more details. Since OpenGL specifies a pipeline the coordinate system vertex data is in depends on the pipeline stage you are looking at,...
  6. Hmm, does it perhaps crash in capture? Have you...

    Hmm, does it perhaps crash in capture? Have you run it under a debugger? Does your code check for errors from OpenCV calls (sorry, not familiar with how OpenCV error reporting/handling works)? I...
  7. You use double buffering but don't call...

    You use double buffering but don't call glutSwapBuffers() at the end of display2().
  8. Please use around source code. The error...

    Please use
    around source code.
    The error message contains the necessary hint: when calling capture() no display function is registered with GLUT, because you only register it in main() after the...
  9. Please use around source code. I'm not really...

    Please use
    around source code. I'm not really sure what you are asking, for example what is drawVertex that you don't want to change? I'd doubt it is possible to avoid making quite substantial...
  10. Replies
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    If your geometric data changes from frame to...

    If your geometric data changes from frame to frame you'll have to upload new data each frame, so, yes in that case buffer objects wont help you reduce the amount of data transferred each frame. Where...
  11. Did you check what OpenGL version GLEW thinks is...

    Did you check what OpenGL version GLEW thinks is available, e.g. using if(GLEW_VERSION_3_2) ? The symptom looks like a not initialized function pointer, which could be the case if GLEW believes you...
  12. Thread: glfw3

    by carsten neumann
    Replies
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    394

    Hmm, it's really kinda difficult to help you,...

    Hmm, it's really kinda difficult to help you, since you are showing neither the error messages you are getting nor what your commands to compile and link look like.
    Are you setting the include and...
  13. It should, provided you make sure that the struct...

    It should, provided you make sure that the struct has a layout that matches whatever you write into the buffer.
  14. Sorry, not sure what you mean. In the code you...

    Sorry, not sure what you mean. In the code you posted the only place you created a variable of type A is commented out, the rest just casts the pointer returned by glMapBuffer to A* and uses that to...
  15. Please use around source code you post. Your...

    Please use
    around source code you post.
    Your primitives (rect/triangle) all have zero area, because you specify the same coordinates for all corners.
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    The viewport is global state.

    The viewport is global state.
  17. One makes a translation matrix (i.e. a matrix...

    One makes a translation matrix (i.e. a matrix that represents a translation by the given vector), the other combines a translation with a given matrix and returns the combined matrix - see also the...
  18. The way ray tracing is usually accelerated is by...

    The way ray tracing is usually accelerated is by building a hierarchical data structure over the primitives, these days bounding volume hierarchies (BVH) seem to be popular, kd-trees, bsp-trees and...
  19. If I understand correctly this is essentially a...

    If I understand correctly this is essentially a shadow calculation: of the vertices facing the light source, you only want those not in shadow. Since you mention ray tracing in the post's subject,...
  20. Replies
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    612

    Did you take that screenshot with the...

    Did you take that screenshot with the multiplication with nDotVP enabled in: colorVarying = diffuseColor; //* nDotVP; ? What happens when you just map the value nDotVP to the surface, i.e....
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    612

    What do you mean by that? Are you checking for...

    What do you mean by that? Are you checking for OpenGL errors (glGetError)? FWIW on a quick reading I did not see anything obviously wrong in the code you posted, but without a better description of...
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    You may want to search with the term...

    You may want to search with the term "constructive solid geometry" (CSG), that will turn up lots of info on the topic. Otherwise, could you be a bit more specific in your question, I'm not really...
  23. AFAIK they essentially are single channel...

    AFAIK they essentially are single channel textures. In a compatibility profile you create them the same way as ever, in a core profile you use GL_RED as a format parameter for the texture - to get a...
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    Sounds to me that you have vsync enabled, and...

    Sounds to me that you have vsync enabled, and normally your time for a frame is just below 1/60 second, while for some views you just go slightly over and then miss the opportunity to swap buffers...
  25. If I'm reading it correctly it converts each RGB...

    If I'm reading it correctly it converts each RGB sample to a luminance value (with the dot product with W). I suppose you could try getting rid of that and just use the alpha component of the...
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