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Type: Posts; User: bsabiston

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  1. Actually this is for Metal -- so maybe it is...

    Actually this is for Metal -- so maybe it is different from OpenGL? With Metal my fragment function does not return a full 4-component color but rather a single float value. And it seems like Metal...
  2. How does blending (color vs alpha) work for single-channel render target?

    I'm porting some code from a technical paper, and they use a render target with only one channel - it's a 16-bit float buffer. But then they set blending operations on it like this:...
  3. Now I'm really confused. I thought the whole...

    Now I'm really confused. I thought the whole point of "incremental" transformations to the matrix is that the new Y or X rotations were applied to the combination of what had come before. If rather...
  4. Okay, I've been tearing my hair out over this --...

    Okay, I've been tearing my hair out over this -- have given up on my original desire for the combo camera. Now I just would like to get a simple FPS style camera to work. I've gone through several...
  5. Switching between "arcball" and "fps-style" camera rotation

    I'm setting up a program where I would like to be able to use two different styles of camera rotation. I want to be able to rotate the camera in the style of a first-person shooter, where you are in...
  6. Thanks -- sounds like I have some things to learn...

    Thanks -- sounds like I have some things to learn before I can tackle this approach, but I like the idea of it.
  7. Thanks -- that's what I was afraid of. Do you...

    Thanks -- that's what I was afraid of. Do you know of any good references to the linked-list approach? How is that different from read-modify-write? All the GPU threads would be accessing the same...
  8. Any way to do depth testing per fragment?

    Hello,

    I'm drawing a bunch of fuzzy lines in 3D space, and they can cross and re-cross each other so that it isn't possible to sort them by depth. If one line is drawn closer to the camera,...
  9. I finally got a chance to try this today -- been...

    I finally got a chance to try this today -- been sidetracked on some other things -- and it works great! I draw the lines twice -- the first time sets the max alpha in the framebuffer's alpha...
  10. Okay, answered my own question. MTKTextureLoader...

    Okay, answered my own question. MTKTextureLoader has an option "SRGB" which affects the loading of textures, whether or not gamma compression/decompression is applied. I guess it is true by default...
  11. Texture sampler values in Metal shader are reduced?

    I'm trying to port an OpenGL project to Metal, and I'm seeing a discrepancy in the texture values I get from the sampler. The Metal values are a little more than half the value of the OpenGL values....
  12. Ah nevermind, I found the documentation where it...

    Ah nevermind, I found the documentation where it specifies that missing component values are taken from the vector (0,0,0,1). I suspect the reason my my z value needs to be 1 in the new code is due...
  13. default values for shader position attribute components?

    Hello,

    I'm looking at some code from a few years ago and trying to remember how it worked. My vertex shader has a position input specified like this:

    in vec4 position;

    But when I am...
  14. Yes, that is what I was asking -- are you certain...

    Yes, that is what I was asking -- are you certain it's possible to fix the triangle mesh when the vertices can all pile up when seen from end-on? I'm not sure about that.

    I haven't had time to...
  15. Are you certain itís possible to do that? I...

    Are you certain itís possible to do that? I mean, imagine you draw a line, say a simple horizontal line across the screen. But then you turn the camera 90 degrees, so that you are looking at the...
  16. Thanks for the reply again! Ok. Sounds like...

    Thanks for the reply again!


    Ok. Sounds like 2.5D. 2D objects, but they have an implicit ordering or layering to them. Even with that choice of blend function and fragment alphas, this is only...
  17. Thanks for replying. I'm not really porting old...

    Thanks for replying. I'm not really porting old code -- by 'old-style line drawing code', I just meant that in the old days, you had a framebuffer with an alpha channel, and you could create a...
  18. I don't want to use any libraries -- would like...

    I don't want to use any libraries -- would like to understand how to do it myself.
  19. ANY way to do proper fuzzy translucent overlapping lines in OpenGL?

    It seems like the OpenGL model of rendering is the way most computer graphics is going, with the triangles and shaders and whatnot. I've been having a lot of trouble duplicating some old-style...
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    Yes, converting to triangles. And yes I just...

    Yes, converting to triangles. And yes I just want to know how to find the distance between the fragment coordinate and the segment. Basically, how do I get the fragment coordinate?
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    569

    Wide line endcaps in a fragment shader?

    I've been looking into various ways to draw wide lines. A couple of times I have run across references to rendering rounded endcaps in the fragment shader, instead of with geometry (by adding a...
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    how to use texture combiners?

    Hello,

    I am having a hard time finding good information about texture combiners. Can they be used to draw a texture half-transparently? The texture already has its own alpha mask which defines...
  23. find the corners of the screen at a given depth?

    Hello,

    If I have a rectangle facing the screen in my scene, how can I determine the four corners so that it fills the screen exactly? In other words I think I want the four points where the...
  24. painting into texture buffer with transparency, overlapping issues

    Hello,

    I am trying to draw an interactive line with openGL triangles, which is working fine. But when I try to draw it at opacity <1, ie with some level of alpha transparency, the colors build...
  25. Still want to know how to do this! Anyone?

    Still want to know how to do this! Anyone?
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