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Type: Posts; User: tamlin

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  1. Replies
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    Re: Alternative to glBlitFramebuffer()

    No great surprise. To me, a blit is basically a memcpy. Conversion like this would require read-modify-write cycle, thereby making it way more than a plain blit.

    Anyway, good you nailed it.
  2. Re: Confusion about the range of opengl Pixelformats

    As Alfonse wrote, floating point data in GPU memory space is not understood for rendering purposes. Most devices have only RGB8 output.

    If you need to access some data on the CPU, and it's not...
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    Re: creating a background image

    A single oversized triangle is probably even faster (you already knew this ;-P).



    Considering the fact that many apps (vast majority I'd say) need/uses billboards (both in the actual scene for...
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    Re: GL_MAX_RENDERBUFFER_SIZE

    The number you get back from GL_MAX_RENDERBUFFER_SIZE is not dynamic. It's a "best case", of what the "engine" (usually hardware) supports. Even if you had fictional gfx hardware with 1TB of VRAM...
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    Re: glDrawArray not seeing VBOs

    glBufferData( GL_ARRAY_BUFFER, sizeof(guiVertexArray), &guiVertexArray, GL_STATIC_DRAW );

    Are you really, really sure you want a pointer to the pointer? I'm not. Drop the '&'.
  6. Re: VBO optimization: bandwidth & culling granularity

    50k triangles is indeed a more suitable number for VBO. :-)

    Put all the vertices for all those triangles in a single VBO (if possible).

    Manually (on the CPU - it's fast) rebase the indices for...
  7. Thread: VBO to VAO

    by tamlin
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    Re: re: VBO to VAO

    "That's still reflected in the fact" ... "despite having turned into attachment points."

    Alfonse has already written words to enlighten mortals, illuminate complexity, and display how much we all...
  8. Re: VBO optimization: bandwidth & culling granularity

    VBO will likely (OK, almost certainly) be slower if you only have 50 triangles. The time to set up+tear down a VBO will easily overshadow the time to submit that data using plain interactive. Half a...
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    Re: VBO - index data gets corrupted

    Suggestions:
    1. Check the return value from the glUnmapBuffer call.
    2. Comment out the memcmp, effectively using the old code but with the additional (but should-be quite redundant) Map/Unmap...
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    Re: Draft released for feedback

    Jon,

    while not directly related to the 3.1 parts, hitting the End key I just found the following (examples for discussion, glGetUniformIndices vs. PFNGLGETUNIFORMINDICESPROC).

    Should it be...
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    Re: Official Bindless Graphics feedback thread

    Point taken. Format objects would likely be a better long-term solution for what I had in mind.
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    Re: Official Bindless Graphics feedback thread

    jeff,

    I don't get these:

    - "A GLsizeiptr is signed". Uh, yeah, that's why I suggested -1 instead of ~0 (a negative size makes no sense, why I thought -1 would fit perfectly).

    - "This is a...
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    Re: GPGPU, SwapBuffers and multithreaded rendering

    Yes. It's however well outside the scope of (even the advanced forum for) OpenGL.
    Not that many of us here likely wouldn't like this kind of pornography :-), it's just waaaay off-topic.
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    Re: Official Bindless Graphics feedback thread

    Kickass!

    This is bringing back the old nvidia I liked - taking the lead in experimentation and actual innovation. If this is a sign of a "new" (or simply reborn) spirit - for all that is dear,...
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    Re: GPGPU, SwapBuffers and multithreaded rendering

    I think it's as simple as; while GPU's today have many, many ALU's, they have but one command input - the FIFO coming from user-mode. Whether the commands come from a separate thread, or a separate...
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    Re: efficiently sending data to GPU

    An algorithmic idea, could be - if possible to predict future updates - to put the data to-be-updated in either separate "pages" (relative the static data), or even in a separate VBO, and (where...
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    Re: OpenGL driver "memory leak"

    Iff this is due to (system) memory fragmentation, the driver writers could fix this, and quite easily too.

    Instead of just failing if there isn't a contigous block of memory large enough to hold...
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    Re: Something in FF Pipe affecting rendering...

    Do you have any translucent surfaces drawn when it fails? I'm just thinking... alpha test/blend state not properly restored/set by you/driver/hardware? Residual FBO not properly unmapped? Perhaps as...
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    Re: Something in FF Pipe affecting rendering...

    Just an idea, but have you tried to reboot?

    I have experienced "unexplainable" errors, from time to time, that have turned out to likely be driver or even h/w bugs; if a problem (not necessarily a...
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    Re: Something wrong with Vertex Buffer Object!

    That code isn't using Begin/End at all. Add some (liberally sprinkled) glGetError calls too.

    Sidenote: Don't use double's - use float. You'll likely experience a quite measurable performance gain....
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    Re: Triple buffering

    Nevermind, I'm too old. Have a look at this instead.

    So why even use it? No, seriously.
    Double-buffering in a 2D sense is drawing stuff to an off-screen bitmap, then simply blitting it to the...
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    Re: 8.11: GL_EXT_transform_feedback on ATI card!

    Would such a 4-texel fetch by chance require DXTn texture compression to not get a performance penalty?
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    Re: Triple buffering

    If only parts of the framebuffer is updated every frame, could Kinetix' buffer region help (assuming it's present, and even used nowadays)?

    Another option could be to simply have a full-screen...
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    Re: The ARB announced OpenGL 3.0 and GLSL 1.30 tod

    While I can sympathize with this whish, I'd personally oppose it if the issue was raised. For one thing it would open a can of worms in areas such as "interpolate between n vertices", "what if the...
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    Re: PBO + glReadPixels not so fast?

    Yes.
    No.
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