• GLUT optimisation - static background

    From Iain Maoileoin@21:1/5 to All on Mon Apr 4 05:38:15 2022
    I am developing an WW2 radar display, C on a PI and on a MAC and on a UBUNTU laptop. Glut does me a good job - portable and fast. BUT the "background" of the display has various static circles and text - range circles and text for the distances.

    This data does not change from frame to frame, but I end up drawing it every refresh. That takes time.

    How can I (kind of)
    generate the static background
    save it to a buffer
    then
    merge that buffer/object/ to the output

    Seems easy, but I cant find enough examples to help -
    1 is the glBufferStorage a way to do this?
    2 is there a better way
    3 how do I size the buffer in glBufferStorage

    I really want to say
    "write to buffer X"
    draw what I want - circles and text - into that buffer
    then later in the show
    merge buffer X into the display

    All clues welcome - or an alternative approach

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    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Josh Vanderhoof@21:1/5 to Iain Maoileoin on Mon Apr 4 19:03:53 2022
    Iain Maoileoin <[email protected]> writes:

    I am developing an WW2 radar display, C on a PI and on a MAC and on a
    UBUNTU laptop. Glut does me a good job - portable and fast. BUT the "background" of the display has various static circles and text -
    range circles and text for the distances.

    This data does not change from frame to frame, but I end up drawing it
    every refresh. That takes time.

    How can I (kind of)
    generate the static background
    save it to a buffer
    then
    merge that buffer/object/ to the output

    Seems easy, but I cant find enough examples to help -
    1 is the glBufferStorage a way to do this?
    2 is there a better way
    3 how do I size the buffer in glBufferStorage

    I really want to say
    "write to buffer X"
    draw what I want - circles and text - into that buffer
    then later in the show
    merge buffer X into the display

    All clues welcome - or an alternative approach

    If it's a one time thing just render the background and then use glReadPixels/glTexImage2d or glCopyTexSubImage2d to copy it to a
    texture. Alternatively you could use a framebuffer object but it's not
    likely to be worth the bother.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)