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FlatFootSam
06-01-2016, 07:15 AM
Is there an OpenGL driver available that uses a Framebuffer rather than acceleration hardware?

I have a graphics platform that does not have OpenGL support, but it does have a framebuffer.
I'm assuming I could use a generic OpenGL driver that could write to a framebuffer given its address.
I realize I would not get the speed benefits of acceleration hardware.

Is a driver like this available?

Thanks
Sam

Alfonse Reinheart
06-01-2016, 07:25 AM
You clearly intend "use a framebuffer" to me something different from using the OpenGL framebuffer (https://www.opengl.org/wiki/Framebuffer). So could you clarify what you're talking about with that?

Agent D
06-01-2016, 10:19 AM
From what I understand, you have some display hardware that can only display the contents of a specific memory location and doesn't have any hardware drawing commands, let alone OpenGL supprt? In that case, you might be interested in Mesa3D (http://mesa3d.org/), a project that strives to implement the GL spec. While it does have some fairly complete hardware drivers (https://mesamatrix.net/), it supports software rasterization up to OpenGL 3.3 and has a platform independend OSMesa (http://www.mesa3d.org/osmesa.html) interface for drawing into an off-screen buffer using software only rendering.

mhagain
06-01-2016, 11:15 AM
I'm assuming I could use a generic OpenGL driver that could write to a framebuffer given its address. I realize I would not get the speed benefits of acceleration hardware. Writing to the framebuffer isn't the only thing that's hardware-accelerated; in fact it's actually the last stage of the OpenGL pipeline (https://www.opengl.org/registry/doc/glspec45.core.pdf). So you're talking about a software implementation, and you're going to lose a lot more performance than you'd like.