Ogre Forums

The Pro Ogre 3D programming book mentions

Ogre is designed, on purpose, to support only hardware-accelerated graphics rendering. This
means that Ogre requires a graphics coprocessor (such as those made by NVIDIA and ATI); direct
software rendering is not an option. This design decision allows Ogre the freedom to work, in
an optimized fashion, with hardware buffers, which are areas of memory shared between the
graphics hardware and the application (Ogre).

I made an executable of a program which displays the Ogre head, and ran it on a decade old system with no separate graphics card. The system can run NFS5 and Age of Empires etc, so I'm assuming it is the onboard graphics card which enabled the ogre program to run.

I'm not very knowledgeble about hardware, and I'd like to be clear about what I'm working with. If a system with no extra graphics card connected is able to display all the graphics of Windows XP, does it mean that the motherboard has an onboard graphics card? If yes, then where exactly does software rendering fit in? Would software rendering happen only on systems which can't support even basic graphics display?
On the other hand, is hardware rendering called so only when the program makes use of the hardware pixel buffer and other hardware buffers? Onboard graphics cards don't have a GPU, right?

If I make a program in ogre which uses shaders, is it necessary to use a graphics card or can we rely on a subtle belief that the program would work using the onboard graphics card (will be trying one such program on a system soon, but would like to know your opinions too)?

If a system with no extra graphics card connected is able to display all the graphics of Windows XP, does it mean that the motherboard has an onboard graphics card?

There's probably graphics hardware with 3D acceleration integrated with your motherboard.
Look for the specs of your motherboard, it could confirm it for you.

If yes, then where exactly does software rendering fit in? Would software rendering happen only on systems which can't support even basic graphics display?

Some time ago (more than a decade ago), you could find graphics card with no 3D acceleration and at that time, a few games shipped with 3d software renderer.
Also, servers usually don't have graphics card.

On the other hand, is hardware rendering called so only when the program makes use of the hardware pixel buffer and other hardware buffers?

Ogre3D always makes use of hardware rendering, whatever the case.

Onboard graphics cards don't have a GPU, right?

Most of them do.

If I make a program in ogre which uses shaders, is it necessary to use a graphics card or can we rely on a subtle belief that the program would work using the onboard graphics card (will be trying one such program on a system soon, but would like to know your opinions too)?

From what I read some time ago, even basic intel chipsets have support for directx 9.0c, hence shaders.
If you find a system that doesn't support shaders, or only an older version of shaders, then Ogre can do automatic fallback to the most appropriate technique that is supported by the hardware (look at the material section of the manual)

I assume you're running windows on your machine?
Just check your display properties, copy the name of the display adapter and google it.

If you're using directX you can also look at what the directX diagnostic tool has to say, there you can also see what DX features your display adapter supports.
Just go to start>run and enter "dxdiag"
There's lots of interesting stuff to test there, like spinning and bouncing cubes, irritating sounds and screen patterns that give you a headache

Basically to run Ogre you need a device (hardware or software emulated) that is able to work with OpenGL or Direct3D

Take a look in ogre.log, it will tell you a heap of details about your cpu, gpu and which features are available.

Mikachu wrote:Also, servers usually don't have graphics card.

Granted, discrete cards are highly unlikely unless the machine is used for specialized computation (CUDA et. al.) But in the x86 realm I've found that most server motherboards have onboard video typically Intel's GMA, Nvidia's ION or (God help you) the PowerVR variant embedded into Atom processors. The current trend to incorporate GPU's directly into the CPU dies makes some sort of 3d hw support a foregone conclusion like truecolor color displays and audio.

*tries to remember where he put that vt100*

I ran a simple shader program on a system which does not have a graphics card installed separately. It rendered the ogre head in plain white and was able to load the material script, but the shader did not apply any blue colour onto the ogre head, which it was supposed to.

So I'm assuming that it's necessary to have a graphics card in order to run shaders. Will get into the system specs soon.

So I'm assuming that it's necessary to have a graphics card in order to run shaders

It's necessary to have a gpu that matches at least shader model 1. Whether it's on a separate card or on the motherboard doesn't matter. These days there are intel and amd cpus which have integrated gpus (plus most mobile devices have cpu and gpu in one chip, called a SOC (System On a Chip).