PDA

View Full Version : hardware cursor using OpenGL



Johnson.N.M.B
07-19-2007, 08:46 PM
Hi, is it possible to enable hardware cursor in opengl like D3D does?

Korval
07-19-2007, 08:51 PM
OpenGL has no concept of a "hardware cursor".

Further, on a more personal note, I would suggest trying to avoid such things. After all, rendering the cursor yourself gives you control over it.

Johnson.N.M.B
07-19-2007, 09:02 PM
Ok, I'm now using a software cursor in my project when OpenGL renderer has been selected. I found it is useful to have a smoothly mouse cursor movement when the FPS is low. I'll try using a true-color windows cursor instead.

Thanks~

sqrt[-1]
07-20-2007, 12:10 AM
It is possible to have a hardware cursor with OpenGL. Many previous projects of mine used this - however I don't have access to the code that does this (win32 stuff) so I can't help you further.

speedy
07-20-2007, 06:22 AM
sqrt[-1]: You mean some OpenGL hack or just using the standard win32 built-in cursor routines?

songho
07-20-2007, 08:10 AM
I am confused.
Should the cursor be always visible, unless you force to hide it explicitly?

And, I think that the hardware cursor means flicker-free. (A video card draws the cursor onto the frame right before the frame is rendered.) If we use double buffer and draw own cursor image, then it should not be flickered.

sqrt[-1]
07-22-2007, 05:08 PM
I did not do the code myself, so I cannot say for sure. But I am reasonably certain it was just win32 calls. (just showcursor calls? perhaps it was the initial screen creation - perhaps they created a full screen boarderless window?)

dorbie
07-23-2007, 11:55 AM
The HW cursor works with OpenGL, and should be flicker free, you have to explicitly disable it to hide it (you can specify this in the window creation structure I think). You can also draw your own cursor of course but you need to make sure you disable the HW cursor if you do that.

I think you need to post more details.

tamlin
08-03-2007, 04:17 AM
If we're talking about the mouse cursor, and fullscreen, I just wanted to share a little something I encountered porting a D3D game to OpenGL.

Profiling the app told me that drawing the cursor was a horrible performance hog. I fixed in just a few lines of code (though the same fix applies to D3D too).

After the UI (2D, though using 3D primitives) was rendered, the code did a color-key "blit". Imagine the pipeline stalls and (lack of) readback speed on slower busses. I did the only obvious thing; I uploaded the mouse cursor image to a texture and after the rest of the UI was rendered I slapped it onto a quad (in ortho mode). I'm not exaggerating when I say that this single change increased UI performance more than 5 times of the whole UI drawing (it has since improved a little more, from 15-30 fps to >2000 fps before adding sanity-Sleep()'ing).

I think this displays it can be better to first try to solve the "problem" within the environment (OpenGL) when possible, not to mention the performance benefits can be... large.

V-man
08-03-2007, 06:25 AM
Originally posted by tamlin:
I'm not exaggerating when I say that this single change increased UI performance more than 5 times of the whole UI drawing (it has since improved a little more, from 15-30 fps to >2000 fps before adding sanity-Sleep()'ing).5 times the speed sounds ridiculous to me. You mean you hid the standard mouse with ShowCursor?
So 30 * 5 = 150 FPS

You added Sleep sometime afterwards and your FPS went to 2000? Again, sounds weird.

What graphics card is this and what driver, what OS?