[no bug]Locking an OpenGL RT Texture Crashes

kkrizka · Post by **kkrizka** » Tue Nov 18, 2008 8:58 pm

Hi all,

I've modified the 13.RenderToTexture example to lock the texture after it has been drawn to and unlock it afterwards. However, when it tries to lock (read-only turn on and off) the texture, the whole thing crashes. This is using the latest trunk revision of Irrlicht.

I didn't want to paste the entire source code, because I only added 4 lines (lock, unlock, debug output) to the example. So make it more readable, the following is the output of s vn diff..

Code: Select all

Index: main.cpp
===================================================================
--- main.cpp	(revision 1775)
+++ main.cpp	(working copy)
@@ -194,7 +194,12 @@
 			// set back old render target
 			// The buffer might have been distorted, so clear it
 			driver->setRenderTarget(0, true, true, 0);
-
+			
+			printf("Run\n");
+			rt->lock(true);
+			printf("Locked\n");
+			rt->unlock();
+			printf("Unlocked\n");
 			// make the cube visible and set the user controlled camera as active one
 			test->setVisible(true);
 			smgr->setActiveCamera(fpsCamera);

The following is the output:

Code: Select all

Irrlicht Engine version 1.4.2
Linux 2.6.24-21-generic #1 SMP Tue Oct 21 23:43:45 UTC 2008 i686
Creating X window...
Visual chosen: : 37
Using renderer: OpenGL 1.4
Mesa DRI Intel(R) 965GM 4.1.3002 x86/MMX/SSE2: Tungsten Graphics, Inc
OpenGL driver version is 1.2 or better.
GLSL not available.
Loaded mesh: ../../media/faerie.md2
Loaded texture: /home/kkrizka/Sources/irrlicht/media/faerie2.bmp
Run
Locked
*** glibc detected *** ./13.RenderToTexture: double free or corruption (fasttop): 0x088107f0 ***
======= Backtrace: =========
/lib/tls/i686/cmov/libc.so.6[0xb776fa85]
/lib/tls/i686/cmov/libc.so.6(cfree+0x90)[0xb77734f0]
/usr/lib/libstdc++.so.6(_ZdlPv+0x21)[0xb793bb11]
/home/kkrizka/Sources/irrlicht/lib/Linux/libIrrlicht.so.1(_ZN3irr4core12irrAllocatorIcE10deallocateEPc+0x1f)[0xb7c58655]
/home/kkrizka/Sources/irrlicht/lib/Linux/libIrrlicht.so.1(_ZN3irr4core6stringIcNS0_12irrAllocatorIcEEED1Ev+0x2a)[0xb7c58aea]
/home/kkrizka/Sources/irrlicht/lib/Linux/libIrrlicht.so.1(_ZN3irr5video8ITextureD0Ev+0x43)[0xb7d712a3]
./13.RenderToTexture[0x80495e8]
/lib/tls/i686/cmov/libc.so.6(__libc_start_main+0xe0)[0xb771a450]
./13.RenderToTexture(__gxx_personality_v0+0x69)[0x8048cf1]
======= Memory map: ========
08048000-0804b000 r-xp 00000000 08:04 16269571   /home/kkrizka/Sources/irrlicht/bin/Linux/13.RenderToTexture
0804b000-0804c000 rwxp 00002000 08:04 16269571   /home/kkrizka/Sources/irrlicht/bin/Linux/13.RenderToTexture
0804c000-099bb000 rwxp 0804c000 00:00 0          [heap]
b3000000-b3021000 rwxp b3000000 00:00 0 
b3021000-b3100000 ---p b3021000 00:00 0 
b31a0000-b3300000 rwxp b31a0000 00:00 0 
b3300000-b3308000 r-xp 00000000 08:02 58736      /usr/lib/libXcursor.so.1.0.2
b3308000-b3309000 rwxp 00007000 08:02 58736      /usr/lib/libXcursor.so.1.0.2
b3317000-b3601000 rwxp b3317000 00:00 0 
b3601000-b5601000 rwxs e2e34000 00:0e 14229      /dev/dri/card0
b5601000-b5d91000 rwxs e26a4000 00:0e 14229      /dev/dri/card0
b5d91000-b6521000 rwxs e1f14000 00:0e 14229      /dev/dri/card0
b6521000-b6ca6000 rwxs e0100000 00:0e 14229      /dev/dri/card0
b6ca6000-b742b000 rwxs e0100000 00:0e 14229      /dev/dri/card0
b742b000-b744a000 r-xp 00000000 08:02 58966      /usr/lib/libexpat.so.1.5.2
b744a000-b744c000 rwxp 0001e000 08:02 58966      /usr/lib/libexpat.so.1.5.2
b745a000-b7672000 r-xp 00000000 08:02 59933      /usr/lib/dri/i965_dri.so
b7672000-b7686000 rwxp 00218000 08:02 59933      /usr/lib/dri/i965_dri.so
b7686000-b7692000 rwxp b7686000 00:00 0 
b7692000-b7696000 r-xp 00000000 08:02 58740      /usr/lib/libXdmcp.so.6.0.0
b7696000-b7697000 rwxp 00003000 08:02 58740      /usr/lib/libXdmcp.so.6.0.0
b7697000-b7698000 rwxp b7697000 00:00 0 
b7698000-b76af000 r-xp 00000000 08:02 59570      /usr/lib/libxcb.so.1.0.0
b76af000-b76b0000 rwxp 00016000 08:02 59570      /usr/lib/libxcb.so.1.0.0
b76b0000-b76b1000 r-xp 00000000 08:02 59568      /usr/lib/libxcb-xlib.so.0.0.0
b76b1000-b76b2000 rwxp 00000000 08:02 59568      /usr/lib/libxcb-xlib.so.0.0.0
b76b2000-b76b4000 r-xp 00000000 08:02 58729      /usr/lib/libXau.so.6.0.0
b76b4000-b76b5000 rwxp 00001000 08:02 58729      /usr/lib/libXau.so.6.0.0
b76b5000-b76be000 r-xp 00000000 08:02 58926      /usr/lib/libdrm.so.2.3.0
b76be000-b76bf000 rwxp 00008000 08:02 58926      /usr/lib/libdrm.so.2.3.0
b76bf000-b76c1000 r-xp 00000000 08:02 19043      /lib/tls/i686/cmov/libdl-2.7.so
b76c1000-b76c3000 rwxp 00001000 08:02 19043      /lib/tls/i686/cmov/libdl-2.7.so
b76c3000-b76c4000 rwxp b76c3000 00:00 0 
b76c4000-b76d8000 r-xp 00000000 08:02 20279      /lib/tls/i686/cmov/libpthread-2.7.so
b76d8000-b76da000 rwxp 00013000 08:02 20279      /lib/tls/i686/cmov/libpthread-2.7.so
b76da000-b76dc000 rwxp b76da000 00:00 0 
b76dc000-b76e0000 r-xp 00000000 08:02 58746      /usr/lib/libXfixes.so.3.1.0
b76e0000-b76e1000 rwxp 00003000 08:02 58746      /usr/lib/libXfixes.so.3.1.0
b76e1000-b76e3000 r-xp 00000000 08:02 58738      /usr/lib/libXdamage.so.1.1.0
b76e3000-b76e4000 rwxp 00001000 08:02 58738      /usr/lib/libXdamage.so.1.1.0
b76e4000-b7703000 r-xp 00000000 08:02 59259      /usr/lib/libjpeg.so.62.0.0
b7703000-b7704000 rwxp 0001e000 08:02 59259      /usr/lib/libjpeg.so.62.0.0
b7704000-b784d000 r-xp 00000000 08:02 19040      /lib/tls/i686/cmov/libc-2.7.so
b784d000-b784e000 r-xp 00149000 08:02 19040      /lib/tls/i686/cmov/libc-2.7.so
b784e000-b7850000 rwxp 0014a000 08:02 19040      /lib/tls/i686/cmov/libc-2.7.so
b7850000-b7854000 rwxp b7850000 00:00 0 
b7854000-b785e000 r-xp 00000000 08:02 595692     /lib/libgcc_s.so.1
b785e000-b785f000 rwxp 0000a000 08:02 595692     /lib/libgcc_s.so.1
b785f000-b7882000 r-xp 00000000 08:02 19045      /lib/tls/i686/cmov/libm-2.7.so
b7882000-b7884000 rwxp 00023000 08:02 19045      /lib/tls/i686/cmov/libm-2.7.so
b7884000-b796c000 r-xp 00000000 08:02 61741      /usr/lib/libstdc++.so.6.0.9
b796c000-b796f000 r-xp 000e8000 08:02 61741      /usr/lib/libstdc++.so.6.0.9
b796f000-b7971000 rwxp 000eb000 08:02 61741      /usr/lib/libstdc++.so.6.0.9
b7971000-b7977000 rwxp b7971000 00:00 0 
b7977000-b7a5b000 r-xp 00000000 08:02 58723      /usr/lib/libX11.so.6.2.0
b7a5b000-b7a5e000 rwxp 000e4000 08:02 58723      /usr/lib/libX11.so.6.2.0
b7a5e000-b7a6b000 r-xp 00000000 08:02 58744      /usr/lib/libXext.so.6.4.0
b7a6b000-b7a6c000 rwxp 0000d000 08:02 58744      /usr/lib/libXext.so.6.4.0
b7a6c000-b7a70000 r-xp 00000000 08:02 58780      /usr/lib/libXxf86vm.so.1.0.0
b7a70000-b7a71000 rwxp 00003000 08:02 58780      /usr/lib/libXxf86vm.so.1.0.0
b7a71000-b7a72000 rwxp b7a71000 00:00 0 
b7a72000-b7acd000 r-xp 00000000 08:02 58682      /usr/lib/libGL.so.1.2
b7acd000-b7ad3000 rwxp 0005b000 08:02 58682      /usr/lib/libGL.so.1.2
b7ad3000-b7ad4000 rwxp b7ad3000 00:00 0 
b7ad6000-b7add000 r-xp 00000000 08:02 58766      /usr/lib/libXrender.so.1.3.0
b7add000-b7ade000 rwxp 00007000 08:02 58766      /usr/lib/libXrender.so.1.3.0
b7ade000-b7ae0000 rwxs f8d31000 00:0e 14229      /dev/dri/card0
b7ae0000-b7ae2000 rwxp b7ae0000 00:00 0 
b7ae2000-b7f15000 r-xp 00000000 08:04 14483562   /home/kkrizka/Sources/irrlicht/lib/Linux/libIrrlicht.so.1.4.2
b7f15000-b7f43000 rwxp 00433000 08:04 14483562   /home/kkrizka/Sources/irrlicht/lib/Linux/libIrrlicht.so.1.4.2
b7f43000-b7f46000 rwxp b7f43000 00:00 0 
b7f46000-b7f47000 r-xp b7f46000 00:00 0          [vdso]
b7f47000-b7f61000 r-xp 00000000 08:02 595749     /lib/ld-2.7.so
b7f61000-b7f63000 rwxp 00019000 08:02 595749     /lib/ld-2.7.so
bf873000-bf888000 rw-p bffeb000 00:00 0          [stack]
Aborted

rogerborg · Post by **rogerborg** » Tue Nov 18, 2008 9:50 pm

Great report, but I am unable to replicate this with SVN 1775 and OpenGL on either WinXP64 or Ubuntu 8.04.

Crashing inside a string allocator is fairly bizarre. Any further clues that you could provide would be much appreciated.

kkrizka · Post by **kkrizka** » Wed Nov 19, 2008 3:25 am

Another hint would be that since my laptop has a simple Intel video card, so I do not have framebuffer objects. I've noticed that there is a special class for RTT textures if the video driver supports FBO.

I will try it on my desktop which has a better nvidia video card, which has FBO and I will let you know.

hybrid · Post by **hybrid** » Wed Nov 19, 2008 1:11 pm

Couldn't replicate it either, but found a mem leak when debugging through this case. Maybe it helps already

BTW: If people with FBO support want to test the other case, just add driver->disableFeature(EVDF_FRAMEBUFFER_OBJECT) somewhere in your main (before the RTT generation).

Oh, one things just springs to my mind: Maybe it's a size issue. The old RTT implementation only allows for RTTs smaller than the screen size. The rest is either undefined or just not used. Maybe this can lead to crashes as well. So which sizes of the screen and RTT do you use?

kkrizka · Post by **kkrizka** » Wed Nov 19, 2008 9:41 pm

Hmm, I can't seem to reproduce it anymore either. I tried to revert back to an older revision and then go up by revisions to see when it started appearing. However it never came back, even I reached the latest checkout. I'm assuming that something got corrupted in my earlier checkout (yes, I did try make clean before I reported this bug).

At least you found that memory leak, so I didn't totally waste your time..