Sometimes transform feedback does not produce any data. Instead, it produces
an array of zeros of the correct size.
I've observed this during
TestDotsMglShaderProgram.testAttributeTransformFeedback()
I expect it could also occur during
TestDotsMglShaderProgram.testUniformTransformFeedback()
The problem is irregular, and seems to go away after the first occurrence.
I wonder if this is a race condition, where OpenGL often loses the race the
first time through, or some other driver issue.
I don't know if this ever happens on other hardware. I'm using my Mac Book:
Hardware Overview:
Model Name: MacBook
Model Identifier: MacBook4,1
Processor Name: Intel Core 2 Duo
Processor Speed: 2.4 GHz
Number Of Processors: 1
Total Number Of Cores: 2
L2 Cache: 3 MB
Memory: 2 GB
Bus Speed: 800 MHz
Boot ROM Version: MB41.00C1.B00
SMC Version (system): 1.31f1
Serial Number (system): RM848UU50P1
Hardware UUID: 69B81DEE-7649-5455-8530-5CDAE5DE8C6B
Sudden Motion Sensor:
State: Enabled
Intel GMA X3100:
Chipset Model: GMA X3100
Type: GPU
Bus: Built-In
VRAM (Total): 144 MB
Vendor: Intel (0x8086)
Device ID: 0x2a02
Revision ID: 0x0003
Displays:
Display Connector:
Status: No Display Connected
VX2033WM:
Resolution: 1600 x 900 @ 60 Hz
Pixel Depth: 32-Bit Color (ARGB8888)
Display Serial Number: RA5093000792
Main Display: Yes
Mirror: Off
Online: Yes
Rotation: Supported
System Software Overview:
System Version: Mac OS X 10.6.8 (10K549)
Kernel Version: Darwin 10.8.0
Boot Volume: Bring It
Boot Mode: Normal
Computer Name: Benjamin Heasly’s MacBook
User Name: Benjamin Heasly (ben)
Secure Virtual Memory: Enabled
64-bit Kernel and Extensions: No
Time since boot: 3:43
Since it's hard to reproduce and possibly nonexistent on other hardware, I'm
not going to pursue this issue yet.
Original issue reported on code.google.com by Benjamin.Heasly on 28 Oct 2011 at 5:36
Original issue reported on code.google.com by
Benjamin.Heaslyon 28 Oct 2011 at 5:36