Posted by jmaasing on Jul 24, 2015; 7:37am
URL: https://forum.jogamp.org/Buffers-newDirectIntBuffer-int-does-not-set-limit-tp4034959.html

I noticed that Buffers.newDirectIntBuffer(int[]) does not set the limit of the buffer. This causes a driver crash on OSX.

When using this form:

final IntBuffer indexBuf = Buffers.newDirectIntBuffer(triIndexes);

This is the trace output when I upload the data to the driver:

glBindBuffer(<int> 0x8893, <int> 0x3)
glBufferData(<int> 0x8893, <long> 0, <java.nio.Buffer> java.nio.DirectIntBufferU[pos=0 lim=0 cap=89034], <int> 0x88E4)

and finally the driver crashes when it is time to render:

glDrawElements(<int> 0x4, <int> 0x15BCA, <int> 0x1405, <long> 0)#
# A fatal error has been detected by the Java Runtime Environment:
#
#  SIGSEGV (0xb) at pc=0x000000010fd4b3b0, pid=1443, tid=31031
#
# JRE version: Java(TM) SE Runtime Environment (8.0-b132) (build 1.8.0-b132)
# Java VM: Java HotSpot(TM) 64-Bit Server VM (25.0-b70 mixed mode bsd-amd64 compressed oops)
# Problematic frame:
# C  [libsystem_platform.dylib+0x13b0]  _platform_memmove$VARIANT$Nehalem+0x70

But if I do this:

final IntBuffer indexBuf = Buffers.newDirectIntBuffer(triIndexes.length);
for (int triIndex : triIndexes) {
	indexBuf.put(triIndex) ;
}

The trace for uploading the buffer is this:

glBindBuffer(<int> 0x8893, <int> 0x3)
glBufferData(<int> 0x8893, <long> 356136, <java.nio.Buffer> java.nio.DirectIntBufferU[pos=0 lim=89034 cap=89034], <int> 0x88E4)

Notice the limit is set to the number of ints I put into the buffer and now the driver does not crash.

Should I write a bug report or is this expected (i.e. limit not set) when using the array version of newDirectIntBuffer?