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Diffstat (limited to 'demos/NVidia')
| -rw-r--r-- | demos/NVidia/VertexArrayRange.java | 22 |
1 files changed, 22 insertions, 0 deletions
diff --git a/demos/NVidia/VertexArrayRange.java b/demos/NVidia/VertexArrayRange.java index 4f49380..f4d0d2f 100644 --- a/demos/NVidia/VertexArrayRange.java +++ b/demos/NVidia/VertexArrayRange.java @@ -28,6 +28,28 @@ import gl4java.drawable.*; from the NVidia-specific routine wglAllocateMemoryNV. This memory region is used in conjunction with glVertexArrayRangeNV. </P> + <P> In contrast to the C++ version of this demo, the Java + programming language version compares the following two + configurations: + + <ul> + <li> JDK 1.4 NIO buffers + VAR extension + <li> pre-JDK 1.4-style OpenGL for Java glVertexPointer calls + taking float[] + </ul> + + The glVertexPointer calls contain a long-standing bug wherein if a + garbage collection occurs at the wrong time, the arrays containing + the data passed down to glVertexPointer may move, leading to + either incorrect data being drawn or a program crash. This is + obviously not suitable for production systems. The solution is to + upgrade to JDK 1.4 and use java.nio direct buffers for the storage + passed down to glVertexPointer and similar routines which take + pointers to persistent regions of memory, regardless of whether an + extension like NVidia's vertex array range is used. More + information on this topic is available <a href = + "http://java.sun.com/products/jfc/tsc/articles/jcanyon/">here</a>. </P> + <P> On a 750 MHz PIII with an SDRAM memory bus and a GeForce 256 running the Java HotSpot[tm] Client VM and OpenGL for Java 2.8, this demonstration attains 90% of the speed of the compiled C++ |