First Post, and thanks in advance to everyone who helps out on this site answering questions - I have found these tutorials a real blessing.
I started out trying to unravel the secrets of an efficient VBO by following this tutorial:
http://www.java-gaming.org/index.php?topic=24272.0
Thinking ahead to my future plans for it, I decided to try to lean out the actual draw methods as much as possible and discovered some weird un-explainable behaviors.
Here is the relevant code:
http://pastebin.com/2enngXsA
Odd Behavior 1:
If I comment out line 43, preventing the Vertex Array Object from drawing, the program will crash with the following error:
Java Result: -1073741819
BUILD SUCCESSFUL (total time: 2 seconds)
If I also comment out the next 4 methods (lines 46, 49, 52, 55) (line 58 doesn’t seem to have this problem) - the error goes away.
Within the method in question, I can comment out the draw command, but if I comment out either of the pointers, I get the error.
I am not sure how or why a couple of VAO pointers impact other VBOs and overall program stability. Why is this doing this? Any illumination on the subject would be appreciated.
Odd Behavior 2:
With all methods functioning (not commented out from OB1) - I get 7 identical triangles as expected.
If You look at lines 252-255 vs. 271-273
These are the drawing functions for the two interleaved examples (hereafter called “5” and “6”). If you notice line 251 is necessary in example “5” but not in example “6”
If I comment it out of example “5” then I get a weird tearing effect on triangle 5.
Not sure what else is different between the two that is requiring the re-buffering of the data in “5” but not in “6”. Why is this doing this? Any illumination on the subject would be appreciated.