[LWJGL] An EXCEPTION_ACCESS_VIOLATION on glDrawElements that really has me.

[quew8]

Background
Before I get into the nitty gritty, I think I need to give a little background. I have written an API which among other things provides an interface to OpenGL and windowing utils for which I have backends for both Android and Desktop (through LWJGL) the purpose of which is obviously to use the same code on Android and Desktop. I also have my own rendering library which uses this OpenGL / windowing interface.

So this game I was originally writing on Android where it was working fine, but this error appeared when I ported it to Desktop. Now I have two other games on Desktop that use the same rendering library and OpenGL interface so it cannot be a fundamental problem with either of those things.

The Error
So here is a pastebin of the native stack trace http://pastebin.com/0fWKe8x7 but long story short it is, as per the thread title, an EXCEPTION_ACCESS_VIOLATION after calling glDrawElements(). My experience is you get this when the indices and pointers you have supplied point to data that doesn’t exist but I can’t see how that is the case. Also my system specs are all there if needed.

Rather than posting reams of code (and it would be a hell of a lot) I’m going to post a list of calls of OpenGL functions (not all of them, only the pertinent ones + a few more - if you think any others are pertinent then ask and I’ll post them too). Don’t worry, the contents of the buffers are below this in a more readable format.

d | 1215971556 | glEnableVertexAttribArray_P() {index = 0}
d | 1215971595 | glEnableVertexAttribArray_P() {index = 1}
d | 1215971596 | glEnableVertexAttribArray_P() {index = 2}
d | 1215971656 | glAttachShader_P() {program = 1, shader = 2}
d | 1215971659 | glAttachShader_P() {program = 1, shader = 3}
d | 1215971660 | glBindAttribLocation_P() {program = 1, index = 0, name = position}
d | 1215971662 | glBindAttribLocation_P() {program = 1, index = 1, name = normal}
d | 1215971663 | glBindAttribLocation_P() {program = 1, index = 2, name = texCoords}
d | 1215972507 | glBindBuffer_P() {target = GL_ARRAY_BUFFER, buffer = 1}
d | 1215972514 | glBufferData_P() {target = GL_ARRAY_BUFFER, data = BB{pos = 0, lim = 128, cap = 128}[0, 0, -96, -64, 0, 0, -96, -64, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -128, -65, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -96, 64, 0, 0, -96, -64, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -128, -65, 0, 0, -128, 63, 0, 0, 0, 0, 0, 0, -96, 64, 0, 0, -96, 64, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -128, -65, 0, 0, -128, 63, 0, 0, -128, 63, 0, 0, -96, -64, 0, 0, -96, 64, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -128, -65, 0, 0, 0, 0, 0, 0, -128, 63], usage = GL_STATIC_DRAW}
d | 1215972517 | glBindBuffer_P() {target = GL_ARRAY_BUFFER, buffer = 0}
d | 1215972658 | glBindBuffer_P() {target = GL_ELEMENT_ARRAY_BUFFER, buffer = 2}
d | 1215972660 | glBufferData_P() {target = GL_ELEMENT_ARRAY_BUFFER, data = BB{pos = 0, lim = 24, cap = 24}[0, 0, 0, 0, 1, 0, 0, 0, 2, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 0, 3, 0, 0, 0], usage = GL_STATIC_DRAW}
d | 1215972679 | glBindBuffer_P() {target = GL_ELEMENT_ARRAY_BUFFER, buffer = 0}
d | 1215972913 | glEnable_P() {cap = GL_DEPTH_TEST}
d | 1215972915 | glEnable_P() {cap = GL_STENCIL_TEST}
d | 1215973067 | glBindBuffer_P() {target = GL_ARRAY_BUFFER, buffer = 1}
d | 1215973068 | glBindBuffer_P() {target = GL_ELEMENT_ARRAY_BUFFER, buffer = 2}
d | 1215973070 | glEnableVertexAttribArray_P() {index = 1}
d | 1215973071 | glEnableVertexAttribArray_P() {index = 2}
d | 1215973074 | glEnableVertexAttribArray_P() {index = 3}
d | 1215973076 | glVertexAttribPointer_P() {index = 0, size = 3, type = GL_FLOAT, normalized = false, stride = 32, bufferOffset = 0}
d | 1215973078 | glVertexAttribPointer_P() {index = 1, size = 3, type = GL_FLOAT, normalized = false, stride = 32, bufferOffset = 12}
d | 1215973080 | glVertexAttribPointer_P() {index = 2, size = 2, type = GL_FLOAT, normalized = false, stride = 32, bufferOffset = 24}
d | 1215973083 | glDrawElements_P() {mode = GL_TRIANGLES, count = 6, type = GL_UNSIGNED_INT, bufferOffset = 0}

Since the BufferData is given in bytes rather than ints or floats, I’ve converted them (and formatted a little) below and I wrote a whole new program to do that so there is no human error.

ARRAY_BUFFER id 1 as floats, divided into vertices and vertex components.
[-5.0 -5.0 0.0] | [0.0 0.0 -1.0] | [0.0 0.0]
[5.0 -5.0 0.0] | [0.0 0.0 -1.0] | [1.0 0.0]
[5.0 5.0 0.0] | [0.0 0.0 -1.0] | [1.0 1.0]
[-5.0 5.0 0.0] | [0.0 0.0 -1.0] | [0.0 1.0]

ELEMENT_ARRAY_BUFFER id 2 as ints.
0 1 2 0 2 3

As you might have guessed, it’s a square I’m trying to draw.

My intention for the interleaving of the vertex data: PPPNNNTT where P = position, N = normal, T = texture coord.

Finally
If you have any ideas at all, or if I have missed out some information then please don’t hesitate to post. I’ve been trying to solve this intermittently for many, many weeks. I’m so frustrated with this that today I found myself grinding my teeth and shouting at the computer when it took longer that a second to load up the JavaDoc which held the answer to another bug entirely.

Thank you for reading and thank you in advance for any help rendered.

Q8.