Vertex Buffer issues - c++

Question

I recently created this VertexBuffer class to and added it to my opengl based engine; but it seems to fail in my main code, causing an "access violation at 0x00000000."...
Here is VertexBuffer.h :
#pragma once
#include "Type.h"
#include "Tags.h"
namespace Spiky {
namespace GLLayer {
template<>
struct GLObjDelAlloc<Tags::VertexBuffer> {
static void Allocate(GLTypeCT<GLType::Integer> count,
Tags::VertexBuffer::internal* names) {
glGenBuffers(count, names);
}
static void Delete(GLTypeCT<GLType::Integer> count, Tags::VertexBuffer::internal* names) {
glDeleteBuffers(count, names);
}
};
template<>
struct GLObjBind<Tags::VertexBuffer> {
private:
static Tags::VertexBuffer::internal _active;
public:
static const int ZERO_BUFFER = GL_NONE;
static void BindRequest(Tags::VertexBuffer::internal name = ZERO_BUFFER) {
if(_active != name) {
glBindBuffer(GL_ARRAY_BUFFER, 0);
_active = name;
}
}
};
Tags::VertexBuffer::internal
GLObjBind<Tags::VertexBuffer>::_active = 0;
//wrapper around GLObjDelAlloc & GLObjBind
class VertexBuffer {
public:
explicit VertexBuffer() {
GLObjDelAlloc<Tags::VertexBuffer>::Allocate(1, &handle_);
}
inline void Bind() {
GLObjBind<Tags::VertexBuffer>::BindRequest(handle_);
}
template<typename T>
static void BufferData(const GLTypeCT<GLType::Integer> count, GLTypeCT<T>* data) {
glBufferData(GL_ARRAY_BUFFER, count *
sizeof(data->stride), data, GL_STATIC_DRAW);
}
VertexBuffer& operator=(const VertexBuffer& other) = delete;
VertexBuffer(const VertexBuffer& other) = delete;
private:
Tags::VertexBuffer::internal handle_;
};
} //namespace GLLayer
} //namespace Spiky
And here is my main:
int main(int argc, char** args)
{
GLTypeCT<GLfloat> quadVertices[] = {
// Positions // Texture Coords
-1.0f, 1.0f, 0.0f, -1.0f, -1.0f, 0.0f,
1.0f, 1.0f, 0.0f, 1.0f, -1.0f, 0.0f,
};
// Setup plane VAO
glGenVertexArrays(1, &quadVAO);
VertexBuffer buffer{};
glBindVertexArray(quadVAO);
buffer.Bind();
VertexBuffer::BufferData(12, quadVertices);
glEnableVertexAttribArray(0);
glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 3 * sizeof(GLfloat),
(GLvoid*)(0));
glBindVertexArray(0);
auto RenderQuad = [&] {
glBindVertexArray(quadVAO);
glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
glBindVertexArray(0);
};
//render calls later on...
}
Do you think the error comes from VertexBuffer ?

Answer 1

I see a few possible issues here.
But first, 1280 means GL_INVALID_ENUM, where did you get this? After which opengl call?
In this:
static void BindRequest(Tags::VertexBuffer::internal name = ZERO_BUFFER) {
if(_active != name) {
glBindBuffer(GL_ARRAY_BUFFER, 0);
_active = name;
}
You should probably pass glBindBuffer what you want to bind. glBindBuffer(GL_ARRAY_BUFFER, name)
I doubt this is causing it to crash but, when you call glVertexAttribPointer you're passing it 3 * sizeof(float) when it should be 6 * sizeof(float), why? Because the stride should be the size of your entire "Vertex" which in your case contains the positions and texcoords, which sums up to 6 floats.
And when you're calling glDrawArrays(GL_TRIANGLE_STRIP, 0, 4) you're saying that the count is 4, but as far as I can tell it's only 2.
The "access violation at 0x00000000", you get that if the function pointer to that function hasn't been retrieved, what are you using to get those pointers? I saw in the comments that you use SDL but that won't do any of that for you. You could do it yourself or use GLEW.