glDrawArrays(...) won't draw anything - c++

Question

I have problems to draw something using glDrawArrays() and no other question here could help me solve it. The code should draw a sphere, but for debuging I fill "m_vertices" with the vertices for a simple cube.
My Code is following:
First the init function.
init()
{
m_shader.compileShaders("Shaders/colorShading.vert", "Shaders/colorShading.frag");
m_shader.addAttribute("position");
m_shader.addAttribute("normal");
m_shader.linkShaders();
//setup VAO and VBO
glGenVertexArrays(1, &m_vao);
glGenBuffers(1, &m_vbo);
//init VAO
glBindVertexArray(m_vao);
//bind Buffer used by VAO
glBindBuffer(GL_ARRAY_BUFFER, m_vbo);
//enable needed AttributeArrays
glEnableVertexAttribArray(0);
glEnableVertexAttribArray(1);
//position attribute pointer
glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, sizeof(VertexBuffer), (void*)offsetof(VertexBuffer, vertex));
glVertexAttribPointer(1, 3, GL_FLOAT, GL_TRUE, sizeof(VertexBuffer), (void*)offsetof(VertexBuffer, normal));
//release VAO
glBindVertexArray(0);
//release VBO
glBindBuffer(GL_ARRAY_BUFFER, 0);
//Set-Up a static scene
// Projection matrix : 45° Field of View, 4:3 ratio, display range : 0.1 unit <-> 100 units
glm::mat4 projection = glm::perspective(45.0f, 4.0f / 3.0f, 0.1f, 100.0f);
// Camera matrix
glm::mat4 view = glm::lookAt(
glm::vec3(4, 3, 3), // Camera is at (4,3,3), in World Space
glm::vec3(0, 0, 0), // and looks at the origin
glm::vec3(0, 1, 0) // Head is up (set to 0,-1,0 to look upside-down)
);
// Model Matrix
glm::mat4 model = glm::mat4(1.0f);
//set ModelViewProjection-Matrix of this object
m_mvp = projection * view * model;
}
This function is used to set up everything needed to draw my Object.
Then there is an update function:
update()
{
//update Sphere and get current vertices
//currently setting vertices for a cube
m_sphere->updateSphere(m_vertices);
//m_vertices is passed in per reference
//it stores 6 quads based on 2 triangles (36 vertices)
//the vertices are stored counter clockwise
//update VBO
//bind buffer
glBindBuffer(GL_ARRAY_BUFFER, m_vbo);
//orphan the buffer
glBufferData(GL_ARRAY_BUFFER, m_vertices.size() * sizeof(VertexBuffer), nullptr, GL_STATIC_DRAW);
//upload data
glBufferSubData(GL_ARRAY_BUFFER, 0, m_vertices.size() * sizeof(VertexBuffer), &m_vertices[0]);
//release buffer
glBindBuffer(GL_ARRAY_BUFFER, 0);
}
The update function updates the VBO. This is needed cause the final Sphere should implement LevelOfDetail.
And finally the draw function:
draw()
{
glEnable(GL_DEPTH_TEST);
//activate shader
m_shader.use();
//set-up the mvp-uniform
GLuint matrixID = m_shader.getUniformLocation("MVP");
glUniformMatrix4fv(matrixID, 1, GL_FALSE, &m_mvp[0][0]);
//draw Planet
glBindVertexArray(m_vao);
glDrawArrays(GL_TRIANGLES, 0, m_vertices.size());
glBindVertexArray(0);
//deactivate shader
m_shader.unuse();
glDisable(GL_DEPTH_TEST);
}
This function should just binds/sets up the shader and draw the object.
The problem is that it doesn't draw the object and I have no idea why.
If someone could spot my mistake and explain what I did wrong here, I would be very grateful.
EDIT:
So as requested I add my code, which fills in the cube data:
static const std::vector<GLfloat> g_vertex_buffer_data = {
-1.0f,-1.0f,-1.0f,
-1.0f,-1.0f, 1.0f,
-1.0f, 1.0f, 1.0f,
1.0f, 1.0f,-1.0f,
-1.0f,-1.0f,-1.0f,
-1.0f, 1.0f,-1.0f,
1.0f,-1.0f, 1.0f,
-1.0f,-1.0f,-1.0f,
1.0f,-1.0f,-1.0f,
1.0f, 1.0f,-1.0f,
1.0f,-1.0f,-1.0f,
-1.0f,-1.0f,-1.0f,
-1.0f,-1.0f,-1.0f,
-1.0f, 1.0f, 1.0f,
-1.0f, 1.0f,-1.0f,
1.0f,-1.0f, 1.0f,
-1.0f,-1.0f, 1.0f,
-1.0f,-1.0f,-1.0f,
-1.0f, 1.0f, 1.0f,
-1.0f,-1.0f, 1.0f,
1.0f,-1.0f, 1.0f,
1.0f, 1.0f, 1.0f,
1.0f,-1.0f,-1.0f,
1.0f, 1.0f,-1.0f,
1.0f,-1.0f,-1.0f,
1.0f, 1.0f, 1.0f,
1.0f,-1.0f, 1.0f,
1.0f, 1.0f, 1.0f,
1.0f, 1.0f,-1.0f,
-1.0f, 1.0f,-1.0f,
1.0f, 1.0f, 1.0f,
-1.0f, 1.0f,-1.0f,
-1.0f, 1.0f, 1.0f,
1.0f, 1.0f, 1.0f,
-1.0f, 1.0f, 1.0f,
1.0f,-1.0f, 1.0f
};
updateSphere(std::vector<VertexBuffer> &vertices)
{
if(!vertices.empty())
vertices.clear();
for (int i = 0; i < g_vertex_buffer_data.size();)
{
VertexBuffer buffer;
glm::vec3 vertex(g_vertex_buffer_data[i], g_vertex_buffer_data[i+1], g_vertex_buffer_data[i+2]);
buffer.setVertex(vertex);
buffer.setNormal(glm::normalize(vertex));
vertices.emplace_back(buffer);
i += 3;
}
}
Also the VertexBuffer struct:
struct Vector3 {
float x;
float y;
float z;
};
struct VertexBuffer {
Vector3 vertex;
Vector3 normal;
void setVertex(glm::vec3 vec)
{
vertex.x = vec.x;
vertex.y = vec.y;
vertex.z = vec.z;
}
void setNormal(glm::vec3 vec)
{
normal.x = vec.x;
normal.y = vec.y;
normal.z = vec.z;
}
};
My shader class is already tested in serveral other projects and works perfectly fine. I assume that I missmanage the VAO and VBO or the cube data. But I could be completly wrong here.
And I corrected the VAO generation, that was my bad and I wonder why I didn't see this. But that didn't fix the problem here.
The color and depth buffer get cleared in the mainloop of my project. Should I clear them on every draw call of an Object?