Instanced drawing with texture atlas - c++

Question

I am currently trying to create a tilemap using instanced drawing. I have been able to draw multiple instances of a tile by sending the vertices corresponding to the geometry combined with the texture coordinates and the offsets of each tiles in a separate VBO and using the attribute divisor.
This however allows me to use only one texture. So I splitted the texture coordinates from the vertices and created a separate VBO like for the offsets, but it doesn't generate the expected results. Let's say the coordinates I send are the coordinates that match the first texture in the atlas for the first tile and the coordinates that match the second texture for the other tiles, if I use glAttributeDivisor(1, 0), all the tiles use only the first texture. If I use any other value, I get some sort of checker pattern with only one pixel of each texture used for the entire tile.
Here's what it does when the attribute divisior is 0:
And this is when the attribute divisor is at 1:
Normally, the first tile in the bottom left corner should be a grass tile, like when the divisor is 0, and all the others should be a dirt tile.
This is what I do to create the buffers:
TileMap::TileMap(std::vector<glm::vec2> positions, std::vector<glm::vec2> texCoords, glm::vec2 tileSize,
std::shared_ptr<graphics::Shader> shader,
std::shared_ptr<graphics::Texture> texture) :
m_positions(positions), m_texCoords(texCoords), m_tileSize(tileSize), m_shader(shader), m_texture(texture) {
m_model = glm::mat4();
m_model = glm::scale(m_model, glm::vec3(tileSize, 1.0f));
GLfloat vertices[] =
{
// Positions
1.0f, 1.0f, // Top Right
1.0f, 0.0f, // Bottom Right
0.0f, 0.0f, // Bottom Left
0.0f, 1.0f // Top Left
};
GLuint indices[] =
{
0, 1, 3,
1, 2, 3
};
glGenVertexArrays(1, &m_vao);
glGenBuffers(1, &m_vbo);
glGenBuffers(1, &m_ebo);
glGenBuffers(1, &m_textureVbo);
glBindBuffer(GL_ARRAY_BUFFER, m_textureVbo);
glBufferData(GL_ARRAY_BUFFER, sizeof(glm::vec2) * m_texCoords.size(), &m_texCoords[0], GL_STATIC_DRAW);
glBindBuffer(GL_ARRAY_BUFFER, 0);
glGenBuffers(1, &m_instanceVbo);
glBindBuffer(GL_ARRAY_BUFFER, m_instanceVbo);
glBufferData(GL_ARRAY_BUFFER, sizeof(glm::vec2) * m_positions.size(), &m_positions[0], GL_STATIC_DRAW);
glBindBuffer(GL_ARRAY_BUFFER, 0);
glBindVertexArray(m_vao);
glBindBuffer(GL_ARRAY_BUFFER, m_vbo);
glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, m_ebo);
glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(indices), indices, GL_STATIC_DRAW);
glEnableVertexAttribArray(0);
glVertexAttribPointer(0, 2, GL_FLOAT, GL_FALSE, 2 * sizeof(GLfloat), (GLvoid*)0);
glEnableVertexAttribArray(1);
glBindBuffer(GL_ARRAY_BUFFER, m_textureVbo);
glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE, 2 * sizeof(GLfloat), (GLvoid*)0);
glBindBuffer(GL_ARRAY_BUFFER, 0);
glEnableVertexAttribArray(2);
glBindBuffer(GL_ARRAY_BUFFER, m_instanceVbo);
glVertexAttribPointer(2, 2, GL_FLOAT, GL_FALSE, 2 * sizeof(GLfloat), (GLvoid*)0);
glBindBuffer(GL_ARRAY_BUFFER, 0);
glVertexAttribDivisor(1, 0);
glVertexAttribDivisor(2, 1);
glBindVertexArray(0);
}
And this is how I generate the tilemap:
std::vector<glm::vec2> positions;
std::vector<glm::vec2> texCoords;
bool test = false;
for(float i = 0.0f; i < 7.0f; i++) {
for(float j = 0.0f; j < 7.0f; j++) {
positions.push_back(glm::vec2(j, i));
if(test){
texCoords.push_back(glm::vec2(1.0f, 1.0f)); // Top Right
texCoords.push_back(glm::vec2(1.0f, 0.0f)); // Bottom Right
texCoords.push_back(glm::vec2(0.5f, 0.0f)); // Bottom Left
texCoords.push_back(glm::vec2(0.5f, 1.0f)); // Top Left
} else {
texCoords.push_back(glm::vec2(0.5f, 1.0f)); // Top Right
texCoords.push_back(glm::vec2(0.5f, 0.0f)); // Bottom Right
texCoords.push_back(glm::vec2(0.0f, 0.0f)); // Bottom Left
texCoords.push_back(glm::vec2(0.0f, 1.0f)); // Top Left
}
test = true; //This is just to test the texture switching after the first tile
}
}
graphics::TileMap tileMap(positions, texCoords, glm::vec2(64.0f), shader, texture);
I am not really familiar with OpenGl so I have absolutely no idea what is causing this nor what to use so that each quad read the 4 texture coordinates that should by tied to them.