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hi everyone I new to OPENGL and I want to update the vertices and indices when I translate the 3d object I make vertices vector and indices vector these vector hold all the data of the 3d object is this possible the code I use :

    // Create buffers/arrays
    glGenVertexArrays(1, &this->VAO);
    glGenBuffers(1, &this->VBO);
    glGenBuffers(1, &this->EBO);

    glBindVertexArray(this->VAO);
    // Load data into vertex buffers
    glBindBuffer(GL_ARRAY_BUFFER, this->VBO);
    // A great thing about structs is that their memory layout is sequential for all its items.
    // The effect is that we can simply pass a pointer to the struct and it translates perfectly to a glm::vec3/2 array which
    // again translates to 3/2 floats which translates to a byte array.
    glBufferData(GL_ARRAY_BUFFER,this->vertices.size() * sizeof(vertex), &this->vertices[0], GL_STATIC_DRAW);
    
    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, this->EBO);
    glBufferData(GL_ELEMENT_ARRAY_BUFFER, this->indices.size() * sizeof(int), &this->indices[0], GL_STATIC_DRAW);

    // Set the vertex attribute pointers
    // Vertex Positions
    glEnableVertexAttribArray(0);
    glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, sizeof(vertex), (GLvoid*)0);
    // Vertex Normals
    glEnableVertexAttribArray(1);
    glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, sizeof(vertex), (GLvoid*)offsetof(vertex, normal));
    // Vertex Texture Coords
    glEnableVertexAttribArray(2);
    glVertexAttribPointer(2, 2, GL_FLOAT, GL_FALSE, sizeof(vertex), (GLvoid*)offsetof(vertex, uv));

    glBindVertexArray(0);

I do not know if this code make change to the vertices and indices or it just make copy of this two vector and render what I want is not make copy this vector and render I want to use this vector directly and make change to this vector is this possible

مهند خليل
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1 Answers1

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Usually on graphics we use what's called a transformation matrix for space operations such as translation / rotation / scale.

This allow us to avoid mixing data between model specific data (such as vertices, normals, etc..) and his state in the 3D world (transform).

So my advice here would be to use transformation matrix and update the model position in the vertex shader.

You can find more info here https://learnopengl.com/Getting-started/Transformations

Aleix Rius
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