/*         +------------------------------------------------------+ 
  ____/  \____   /| - Open source game framework licensed to freely use, |
  \          /  / |   copy, modify and sell without restriction          |
+--\ ^__^   /--+  |                                                      |
| ~/        \~ |  | - created for <https://foam.shampoo.ooo>             |
| ~~~~~~~~~~~~ |  +------------------------------------------------------+
| SPACE ~~~~~  | /
|  ~~~~~~~ BOX |/
+-------------*/

#include "VBO.hpp"

using namespace sb;

VBO::VBO() : Buffer(GL_ARRAY_BUFFER) {}

void VBO::generate()
{
    Buffer::generate();
    offset = 0;
}

void VBO::allocate(GLsizeiptr size, GLenum usage)
{
    /* Create data store, making sure the buffer currently bound matches this object's ID */
    GLint bound_id;
    glGetIntegerv(GL_ARRAY_BUFFER_BINDING, &bound_id);
    if (static_cast<GLuint>(bound_id) == id())
    {
        glBufferData(target(), size, nullptr, usage);
    }
    else
    {
        std::ostringstream message;
        message << "Error allocating vertex memory for " << *this << ": ";
        if (bound_id == 0)
        {
            message << "no buffer is currently bound";
        }
        else
        {
            message << "currently bound buffer ID " << bound_id << " does not match " << *this;
        }
        throw std::runtime_error(message.str());
    }

    /* Debug */
    std::ostringstream message;
    message << "After allocating memory for " << *this;
    sb::Log::gl_errors(message.str());
}

GLintptr VBO::add(sb::Attributes& attributes)
{
    /* Set memory and update offset value in attributes object */
    glBufferSubData(target(), offset, attributes.size(), attributes);
    attributes.offset(offset);

    /* Debug */
    std::ostringstream initialization_message;
    initialization_message << "After setting " << attributes.size() << " bytes in " << *this;
    sb::Log::gl_errors(initialization_message.str());

    /* Increase offset and return */
    offset += attributes.size();
    return offset;
}

std::ostream& sb::operator<<(std::ostream& out, const VBO& vbo)
{
    out << "<Vertex Buffer Object (id: " << vbo.id() << ")>";
    return out;
}