#include "orbitvisualizer.hpp"
#include "gfx.hpp"

OrbitVisualizer::OrbitVisualizer(const Orbit& orbit, const GLuint shaderProgram)
    : _orbit(orbit), _shaderProgram(shaderProgram)
{
    glGenVertexArrays(1, &_vao);
    glGenBuffers(1, &_vbo);
}

void OrbitVisualizer::render(const float time)
{
    regenerateVertices();

    glUseProgram(_shaderProgram);
    updateModelViewProjectionMatrix(_shaderProgram, time);

    glBindVertexArray(_vao);
    glBindBuffer(GL_ARRAY_BUFFER, _vbo);

    glDrawArrays(GL_LINE_LOOP, 0, _vertices.size() / 3);
}

void OrbitVisualizer::regenerateVertices()
{
    _vertices.clear();

    for (int i = 0; i < _vertexCount; i++)
    {
        float t = (float)i / (float)_vertexCount * 2.0 * _pi;
        glm::vec3 pos = _orbit.getPosition(t);

        _vertices.push_back(pos.x);
        _vertices.push_back(pos.y);
        _vertices.push_back(pos.z);
    }

    glBindVertexArray(_vao);

    glBindBuffer(GL_ARRAY_BUFFER, _vbo);
    size_t vboBufferSize = _vertices.size() * sizeof(float);
    glBufferData(GL_ARRAY_BUFFER, vboBufferSize, &_vertices[0], GL_STATIC_DRAW);

    glEnableVertexAttribArray(0);
    glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 3 * sizeof(float), (void*)0);

    glBindBuffer(GL_ARRAY_BUFFER, 0);
    glBindVertexArray(0);
}

OrbitVisualizer::~OrbitVisualizer()
{
    glDeleteVertexArrays(1, &_vao);
    glDeleteBuffers(1, &_vbo);
}