VAOSample.cpp

void Start() {
  Vec3 vertices[3] = {
  Vec3(),
  Vec3(1, 1, 0),
  Vec3(1, -1, 0) };
  glGenVertexArrays(1, &_vao);
  glGenBuffers(1, &_vboV);
  glBindBuffer(GL_ARRAY_BUFFER, _vboV);
  glBufferStorage(GL_ARRAY_BUFFER, _vboSz * sizeof(Vec3), vertices, GL_DYNAMIC_STORAGE_BIT);
  glBindBuffer(GL_ARRAY_BUFFER, 0);
  glBindVertexArray(_vao);
  glEnableVertexAttribArray(0);
  glBindBuffer(GL_ARRAY_BUFFER, _vboV);
  glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 0, NULL);
  glBindBuffer(GL_ARRAY_BUFFER, 0);
  glBindVertexArray(0);
}

void Draw() {
  glBindBuffer(GL_ARRAY_BUFFER, _vbo);
  auto d = glMapBuffer(GL_ARRAY_BUFFER, GL_WRITE_ONLY);
  *(Vec3*)d = Vec3(0, sinf(Time::time), 0);
  glUnmapBuffer(GL_ARRAY_BUFFER);
  glBindBuffer(GL_ARRAY_BUFFER, 0);

  glUseProgram(defProgram);
  glUniform4f(defColLoc, 1.0f, 0.0f, 0.0f, 1.0f);
  glBindVertexArray(_vao);
  glDrawArrays(GL_TRIANGLES, 0, 3);
  glBindVertexArray(0);
  glUseProgram(0);
}