#include <vector>
#include <glbinding/gl/gl.h>

#include "shaders.hh"
#include "Overlay.hh"

using namespace gl;

Overlay::Overlay(VBOManager& vboManager, std::vector<ovlVertexAttribs> const& vas,
		 Program& prog)
  : vboManager_(vboManager), vbo_(vboManager_.alloc(sizeof(ovlVertexAttribs)*vas.size())),
    prog_(prog), vaID_(0), vertices_(vas.size())
{
  glBindBuffer(GL_ARRAY_BUFFER, vbo_.getVBOId());
  glBufferSubData(GL_ARRAY_BUFFER, vbo_.getOfs(),
		  sizeof(ovlVertexAttribs)*vas.size(),
		  static_cast<void const*>(vas.data()));

  glGenVertexArrays(1, &vaID_);
  try {
    glBindVertexArray(vaID_);
    GLint al;
    if((al = prog_.getAttribLocation("vertex")) != -1) {
      glEnableVertexAttribArray(al);
      glVertexAttribPointer(al, 2, GL_SHORT, GL_TRUE, sizeof(ovlVertexAttribs),
			    (void*)(vbo_.getOfs()+offsetof(ovlVertexAttribs, vertex)));
    }
    if((al = prog_.getAttribLocation("vertexTC")) != -1) {
      glEnableVertexAttribArray(al);
      glVertexAttribPointer(al, 2, GL_UNSIGNED_SHORT, GL_TRUE,
			    sizeof(ovlVertexAttribs),
			    (void*)(vbo_.getOfs()+offsetof(ovlVertexAttribs, texCoords)));
    }
  } catch(...) {
    glDeleteVertexArrays(1, &vaID_);
    throw;
  }
}

Overlay::~Overlay()
{
  glDeleteVertexArrays(1, &vaID_);
}

void Overlay::draw(Program *override) const
{
  glBindVertexArray(vaID_);
  if (override)
    override->use();
  else
    prog_.use();
  glDrawArrays(GL_TRIANGLES, 0, vertices_);
}