/*
 * SourceGLCanvas.cpp
 *
 * (c) 2013 Sofian Audry -- info(@)sofianaudry(.)com
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#include "SourceGLCanvas.h"

SourceGLCanvas::SourceGLCanvas(QWidget* parent)
  : MapperGLCanvas(parent)
{
}

Quad& SourceGLCanvas::getQuad()
{
  std::tr1::shared_ptr<TextureMapping> textureMapping = std::tr1::static_pointer_cast<TextureMapping>(Common::currentMapping);
  Q_CHECK_PTR(textureMapping);

  std::tr1::shared_ptr<Quad> inputQuad = std::tr1::static_pointer_cast<Quad>(textureMapping->getInputShape());
  Q_CHECK_PTR(inputQuad);

  return (*inputQuad);
}

void SourceGLCanvas::doDraw()
{
  // TODO: Ceci est un hack necessaire car tout est en fonction de la width/height de la texture.
  // Il faut changer ca.
  std::tr1::shared_ptr<TextureMapping> textureMapping = std::tr1::static_pointer_cast<TextureMapping>(Common::currentMapping);
  Q_CHECK_PTR(textureMapping);

  std::tr1::shared_ptr<Texture> texture = std::tr1::static_pointer_cast<Texture>(textureMapping->getPaint());
  Q_CHECK_PTR(texture);

  std::cout << width() << " " << height() << std::endl;
  if (texture->getTextureId() == 0) {
    texture->loadTexture();
  }

  // Now, draw
  // DRAW THE TEXTURE
  glPushMatrix();

  // Enable blending mode (for alphas).
  glEnable (GL_BLEND);
  glBlendFunc (GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);

  glDisable (GL_LIGHTING);
  glEnable (GL_TEXTURE_2D);
  glBindTexture(GL_TEXTURE_2D, texture->getTextureId());

  glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, texture->getWidth(), texture->getHeight(), 0, GL_RGBA,
               GL_UNSIGNED_BYTE, texture->getBits());

  std::cout << texture->getX() << "x" << texture->getY() << " : " << texture->getWidth() << "x" << texture->getHeight() << " " << texture->getTextureId() << std::endl;

  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP);
  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP);
  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);

  // TODO: Exact projection of texture
  // see http://stackoverflow.com/questions/15242507/perspective-correct-texturing-of-trapezoid-in-opengl-es-2-0

  // Draw source texture (not moving) in the center of the area.

  // float centerX = (float) width()  / 2.0f;
  // float centerY = (float) height() / 2.0f;
  // float textureHalfWidth  = (float) texture->getWidth()  / 2.0f;
  // float textureHalfHeight = (float) texture->getHeight() / 2.0f;

  //printf("SRC: %f %f %f %f\n", centerX, centerY, textureHalfWidth, textureHalfHeight);
  glColor4f (1.0f, 1.0f, 1.0f, 1.0f);
  // FIXME: Does this draw the quad counterclockwise?
  glBegin (GL_QUADS);
  {
    Util::correctGlTexCoord(0, 0);
    glVertex3f (texture->getX(), texture->getY(), 0);

    Util::correctGlTexCoord(1, 0);
    glVertex3f (texture->getX()+texture->getWidth(), texture->getY(), 0);

    Util::correctGlTexCoord(1, 1);
    glVertex3f (texture->getX()+texture->getWidth(), texture->getY() + texture->getHeight(), 0);

    Util::correctGlTexCoord(0, 1);
    glVertex3f (texture->getX(), texture->getY() + texture->getHeight(), 0);
  }
  glEnd ();

  glDisable(GL_TEXTURE_2D);

  // Draw the quad.
  Quad& quad = getQuad();

  glColor4f(1.0f, 0.0f, 0.0f, 1.0f);

  // Source quad.
  glLineWidth(5);
  glBegin (GL_LINE_STRIP);
  {
    for (int i = 0; i < 5; i++)
    {
      glVertex2f(
        quad.getVertex(i % 4).x,
        quad.getVertex(i % 4).y
                 );
    }
  }
  glEnd ();

  glPopMatrix();
}