/* Copyright 2016 The TensorFlow Authors. All Rights Reserved.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
==============================================================================*/

#ifndef THIRD_PARTY_TENSORFLOW_EXAMPLES_ANDROID_JNI_OBJECT_TRACKING_GL_UTILS_H_
#define THIRD_PARTY_TENSORFLOW_EXAMPLES_ANDROID_JNI_OBJECT_TRACKING_GL_UTILS_H_

#include <GLES/gl.h>
#include <GLES/glext.h>

#include "tensorflow/examples/android/jni/object_tracking/geom.h"

namespace tf_tracking {

// Draws a box at the given position.
inline static void DrawBox(const BoundingBox& bounding_box) {
  const GLfloat line[] = {
      bounding_box.left_, bounding_box.bottom_,
      bounding_box.left_, bounding_box.top_,
      bounding_box.left_, bounding_box.top_,
      bounding_box.right_, bounding_box.top_,
      bounding_box.right_, bounding_box.top_,
      bounding_box.right_, bounding_box.bottom_,
      bounding_box.right_, bounding_box.bottom_,
      bounding_box.left_, bounding_box.bottom_
  };

  glVertexPointer(2, GL_FLOAT, 0, line);
  glEnableClientState(GL_VERTEX_ARRAY);

  glDrawArrays(GL_LINES, 0, 8);
}


// Changes the coordinate system such that drawing to an arbitrary square in
// the world can thereafter be drawn to using coordinates 0 - 1.
inline static void MapWorldSquareToUnitSquare(const BoundingSquare& square) {
  glScalef(square.size_, square.size_, 1.0f);
  glTranslatef(square.x_ / square.size_, square.y_ / square.size_, 0.0f);
}

}  // namespace tf_tracking

#endif  // THIRD_PARTY_TENSORFLOW_EXAMPLES_ANDROID_JNI_OBJECT_TRACKING_GL_UTILS_H_
