chrome/browser/vr/elements/laser.h

// Copyright 2017 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef CHROME_BROWSER_VR_ELEMENTS_LASER_H_
#define CHROME_BROWSER_VR_ELEMENTS_LASER_H_

#include "chrome/browser/vr/elements/ui_element.h"
#include "chrome/browser/vr/renderers/base_quad_renderer.h"
#include "ui/gfx/geometry/point3_f.h"

namespace vr {

struct Model;

class Laser : public UiElement {
 public:
  explicit Laser(Model* model);
  ~Laser() override;

  class Renderer : public BaseQuadRenderer {
   public:
    Renderer();
    ~Renderer() override;

    void Draw(float opacity, const gfx::Transform& view_proj_matrix);

   private:
    GLuint model_view_proj_matrix_handle_;
    GLuint texture_unit_handle_;
    GLuint texture_data_handle_;
    GLuint color_handle_;
    GLuint fade_point_handle_;
    GLuint fade_end_handle_;
    GLuint opacity_handle_;

    DISALLOW_COPY_AND_ASSIGN(Renderer);
  };

 private:
  void Render(UiElementRenderer* renderer,
              const CameraModel& model) const final;

  // Since the laser needs to render in response to model changes that occur
  // after the scene update (i.e., after input), we cannot rely on the usual
  // data binding flow since that would result in a frame of latency. Opacity
  // changes, however, are not latency sensitive and are bound in the usual way
  // (they also do not update due to input).
  Model* model_;

  DISALLOW_COPY_AND_ASSIGN(Laser);
};

}  // namespace vr

#endif  // CHROME_BROWSER_VR_ELEMENTS_LASER_H_