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/*  Visualization Library                                                             */
/*  http://visualizationlibrary.org                                                   */
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#ifndef MorphingCallback_INCLUDE_ONCE
#define MorphingCallback_INCLUDE_ONCE

#include <vlGraphics/Actor.hpp>
#include <vlGraphics/Geometry.hpp>

namespace vl
{
  class ResourceDatabase;

  /** The MorphingCallback class implements a simple morphing animation mechanism using the
      GPU acceleration where available. */
  class VLGRAPHICS_EXPORT MorphingCallback: public ActorEventCallback
  {
    VL_INSTRUMENT_CLASS(vl::MorphingCallback, ActorEventCallback)

  public:
    MorphingCallback();

    ~MorphingCallback();

    virtual void onActorRenderStarted(Actor* actor, real frame_clock, const Camera* cam, Renderable* renderable, const Shader*, int pass);

    virtual void onActorDelete(Actor*) {}

    void bindActor(Actor* actor);

    /** Initializes a MorphingCallback from a ResourceDatabase.
     *
     * The given ResourceDatabase must contain a Geometry with all the desired DrawCalls and vertex attributes setup
     * with the exception of the vertex position array and vertex normal array since they are automatically generated
     * in realtime time during the rendering from the vertex and normal frames specified below.
     * In addition ResourceDatabase must contain:
     * - N ArrayFloat3 objects named 'vertex_frame' containing the vertex position for every frame
     * - N ArrayFloat3 objects named 'normal_frame' containing the vertex normal for every frame
     * where N is the number of animation frames.
    */
    void init(ResourceDatabase* res_db);

    void blendFrames(int a, int b, float t);

    void setAnimation(int start, int end, float period);

    void startAnimation(real time = -1);

    void stopAnimation();

    void initFrom(MorphingCallback* morph_cb);

    void resetGLSLBindings();

    bool glslVertexBlendEnabled() const { return mGLSLVertexBlendEnabled; }
    void setGLSLVertexBlendEnabled(bool enable) { mGLSLVertexBlendEnabled = enable; }

    Geometry* geometry() { return mGeometry.get(); }
    const Geometry* geometry() const { return mGeometry.get(); }

    bool animationStarted() const { return mAnimationStarted; }

  protected:
    ref<Geometry> mGeometry;
    ref<ArrayFloat3> mVertices;
    ref<ArrayFloat3> mNormals;
    std::vector< ref<ArrayFloat3> > mVertexFrames;
    std::vector< ref<ArrayFloat3> > mNormalFrames;

    real mLastUpdate;
    real mElapsedTime;
    real mAnimationStartTime;
    int mAnimationStart;
    int mAnimationEnd;
    float mAnimationPeriod;
    bool mAnimationStarted;
    int mFrame1;
    int mFrame2;

    bool mGLSLVertexBlendEnabled;
    int mVertex2_Binding;
    int mNormal2_Binding;
    int mAnim_t_Binding;
    float mAnim_t;
  };
  //-----------------------------------------------------------------------------
}

#endif