cannyedge.h

#ifndef CANNYEDGE_H
#define CANNYEDGE_H

#include <QtGui>
#include <QWindow>
#include <QtOpenGL>
#include <QOpenGLFunctions_3_2_Core>
#include "junctiondetector.h"

#define PI acos(-1.0f)


class CannyEdge
{
public:
    CannyEdge(QWindow *_qgl_window, QOpenGLContext *_qgl_contex, float _sigma, int _filterSize, int _width, int _height);

    ~CannyEdge();

    void setSigma(float _sigma);
    float getSigma();
    void setFilterSize(int _filterSize);
    int getFilterSize();

    void detectEdges(GLuint texture);

    GLuint getGradientFieldTexture();
    GLuint getCannyEdgeTexture();
    QImage getGradientFieldImage();
    QImage getCannyEdgeImage();

private:
    float sigma;
    int filterSize;
    float *filterCoefficients;
    int width, height;
    float *verticesFullscreenQuad;

    QWindow *qgl_window;

    GLuint image;
    GLuint filterTex;

    QOpenGLContext *qgl_context;
    QOpenGLFunctions_3_2_Core *qgl_funcs;
    
    QOpenGLShaderProgram qgl_cannyBlurShader;
    QOpenGLShaderProgram qgl_cannyMagnitudeShader;
    QOpenGLShaderProgram qgl_cannyEdgeShader;
    QOpenGLFramebufferObject *qgl_cannyFBO1;
    QOpenGLFramebufferObject *qgl_cannyFBO2;

    QOpenGLVertexArrayObject qgl_quad;

    void prepareShaders();
    void prepareVertexArrayObject();

    void updateFilterCoefficients();

    void imageBlur(QOpenGLFramebufferObject *fbo, GLuint texture);
    void imageMagnitude(QOpenGLFramebufferObject *fbo, GLuint texture);
    void imageNonMaximaSuppression(QOpenGLFramebufferObject *fbo, GLuint texture);
};

#endif //CANNYEDGE