//MouseMotion
//  Drawing polyline
//  glutMotionFunc(onDrag); // mouse drag event call back
//  void onDrag(int x, int y_inv)
// T. Kosaka CS TNCT 2001

#include <stdio.h>
#include <math.h>
#include <GL/glut.h>
#include "drawShape2D.h"

void userdraw(void);

void display(void)
{
    glClear( GL_COLOR_BUFFER_BIT);
    userdraw();
    glutSwapBuffers();
}

int NumberofPoints=1;
point2D_t PointBuffer[4096]={{0,0}};
int drag=0;
point2D_t CurrentPoint;

void onMouseButton(int button, int state, int x, int y_inv)
{
    int y=480-y_inv-1;  // device coordinate -> view coordinate
    switch (button) {
    case GLUT_LEFT_BUTTON:
        if (state == GLUT_UP && NumberofPoints!=4096) {
            PointBuffer[NumberofPoints].x=x;
            PointBuffer[NumberofPoints].y=y;
            NumberofPoints++;
            drag=0;
        }
        break;
    case GLUT_MIDDLE_BUTTON:
        // do nothing
        break;
    case GLUT_RIGHT_BUTTON:
        // do nothing
        break;
    default:
        break;
    }
}

//マウスがドラッグされた時に呼び出される関数
void onDrag(int x, int y_inv)
{
    int y=480-y_inv-1;  // device coordinate -> view coordinate
    drag=1;
    CurrentPoint.x=x;
    CurrentPoint.y=y;
}

void userdraw(void)
{
    int i;
    color_t white={1.,1.,1.};
    color_t cyan={0.,1.,1.};
    setColor(white);
    if (1<NumberofPoints) {
        for(i=0;i<NumberofPoints;i++) {
            drawPolyline(PointBuffer,NumberofPoints);
        }
    }
    setColor(cyan);
    if (0<NumberofPoints && drag==1) {
        drawLine(PointBuffer[NumberofPoints-1],CurrentPoint);
    }
}

int main(int argc, char **argv)
{
    glutInit(&argc,argv);
    glutInitDisplayMode ( GLUT_DOUBLE | GLUT_RGB );
    glutInitWindowPosition(100,100);
    glutInitWindowSize(640,480);
    glutCreateWindow ("MouseMotion  !!! Drag the pointer on the screen with the mouse. !!!");
    glClearColor(0.0, 0.0, 0.0, 0.0);
    gluOrtho2D(0., 640., 0., 480.0);
      // Define the dimensions of the Orthographic Viewing Volume
    glutIdleFunc(display); // idle event call back
    glutDisplayFunc(display);
    glutMouseFunc(onMouseButton);   // mouse button event call back
    glutMotionFunc(onDrag); // mouse drag event call back
    glutMainLoop();
    return 0;
}