rotating planes in 3D

strinda

Hi, trying some simple projects in 3D.

For my step 1 project I decided to rotate a plane. I created a plane, however, simple rotateY doesn't help me much, as I would like to rotate against some arbitrary point.

But then I run it this: - I first translate to the point against which I want to rotate - I rotate by some angle - I draw the plane (but as I have previously 'translated' my plane is no a bit off)

In the end, I want the plane to be rotated against any axis. For instance, against the middle of the plane.

This is my code:

int step  = 10;
int a = 1;
void setup() {
  size (800, 800, P3D);
}



void draw() {
  background (0, 0, 0);

  a = a + 1; 

  translate (width/2, 0);

  for (int y = 0; y < height; y += 10) {
    fill (255,0,0);
    ellipse (0, y, 5, 5);
  }
  rotateY (radians(a));




  for (int i = width/2 - 100; i < width/2 + 100; ) {
    i += step;
    for (int j = height/2 - 100; j < height/2 + 100; j += step) {
      pushMatrix();
      translate (i, j);
      fill (255, 255, 255);
      ellipse (0, 0, 5, 5);
      popMatrix();
    }
  }
}

tlecoz

Hello !

Your first "translate" should be inside an another pushMatrix/popMatrix. Then, in your loop, apply the rotation in the push/popMatrix corresponding to each element, but it's important to apply the rotation BEFORE the translation - the result will be very different if you put it after the translation -

(if you define the rotation before the translation, it means that the origin of the mesh is at the center of the object ; when you apply a translation, you move the object from its center )

Good luck !

strinda

Tried out, but missed something, I guess - so it didn't work in the end. And, if I enclose the translate operator in push/pop Matrix ... It won't play any role at all.

    int step  = 10;
    int a = 1;
    void setup() {
      size (800, 800, P3D);
    }



    void draw() {
      background (0, 0, 0);

      a = a + 1; 




      for (int y = 0; y < height; y += 10) {
        fill (255, 0, 0);
        ellipse (0, y, 5, 5);
      }





      for (int i = width/2 - 100; i < width/2 + 100; ) {
        i += step;
        for (int j = height/2 - 100; j < height/2 + 100; j += step) {
          pushMatrix();


          rotateY (radians(a));


          translate (i, j);
          fill (255, 255, 255);
          ellipse (0, 0, 5, 5);
          popMatrix();
        }
      }
    }

strinda

Decided there is no need to draw everything every frame - decided to make a shape... Unfortunately, doesn't work at the moment.

    int step  = 10;
    int a = 1;

    PShape plane;
    void setup() {
      size (800, 800, OPENGL);
      //  noLoop();
      plane = createShape();
      plane.beginShape(LINES);
      for (int i = 0; i < width; ) {
        i += step;

        for (int j = 0; j < height; j += step) {
          pushMatrix();

          translate (i, j, dist(i, j, width/2, height/2)*dist(i, j, width/2, height/2)/100);
          plane.fill (255, 255, 255);

          plane.vertex (0, 0, 10, 10);
          popMatrix();
        }
      }
      endShape(CLOSE);
    }



    void draw() {
      background (0, 0, 0);

      translate (0, 400);
      rotateX (radians(mouseX));
      translate (0, -400);

      shape(plane, 0, 0);
    }

Chrisir

you has made few mistakes

int step  = 10;
int a = 1;

PShape plane;
void setup() {
  size (800, 800, OPENGL);
  //  noLoop();
  plane = createShape();
  plane.beginShape(LINES);
  for (int i = 0; i < width; ) {
    i += step;

    for (int j = 0; j < height; j += step) {
      //  plane.pushMatrix();

      //plane.translate (i, j, dist(i, j, width/2, height/2)*dist(i, j, width/2, height/2)/100);
      //plane.translate ();
      plane.fill (255, 255, 255);
      plane.stroke (255, 255, 255);
      plane.vertex (i, j, -333);
      // plane.popMatrix();
    }
  }
  plane.endShape(CLOSE);
}



void draw() {
  background (0, 0, 0);

  translate (0, 400);
  rotateX (radians(map(mouseX, 0, width, 0, 360)));
  translate (0, -400);

  shape(plane, 0, 0);
}

Chrisir

move mouse left and right please

Chrisir

here

int step  = 30;
int a = 1;

// Make the parent shape
PShape plane ; // see https: // www.processing.org/tutorials/pshape/

void setup() {
  size (800, 800, OPENGL);

  plane = createShape(GROUP);
  PShape mySphere;

  for (int i = 0; i < width; ) {
    i += step;

    for (int j = 0; j < height; j += step) {

      // make sphere 
      mySphere = createShape(SPHERE, 15 );
      //  mySphere.translate(i, j, -.01*i*j);
      if (i>600&&j>600)
        mySphere.translate(i, j, -266);
      else 
        mySphere.translate(i, j, -222);
      mySphere.setStroke(false); // noStroke
      mySphere.setFill(color(255, 2, 2));

      // Add the "child" shape to the parent group
      plane.addChild(mySphere);
      mySphere=null;
    }
  }

  println ("here 2");
}



void draw() {
  background (0, 0, 0);
  lights();

  translate (0, 400, -400);
  rotateX (radians(map(mouseX, 0, width, 0, 360)));
  translate (0, -400);

  shape(plane, 0, 0);
}