If object A and B have the same size but different world origin positions, and should be scaled by factor 0,5, the following would be the case in jPCT (if I got you right):



The gray objects is the scale result. Because the scaling is done on the object's world vertices, A' and B' dont have the same size anymore. Moving B to A, make the scaling and move B' back to it's original position solves the problem, but only while the two objects have the same size.

I find it strange that relative scaling hasn't been requested earlier, but one should not implement something thats not requested. Would you take this feature into considerations, or does it not easily fit into the engine?

So you're saying that the API has no relative scale feature, and this must be done by vertex management?

Hello.

Using Object3D.scale(float) to scale the object causing a tranformation to the object in world space. I though this method was related to object space? Why isn't a matrix needed to scale (transform) the object?

My other approach did have same result:
SimpleVector origin = o3d.getOrigin();
o3d.setScale(0.95f);
o3d.setTranslationMatrix(new Matrix());
o3d.translate(origin);

Truely something I've got wrong here. Please help.

Hello.

I need to solve a problem where two objects have (partial) identical plane coordinates. Imagine two boxes with same size and position but different textures. This causes flicker once transforming the objects together. Before I go to dramatic changes I'd like to know if jPCT is capable of prior the rendering of one object, by defining which object to appear.

Regards
Ducky

Hello guys.

I want to assign text to objects. Putting the text at the objects transformed center is the goal. In my solution I have one "origin object" which has several childs attached to it, and the camera towards it.

Now, placing the text should be something like this (just after the framebuffer has been flushed):

SimpleVector origin = Interact2D.project3D2D(camera, buffer, originObject.getCenter());
int length = gFrame.getFontMetrics().stringWidth(originObject.getName());
length /= 2;
gFrame.drawString(originObject.getName(), (int)origin.x-length, (int)origin.y);
... but it's not. The origin object's name appear at coordinate (frame_width; frame_height), leaving 1/4 of the text visible at the buttom to the right. First question is why it that?

Rewriting last line to this:

gFrame.drawString(originObject.getName(), (int)origin.x-length-(getWidth()/2), (int)origin.y-(getHeight()/2));
...solves the wrong position. The text appears right in the center of the object.

Now for the child objects:

for (Object3D o3d: childObjects) {
    SimpleVector v = o3d.getTransformedCenter();
    v = Interact2D.project3D2D(camera, buffer, v);

    length = gFrame.getFontMetrics().stringWidth(o3d.getName());
    length /= 2;
    gFrame.drawString(o3d.getName(), (int)v.x-length-(getWidth()/2), (int)v.y-(getHeight()/2));
    // Still should be: gFrame.drawString(o3d.getName(), (int)v.x-length, (int)v.y);
}
The transformation is correct, but the positioning have some kind of offset, like the distance from object's transformed center and it's assigned text is like the distance from origin and transformed object * 2.



What am I doing wrong?

Hello all!

First of all I'd like to appreciate the work that have made so intuitive 3D handling feasible in Java.

About my question:
Once an object is created in the world, a solid gray texture has been assigned to it and lights have been set up, the object shows to the camera like one could expect. I'm scaling the object to make a zoom effect when using the mouse. What I find strange is that the object appears brighter the closer the camera get (almost white), and darker as the distance grows (almost black).

I've tried to move the lights far away but no improvement.

Could someone explain what is happening, and how to avoid it?

Regards