Comments on: New Year’s Teapot

By: Brief Look at the Interactive Rendering Course – MOOC Feeds from around the World

Fri, 01 Feb 2013 23:35:34 +0000

[...] a quick taste of the technology and a program in the course. This post originally posted on the Real-Time Rendering blog about the Interactive Rendering class. New Year’s TeapotI’ve been beavering away on my part of [...]

By: Eric

Eric — Fri, 25 Jan 2013 18:47:26 +0000

And I burnt the morning on fixing this orbit controller - three.js doesn't have one I like, so I extended OrbitControls.js to make a better one. Done! Try the new version and see if you like it. I'll check it into three.js once I feel great about it (needs a few weeks of iteration). Unfortunately, this new control does not work on mobile devices (yet), so it's not the default. It's here.

By: Eric

Eric — Fri, 25 Jan 2013 14:00:38 +0000

That’s a very fair comment on the trackball, and I’ve debated this myself: full flexibility, or up always up and gimbal lock when you try to look down on the model? “My” trackball is simply the canned trackball that a bunch of three.js demos use, called “TrackballControls.js”. Hmmm, thinking about it, maybe the answer is yet another thing to toggle: trackball vs. what I call “turntable”. Anyway, thanks for the feedback, it’s definitely good to get this sensible for the course itself.

By: jonogibbs

jonogibbs — Fri, 25 Jan 2013 08:11:08 +0000

Ok, super cool, but a short rant. I’m not sure if this is your fault or three.js’s fault, but the madness must stop. For camera movement you have the typical “virtual trackball”. But most implementations of this – and yours! – suffer a terrible problem. The up in the scene drifts all over the place making navigation super hard. Here’s the test: drag the mouse in small circles on the screen. If the teapot slowly turns upside down, you have the problem. Even though the user is bringing the mouse right back to where it started, the teapot is not in the same position. And really, how often when navigating a scene do you want to see it upside down?

The better way to do this is also simpler! No “virtual trackball”. Just map the mouse movement in screen X to a rotation around the “up” axis (be it Y or Z). Map the mouse movement in screen Y to a rotation tipping the object forward and backwards towards and away from the viewer. the X rotations spins all the way around the object 360 degrees, over and over as you drag in X. But the Y rotations never go more than +/ 90 degrees. You can look down from the top, from the side, or up from the bottom. But never back down the back upside down.

You can add extra controls to spin about the axis pointing out of the screen in cases where you really want to go upside down.

So, I know this is not the point of the demo, but I just had to rant and doing so here might do some good.

DEATH TO THE VIRTUAL TRACKBALL!

By: Real-Time Rendering · Wow, that worked?

Real-Time Rendering · Wow, that worked? — Fri, 25 Jan 2013 02:46:55 +0000

[...] The demo I made for the Interactive Rendering course actually runs on my phone (Samsung Galaxy S3). My course assistant found it runs on her HTC phone, too. Passing on a screen shot. Good luck hitting the up-arrow on my phone, like the documentation on the screen wants me to do… (I should fix that) It runs only on Firefox, from what I can tell. [...]

By: mortennobel

mortennobel — Wed, 02 Jan 2013 09:57:32 +0000

… Problem is limited to Chrome. In Safari and Firefox it works fine

By: mortennobel

mortennobel — Wed, 02 Jan 2013 09:47:00 +0000

Nice, but there is a problem on MacBook Pro Retina; Only the upper 1/4th of the page is rendered