Have any friends with an iPad you could try it on? That is the first thing I would check. Make sure the problem is not isolated to one old iPad (iPad 2 launched in 2011).

I watched the video (OBS can record in MP4 format). Every time the cannon is pointed up, you stopped the animation before I could see where the ball will go. Does it arc downward or keep going up?

I have been doing some work on the diamond material. It is already pretty amazing but I am trying to make it more like your example. I still need to study more on nodes but I will show you what I have found so far.


I made a few changes to the Blend4Web stock diamond material example. It has two meshes, and inside and an outside. I deleted the inside mash (back up your original) then duplicated the outside mesh and left it in the same place. Then, in edit mode I flipped all the normals and made a simple reflective material. I activated Reflective in the Object tab.
Then, I made a change to the original diamond material.

The part shown here is in the gem_outside_material-core. Here is a video that shows you how to access the inner core materials using the TAB key:
https://youtu.be/DswQhRFo6OQ

But so far, the diamond in your example is still much nicer. I am going to spend some more time learning the material nodes and see if I can do better.

It looks like your velocity is hard coded in:

When you apply velocity, can you make your X, Y, and Z into variables that depend on other factors?
Since I do not know what your application does, I can only guess but you may need to feed some kind of variable value into your apply_velocity_world() function. For example your character's rotation multiplied by some strength factor.

If you use the apply_velocity() function instead, it may move in the direction you happen to be facing(Guessing here, I haven't tried this).

"What's strange is that on iphone there is no problem…." So iPhone is okay but iPad is no good? Have you tried any other iPads? How old is the iPad?

What browser are you using on iPad?

It is difficult to know the answer for you. What code are you currently using?
Physics API.

*EDIT* Oh, I see your link…
Yes, it is very beautiful.
A real diamond reflects bright lights but it also reflects dark spots. I will see what I can figure out. No guarantees though

Here is an effect using the Fresnel node as input for a Mix node. Basically it mixes a UV map with black. The Fresnel node tells it which material to show at which angle. These are Cycles nodes. Blender file attached.

Hi zhangchuanjia,
Do you want more reflective metal or a different diamond effect?