[Cuis-dev] The Cuis book and rotation in chapter 7 + typo

[Juan Vuletich]

On 2/27/2023 5:33 PM, Hilaire Fernandes via Cuis-dev wrote:
> Le 26/02/2023 à 11:07, Barry Perryman via Cuis-dev a écrit :
>>
>> It doesn’t look like the information on morph rotation is correct any 
>> longer - exercises 7.3 and 7.4 and the associated text around that on 
>> page 115.
>
> I see.
>
> I have not checked it yet, I remember discussing with Juan about the 
> possibility to alter the center of rotation.
>
> Juan will it not be better to keep it backward compatible: if not 
> specified the center of rotation will be (0;0)?
>

I felt that for casual playing with Morphs with (for instance) the 
halos, it was more intuitive to just rotate around the center. Of 
course, any morph is free to redefine #rotationCenter as appropriate.

Thanks,

>>
>> When I rotate any of the example morphs from this chapter - the 
>> line/cross, triangle and the rectangle - they all rotate about the 
>> centre and not the  0 at 0 point; this includes the triangle, which is 
>> fun to see.
>>
>> I’ve had a little dig through the morph handle code - just enough to 
>> be potentially wrong - and it seems that if a rotation centre isn’t 
>> specified then one is computed to be the middle of the morph bounds.
>>
>> Finally a really tiny typo - in section 6.2.2, first sentence of 
>> third paragraph it reads:
>>
>> So far in our model, a torpedo is not subjected to the /central 
>> start//gravity pull/ nor its engine acceleration
>>
>> I think that the central start should be central star’s.
>
> Yep.
>
> Thanks
>
> -- 
> GNU Dr. Geo
> http://drgeo.eu
> http://blog.drgeo.eu


-- 
Juan Vuletich
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