[GEM-dev] [ pd-gem-Bugs-1883795 ] shader IDs break when converted to float

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Bugs item #1883795, was opened at 2008-01-31 18:47
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Category: None
Group: None
Status: Open
Resolution: None
Priority: 5
Private: No
Submitted By: ClaudiusMaximus (claudiusmaximus)
Assigned to: Nobody/Anonymous (nobody)
Summary: shader IDs break when converted to float

Initial Comment:
The problem:

Shaders don't work, linking fails.

The reason:

Mathieu Bouchard wrote:
> On Mon, 7 Jan 2008, cyrille henry wrote:
>> i remember a problem i had once with long shader id. the Id was to 
>> long, pd converted it to exponentian notation (1234e+7), so some 
>> precision was lost.
> 
> Until the ID gets over 16777216, it is ok

I just did a quick test in C++, seems my shader ID's are indeed too big for 32bit float.

int|float: 16777216
Shader ID: 536870913
Shader ID: 2147483649


Possible solutions:

1. use symbols instead of floats
2. use small floats with an internal map from id -> real id
3. split shader ids into as many floats as necessary


I prefer solution 2, as it doesn't change the externally visible interface to the Pd user.


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