Quite simple. OpenGFX is GPL'ed so we expect you to follow everything outlined by the GPL (version 2) license. We cannot require you to do more than that.regi wrote:I would be happy if you clearly expose me what are your expectations.
In principle that means that your PHP game needs to be GPL as well. There are some constructions possible where you seperate the graphics from the acual game which allow you to license the game files differently while keeping the OpenGFX files GPL'ed. Those constructions are rather tricky though and I wouldn't recommend them unless you know exactly what you're doing...
Apart from that a link to OpenGFX and OpenTTD on your games website would be nice
I don't think we can dual license OpenGFX both GPL and some CC license. There are a lot of people involved who'd need to agree to that; some of which inactive and possibly unreachable. If you have any more questions, don't hesitate!