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arno

FSDSv2 and transparencies/ Object vs. Scasm/API files

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Hi Folks,I am fairly new at using FSDSv2. I have an antenna tower I have been fighting with as far as transparent textures goes. I found that to make the inside and outside of the tower, I have to make two objects of the same shape, but the inside one has to be just a bit smaller than the outside one. Also, the polygons need to be flipped on the inside object in regards to the outside object.I have applied all the different formats for transparent textures, but none of the inside tower textures show through the outside tower textures. Also, this only happens when I assemble the Scasm/Api file for the object. When I assemble the Object file directly to the scenery folder the textures work fine, but as an API macro, the textures on the outside of the tower are transparent in relation to the ground texture, but the inside tower textures don't show through the outside tower textures.I would appreciate some help on this problem. It usually is something simple that I have overlooked. Thanks in advance.Take care.John Williams

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Hi John,Sounds like a drawing order problem to me. Try to make sure that the inside polygons are drawn before the outside (so they must be in the source before the outside). You can achieve this by selecting the "Uses transparant textures" option for the outside polygons.

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Thanks Arno, that was the problem. I knew it was something simple, and I did overlook the drawing order, geez. I couldn't achieve the proper order by just using the "uses transparent textures" alone. I did go into the source code and actually change the order of all the inside and outside routines for the Call32s and the Transform_Mat, and that worked.I don't post here alot, but I do visit quite often, and I always learn something from my visits. Thanks again arno.Take care.John Williams

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Hi guysYes, it seems that drawing order is very important with transparency because of the way that DirectX works. As I understand it, transparency in a new triangle being drawn is done by 'adding' the new transparent or semi-transparent image to what has already been drawn in the frame buffer. So it is important that parts visible through a transparent part have been drawn BEFORE. At the macro level this should be handled by the z-sorting / 'painter's algorithm', but within the same object it is probably important to get the drawing order of the triangles correct i.e. always draw transparent surfaces last, and draw internal surfaces before external ones.There is increasing evidence that the z-sorting does not work correctly in these circumstances, or may not even be applied to triangles within the same draw list at all, despite the suggestion by MS that z-sorting is done at the triangle level ?RegardsGerrish

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Hi Gerrish,Thanks for the supporting information. I have also found that the z-sorting is a bit tricky in my experiments with the graphic programs available. The drawing order seems to be the most important operation when transparencies are involved. I knew this, but in my haste to overcome a problem, I created myself, I forgot to check the drawing order.Take care. John Williams

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