TomCrypto
commented
8 years ago Hi there, thanks!
It's been a while since I looked into this source code, but basically, the file format is binary and record-based. I don't have a formal specification, but here is the gist of it:
1) It starts with a RenderParams structure (see renderer.hpp) which defines the width, height in pixels and number of samples for the scene.
2) Then, follow any number of Entities, which consist of an EntityHeader (see renderer.cpp) with an EntityType (the general type of the object, e.g. a light, a material, a primitive) and a subtype (e.g. if it's a primitive, it could be a triangle or sphere).
3) The data in the file after the header depends on the entity type and subtype, and can be understood by following the source code. For instance, if the entity is a primitive, we call GetPrimitive with the subtype as a parameter, this will read two 32-bit integers from the file after the header (see primitive.cpp) which are the primitive's material and/or light. Then, if the subtype is Triangle, then the triangle.cpp file shows that the data after that consists of three vertices, in X-Y-Z float format (the reason the Primitive constructor is called first is because Triangle inherits from Primitive).
(the exception is for the ColorSystem type, which has no data after the header; the color system is directly determined by the subtype field in the header, see line 71 of renderer.cpp)
Records are appended into an array for each type (so one array for lights, one array for materials, one array for primitives, etc...) as they are read in, and the different types of entities refer to one another via hardcoded indices inside these arrays; these indices were all calculated and set when the scene was constructed.
The format itself is pretty poorly designed all things considered, although it did get the job done. In my opinion it was a mistake and I should have used an existing text-based format, like I did in my later renderers. But at least it isn't too hard to decipher.
Feel free to ask if you have any further questions :) it should not be very hard to implement a standalone parser for these scene files, I'd say the difficulty would be about the same as implementing a basic OBJ loader.
karkinos-krakatoa
Your Renderer is great ! Is making me learn a lot.Please can we have at least one raw description of a scene file ? A readable one(with the actual text) .I would really like to know the exact format of the Scene Items and their respective values.It will really help me decipher a problem.You can use the Lucy/Ajax Scene for example.Thank You ! :)