seperating shaders and materials, what do you do?,
GDNet+ - Reputation: 6223
Posted 07 November 2012 - 09:27 AM
firstly, what i have:
I have a renderobject class, this class stores the type of way to draw an object(triangle, lines, etc), and the vertices that make up the object, as well as a single material which is used to draw the object.
I have a mesh class that can contain multiple renderobjects, and draw's them.
I have a material class, this class can store a color value, and upto 4 textures in 4 "slots", it also can store the shader which should be used to draw the object with this material.
then i have my shader class, which has three callbacks, a set callback, used when a material in the video driver is changed, or the shader is first set, this initialized the shader uniforms, and setups the shader to recieve renderobjects.. a render callback, which takes a renderobject, and appropiatly draws it. and finally, an disable callback, for when the shader is removed from being active.
now then, when i load a model(and let's say it's loaded from a simply .obj file, so it only contains basic material/vertice information). lets say it has a uv texture, and a color for it's material, basically I have to setup the model with a shader, and I have to do this with every object loaded, it can get tedious, and i don't really like the overall design, this method also limits me pretty severly with what i can do with shaders, and it also means that everything has to be a renderobject to be submitted to the shader for drawing.
in short, this system is a pretty big burden on how much i can do with building games, and i'd like a better idea for a simple, and easier implementable system.
Members - Reputation: 841
Posted 07 November 2012 - 10:07 AM
- Vertexbuffer, Indexbuffer - contain all vertices and indices of certain geometry. VB has flexible system of vertex attributes - i.e. there are slots for "normal" attributes like 3D coordinates, normals and UV, but one can add as many extra attributes as needed.
- Mesh - binds together VB, IB and Material(s), also has 3D transformation and bbox assigned to it. Mesh has list of fragments, each fragment can be rendered with different material. ::display() method of mesh submits a renderdata to list for later processing (renderdata has link to VB, IB, transformation and material).
Multiple meshes may share materials and vertex/index buffers.
- Shader, Program - these are just frontends of OpenGL shader and program objects. ::bind() method of program sets it as active OpneGL program but does not set up uniforms - the latter is left for material.
- Material - the heavy duty class. Material has one or more programs (i.e. shader frontends) (depending on render pass, the same mesh fragment - having same material - may be rendered with different shader). In ::render() method of material the renderdata is parsed, uniforms set up, relevant attributes of associated VB bound and glDrawElements... called.
Multiple materials may share programs.
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Khayyam 3D - a freeware poser and scene builder application: http://khayyam.kaplinski.com/