Hi,
I'm working on new asset importer (https://github.com/recp/assetkit) based on COLLADA specs, the question is not about COLLADA directly
also I'm working on a new renderer to render (https://github.com/recp/libgk) imported document.
In the future I'll spend more time on this renderer of course, currently rendering imported (implemented parts) is enough for me
assetkit imports COLLADA document (it will support glTF too),
importing scene, geometries, effects/materials, 2d textures and rendering them seems working
My actual confusion is about shaders. COLLADA has COMMON profile and GLSL... profiles,
GLSL profile provides shaders for effects so I don't need to wory about them just compile, link, group them before render
The problem occours in COMMON profile because I need to write shaders,
Actually I wrote them for basic matrials and another version for 2d texture
I would like to create multiple program but I am not sure how to split this this shader into smaller ones,
Basic material version (only colors): https://github.com/recp/libgk/blob/master/src/default/shader/gk_default.frag
Texture version: https://gist.github.com/recp/b0368c74c35d9d6912f524624bfbf5a3
I used subroutines to bind materials, actually I liked it,
In scene graph every node can have different program, and it switches between them if parentNode->program != node->program
(I'll do scene graph optimizations e.g. view frustum culling, grouping shaders... later)
I'm going to implement transparency but I'm considering to create separate shaders,
because default shader is going to be branching hell
I can't generate shader for every node because I don't know how many node can be exist, there is no limit.
I don't know how to write a good uber-shader for different cases:
Here material struct:
struct Material {
ColorOrTexture emission;
ColorOrTexture ambient;
ColorOrTexture specular;
ColorOrTexture reflective;
ColorOrTexture transparent;
ColorOrTexture diffuse;
float shininess;
float reflectivEyety;
float transparency;
float indexOfRefraction;
};
ColorOrTexture could be color or 2d texture, if there would be single colorOrTex then I could split into two programs,
Also I'm going to implement transparency, I am not sure how many program that I needed
I'm considering to maintain a few default shaders for COMMON profile,
1-no-texture, 2-one of colorOrTexture contains texture, 3-........
Any advices in general or about how to optimize/split (if I need) these shaders which I provied as link?
What do you think the shaders I wrote, I would like to write them without branching if posible,
I hope I don't need to write 50+ or 100+ shaders, and 100+ default programs
PS: These default shaders should render any document, they are not specific, they are general purpose...
I'm compiling and linking default shaders when app launched
Thanks
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