Shader - list of useful variables / making Snippets for GLSL-Armory within Kode Studio

Armory Engine General
,
1

When programming a vertex shader, OpenGL creates for us some useful variables** … do you know if we have a kind of list of those created for us in Armory ?
(for example somewhere to read those variables that exist for us in Armory as input/output of a vertex shader ?)

Another example with “uniform mat4 WVP” which is to be compared with “gl_ModelViewProjectionMatrix” in OpenGl … another list too somewhere ?

** exemple with gl_Vertex Position du sommet; gl_Color Couleur du sommet; gl_Normal Normale du sommet; gl_MultiTexCoord Coordonnées de l’unité de texture; gl_SecondaryColor Couleur secondaire du sommet; gl_FogCoord …

1 Like
2

They are here:


They are called link. These links look like _SomeLink

1 Like
3

@BlackGoku36 if I take the example of WVP , then effectively I find in this file
if (c.link == “_worldViewProjectionMatrix”) {
helpMat.setFrom(object.transform.worldUnpack);
helpMat.multmat(camera.V);
helpMat.multmat(camera.P);
m = helpMat; …
and then if we want to find a list of things like WVP … where can we make for this example then the link between WVP and worldViewProjectionMatrix ?
… maybe best answer could be in the make_attrib.py ** or in the make_decal.py where uniform are set like with “vert.add_uniform(‘mat4 WVP’, ‘_worldViewProjectionMatrix’)”

** ArmorySDK\armory\blender\arm\material\make_attrib.py and ArmorySDK\armory\blender\arm\material\make_decal.py

4

You will have to add constant in your material json, like:

name is your link variable name, like in your example, the constant would be:

{ 
    "name": "WVP", 
    "type": "mat4", 
    "link": "_worldViewProjectionMatrix" 
}
5

yes it’s a very interesting thing to have the possibilty to add new “uniform” to a shader, it seems that things like “WVP” are already available in Armory by default, and I was trying to set an exhaustiv list of what is already available by default, like what you can find when using OpenGL.

1 Like
6

For your info, OpenGL implements an approximation of the derivatives I would like to use for the IA/Deep Learning/Neural Network, thus using the strength of the GPU to parallelize backpropagation in the Neural Network. (to improve this IA, Python and Armory 3d/Blender ). It’s available as fragment processing functions, only available in fragment shaders.

It will be more a training algorithm being within a statistical logic, for exemple to calculate the error and propagate it back to the earlier layers, not trying to get exact calculations, in order to maximize neural network learning rapidity … rather imagine now a neural network based on optical principles (incident wave and reflection) and you will see quite well what I trying to do with Armory and the shaders… I am exiting to see the first results :checkered_flag:

1 Like
7

Another kind of things to list (or get link to in the source code), if we want to realize something with Texture2D, like retrieves texels from a texture, in OpenGL we use

vec4 texture2D(sampler2D sampler, vec2 coord)  
vec4 texture2D(sampler2D sampler, vec2 coord, float bias)

How/where to find the equivalent thing with Armory … and maybe then set a preliminary list of useful things that’s help users on shaders … and sure that the best thing would be to have it as a glslArmory.json snippets file to use for Kode Studio
(similar to the one of Lewis Lepton usable for glsl in Kode Studio https://gist.github.com/lewislepton/8b17f56baa7f1790a70284e7520f9623)

PS: in reality the texture2D is now deprecated and replaced by textureLod … for those interested look at https://www.khronos.org/registry/OpenGL/specs/gl/GLSLangSpec.1.40.pdf at the page 89
and you can read too that for the Fragment Shader Special Variables, the built-in special variables that are accessible from a fragment shader are intrinsically declared as follows:
in vec4 gl_FragCoord;
in bool gl_FrontFacing;
in float gl_ClipDistance[];
out vec4 gl_FragColor; // deprecated
out vec4 gl_FragData[gl_MaxDrawBuffers]; // deprecated
out float gl_FragDepth;

Thus according to the doc, both gl_FragColor and gl_FragData are deprecated; the preferred usage is to explicitly declare these outputs in the fragment shader using the out storage qualifier, thus doing the same in Armory … thus it could be cool to have this list of available or “have to do yourself in/out variable” list of variables for shaders and maintained thanks to @lubos when a new version of Armory is available.

8

This conversation helped me really a lot!! But the thing is that I’m pretty stuck at figuring out how the sampler2D works. My Question is “where is the texture location, where do I have to set the texture”. Im trying to set a reflection texture to an object through the fragment shader. I hope you can help me :grin:

1 Like