Shader node "duplicate variable name"

aegroto · April 28, 2018, 10:08pm

TerrainFactor.j3sn

   ShaderNodeDefinitions {
         ShaderNodeDefinition TerrainFactor {
            Type: Fragment
            Shader GLSL100: MatDefs/PBRTerrain/ShaderNodes/TerrainFactor.frag

            Documentation { 
                Terrain Fragment shader node

                @input HillMinHeight HillMinHeight
                @input HillMaxHeight HillMaxHeight

                @input MountainMinHeight MountainMinHeight
            }

            Input {
                vec3 vVertex;

                float PrevLayerMaxHeight;

                float LayerMinHeight;
                float LayerMaxHeight;

                float NextLayerMinHeight;
            }

            Output {
                float factor;
            }
        }
    }

TerrainFactor.frag:

void main(){
    factor = 1.0
    if(vVertex.y >= NextLayerMinHeight) {
        factor -= ((vVertex.y - NextLayerMinHeight) / (LayerMaxHeight - NextLayerMinHeight));
    }
}

If i try to compile this shader I get this error:

Caused by: com.jme3.material.plugins.MatParseException: Error On line 21 : float LayerMaxHeight
->Duplicate variable name LayerMaxHeight

What does it mean? I don’t have any other variable with the same name in this node or in the entire shader either.

pspeed · April 28, 2018, 10:39pm

I think we’d probably like to be sure.

Didn’t it also dump the shader source?

nehon · April 29, 2018, 7:02am

Yeah the source of the terrainFactor.frag could help too.

aegroto · April 29, 2018, 8:24am

Why should variables from different shader nodes have to be named differently? They could still be dereferenced by theirs node name.

No, it doesn’t dump shader source.

However, I added TerrainFactor.frag source code.

nehon · April 29, 2018, 9:38am

the error seems to occur when parsing the j3md

nehon · April 29, 2018, 9:55am

btw there is a missing semi colon after factor = 1.0
It’s probably not the issue, but it will eventually becomes one.

Could you also provide the j3md? or a test case

nehon · April 29, 2018, 10:03am

ho ok… I found the issue… it’s here

github.com

jMonkeyEngine/jmonkeyengine/blob/master/jme3-core/src/plugins/java/com/jme3/material/plugins/ShaderNodeLoaderDelegate.java#L238


    if (varName.contains("[")) {
        //we have an array
        String[] arr = splitVar[1].split("\\[");
        varName = arr[0].trim();
        multiplicity = arr[1].replaceAll("\\]", "").trim();
    }

    if (varNames.contains(varName)) {
        throw new MatParseException("Duplicate variable name " + varName, statement);
    }

    varNames.add(varName);

    final ShaderNodeVariable variable = new ShaderNodeVariable(varType, "", varName, multiplicity);
    variable.setDefaultValue(defaultValue);

    return variable;
}

/**
 * reads the VertexShaderNodes{} block

Maybe not the best way to check for already existing variables. here contains returns true for “LayerMaxHeight” because there is a “PrevLayerMaxHeight” variable defined…
That’s dumb, I’m gonna fix it.
Meanwhile you can declare “PrevLayerMaxHeight” after “LayerMaxHeight” and it should work.

aegroto · April 29, 2018, 10:24am

I may fix it if you want, I’d like to contribute to the Shader Nodes system and I have other ideas I’d like to implement on it.

EDIT: I made a pull request about this issue.