material {
    name : Highlight,
    requires : [ position ],
    parameters : [
    {
        type : sampler2d,
        name : depth,
        precision: high
    },
    {
        type : float,
        name : scale
    },
    {
        type : float3,
        name : bbCenter
    },
    {
        type : float3,
        name : color
    }
    ],
    depthWrite : true,
    depthCulling : true,
    shadingModel : unlit,
    blending: transparent,
    culling: none,
    instanced: false,
    vertexDomain: object,
}

vertex {
    void materialVertex(inout MaterialVertexInputs material) {
        vec3 position = getPosition().xyz;
        mat4 transform = getWorldFromModelMatrix();
        vec4 bbCenter = mulMat4x4Float3(transform, materialParams.bbCenter);
          // Transform position to world space first
        vec4 worldPos = mulMat4x4Float3(transform, position);
        
        // Translate to bbCenter, scale, then translate back
        vec3 relativePos = worldPos.xyz - bbCenter.xyz;
        vec3 scaledPos = relativePos * materialParams.scale;
        material.worldPosition = vec4(bbCenter.xyz + scaledPos, worldPos.w);
    }
}
   
fragment {
    void material(inout MaterialInputs material) {
        float2 vp = uvToRenderTargetUV( getNormalizedViewportCoord().xy );
        prepareMaterial(material);           
       
        float depth = texture( materialParams_depth, vp ).r;
        float dDepthDx = dFdx(depth);
        float dDepthDy = dFdy(depth);

        vec2 texelSize = 1.0f / float2(textureSize(materialParams_depth, 0));
        
        float depth_up = texture(materialParams_depth, vp + vec2(0.0, texelSize.y)).r;
        float depth_down = texture(materialParams_depth, vp - vec2(0.0, texelSize.y)).r;
        float depth_left = texture(materialParams_depth, vp - vec2(texelSize.x, 0.0)).r;
        float depth_right = texture(materialParams_depth, vp + vec2(texelSize.x, 0.0)).r;
        
        // Check if any neighbor is background (edge detection)
        bool isEdge = (depth_up >= 1.0) || (depth_down >= 1.0) || 
                      (depth_left >= 1.0) || (depth_right >= 1.0);
        
        if (isEdge) {
            material.baseColor.rgb = materialParams.color;
            material.baseColor.a = 1.0f;
        } else {
            // Interior pixel - discard or make transparent
            discard;
        }
           
        //if(depth == 1.0f) {
        //    material.baseColor = vec4(depth, 0.0f, 0.0f, 1.0f);
        //} else { 
        //    discard;
        //}
    }
}