#Encoding Barycentric coordinates into vertex colors

1 messages · Page 1 of 1 (latest)

native linden
# 

            // This applies the barycentric coordinates to each vertex in a triangle.
            [maxvertexcount(3)]
            void geom(triangle v2f IN[3], inout TriangleStream<g2f> triStream) {
                float edgeLengthX = length(IN[1].vertex - IN[2].vertex);
                float edgeLengthY = length(IN[0].vertex - IN[2].vertex);
                float edgeLengthZ = length(IN[0].vertex - IN[1].vertex);
                float3 modifier = float3(0.0, 0.0, 0.0);
                // We're fine using if statments it's a trivial function.
                if ((edgeLengthX > edgeLengthY) && (edgeLengthX > edgeLengthZ)) {
                    modifier = float3(1.0, 0.0, 0.0);
                }
                else if ((edgeLengthY > edgeLengthX) && (edgeLengthY > edgeLengthZ)) {
                    modifier = float3(0.0, 1.0, 0.0);
                }
                else if ((edgeLengthZ > edgeLengthX) && (edgeLengthZ > edgeLengthY)) {
                    modifier = float3(0.0, 0.0, 1.0);
                }

                g2f o;
                o.pos = UnityObjectToClipPos(IN[0].vertex);
                o.barycentric = float3(1.0, 0.0, 0.0) + modifier;
                triStream.Append(o);
                o.pos = UnityObjectToClipPos(IN[1].vertex);
                o.barycentric = float3(0.0, 1.0, 0.0) + modifier;
                triStream.Append(o);
                o.pos = UnityObjectToClipPos(IN[2].vertex);
                o.barycentric = float3(0.0, 0.0, 1.0) + modifier;
                triStream.Append(o);
            }```

This is the shader code I am attempting to move over into a C# method
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I found someone's cs online that does the triangles correctly, but I haven't had much success refactoring their code to include the additional longest side culling

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I've tried 3-4 attempts to write the whole thing from scratch (eg. iterate through each triangle, assign the vertex colors correctly, test longest, add that extra, assign vert colors)

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but none of my attempts to write it from scratch functioned as desired, and only theirs even does the triangles correctly

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here is my various attempts, ultimately none of them improved upon the original code

ornate heath
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@native linden The issue might be with shared vertices? I think with the shader it's at the point when it's dealing with the triangles so it never has to care about the value of a vertex affecting other triangles since it's already past that stage, while in vertex color you would probably need every single triangle to have unique vertices (you might be able to get around it with some very careful mesh but idk)

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Not sure though

native linden
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I almost have it working (probably not actually?) but I am running into a wall

# 
    private List<int[]> _GetSortedTriangles(int[] triangles)
    {
        List<int[]> result = new List<int[]>();
        for (int i = 0; i < triangles.Length; i += 3)
        {
            List<int> t = new List<int> { triangles[i], triangles[i + 1], triangles[i + 2] };
            t.Sort();
            result.Add(t.ToArray());
        }
        return result;
    }

        List<int[]> triangles = _GetSortedTriangles(mesh.triangles);
        triangles.Sort((int[] t1, int[] t2) =>
        {
            int i = 0;
            while (i < t1.Length && i < t2.Length)
            {
                if (t1[i] < t2[i]) return -1;
                if (t1[i] > t2[i]) return 1;
                i += 1;
            }
            if (t1.Length < t2.Length) return -1;
            if (t1.Length > t2.Length) return 1;
            return 0;
        });

        Color[] colors = new Color[vertexCount];
        for (int i = 0; i < vertexCount; i++)
            colors[i] = vertexLables[i] > 0 ? _COLORS[vertexLables[i] - 1] : _COLORS[0];```
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their code (across different methods) fucks around with sorting orders and rearranging

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I can't just GET the three world positions of the vertexes per triangle from this

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I've tried dozens of ways to get the right vertexes in the right order, but its buried under so much shit

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shit that I dont understand but is critical for the code to work to do it in this exact way

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this is the most recent cleaned up code

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they repeatedly do all kinds of shit to the vertex order

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I can't figure out how to extract from this the exact final vertex order to use the exact same order in my method to test longest edge

# 
    private Color[] ComputeLongestEdge(List<int[]> triangles, int[] vertexLables, int vertexCount)
    {
        Color[] modColors = new Color[vertexCount];

        foreach (int[] triangle in triangles)
        {
            int vertexIndex0 = triangle[0];
            int vertexIndex1 = triangle[1];
            int vertexIndex2 = triangle[2];

            //   this is the problem: HOW DO I FIND THE VORRECT VERTEXES.
            Vector3 vertex0 = vertexLables[vertexIndex0].vertex;
            Vector3 vertex1 = vertexLables[vertexIndex1].vertex;
            Vector3 vertex2 = vertexLables[vertexIndex2].vertex;

            float edgeLengthX = Vector3.Distance(vertex1, vertex2);
            float edgeLengthY = Vector3.Distance(vertex0, vertex2);
            float edgeLengthZ = Vector3.Distance(vertex0, vertex1);
            Vector3 modifier = Vector3.zero;

            if ((edgeLengthX > edgeLengthY) && (edgeLengthX > edgeLengthZ))
            {
                modifier = new Vector3(1.0f, 0.0f, 0.0f);
            }
            else if ((edgeLengthY > edgeLengthX) && (edgeLengthY > edgeLengthZ))
            {
                modifier = new Vector3(0.0f, 1.0f, 0.0f);
            }
            else if ((edgeLengthZ > edgeLengthX) && (edgeLengthZ > edgeLengthY))
            {
                modifier = new Vector3(0.0f, 0.0f, 1.0f);
            }

            Color modColor = new Color(modifier.x, modifier.y, modifier.z);

            modColors[vertexIndex0] = modColor;
            modColors[vertexIndex1] = modColor;
            modColors[vertexIndex2] = modColor;
        }
        return modColors;
    }```
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this is my method for determining the longest edge

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but it needs reference to the vector3 positions, which dont exist, because its passing all kinds of wtf sorted vertex labels around

ornate heath
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Are they sorting the vertex array or just the triangles array?

native linden
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none of this makes any sense to me, all I want from this is the world positions of each triangles vertexes, in the exact same order as this

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the reason I need it in the exact same order is because I need to add colors to each vertex, but the colors being added must line up exactly with the colors they're adding

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and every time I try to do this, it fails, because I am not adding the color to the correct vertexes bcause I cant find the order theyre using

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theirs working on the left, mine not working because I cant find the exact same order theirs uses

ornate heath
native linden
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the result is obviously completely fucked and unusuable

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but I cant figure out how to fix it because I'm just too stupid

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their code works, mine doesnt, ergo I am the problem, but knowing that doesnt help me fix my mistakes to make it work, make it go

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im starting to get distressed and go into crisis so im just going to quit again for now

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if I change the order in the longest edge code

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you can see more obviously how it keeps getting the order wrong

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I need the right order

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but the order is wrong

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and I cant figure out the order because theyve hidden it behind 20 layers of stupid bullshit

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and im just too stupid to disentangle it

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wrong order, again

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its clear the wrong colors are being assigned to the wrong vertexes

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but I cant parse the correct

native linden
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yeah im stumped

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