My Mesh (terrain) seems to be rendered backward depending on where your are looking from.

Unity Engine
,
1

Hi everyone,

I’m creating a mesh for my terrain. But when unity render it, it seems the lowest triangles (in terms of altitude) are render in front of the other.

Do you have any idea where it’s coming from ?

void GenerateTerrain()
    {
        mesh = new Mesh();
        GetComponent<MeshFilter>().mesh = mesh;
        CreateShape();
        ApplyTexture();
        UpdateMesh();
    }

    void CreateShape()
    {
        vertices = new Vector3[(width + 1) * (height + 1)];
        uvs = new Vector2[(width + 1) * (height + 1)];

        for (int i = 0, z = 0; z <= height; z++)
        {
            for (int x = 0; x <= width; x++)
            {
                float y = Mathf.Round(Mathf.Max(0, (Mathf.PerlinNoise(x * 0.05f, z * 0.05f) + Mathf.PerlinNoise(10+ x * 0.1f, 10+ z * 0.1f)) - 0.2f )*8);
                vertices[i] = new Vector3(x, y, z);
                uvs[i] = new Vector2((float)x / width, (float)z / height);
                i++;
            }
        }

        triangles = new int[width * height * 6];
        int vert = 0;
        int tris = 0;

        for (int z = 0; z < height; z++)
        {
            for (int x = 0; x < width; x++)
            {
                triangles[tris + 0] = vert + 0;
                triangles[tris + 1] = vert + width + 1;
                triangles[tris + 2] = vert + 1;
                triangles[tris + 3] = vert + 1;
                triangles[tris + 4] = vert + width + 1;
                triangles[tris + 5] = vert + width + 2;

                vert++;
                tris += 6;
            }
            vert++;
        }
    }

    void UpdateMesh()
    {
        mesh.Clear();

        mesh.vertices = vertices;
        mesh.triangles = triangles;
        mesh.uv = uvs;

        mesh.RecalculateNormals();

        Renderer renderer = GetComponent<Renderer>();
        renderer.material = terrainMaterial;
        //renderer.material.mainTexture = terrainMaterial;
       
       
    }
2

Wrong winding, would be my guess. Flip the order of your vertices in lines 34-39.

Or depth testing is off, that could also be.

1 Like
3

I tried to flip the vertices but I could’t make it work.

I never made a shader before but it seems that this one did the trick :

Shader "Custom/myFirstShader"
{
    Properties
    {
        _Color ("Color", Color) = (1,1,1,1)
        _MainTex ("Albedo (RGB)", 2D) = "white" {}
        _Glossiness ("Smoothness", Range(0,1)) = 0.5
        _Metallic ("Metallic", Range(0,1)) = 0.0
    }
    SubShader
    {
        Tags { "RenderType"="Opaque" }
        LOD 200

        ZWrite On
        ZTest LEqual

        CGPROGRAM
        // Physically based Standard lighting model, and enable shadows on all light types
        #pragma surface surf Standard fullforwardshadows

        // Use shader model 3.0 target, to get nicer looking lighting
        #pragma target 3.0

        sampler2D _MainTex;

        struct Input
        {
            float2 uv_MainTex;
        };

        half _Glossiness;
        half _Metallic;
        fixed4 _Color;

        // Add instancing support for this shader. You need to check 'Enable Instancing' on materials that use the shader.
        // See https://docs.unity3d.com/Manual/GPUInstancing.html for more information about instancing.
        // #pragma instancing_options assumeuniformscaling
        UNITY_INSTANCING_BUFFER_START(Props)
            // put more per-instance properties here
        UNITY_INSTANCING_BUFFER_END(Props)

        void surf (Input IN, inout SurfaceOutputStandard o)
        {
            // Albedo comes from a texture tinted by color
            fixed4 c = tex2D (_MainTex, IN.uv_MainTex) * _Color;
            o.Albedo = c.rgb;
            // Metallic and smoothness come from slider variables
            o.Metallic = _Metallic;
            o.Smoothness = _Glossiness;
            o.Alpha = c.a;
        }
        ENDCG
    }
    FallBack "Diffuse"
}

Thanks for the reply !

1 Like