First square of the makeroads mesh has broken UVs (for both the road and edge)

Question

First square of the makeroads mesh has broken UVs (for both the road and edge)

Opened this issue 2 years ago · 4 comments

This is caused by the prevPosition, prevLeft and prevRight variables being set to Vector3.zero in the first iteration, which causes problems in most cases.
The result is not so pretty:

Answer 1 · 2023-02-16T11:47:27.000Z

I tried doing a pull request but don't have permission.

The key piece of code is this:


            if (first && PointProvider.Count > 1)
            {
                // creating a virtual previous position by looking ahead, then pretending
                // that was the previous position but inverse
                prevPosition = position + (PointProvider[i + 1].Position - position);
            }
            
			Vector3 leftFlatLateral = Quaternion.Euler( 0, heading - 90, 0) * Vector3.forward * HalfWidth;
			Vector3 rightFlatLateral = Quaternion.Euler( 0, heading + 90, 0) * Vector3.forward * HalfWidth;;
            
            if (first && PointProvider.Count > 1)
            {
                // creating a virtual left/right previous position with the same logic
                prevLeft = prevPosition + leftFlatLateral + Vector3.up * Config.Height;
                prevRight = prevPosition + rightFlatLateral + Vector3.up * Config.Height;
            }

Changed the loop to be an iterating for loop. In general, the idea is to just assume the non-existent previous position to the very first one is the second position, but inversed so to speak.

Answer 2 · 2023-02-16T18:38:22.000Z

Hey, cool, I went to try and integrate the above but I think you changed some more stuff than I realized...

It appears you may have changed PointProvider into a List so that it has a .Count perhaps??

Could you just drop the entire function in here and I'll drop it into my repo and see what happens?

If it works I'd be happy to integrate and give you credit in the commit.

Answer 3 · 2023-02-16T18:42:33.000Z

Yeah I made it into a list so that I could access the index ahead.

/*
	The following license supersedes all notices in the source code.

	Copyright (c) 2019 Kurt Dekker/PLBM Games All rights reserved.

	http://www.twitter.com/kurtdekker

	Redistribution and use in source and binary forms, with or without
	modification, are permitted provided that the following conditions are
	met:

	Redistributions of source code must retain the above copyright notice,
	this list of conditions and the following disclaimer.

	Redistributions in binary form must reproduce the above copyright
	notice, this list of conditions and the following disclaimer in the
	documentation and/or other materials provided with the distribution.

	Neither the name of the Kurt Dekker/PLBM Games nor the names of its
	contributors may be used to endorse or promote products derived from
	this software without specific prior written permission.

	THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
	IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
	TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
	PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
	HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
	SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
	TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
	PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
	LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
	NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
	SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/

using System.Collections;
using System.Collections.Generic;
using System.Linq;
using UnityEngine;

public class MakeRoads
{
	// How high to lift up so we can raycast down, and how far to cast down.
	// If your point provider gives results that are close to the surface,
	// these can be made smaller.
	const float CastPullUp = 25.0f;
	const float CastRayDown = 50.0f;

    public static GameObject Create( RoadConfiguration Config, List<PositionAndHeading> PointProvider)
    {
		GameObject go = new GameObject ("MakeRoad1.Create();");

		MeshFilter mf = go.AddComponent<MeshFilter> ();
		Mesh mesh = new Mesh();

		List<Vector3> verts = new List<Vector3> ();
		List<int> tris0 = new List<int> ();
		List<int> tris1 = new List<int> ();
		List<Vector2> uvs = new List<Vector2> ();

		bool first = true;

		float HalfWidth = Config.Width / 2;

		Vector3 prevLeft = Vector3.zero;
		Vector3 prevRight = Vector3.zero;

		int prevNTopLeft = -1;

		int prevNEdgeLeft = -1;
		int prevNEdgeRight = -1;

		Vector3 prevPosition = Vector3.zero;

		float u = 0.0f;

        for (int i = 0; i < PointProvider.Count; i++)
        {
            var pt = PointProvider[i];
            
			Vector3 position = pt.Position;
			float heading = pt.Heading;
            
            if (first && PointProvider.Count > 1)
            {
                // creating a virtual previous position by looking ahead, then pretending
                // that was the previous position but inverse
                prevPosition = position + (PointProvider[i + 1].Position - position);
            }
            
			Vector3 leftFlatLateral = Quaternion.Euler( 0, heading - 90, 0) * Vector3.forward * HalfWidth;
			Vector3 rightFlatLateral = Quaternion.Euler( 0, heading + 90, 0) * Vector3.forward * HalfWidth;;
            
            if (first && PointProvider.Count > 1)
            {
                // creating a virtual left/right previous position with the same logic
                prevLeft = prevPosition + leftFlatLateral + Vector3.up * Config.Height;
                prevRight = prevPosition + rightFlatLateral + Vector3.up * Config.Height;
            }


			Vector3 left = position + leftFlatLateral;
			Vector3 right = position + rightFlatLateral;

			Vector3 leftEdgeBottom = left;
			Vector3 rightEdgeBottom = right;

			if (Config.FollowUnderlyingSurface)
			{
				Ray rayLeft = new Ray( left + Vector3.up * CastPullUp, Vector3.down);
				Ray rayRight = new Ray( right + Vector3.up * CastPullUp, Vector3.down);
				RaycastHit rchLeft, rchRight;
				bool hitLeft = Physics.Raycast( rayLeft, out rchLeft, CastRayDown);
				bool hitRight = Physics.Raycast( rayRight, out rchRight, CastRayDown);

				if (hitLeft && hitRight)
				{
					left = rchLeft.point;
					right = rchRight.point;

					if (!Config.TiltWithUnderlyingSurface)
					{
						float highestPoint = Mathf.Max( left.y, right.y);

						float originalHighestPoint = highestPoint;

						// To make sure we don't have ground poking through, we can
						// check spanwise going across, and adjust upwards more.
						for (int spanWiseCheckNo = 0; spanWiseCheckNo < Config.ExtraSpanWiseHeightSamples; spanWiseCheckNo++)
						{
							int n = spanWiseCheckNo + 1;

							float fraction = (float)n / (Config.ExtraSpanWiseHeightSamples + 2);

							Ray rayCenter = new Ray( Vector3.Lerp( left, right, fraction) + Vector3.up * CastPullUp, Vector3.down);
							RaycastHit rch;
							if (Physics.Raycast( rayCenter, out rch, CastRayDown))
							{
								if (rch.point.y > highestPoint)
								{
									highestPoint = rch.point.y;
								}
							}
						}

						left.y += highestPoint - originalHighestPoint;
						right.y += highestPoint - originalHighestPoint;
					}

					// keep roadway flat?
					if (!Config.TiltWithUnderlyingSurface)
					{
						if (left.y > right.y)
						{
							right.y = left.y;
						}
						if (right.y > left.y)
						{
							left.y = right.y;
						}
					}
				}
			}

			left += Vector3.up * Config.Height;
			right += Vector3.up * Config.Height;
            
			int nTopLeft = verts.Count;

			verts.Add( left);
			verts.Add( right);

			uvs.Add( new Vector2( u, 0));
			uvs.Add( new Vector2( u, 1));

			if (!first)
			{
				tris0.Add( prevNTopLeft);
				tris0.Add( nTopLeft);
				tris0.Add( prevNTopLeft + 1);
				
				tris0.Add( nTopLeft);
				tris0.Add( nTopLeft + 1);
				tris0.Add( prevNTopLeft + 1);
			}

			// we need this early so we can scale the edge UVs properly and keep them nearly square
			float uAdvance = Vector3.Distance( position, prevPosition) / Config.Width;

			if (Config.MakeEdges)
			{
				leftEdgeBottom += Vector3.down * Config.EdgeExtraHeight;
				rightEdgeBottom += Vector3.down * Config.EdgeExtraHeight;

				float leftRaise = left.y - leftEdgeBottom.y;
				float rightRaise = right.y - rightEdgeBottom.y;

				float EdgeTangentOutwards = Mathf.Tan( (90 - Config.EdgeAngle) * Mathf.Deg2Rad);
				float leftOutward = leftRaise * EdgeTangentOutwards;
				float rightOutward = rightRaise * EdgeTangentOutwards;

				leftEdgeBottom += leftFlatLateral.normalized * leftOutward;
				rightEdgeBottom += rightFlatLateral.normalized * rightOutward;

				{
					int nEdgeLeft = verts.Count;

					verts.Add( leftEdgeBottom);
					verts.Add( left);
                    
					float v = uAdvance * Vector3.Distance( leftEdgeBottom, left) / Vector3.Distance( prevLeft, left);

					uvs.Add( new Vector2( u, -v));
					uvs.Add( new Vector2( u, 0));

					if (!first)
					{
						tris1.Add( prevNEdgeLeft + 1);
						tris1.Add( prevNEdgeLeft);
						tris1.Add( nEdgeLeft);

						tris1.Add( prevNEdgeLeft + 1);
						tris1.Add( nEdgeLeft);
						tris1.Add( nEdgeLeft + 1);
					}

					prevNEdgeLeft = nEdgeLeft;
				}

				{
					int nEdgeRight = verts.Count;

					verts.Add( right);
					verts.Add( rightEdgeBottom);

					float v = uAdvance * Vector3.Distance( rightEdgeBottom, right) / Vector3.Distance( prevRight, right);

					uvs.Add( new Vector2( -u, 0));
					uvs.Add( new Vector2( -u, -v));

					if (!first)
					{
						tris1.Add( prevNEdgeRight + 1);
						tris1.Add( prevNEdgeRight);
						tris1.Add( nEdgeRight);

						tris1.Add( prevNEdgeRight + 1);
						tris1.Add( nEdgeRight);
						tris1.Add( nEdgeRight + 1);
					}

					prevNEdgeRight = nEdgeRight;
				}
			}

			u -= uAdvance;

			prevPosition = position;

			prevLeft = left;
			prevRight = right;

			first = false;
			prevNTopLeft = nTopLeft;
		}

		mesh.subMeshCount = 2;

		mesh.vertices = verts.ToArray ();
		mesh.uv = uvs.ToArray ();

		mesh.SetTriangles( tris0.ToArray (), 0);
		mesh.SetTriangles( tris1.ToArray (), 1);

		mesh.RecalculateBounds ();
		mesh.RecalculateNormals ();

		mf.mesh = mesh;

		var mr = go.AddComponent<MeshRenderer> ();
		mr.materials = new[] {
			Config.RoadSurfaceMaterial,
			Config.RoadEdgeMaterial,
		};

		return go;
	}
}

Thats the whole makeroads

/*
	The following license supersedes all notices in the source code.

	Copyright (c) 2022 Kurt Dekker/PLBM Games All rights reserved.

	http://www.twitter.com/kurtdekker

	Redistribution and use in source and binary forms, with or without
	modification, are permitted provided that the following conditions are
	met:

	Redistributions of source code must retain the above copyright notice,
	this list of conditions and the following disclaimer.

	Redistributions in binary form must reproduce the above copyright
	notice, this list of conditions and the following disclaimer in the
	documentation and/or other materials provided with the distribution.

	Neither the name of the Kurt Dekker/PLBM Games nor the names of its
	contributors may be used to endorse or promote products derived from
	this software without specific prior written permission.

	THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
	IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
	TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
	PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
	HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
	SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
	TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
	PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
	LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
	NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
	SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/

using System.Collections.Generic;
using System.Linq;
using UnityEngine;

public class MakeRoadsFromChildTransforms : MonoBehaviour
{
    public RoadConfiguration Config;

    public bool shouldRegenerateEveryUpdate;
    public float maxLinearVertexSpacing;
    public bool Looping;

    // maxLinearVertexSpacing: max allowable spacing in the direction of road travel
    IEnumerable<PositionAndHeading> PointFeeder(float maxLinearVertexSpacing, bool looping = false)
    {
        int count = transform.childCount;
        if (looping)
        {
            count++;
        }

        var children = new Transform[count];

        // pick up the transforms, including looping the last one
        // if we added the +1 to count above.
        for (int i = 0; i < count; i++)
        {
            int childNo = i % transform.childCount;
            children[i] = transform.GetChild(childNo);
        }

        int point = 0;

        // walk all the points in the roadway
        while (point < children.Length)
        {
            if (point > 0)
            {
                var t1 = children[point - 1];
                var t2 = children[point];

                float distance = Vector3.Distance(t2.position, t1.position);

                float heading1 = t1.rotation.eulerAngles.z;
                float heading2 = t2.rotation.eulerAngles.z;

                // Compute steps required so we don't exceed maxLinearVertexSpacing
                //
                // TODO: one day this should be dynamic according to how sharply the local
                // terrain slope is changing, eg, second derivative of dHeight / dDistance.
                //
                // This woud allow reduced geometry overall while maintaing ground
                // contour fidelity without impinging on the ground.
                int steps = 1 + (int) (distance / maxLinearVertexSpacing);

                int limit = steps;
                if (point == children.Length - 1) limit++;

                for (int i = 0; i < limit; i++)
                {
                    float fraction = (float) i / steps;

                    Vector3 position = Vector3.Lerp(t1.position, t2.position, fraction);
                    float heading = Mathf.LerpAngle(heading1, heading2, fraction);

                    yield return new PositionAndHeading(position, heading);
                }
            }

            point++;
        }
    }

    private GameObject previous;

    private void Start()
    {
        List<PositionAndHeading> PointProvider = PointFeeder(maxLinearVertexSpacing: 2.0f, looping: Looping).ToList();
        previous = MakeRoads.Create(Config, PointProvider);
    }

    void Update()
    {
        if (shouldRegenerateEveryUpdate)
        {
            List<PositionAndHeading> PointProvider =
                PointFeeder(maxLinearVertexSpacing, looping: Looping).ToList();
            if (previous != null)
            {
                Destroy(previous);
            }

            previous = MakeRoads.Create(Config, PointProvider);
        }
    }
}

Thats the whole make roads from transform code.

Answer 4 · 2023-02-16T18:43:30.000Z

I also added some possibilities to choose the maxLinearVertexSpacing and allowing to regenerate continuously in update. just some small debug stuff.
Overall the code might not be super clean, can't remember if I left some stuff. Feel free to take only the relevant parts.