public static Bounds GenerateParametricMesh(Mesh mesh, float radius, float falloffDistance, float angle, int sides)
{
var angleOffset = Mathf.PI / 2.0f + Mathf.Deg2Rad * angle;
if (sides < 3)
{
radius = 0.70710678118654752440084436210485f * radius;
sides = 4;
}
if (sides == 4)
{
angleOffset = Mathf.PI / 4.0f + Mathf.Deg2Rad * angle;
}
var vertexCount = 1 + 2 * sides;
var indexCount = 3 * 3 * sides;
var vertices = new NativeArray <ParametricLightMeshVertex>(vertexCount, Allocator.Temp);
var triangles = new NativeArray <ushort>(indexCount, Allocator.Temp);
var centerIndex = (ushort)(2 * sides);
// Color will contain r,g = x,y extrusion direction, a = alpha. b is unused at the moment. The inner shape should not be extruded
var color = new Color(0, 0, 0, 1);
vertices[centerIndex] = new ParametricLightMeshVertex
{
position = float3.zero,
color = color
};
var radiansPerSide = 2 * Mathf.PI / sides;
var min = new float3(float.MaxValue, float.MaxValue, 0);
var max = new float3(float.MinValue, float.MinValue, 0);
for (var i = 0; i < sides; i++)
{
var endAngle = (i + 1) * radiansPerSide;
var extrudeDir = new float3(math.cos(endAngle + angleOffset), math.sin(endAngle + angleOffset), 0);
var endPoint = radius * extrudeDir;
var vertexIndex = (2 * i + 2) % (2 * sides);
vertices[vertexIndex] = new ParametricLightMeshVertex
{
position = endPoint,
color = new Color(extrudeDir.x, extrudeDir.y, 0, 0)
};
vertices[vertexIndex + 1] = new ParametricLightMeshVertex
{
position = endPoint,
color = color
};
// Triangle 1 (Tip)
var triangleIndex = 9 * i;
triangles[triangleIndex] = (ushort)(vertexIndex + 1);
triangles[triangleIndex + 1] = (ushort)(2 * i + 1);
triangles[triangleIndex + 2] = centerIndex;
// Triangle 2 (Upper Top Left)
triangles[triangleIndex + 3] = (ushort)(vertexIndex);
triangles[triangleIndex + 4] = (ushort)(2 * i);
triangles[triangleIndex + 5] = (ushort)(2 * i + 1);
// Triangle 2 (Bottom Top Left)
triangles[triangleIndex + 6] = (ushort)(vertexIndex + 1);
triangles[triangleIndex + 7] = (ushort)(vertexIndex);
triangles[triangleIndex + 8] = (ushort)(2 * i + 1);
min = math.min(min, endPoint + extrudeDir * falloffDistance);
max = math.max(max, endPoint + extrudeDir * falloffDistance);
}
mesh.SetVertexBufferParams(vertexCount, ParametricLightMeshVertex.VertexLayout);
mesh.SetVertexBufferData(vertices, 0, 0, vertexCount);
mesh.SetIndices(triangles, MeshTopology.Triangles, 0, false);
return(new Bounds
{
min = min,
max = max
});
}
public static Bounds GenerateShapeMesh(Mesh mesh, Vector3[] shapePath, float falloffDistance)
{
var meshInteriorColor = new Color(0, 0, 0, 1);
var min = new float3(float.MaxValue, float.MaxValue, 0);
var max = new float3(float.MinValue, float.MinValue, 0);
// Create interior geometry
var pointCount = shapePath.Length;
var inputs = new ContourVertex[pointCount];
for (var i = 0; i < pointCount; ++i)
{
inputs[i] = new ContourVertex()
{
Position = new Vec3()
{
X = shapePath[i].x, Y = shapePath[i].y
}
}
}
;
var tessI = new Tess();
tessI.AddContour(inputs, ContourOrientation.Original);
tessI.Tessellate(WindingRule.EvenOdd, ElementType.Polygons, 3);
var indicesI = tessI.Elements.Select(i => i);
var verticesI = tessI.Vertices.Select(v => new float3(v.Position.X, v.Position.Y, 0));
var finalVertices = new NativeArray <ParametricLightMeshVertex>(verticesI.Count() + 2 * shapePath.Length, Allocator.Temp);
var finalIndices = new NativeArray <ushort>(indicesI.Count() + 6 * shapePath.Length, Allocator.Temp);
var vertexOffset = 0;
foreach (var v in verticesI)
{
finalVertices[vertexOffset++] = new ParametricLightMeshVertex
{
position = v,
color = meshInteriorColor
};
}
var indexOffset = 0;
foreach (var v in indicesI)
{
finalIndices[indexOffset++] = (ushort)v;
}
// Create falloff geometry
var extrusionDirs = GetFalloffShape(shapePath);
var falloffPointCount = 2 * shapePath.Length;
for (var i = 0; i < shapePath.Length; i++)
{
// Making triangles ABD and DCA
var triangleIndex = 2 * i;
var aIndex = vertexOffset + triangleIndex;
var bIndex = vertexOffset + triangleIndex + 1;
var cIndex = vertexOffset + (triangleIndex + 2) % falloffPointCount;
var dIndex = vertexOffset + (triangleIndex + 3) % falloffPointCount;
// We are making degenerate triangles which will be extruded by the shader
var point = new ParametricLightMeshVertex
{
position = shapePath[i],
color = new Color(0, 0, 0, 1)
};
finalVertices[vertexOffset + i * 2] = point;
point.color = new Color(extrusionDirs[i].x, extrusionDirs[i].y, 0, 0);
finalVertices[vertexOffset + i * 2 + 1] = point;
finalIndices[indexOffset + i * 6 + 0] = (ushort)aIndex;
finalIndices[indexOffset + i * 6 + 1] = (ushort)bIndex;
finalIndices[indexOffset + i * 6 + 2] = (ushort)dIndex;
finalIndices[indexOffset + i * 6 + 3] = (ushort)dIndex;
finalIndices[indexOffset + i * 6 + 4] = (ushort)cIndex;
finalIndices[indexOffset + i * 6 + 5] = (ushort)aIndex;
var extrudeDir = new float3(extrusionDirs[i].x, extrusionDirs[i].y, 0);
min = math.min(min, point.position + extrudeDir * falloffDistance);
max = math.max(max, point.position + extrudeDir * falloffDistance);
}
mesh.SetVertexBufferParams(finalVertices.Length, ParametricLightMeshVertex.VertexLayout);
mesh.SetVertexBufferData(finalVertices, 0, 0, finalVertices.Length);
mesh.SetIndices(finalIndices, MeshTopology.Triangles, 0, false);
return(new Bounds
{
min = min,
max = max
});
}
