108 lines
3.7 KiB
C#
108 lines
3.7 KiB
C#
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namespace UnityEngine.U2D.Animation.TriangleNet
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.Tools
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{
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using Animation.TriangleNet.Geometry;
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internal static class Interpolation
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{
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#if USE_ATTRIBS
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/// <summary>
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/// Linear interpolation of vertex attributes.
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/// </summary>
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/// <param name="vertex">The interpolation vertex.</param>
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/// <param name="triangle">The triangle containing the vertex.</param>
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/// <param name="n">The number of vertex attributes.</param>
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/// <remarks>
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/// The vertex is expected to lie inside the triangle.
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/// </remarks>
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internal static void InterpolateAttributes(Vertex vertex, ITriangle triangle, int n)
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{
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Vertex org = triangle.GetVertex(0);
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Vertex dest = triangle.GetVertex(1);
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Vertex apex = triangle.GetVertex(2);
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double xdo, ydo, xao, yao;
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double denominator;
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double dx, dy;
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double xi, eta;
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// Compute the circumcenter of the triangle.
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xdo = dest.x - org.x;
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ydo = dest.y - org.y;
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xao = apex.x - org.x;
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yao = apex.y - org.y;
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denominator = 0.5 / (xdo * yao - xao * ydo);
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//dx = (yao * dodist - ydo * aodist) * denominator;
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//dy = (xdo * aodist - xao * dodist) * denominator;
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dx = vertex.x - org.x;
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dy = vertex.y - org.y;
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// To interpolate vertex attributes for the new vertex, define a
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// coordinate system with a xi-axis directed from the triangle's
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// origin to its destination, and an eta-axis, directed from its
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// origin to its apex.
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xi = (yao * dx - xao * dy) * (2.0 * denominator);
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eta = (xdo * dy - ydo * dx) * (2.0 * denominator);
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for (int i = 0; i < n; i++)
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{
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// Interpolate the vertex attributes.
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vertex.attributes[i] = org.attributes[i]
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+ xi * (dest.attributes[i] - org.attributes[i])
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+ eta * (apex.attributes[i] - org.attributes[i]);
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}
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}
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#endif
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#if USE_Z
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/// <summary>
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/// Linear interpolation of a scalar value.
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/// </summary>
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/// <param name="p">The interpolation point.</param>
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/// <param name="triangle">The triangle containing the point.</param>
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/// <remarks>
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/// The point is expected to lie inside the triangle.
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/// </remarks>
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internal static void InterpolateZ(Point p, ITriangle triangle)
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{
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Vertex org = triangle.GetVertex(0);
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Vertex dest = triangle.GetVertex(1);
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Vertex apex = triangle.GetVertex(2);
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double xdo, ydo, xao, yao;
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double denominator;
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double dx, dy;
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double xi, eta;
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// Compute the circumcenter of the triangle.
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xdo = dest.x - org.x;
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ydo = dest.y - org.y;
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xao = apex.x - org.x;
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yao = apex.y - org.y;
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denominator = 0.5 / (xdo * yao - xao * ydo);
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//dx = (yao * dodist - ydo * aodist) * denominator;
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//dy = (xdo * aodist - xao * dodist) * denominator;
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dx = p.x - org.x;
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dy = p.y - org.y;
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// To interpolate z value for the given point inserted, define a
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// coordinate system with a xi-axis, directed from the triangle's
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// origin to its destination, and an eta-axis, directed from its
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// origin to its apex.
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xi = (yao * dx - xao * dy) * (2.0 * denominator);
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eta = (xdo * dy - ydo * dx) * (2.0 * denominator);
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p.z = org.z + xi * (dest.z - org.z) + eta * (apex.z - org.z);
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}
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#endif
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}
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}
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