/// <summary>
/// Generates the unit sphere to arbitrary resolution.
/// </summary>
/// <remarks>
/// Copied verbatim from the Embree benchmark code.
/// </remarks>
public static IMesh GenerateSphere(int numPhi)
{
var numTheta = 2 * numPhi; // we tessellate the unit sphere
var vertices = new IEmbreePoint[numTheta * (numPhi + 1)];
var indices = new int[3 * 2 * numTheta * (numPhi - 1)];
int tri = 0;
float rcpNumTheta = 1.0f / (float)numTheta;
float rcpNumPhi = 1.0f / (float)numPhi;
for (var phi = 0; phi <= numPhi; ++phi)
{
for (var theta = 0; theta < numTheta; ++theta)
{
float phif = phi * (float)Math.PI * rcpNumPhi;
float thetaf = theta * 2 * (float)Math.PI * rcpNumTheta;
float x = (float)(Math.Sin(phif) * Math.Sin(thetaf));
float y = (float)(Math.Cos(phif));
float z = (float)(Math.Sin(phif) * Math.Cos(thetaf));
vertices[phi * numTheta + theta] = new Vector(x, y, z);
}
if (phi == 0)
{
continue;
}
for (var theta = 1; theta <= numTheta; ++theta)
{
int p00 = (phi - 1) * numTheta + theta - 1;
int p01 = (phi - 1) * numTheta + theta % numTheta;
int p10 = phi * numTheta + theta - 1;
int p11 = phi * numTheta + theta % numTheta;
if (phi > 1)
{
indices[3 * tri + 0] = p10;
indices[3 * tri + 1] = p00;
indices[3 * tri + 2] = p01;
++tri;
}
if (phi < numPhi)
{
indices[3 * tri + 0] = p11;
indices[3 * tri + 1] = p10;
indices[3 * tri + 2] = p01;
++tri;
}
}
}
return(new TriangleMesh(indices, vertices));
}
/// <summary>
/// Generates the unit sphere to arbitrary resolution.
/// </summary>
/// <remarks>
/// Copied verbatim from the Embree benchmark code.
/// </remarks>
public static IMesh GenerateSphere(int numPhi)
{
var numTheta = 2 * numPhi; // we tessellate the unit sphere
var vertices = new IEmbreePoint[numTheta * (numPhi + 1)];
var indices = new int[3 * 2 * numTheta * (numPhi - 1)];
int tri = 0;
float rcpNumTheta = 1.0f / (float)numTheta;
float rcpNumPhi = 1.0f / (float)numPhi;
for (var phi = 0; phi <= numPhi; ++phi)
{
for (var theta = 0; theta < numTheta; ++theta)
{
float phif = phi * (float)Math.PI * rcpNumPhi;
float thetaf = theta * 2 * (float)Math.PI * rcpNumTheta;
float x = (float)(Math.Sin(phif) * Math.Sin(thetaf));
float y = (float)(Math.Cos(phif));
float z = (float)(Math.Sin(phif) * Math.Cos(thetaf));
vertices[phi * numTheta + theta] = new Vector(x, y, z);
}
if (phi == 0)
continue;
for (var theta = 1; theta <= numTheta; ++theta)
{
int p00 = (phi - 1) * numTheta + theta - 1;
int p01 = (phi - 1) * numTheta + theta % numTheta;
int p10 = phi * numTheta + theta - 1;
int p11 = phi * numTheta + theta % numTheta;
if (phi > 1)
{
indices[3 * tri + 0] = p10;
indices[3 * tri + 1] = p00;
indices[3 * tri + 2] = p01;
++tri;
}
if (phi < numPhi)
{
indices[3 * tri + 0] = p11;
indices[3 * tri + 1] = p10;
indices[3 * tri + 2] = p01;
++tri;
}
}
}
return new TriangleMesh(indices, vertices);
}
