inline void GenerateTriangleFan(unsigned int segments)
{
vertices.clear();
normals.clear();
indicies.clear();
texCoords.clear();
float thetaStep = static_cast<float>(PI2 / static_cast<double>(segments));
int numVerts = segments + 2; // Edge points + center + return to start
int numTexCoords = (numVerts / 3) * 2;
vertices.reserve(numVerts);
normals.reserve(numVerts);
texCoords.reserve(numVerts);
// Store start center of the disc
vertices.push_back(0.0f);
vertices.push_back(0.0f);
vertices.push_back(0.0f);
normals.push_back(0.0f);
normals.push_back(1.0f);
normals.push_back(0.0f);
texCoords.push_back(0.5f);
texCoords.push_back(0.5f);
float theta = 0.0f;
for (unsigned int i = 0; i < segments + 1; i++)
{
// Find point on edge
Vector3 xyz(sinf(theta), 0.0f, cosf(theta));
// Calculate vertex on edge
vertices.push_back(xyz.x);
vertices.push_back(0.0f);
vertices.push_back(xyz.z);
// Add Normal
normals.push_back(0.0f);
normals.push_back(1.0f);
normals.push_back(0.0f);
// Work out texture coordinate
Vector2 uv((xyz.x * 0.5f) + 0.5f, (xyz.z * 0.5f) + 0.5f);
texCoords.push_back(uv.x);
texCoords.push_back(uv.y);
if(i < segments)
{
theta += thetaStep;
}
else
{
theta = 0.0f; // Clamp the final value back to the beginning
}
}
}
quat quat::rotation(float theta, float x, float y, float z)
{
using std::sinf;
using std::cosf;
const float haversine = sinf(0.5f * theta);
const float havercosine = cosf(0.5f * theta);
return quat(
havercosine,
haversine * x,
haversine * y,
haversine * z
);
}
inline void GenerateTriangles(unsigned int segments)
{
vertices.clear();
normals.clear();
indicies.clear();
texCoords.clear();
float thetaStep = static_cast<float>(PI2) / static_cast<float>(segments);
int numVerts = (segments) * 3; // Edge points + center + return to start
int numTexCoords = (numVerts / 3) * 2;
vertices.reserve(numVerts);
normals.reserve(numVerts);
texCoords.reserve(numVerts);
float theta1 = 0.0f, theta2 = thetaStep;
for (unsigned int i = 0; i < segments + 1; i++)
{
// Find the two points for this segment
Vector3 xyz1, xyz2;
xyz1 = Vector3(sinf(theta1), 0.0f, cosf(theta1));
xyz2 = Vector3(sinf(theta2), 0.0f, cosf(theta2));
Vector2 uv1, uv2;
uv1 = Vector2((xyz1.x * 0.5f) + 0.5f, (xyz1.z * 0.5f) + 0.5f);
uv2 = Vector2((xyz2.x * 0.5f) + 0.5f, (xyz2.z * 0.5f) + 0.5f);
// Push the vertices, normals and texture coordinates
// Center of disc
vertices.push_back(0.0f);
vertices.push_back(0.0f);
vertices.push_back(0.0f);
vertices.push_back(xyz1.x);
vertices.push_back(0.0f);
vertices.push_back(xyz1.z);
vertices.push_back(xyz2.x);
vertices.push_back(0.0f);
vertices.push_back(xyz2.z);
for (int i = 0; i < 3; i++)
{
normals.push_back(0.0f);
normals.push_back(1.0f);
normals.push_back(0.0f);
}
texCoords.push_back(0.5f);
texCoords.push_back(0.5f);
texCoords.push_back(uv1.x);
texCoords.push_back(uv1.y);
texCoords.push_back(uv2.x);
texCoords.push_back(uv2.y);
if (i < segments)
{
theta1 += thetaStep;
theta2 += thetaStep;
}
else
{
theta1 += thetaStep;
theta2 = 0.0f; // Clamp back to the beginning
}
}
}
