SphereShape.h

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#ifndef ULT_SPHERE_SHAPE_H_INCLUDED
#define ULT_SPHERE_SHAPE_H_INCLUDED
 
#include <cmath>
#include "../ModelData.h"
 
#define ULT_UNIT_SPHERE_STRIDE sizeof(Ult::stUnitSphereVertex)
 
namespace Ult
{
 
struct stUnitSphereVertex
{
    float x,y,z;
    float tu1,tv1;
    float nx,ny,nz;
};

static inline bool CreateSphereMesh(
    float radius,
    int hRes, int vRes,
    ModelData* model
)
{
    if (!model) { return false; }
    model->Clear();
 
    int numFaces = hRes * (vRes*2) * 2;
    int numIndices = numFaces * 3;
    int numVerts = (hRes+1) * (vRes+1);
    const float fPI = 3.141592654f;
 
    stUnitSphereVertex* verts = new stUnitSphereVertex[numVerts];
    stUnitSphereVertex* vertPtr = verts;
    if (!verts) {
        return false;
    }
 
    unsigned int* indices = new unsigned int[numFaces*3];
    unsigned int* indexPtr = indices;
    if (!indices) {
        return false;
    }
 
    for (int i=0; i<=hRes; i++) {
        for (int j=0; j<=vRes; j++) {
            float ii = i/float(hRes);
            float jj = j/float(vRes);
            float theta = ii*2*fPI;
            float phi = (jj-0.5f)*fPI;
            float phi2 = phi + fPI * 0.5f;
            float nx = cosf(theta)*cosf(phi);
            float ny = sinf(theta)*cosf(phi);
            float nz = sinf(phi);
 
            vertPtr->x = radius * nx;
            vertPtr->y = radius * ny;
            vertPtr->z = radius * nz;
 
            vertPtr->tu1 = ii;
            vertPtr->tv1 = jj;
 
            vertPtr->nx = -nx;
            vertPtr->ny = -ny;
            vertPtr->nz = -nz;
 
            vertPtr++;
        }
    }
 
    for (int i=0; i<hRes; i++) {
        for (int j=0; j<vRes; j++) {
            *indexPtr++ = (i+0) * (vRes+1) + j + 0;
            *indexPtr++ = (i+1) * (vRes+1) + j + 1;
            *indexPtr++ = (i+0) * (vRes+1) + j + 1;
 
            *indexPtr++ = (i+0) * (vRes+1) + j + 0;
            *indexPtr++ = (i+1) * (vRes+1) + j + 0;
            *indexPtr++ = (i+1) * (vRes+1) + j + 1;
        }
    }
 
    model->AddDescriptorElement(ULT_VERTEX_3F);
    model->AddDescriptorElement(ULT_TEX1_2F);
    model->AddDescriptorElement(ULT_NORMAL_3F);
 
    if (!model->SetVertices(ULT_TRI_LIST, numVerts, ULT_UNIT_SPHERE_STRIDE, (char*)verts)) {
        return false;
    }
    if (!model->SetIndices(numIndices, indices)) {
        return false;
    }
    if (verts) { delete[] verts; }
    if (indices) { delete[] indices; }
 
    return true;
}
 
} // namespace Ult
 
#endif // ULT_SPHERE_SHAPE_H_INCLUDED