int calc_vertex_normal(struct stl_reader *r, int fi, int vi, float normal[3])
{
int i, ref = 0;
float n[3];
assert(fi>-1);
assert(vi>-1);
assert(fi<r->nf);
assert(vi<r->nv);
n[0] = r->f[fi].normal[0];
n[1] = r->f[fi].normal[1];
n[2] = r->f[fi].normal[2];
for (i=0; i<r->nf && ref<r->v[vi].refcnt; i++) {
if (i!=fi && (r->f[i].vertex[0]==vi
||r->f[i].vertex[1]==vi
||r->f[i].vertex[2]==vi)) {
ref++;
if (cosphi(r->f[i].normal,r->f[fi].normal)>cflimit
&& maxdim(r, i)/maxdim(r, fi)>dimlimit) {
n[0] += r->f[i].normal[0];
n[1] += r->f[i].normal[1];
n[2] += r->f[i].normal[2];
}
}
}
normalize(n);
memcpy(normal, n, sizeof(float[3]));
if (fabsf(n[0]-r->f[fi].normal[0])>eps
|| fabsf(n[1]-r->f[fi].normal[1])>eps
|| fabsf(n[2]-r->f[fi].normal[2])>eps)
return 1; /* vertex normal _not_ equal to facet normal */
return 0; /* vertex normal equal to facet normal */
}
///< The function projects latitude-longitude environment map to SH basis up to lmax band
void ShProjectEnvironmentMap(float3 const* envmap, int width, int height, int lmax, float3* coeffs)
{
// Resulting coefficients for RGB
// std::vector<float3> coeffs(NumShTerms(lmax));
// Temporary coefficients storage
std::vector<float> ylm(NumShTerms(lmax));
// Precompute sin and cos for the sphere
std::vector<float> sintheta(height);
std::vector<float> costheta(height);
std::vector<float> sinphi(width);
std::vector<float> cosphi(width);
float thetastep = PI / height;
float phistep = 2.f * PI / width;
float theta0 = PI / height / 2;
float phi0 = 2.f * PI / width / 2;
for (int i = 0; i < width; ++i)
{
sinphi[i] = std::sin(phi0 + i * phistep);
cosphi[i] = std::cos(phi0 + i * phistep);
}
for (int i = 0; i < height; ++i)
{
sintheta[i] = std::sin(theta0 + i * thetastep);
costheta[i] = std::cos(theta0 + i * thetastep);
}
// Iterate over the pixels calculating Riemann sum
for (int phi = 0; phi < width; ++phi)
{
for (int theta = 0; theta < height; ++theta)
{
// Construct direction vector
float3 w = normalize(float3(sintheta[theta] * cosphi[phi], costheta[theta], sintheta[theta] * sinphi[phi]));
// Construct uv sample coordinates
float2 uv = float2((float)phi / width, (float)theta / height);
// Sample environment map
int iu = (int)floor(uv.x * width);
int iv = (int)floor(uv.y * height);
float3 le = envmap[width * iv + iu];
// Evaluate SH functions at w up to lmax band
ShEvaluate(w, lmax, &ylm[0]);
// Evaluate Riemann sum accouting for solid angle conversion (sin term)
for (int i = 0; i < NumShTerms(lmax); ++i)
{
coeffs[i] += le * ylm[i] * sintheta[theta] * (PI / height) * (2.f * PI / width);
}
}
}
}
///< The function evaluates SH functions and dumps values to latitude-longitude map
void ShEvaluateAndDump(ImageIo& io, std::string const& filename, int width, int height, int lmax, float3 const* coeffs)
{
// Prepare image memory
std::vector<float> imagedata(width * height * 3);
// Allocate space for SH functions
std::vector<float> ylm(NumShTerms(lmax));
// Precalculate sin and cos terms
std::vector<float> sintheta(height);
std::vector<float> costheta(height);
std::vector<float> sinphi(width);
std::vector<float> cosphi(width);
float thetastep = PI / height;
float phistep = 2.f*PI / width;
float theta0 = PI / height / 2;
float phi0= 2.f*PI / width / 2;
for (int i = 0; i < width; ++i)
{
sinphi[i] = std::sin(phi0 + i * phistep);
cosphi[i] = std::cos(phi0 + i * phistep);
}
for (int i = 0; i < height; ++i)
{
sintheta[i] = std::sin(theta0 + i * thetastep);
costheta[i] = std::cos(theta0 + i * thetastep);
}
// Iterate thru image pixels
for (int phi = 0; phi < width; ++phi)
{
for (int theta = 0; theta < height; ++theta)
{
// Calculate direction
float3 w = normalize(float3(sintheta[theta] * cosphi[phi], costheta[theta], sintheta[theta] * sinphi[phi]));
// Evaluate SH functions at w up to lmax band
ShEvaluate(w, lmax, &ylm[0]);
// Evaluate function injecting SH coeffs
for (int i = 0; i < NumShTerms(lmax); ++i)
{
imagedata[theta * width * 3 + phi * 3] += ylm[i] * coeffs[i].x;
imagedata[theta * width * 3 + phi * 3 + 1] += ylm[i] * coeffs[i].y;
imagedata[theta * width * 3 + phi * 3 + 2] += ylm[i] * coeffs[i].z;
}
}
}
// Write image to file
ImageIo::ImageDesc imgdesc(width, height, 3);
io.Write(filename, imagedata, imgdesc);
}
///< The function projects latitude-longitude environment map to SH basis up to lmax band
void ShProjectEnvironmentMap(TextureSystem const& texsys, std::string const& texture, int lmax, float3* coeffs)
{
// Resulting coefficients for RGB
// std::vector<float3> coeffs(NumShTerms(lmax));
// Temporary coefficients storage
std::vector<float> ylm(NumShTerms(lmax));
// Get texture width and height
TextureSystem::TextureDesc texdesc;
texsys.GetTextureInfo(texture, texdesc);
// Precompute sin and cos for the sphere
std::vector<float> sintheta(texdesc.height);
std::vector<float> costheta(texdesc.height);
std::vector<float> sinphi(texdesc.width);
std::vector<float> cosphi(texdesc.width);
float thetastep = PI / texdesc.height;
float phistep = 2.f*PI / texdesc.width;
float theta0 = PI / texdesc.height / 2;
float phi0 = 2.f*PI / texdesc.width / 2;
for (int i = 0; i < texdesc.width; ++i)
{
sinphi[i] = std::sin(phi0 + i * phistep);
cosphi[i] = std::cos(phi0 + i * phistep);
}
for (int i = 0; i < texdesc.height; ++i)
{
sintheta[i] = std::sin(theta0 + i * thetastep);
costheta[i] = std::cos(theta0 + i * thetastep);
}
// Iterate over the pixels calculating Riemann sum
for (int phi = 0; phi < texdesc.width; ++phi)
{
for (int theta = 0; theta < texdesc.height; ++theta)
{
// Construct direction vector
float3 w = normalize(float3(sintheta[theta] * cosphi[phi], costheta[theta], sintheta[theta] * sinphi[phi]));
// Construct uv sample coordinates
float2 uv = float2((float)phi / texdesc.width, (float)theta / texdesc.height);
// Sample environment map
TextureSystem::Options opts;
opts.wrapmode = TextureSystem::Options::kRepeat;
opts.filter= TextureSystem::Options::kPoint;
float3 le = texsys.Sample(texture, uv, float2());
// Evaluate SH functions at w up to lmax band
ShEvaluate(w, lmax, &ylm[0]);
// Evaluate Riemann sum accouting for solid angle conversion (sin term)
for (int i = 0; i < NumShTerms(lmax); ++i)
{
coeffs[i] += le * ylm[i] * sintheta[theta] * (PI / texdesc.height) * (2.f * PI / texdesc.width);
}
}
}
}
