void Generate(int cubesize, int maxwidth,
const std::string & outputfile,
const std::string & configfile,
const std::string & incolorspace,
const std::string & outcolorspace)
{
int width = 0;
int height = 0;
int numchannels = 3;
GetLutImageSize(width, height, cubesize, maxwidth);
std::vector<float> img;
img.resize(width*height*numchannels, 0);
GenerateIdentityLut3D(&img[0], cubesize, numchannels, LUT3DORDER_FAST_RED);
if(!incolorspace.empty() || !outcolorspace.empty())
{
OCIO::ConstConfigRcPtr config = OCIO::Config::Create();
if(!configfile.empty())
{
config = OCIO::Config::CreateFromFile(configfile.c_str());
}
else if(getenv("OCIO"))
{
config = OCIO::Config::CreateFromEnv();
}
else
{
std::ostringstream os;
os << "You must specify an ocio configuration ";
os << "(either with --config or $OCIO).";
throw Exception(os.str().c_str());
}
OCIO::ConstProcessorRcPtr processor =
config->getProcessor(incolorspace.c_str(), outcolorspace.c_str());
OCIO::PackedImageDesc imgdesc(&img[0], width, height, 3);
processor->apply(imgdesc);
}
OIIO::ImageOutput* f = OIIO::ImageOutput::create(outputfile);
if(!f)
{
throw Exception( "Could not create output image.");
}
OIIO::ImageSpec spec(width, height, numchannels, OIIO::TypeDesc::TypeFloat);
// TODO: If DPX, force 16-bit output?
f->open(outputfile, spec);
f->write_image(OIIO::TypeDesc::FLOAT, &img[0]);
f->close();
delete f;
}
///< 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);
}
