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WaveFrontReader: handle MTL xyz and spectral colors and 'd -halo' #324

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WaveFrontReader: handle MTL xyz and spectral colors and 'd -halo' #324

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4cc5b25
WaveFrontReader: handle MTL xyz and spectral colors and 'd -halo'
Kiptoo-Deus Sep 29, 2026
d339f01
WaveFrontReader: apply clang-format
Kiptoo-Deus Oct 9, 2026
490145d
Merge remote-tracking branch 'origin/main' into wavefront-mtl-xyz-colors
Kiptoo-Deus Oct 9, 2026
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133 changes: 111 additions & 22 deletions Utilities/WaveFrontReader.h
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Original file line number Diff line number Diff line change
Expand Up @@ -49,6 +49,7 @@
#include <cwctype>
#include <fstream>
#include <locale>
#include <sstream>
#include <string>
#include <vector>
#include <unordered_map>
Expand Down Expand Up @@ -500,46 +501,59 @@ namespace DX
if (0 == wcscmp(strCommand.c_str(), L"Ka"))
{
// Ambient color
// TODO: check for 'spectral' or 'xyz'
float r, g, b;
InFile >> r >> g >> b;
curMaterial->vAmbient = XMFLOAT3(r, g, b);
LoadColor(InFile, curMaterial->vAmbient);
}
else if (0 == wcscmp(strCommand.c_str(), L"Kd"))
{
// Diffuse color
// TODO: check for 'spectral' or 'xyz'
float r, g, b;
InFile >> r >> g >> b;
curMaterial->vDiffuse = XMFLOAT3(r, g, b);
LoadColor(InFile, curMaterial->vDiffuse);
}
else if (0 == wcscmp(strCommand.c_str(), L"Ks"))
{
// Specular color
// TODO: check for 'spectral' or 'xyz'
float r, g, b;
InFile >> r >> g >> b;
curMaterial->vSpecular = XMFLOAT3(r, g, b);
LoadColor(InFile, curMaterial->vSpecular);
}
else if (0 == wcscmp(strCommand.c_str(), L"Ke"))
{
// Emissive color
// TODO: check for 'spectral' or 'xyz'
float r, g, b;
InFile >> r >> g >> b;
curMaterial->vEmissive = XMFLOAT3(r, g, b);
if (r > 0.f || g > 0.f || b > 0.f)
XMFLOAT3 emissive;
if (LoadColor(InFile, emissive))
{
curMaterial->bEmissive = true;
curMaterial->vEmissive = emissive;
if (emissive.x > 0.f || emissive.y > 0.f || emissive.z > 0.f)
{
curMaterial->bEmissive = true;
}
}
}
else if (0 == wcscmp(strCommand.c_str(), L"Tf"))
{
// Transmission filter (not supported)
#ifdef _DEBUG
OutputDebugStringW(L"WaveFrontReader: MTL 'Tf' (transmission filter) is not supported\n");
#endif
}
else if (0 == wcscmp(strCommand.c_str(), L"d"))
{
// Alpha
// TODO: check for '-halo'
// The '-halo' form makes dissolve depend on the surface orientation, which is not
// supported, so only the factor is used.
std::wistringstream args(LoadLineArguments(InFile));
args.imbue(std::locale::classic());

std::wstring token;
args >> token;
if (token != L"-halo")
{
args.clear();
args.seekg(0);
}

float alpha;
InFile >> alpha;
curMaterial->fAlpha = std::min(1.f, std::max(0.f, alpha));
if (args >> alpha)
{
curMaterial->fAlpha = std::min(1.f, std::max(0.f, alpha));
}
}
else if (0 == wcscmp(strCommand.c_str(), L"Tr"))
{
Expand Down Expand Up @@ -599,7 +613,7 @@ namespace DX

// bump, decal, disp, map_d, map_Ka, map_Ns
// map_aat
// Ni, sharpness, Tf
// Ni, sharpness
// refl
}

Expand Down Expand Up @@ -770,6 +784,81 @@ namespace DX
return index;
}

// Returns the rest of the current line without any end-of-line comment,
// leaving the newline in the stream
std::wstring LoadLineArguments(std::wifstream& InFile)
{
wchar_t buff[1024] = {};
InFile.getline(buff, 1024, L'\n');
InFile.putback(L'\n');

std::wstring args = buff;
size_t pos = args.find_first_of(L'#');
if (pos != std::wstring::npos)
{
args.resize(pos);
}

return args;
}

// Reads the arguments of an MTL color statement (Ka, Kd, Ks, Ke, Tf), which can be
// r [g b] (g and b default to r)
// xyz x [y z] CIE XYZ, converted to linear sRGB (y and z default to x)
// spectral file.rfl [factor] spectral curve, not supported
// Returns false and leaves 'color' unchanged if the color could not be read.
bool LoadColor(std::wifstream& InFile, DirectX::XMFLOAT3& color)
{
std::wistringstream args(LoadLineArguments(InFile));
args.imbue(std::locale::classic());

std::wstring token;
args >> token;
if (token == L"spectral")
{
#ifdef _DEBUG
OutputDebugStringW(L"WaveFrontReader: MTL 'spectral' colors are not supported\n");
#endif
return false;
}

const bool xyz = (token == L"xyz");
if (!xyz)
{
args.clear();
args.seekg(0);
}

float c[3] = {};
if (!(args >> c[0]))
return false;

if (args >> c[1])
{
if (!(args >> c[2]))
return false;
}
else
{
c[1] = c[2] = c[0];
}

if (xyz)
{
// CIE XYZ to linear sRGB (D65 white point), clamping out-of-gamut values
const float r = 3.2404542f * c[0] - 1.5371385f * c[1] - 0.4985314f * c[2];
const float g = -0.9692660f * c[0] + 1.8760108f * c[1] + 0.0415560f * c[2];
const float b = 0.0556434f * c[0] - 0.2040259f * c[1] + 1.0572252f * c[2];
color = DirectX::XMFLOAT3(std::max(0.f, r), std::max(0.f, g), std::max(0.f, b));
}
else
{
color = DirectX::XMFLOAT3(c[0], c[1], c[2]);
}

return true;
}

void LoadTexturePath(std::wifstream& InFile, _Out_writes_(maxChar) wchar_t* texture, size_t maxChar)
{
wchar_t buff[1024] = {};
Expand Down
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