Added functions to scattertable tool to write out atmospheric scattering
tables as half float textures in .dds files.sensor-dev
Chris Laurel
parent
672682b380
commit
dc32eedc9c
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@ -78,7 +78,6 @@ static Vector3f RayleighScatteringCoeff(float n, float N)
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}
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class Atmosphere
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{
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public:
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@ -171,7 +170,14 @@ static inline float toMu(float u)
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// Map a unorm to the cosine of the sun angle
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static inline float toMuS(float u)
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{
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return (-1.0f / 3.0f) * (log(1.0f - u * (1.0f - exp(-3.6f))) + 0.6f);
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// Original version from Bruneton paper:
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//return (-1.0f / 3.0f) * (log(1.0f - u * (1.0f - exp(-3.6f))) + 0.6f);
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// Modifier version has a wider range, allowing more negative angles. This
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// eliminates the faint but persistent illumination that appears even
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// when the sun is far below the horizon. Even the adjusted function may
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// still not be adequate when very large scale heights are used.
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return (-1.0f / 2.0f) * (log(1.0f - u * (1.0f - exp(-2.6f))) + 0.6f);
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}
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@ -347,6 +353,12 @@ Atmosphere::computeInscatterTable() const
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unsigned int index = (i * ViewAngleSamples + j) * SunAngleSamples + k;
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inscatter[index] << rayleigh.cwise() * rayleighCoeff,
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mie * mieCoeff;
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if (i == HeightSamples - 1 && k == 0)
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{
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cout << acos(muS) * 180.0/M_PI << ", "
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<< acos(mu) * 180.0/M_PI << ", "
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<< inscatter[index].transpose() << endl;
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}
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#if 0
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// Emit warnings about NaNs in scatter table
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@ -537,6 +549,7 @@ bool parseCommandLine(int argc, char* argv[])
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typedef unsigned int uint32;
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typedef unsigned short uint16;
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union Uint32
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{
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@ -550,6 +563,210 @@ union Float
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float f;
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};
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union FloatInt
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{
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float f;
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uint32 u;
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};
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// Convert a single precision floating point value to half precision
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uint16 floatToHalf(float f)
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{
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FloatInt fi;
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fi.f = f;
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uint16 half = 0;
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uint16 signBit = uint16((fi.u & 0x80000000) >> 16);
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if (f > 65504.0f)
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{
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// overflow
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return 0x7c00;
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}
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else if (f < -65504.0f)
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{
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// overflow
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return 0xfc00;
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}
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int exponent = int((fi.u >> 23) & 0xff) - 127 + 15;
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uint32 significand = fi.u & 0x007fffff;
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if (exponent < -9)
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{
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// Value is too small even to represent as a subnormal
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return signBit;
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}
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else if (exponent <= 0)
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{
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// Convert to a subnormal
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return signBit + (significand >> (13 - exponent));
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}
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else if (exponent + 127 - 15 == 0xff)
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{
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// Special values: infinities and NaNs
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if (significand == 0)
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{
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// Infinity
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return signBit + 0x7c00;
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}
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else
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{
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// NaN - preserve bits, but make sure that we don't
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// make the significand zero, as that would indicate
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// an infinity, not a NaN
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uint16 nanBits = uint16(significand >> 13);
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if (nanBits == 0)
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{
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nanBits = 1;
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}
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return signBit + 0x7c00 + nanBits;
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}
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}
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else if (exponent > 30)
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{
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// Overflow; return infinity
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return signBit + 0x7c00;
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}
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else
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{
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// Normal value
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return signBit + (exponent << 10) +
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((significand + 0x00001000) >> 13); // round
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}
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}
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struct DDSPixelFormat
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{
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DDSPixelFormat() :
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dwSize(0),
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dwFlags(0),
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dwFourCC(0),
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dwRGBBitCount(0),
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dwRBitMask(0),
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dwGBitMask(0),
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dwBBitMask(0),
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dwABitMask(0)
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{
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}
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uint32 dwSize;
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uint32 dwFlags;
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uint32 dwFourCC;
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uint32 dwRGBBitCount;
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uint32 dwRBitMask;
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uint32 dwGBitMask;
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uint32 dwBBitMask;
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uint32 dwABitMask;
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};
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// Header for Microsoft DDS file format
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struct DDSHeader
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{
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DDSHeader() :
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dwSize(sizeof(DDSHeader)),
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dwFlags(DDSD_PIXELFORMAT),
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dwHeight(0),
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dwWidth(0),
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dwLinearSize(0),
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dwDepth(0),
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dwMipMapCount(0),
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dwCaps(0),
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dwCaps2(0),
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dwCaps3(0),
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dwCaps4(0),
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dwReserved2(0)
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{
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for (unsigned int i = 0; i < sizeof(dwReserved1) / sizeof(uint32); i++)
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{
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dwReserved1[i] = 0;
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}
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}
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static const uint32 CAPS_COMPLEX = 0x000008;
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static const uint32 CAPS_MIPMAP = 0x400000;
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static const uint32 CAPS_TEXTURE = 0x001000;
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static const uint32 CAPS2_VOLUME = 0x200000;
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static const uint32 CAPS2_CUBEMAP = 0x00000200;
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static const uint32 CAPS2_CUBEMAP_POSITIVEX = 0x00000400;
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static const uint32 CAPS2_CUBEMAP_NEGATIVEX = 0x00000800;
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static const uint32 CAPS2_CUBEMAP_POSITIVEY = 0x00001000;
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static const uint32 CAPS2_CUBEMAP_NEGATIVEY = 0x00002000;
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static const uint32 CAPS2_CUBEMAP_POSITIVEZ = 0x00004000;
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static const uint32 CAPS2_CUBEMAP_NEGATIVEZ = 0x00008000;
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static const uint32 DDSD_CAPS = 0x1;
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static const uint32 DDSD_HEIGHT = 0x2;
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static const uint32 DDSD_WIDTH = 0x4;
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static const uint32 DDSD_PITCH = 0x8;
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static const uint32 DDSD_PIXELFORMAT = 0x1000;
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static const uint32 DDSD_MIPMAPCOUNT = 0x20000;
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static const uint32 DDSD_LINEARSIZE = 0x80000;
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static const uint32 DDSD_DEPTH = 0x800000;
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static const uint32 D3DFMT_A16B16G16R16 = 36;
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static const uint32 D3DFMT_A16B16G16R16F = 113;
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static const uint32 D3DFMT_DXT1 = 0x31545844;
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static const uint32 D3DFMT_DXT3 = 0x33545844;
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static const uint32 D3DFMT_DXT5 = 0x35545844;
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static const uint32 FOURCC = 0x04;
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uint32 dwSize;
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uint32 dwFlags;
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uint32 dwHeight;
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uint32 dwWidth;
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uint32 dwLinearSize;
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uint32 dwDepth;
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uint32 dwMipMapCount;
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uint32 dwReserved1[11];
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DDSPixelFormat ddpf;
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uint32 dwCaps;
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uint32 dwCaps2;
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uint32 dwCaps3;
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uint32 dwCaps4;
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uint32 dwReserved2;
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void setTexture()
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{
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dwCaps |= CAPS_TEXTURE;
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}
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void setFourCC(uint32 fcc)
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{
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dwFlags |= FOURCC;
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ddpf.dwFourCC = fcc;
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}
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void setMipMapLevels(uint32 levels)
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{
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dwCaps |= (CAPS_COMPLEX | CAPS_MIPMAP);
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dwFlags |= DDSD_MIPMAPCOUNT;
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dwMipMapCount = levels;
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}
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void setDimensions(uint32 width, uint32 height)
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{
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dwFlags |= (DDSD_WIDTH | DDSD_HEIGHT);
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dwWidth = width;
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dwHeight = height;
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}
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void setVolumeDimensions(uint32 width, uint32 height, uint32 depth)
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{
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dwCaps |= CAPS_COMPLEX;
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dwFlags |= (DDSD_WIDTH | DDSD_HEIGHT | DDSD_DEPTH);
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dwWidth = width;
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dwHeight = height;
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dwDepth = depth;
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}
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};
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static bool ByteSwapRequired = false;
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static bool IsLittleEndian()
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{
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@ -593,6 +810,61 @@ static void WriteFloat(ostream& out, float f)
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}
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void WriteDDSHeader(ostream& out, const DDSHeader& dds)
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{
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WriteUint32(out, dds.dwSize);
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WriteUint32(out, dds.dwFlags);
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WriteUint32(out, dds.dwHeight);
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WriteUint32(out, dds.dwWidth);
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WriteUint32(out, dds.dwLinearSize);
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WriteUint32(out, dds.dwDepth);
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WriteUint32(out, dds.dwMipMapCount);
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for (unsigned int i = 0; i < sizeof(dds.dwReserved1) / sizeof(uint32); i++)
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{
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WriteUint32(out, dds.dwReserved1[i]);
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}
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WriteUint32(out, dds.ddpf.dwSize);
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WriteUint32(out, dds.ddpf.dwFlags);
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WriteUint32(out, dds.ddpf.dwFourCC);
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WriteUint32(out, dds.ddpf.dwRGBBitCount);
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WriteUint32(out, dds.ddpf.dwRBitMask);
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WriteUint32(out, dds.ddpf.dwGBitMask);
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WriteUint32(out, dds.ddpf.dwBBitMask);
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WriteUint32(out, dds.ddpf.dwABitMask);
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WriteUint32(out, dds.dwCaps);
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WriteUint32(out, dds.dwCaps2);
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WriteUint32(out, dds.dwCaps3);
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WriteUint32(out, dds.dwCaps4);
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WriteUint32(out, dds.dwReserved2);
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}
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static void WriteScatterTableDDS(ostream& out, Vector4f* inscatterTable)
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{
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DDSHeader dds;
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dds.setTexture();
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dds.setFourCC(DDSHeader::D3DFMT_A16B16G16R16F);
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dds.setVolumeDimensions(SunAngleSamples, ViewAngleSamples, HeightSamples);
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//dds.setMipMapLevels();
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}
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#if TEST_FLOAT_TO_HALF
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int main(void)
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{
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while (cin.good())
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{
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float f = 0.0f;
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cin >> f;
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cout << hex << floatToHalf(f) << endl;
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}
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return 0;
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}
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#endif
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int main(int argc, char* argv[])
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{
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bool commandLineOK = parseCommandLine(argc, argv);
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@ -634,6 +906,7 @@ int main(int argc, char* argv[])
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ofstream out(OutputFileName.c_str(), ostream::binary);
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// Table dimensions
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WriteUint32(out, ViewAngleSamples);
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WriteUint32(out, HeightSamples);
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