///////////////////////////////////////////////////////////////////////////
//
// Copyright (c) 2004, Industrial Light & Magic, a division of Lucas
// Digital Ltd. LLC
//
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following disclaimer
// in the documentation and/or other materials provided with the
// distribution.
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// from this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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///////////////////////////////////////////////////////////////////////////
//-----------------------------------------------------------------------------
//
// class EnvmapImage
//
//-----------------------------------------------------------------------------
#include "EnvmapImage.h"
#include <ImathFun.h>
#include "namespaceAlias.h"
using namespace IMF;
using namespace IMATH;
EnvmapImage::EnvmapImage ():
_type (ENVMAP_LATLONG),
_dataWindow (V2i (0, 0), V2i (0, 0)),
_pixels (1, 1)
{
clear();
}
EnvmapImage::EnvmapImage (Envmap type, const Box2i &dataWindow):
_type (type),
_dataWindow (dataWindow),
_pixels (dataWindow.max.y - dataWindow.min.y + 1,
dataWindow.max.x - dataWindow.min.x + 1)
{
clear();
}
void
EnvmapImage::resize (Envmap type, const Box2i &dataWindow)
{
_pixels.resizeEraseUnsafe (dataWindow.max.y - dataWindow.min.y + 1,
dataWindow.max.x - dataWindow.min.x + 1);
_type = type;
_dataWindow = dataWindow;
clear();
}
void
EnvmapImage::clear ()
{
int w = _dataWindow.max.x - _dataWindow.min.x + 1;
int h = _dataWindow.max.y - _dataWindow.min.y + 1;
for (int y = 0; y < h; ++y)
{
for (int x = 0; x < w; ++x)
{
Rgba &p = _pixels[y][x];
p.r = 0;
p.g = 0;
p.b = 0;
p.a = 0;
}
}
}
Envmap
EnvmapImage::type () const
{
return _type;
}
const Box2i &
EnvmapImage::dataWindow () const
{
return _dataWindow;
}
Array2D<Rgba> &
EnvmapImage::pixels ()
{
return _pixels;
}
const Array2D<Rgba> &
EnvmapImage::pixels () const
{
return _pixels;
}
namespace {
V2f
dirToPosLatLong (const Box2i &dataWindow, const V3f &dir)
{
return LatLongMap::pixelPosition (dataWindow, dir);
}
V2f
dirToPosCube (const Box2i &dataWindow, const V3f &dir)
{
CubeMapFace face;
V2f posInFace;
CubeMap::faceAndPixelPosition (dir, dataWindow, face, posInFace);
return CubeMap::pixelPosition (face, dataWindow, posInFace);
}
} // namespace
Rgba
EnvmapImage::filteredLookup (V3f d, float r, int n) const
{
//
// Filtered environment map lookup: Take n by n point samples
// from the environment map, clustered around direction d, and
// combine the samples with a tent filter.
//
//
// Depending on the type of map, pick an appropriate function
// to convert 3D directions to 2D pixel poitions.
//
V2f (* dirToPos) (const Box2i &, const V3f &);
if (_type == ENVMAP_LATLONG)
dirToPos = dirToPosLatLong;
else
dirToPos = dirToPosCube;
//
// Pick two vectors, dx and dy, of length r, that are orthogonal
// to the lookup direction, d, and to each other.
//
d.normalize();
V3f dx, dy;
if (abs (d.x) > 0.707f)
dx = (d % V3f (0, 1, 0)).normalized() * r;
else
dx = (d % V3f (1, 0, 0)).normalized() * r;
dy = (d % dx).normalized() * r;
//
// Take n by n point samples from the map, and add them up.
// The directions for the point samples are all within the pyramid
// defined by the vectors d-dy-dx, d-dy+dx, d+dy-dx, d+dy+dx.
//
float wt = 0;
float cr = 0;
float cg = 0;
float cb = 0;
float ca = 0;
for (int y = 0; y < n; ++y)
{
float ry = float (2 * y + 2) / float (n + 1) - 1;
float wy = 1 - abs (ry);
V3f ddy (ry * dy);
for (int x = 0; x < n; ++x)
{
float rx = float (2 * x + 2) / float (n + 1) - 1;
float wx = 1 - abs (rx);
V3f ddx (rx * dx);
Rgba s = sample (dirToPos (_dataWindow, d + ddx + ddy));
float w = wx * wy;
wt += w;
cr += s.r * w;
cg += s.g * w;
cb += s.b * w;
ca += s.a * w;
}
}
wt = 1 / wt;
Rgba c;
c.r = cr * wt;
c.g = cg * wt;
c.b = cb * wt;
c.a = ca * wt;
return c;
}
Rgba
EnvmapImage::sample (const V2f &pos) const
{
//
// Point-sample the environment map image at 2D position pos.
// Interpolate bilinearly between the four nearest pixels.
//
int x1 = IMATH::floor (pos.x);
int x2 = x1 + 1;
float sx = x2 - pos.x;
float tx = 1 - sx;
x1 = clamp (x1, _dataWindow.min.x, _dataWindow.max.x) - _dataWindow.min.x;
x2 = clamp (x2, _dataWindow.min.x, _dataWindow.max.x) - _dataWindow.min.x;
int y1 = IMATH::floor (pos.y);
int y2 = y1 + 1;
float sy = y2 - pos.y;
float ty = 1 - sy;
y1 = clamp (y1, _dataWindow.min.y, _dataWindow.max.y) - _dataWindow.min.y;
y2 = clamp (y2, _dataWindow.min.y, _dataWindow.max.y) - _dataWindow.min.y;
Rgba p11 = _pixels[y1][x1];
Rgba p12 = _pixels[y1][x2];
Rgba p21 = _pixels[y2][x1];
Rgba p22 = _pixels[y2][x2];
Rgba p;
p.r = (p11.r * sx + p12.r * tx) * sy + (p21.r * sx + p22.r * tx) * ty;
p.g = (p11.g * sx + p12.g * tx) * sy + (p21.g * sx + p22.g * tx) * ty;
p.b = (p11.b * sx + p12.b * tx) * sy + (p21.b * sx + p22.b * tx) * ty;
p.a = (p11.a * sx + p12.a * tx) * sy + (p21.a * sx + p22.a * tx) * ty;
return p;
}