431 lines
11 KiB
C++
431 lines
11 KiB
C++
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///////////////////////////////////////////////////////////////////////////
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//
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// Copyright (c) 2007, Industrial Light & Magic, a division of Lucas
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// Digital Ltd. LLC
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//
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// All rights reserved.
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//
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// Redistribution and use in source and binary forms, with or without
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// modification, are permitted provided that the following conditions are
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// met:
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// * Redistributions of source code must retain the above copyright
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// notice, this list of conditions and the following disclaimer.
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// * Redistributions in binary form must reproduce the above
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// copyright notice, this list of conditions and the following disclaimer
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// in the documentation and/or other materials provided with the
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// distribution.
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// * Neither the name of Industrial Light & Magic nor the names of
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// its contributors may be used to endorse or promote products derived
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// from this software without specific prior written permission.
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//
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// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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//
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///////////////////////////////////////////////////////////////////////////
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//-----------------------------------------------------------------------------
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//
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// function blurImage() -- performs a hemispherical blur
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//
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//-----------------------------------------------------------------------------
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#include "blurImage.h"
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#include "namespaceAlias.h"
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#include <resizeImage.h>
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#include <cstring>
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#include "Iex.h"
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#include <iostream>
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#include <algorithm>
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#include <string.h>
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using namespace IMF;
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using namespace std;
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using namespace IMATH;
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inline int
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toInt (float x)
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{
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return int (x + 0.5f);
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}
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inline double
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sqr (double x)
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{
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return x * x;
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}
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void
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blurImage (EnvmapImage &image1, bool verbose)
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{
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//
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// Ideally we would blur the input image directly by convolving
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// it with a 180-degree wide blur kernel. Unfortunately this
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// is prohibitively expensive when the input image is large.
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// In order to keep running times reasonable, we perform the
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// blur on a small proxy image that will later be re-sampled
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// to the desired output resolution.
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//
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// Here's how it works:
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//
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// * If the input image is in latitude-longitude format,
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// convert it into a cube-face environment map.
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//
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// * Repeatedly resample the image, each time shrinking
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// it to no less than half its current size, until the
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// width of each cube face is MAX_IN_WIDTH pixels.
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//
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// * Multiply each pixel by a weight that is proportinal
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// to the solid angle subtended by the pixel as seen
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// from the center of the environment cube.
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//
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// * Create an output image in cube-face format.
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// The cube faces of the output image are OUT_WIDTH
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// pixels wide.
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//
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// * For each pixel of the output image:
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//
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// Set the output pixel's color to black
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//
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// Determine the direction, d2, from the center of the
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// output environment cube to the center of the output
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// pixel.
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//
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// For each pixel of the input image:
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//
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// Determine the direction, d1, from the center of
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// the input environment cube to the center of the
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// input pixel.
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//
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// Multiply the input pixel's color by max (0, d1.dot(d2))
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// and add the result to the output pixel.
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//
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const int MAX_IN_WIDTH = 40;
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const int OUT_WIDTH = 100;
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if (verbose)
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cout << "blurring map image" << endl;
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EnvmapImage image2;
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EnvmapImage *iptr1 = &image1;
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EnvmapImage *iptr2 = &image2;
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int w = image1.dataWindow().max.x - image1.dataWindow().min.x + 1;
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int h = w * 6;
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if (iptr1->type() == ENVMAP_LATLONG)
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{
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//
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// Convert the input image from latitude-longitude
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// to cube-face format.
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//
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if (verbose)
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cout << " converting to cube-face format" << endl;
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w /= 4;
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h = w * 6;
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Box2i dw (V2i (0, 0), V2i (w - 1, h - 1));
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resizeCube (*iptr1, *iptr2, dw, 1, 7);
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swap (iptr1, iptr2);
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}
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while (w > MAX_IN_WIDTH)
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{
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//
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// Shrink the image.
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//
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if (w >= MAX_IN_WIDTH * 2)
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w /= 2;
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else
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w = MAX_IN_WIDTH;
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h = w * 6;
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if (verbose)
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{
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cout << " resizing cube faces "
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"to " << w << " by " << w << " pixels" << endl;
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}
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Box2i dw (V2i (0, 0), V2i (w - 1, h - 1));
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resizeCube (*iptr1, *iptr2, dw, 1, 7);
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swap (iptr1, iptr2);
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}
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if (verbose)
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cout << " computing pixel weights" << endl;
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{
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//
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// Multiply each pixel by a weight that is proportinal
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// to the solid angle subtended by the pixel.
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//
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Box2i dw = iptr1->dataWindow();
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int sof = CubeMap::sizeOfFace (dw);
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Array2D<Rgba> &pixels = iptr1->pixels();
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double weightTotal = 0;
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for (int f = CUBEFACE_POS_X; f <= CUBEFACE_NEG_Z; ++f)
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{
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if (verbose)
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cout << " face " << f << endl;
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CubeMapFace face = CubeMapFace (f);
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V3f faceDir (0, 0, 0);
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int ix = 0, iy = 0, iz = 0;
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switch (face)
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{
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case CUBEFACE_POS_X:
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faceDir = V3f (1, 0, 0);
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ix = 0;
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iy = 1;
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iz = 2;
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break;
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case CUBEFACE_NEG_X:
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faceDir = V3f (-1, 0, 0);
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ix = 0;
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iy = 1;
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iz = 2;
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break;
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case CUBEFACE_POS_Y:
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faceDir = V3f (0, 1, 0);
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ix = 1;
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iy = 0;
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iz = 2;
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break;
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case CUBEFACE_NEG_Y:
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faceDir = V3f (0, -1, 0);
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ix = 1;
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iy = 0;
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iz = 2;
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break;
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case CUBEFACE_POS_Z:
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faceDir = V3f (0, 0, 1);
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ix = 2;
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iy = 0;
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iz = 1;
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break;
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case CUBEFACE_NEG_Z:
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faceDir = V3f (0, 0, -1);
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ix = 2;
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iy = 0;
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iz = 1;
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break;
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}
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for (int y = 0; y < sof; ++y)
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{
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bool yEdge = (y == 0 || y == sof - 1);
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for (int x = 0; x < sof; ++x)
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{
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bool xEdge = (x == 0 || x == sof - 1);
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V2f posInFace (x, y);
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V3f dir =
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CubeMap::direction (face, dw, posInFace).normalized();
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V2f pos =
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CubeMap::pixelPosition (face, dw, posInFace);
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//
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// The solid angle subtended by pixel (x,y), as seen
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// from the center of the cube, is proportional to the
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// square of the distance of the pixel from the center
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// of the cube and proportional to the dot product of
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// the viewing direction and the normal of the cube
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// face that contains the pixel.
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//
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double weight =
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(dir ^ faceDir) *
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(sqr (dir[iy] / dir[ix]) + sqr (dir[iz] / dir[ix]) + 1);
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//
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// Pixels at the edges and corners of the
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// cube are duplicated; we must adjust the
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// pixel weights accordingly.
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//
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if (xEdge && yEdge)
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weight /= 3;
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else if (xEdge || yEdge)
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weight /= 2;
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Rgba &pixel = pixels[toInt (pos.y)][toInt (pos.x)];
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pixel.r *= weight;
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pixel.g *= weight;
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pixel.b *= weight;
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pixel.a *= weight;
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weightTotal += weight;
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}
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}
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}
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//
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// The weighting operation above has made the overall image darker.
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// Apply a correction to recover the image's original brightness.
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//
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int w = dw.max.x - dw.min.x + 1;
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int h = dw.max.y - dw.min.y + 1;
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size_t numPixels = w * h;
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double weight = numPixels / weightTotal;
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Rgba *p = &pixels[0][0];
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Rgba *end = p + numPixels;
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while (p < end)
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{
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p->r *= weight;
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p->g *= weight;
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p->b *= weight;
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p->a *= weight;
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++p;
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}
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}
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{
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if (verbose)
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cout << " generating blurred image" << endl;
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Box2i dw1 = iptr1->dataWindow();
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int sof1 = CubeMap::sizeOfFace (dw1);
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Box2i dw2 (V2i (0, 0), V2i (OUT_WIDTH - 1, OUT_WIDTH * 6 - 1));
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int sof2 = CubeMap::sizeOfFace (dw2);
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iptr2->resize (ENVMAP_CUBE, dw2);
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iptr2->clear ();
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Array2D<Rgba> &pixels1 = iptr1->pixels();
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Array2D<Rgba> &pixels2 = iptr2->pixels();
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for (int f2 = CUBEFACE_POS_X; f2 <= CUBEFACE_NEG_Z; ++f2)
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{
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if (verbose)
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cout << " face " << f2 << endl;
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CubeMapFace face2 = CubeMapFace (f2);
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for (int y2 = 0; y2 < sof2; ++y2)
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{
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for (int x2 = 0; x2 < sof2; ++x2)
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{
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V2f posInFace2 (x2, y2);
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V3f dir2 = CubeMap::direction
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(face2, dw2, posInFace2);
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V2f pos2 = CubeMap::pixelPosition
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(face2, dw2, posInFace2);
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double weightTotal = 0;
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double rTotal = 0;
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double gTotal = 0;
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double bTotal = 0;
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double aTotal = 0;
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Rgba &pixel2 =
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pixels2[toInt (pos2.y)][toInt (pos2.x)];
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for (int f1 = CUBEFACE_POS_X; f1 <= CUBEFACE_NEG_Z; ++f1)
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{
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CubeMapFace face1 = CubeMapFace (f1);
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for (int y1 = 0; y1 < sof1; ++y1)
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{
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for (int x1 = 0; x1 < sof1; ++x1)
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{
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V2f posInFace1 (x1, y1);
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V3f dir1 = CubeMap::direction
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(face1, dw1, posInFace1);
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V2f pos1 = CubeMap::pixelPosition
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(face1, dw1, posInFace1);
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double weight = dir1 ^ dir2;
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if (weight <= 0)
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continue;
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Rgba &pixel1 =
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pixels1[toInt (pos1.y)][toInt (pos1.x)];
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weightTotal += weight;
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rTotal += pixel1.r * weight;
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gTotal += pixel1.g * weight;
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bTotal += pixel1.b * weight;
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aTotal += pixel1.a * weight;
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}
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}
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}
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pixel2.r = rTotal / weightTotal;
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pixel2.g = gTotal / weightTotal;
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pixel2.b = bTotal / weightTotal;
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pixel2.a = aTotal / weightTotal;
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}
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|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
swap (iptr1, iptr2);
|
||
|
|
}
|
||
|
|
|
||
|
|
//
|
||
|
|
// Depending on how many times we've re-sampled the image,
|
||
|
|
// the result is now either in image1 or in image2.
|
||
|
|
// If necessary, copy the result into image1.
|
||
|
|
//
|
||
|
|
|
||
|
|
if (iptr1 != &image1)
|
||
|
|
{
|
||
|
|
if (verbose)
|
||
|
|
cout << " copying" << endl;
|
||
|
|
|
||
|
|
Box2i dw = iptr1->dataWindow();
|
||
|
|
image1.resize (ENVMAP_CUBE, dw);
|
||
|
|
|
||
|
|
int w = dw.max.x - dw.min.x + 1;
|
||
|
|
int h = dw.max.y - dw.min.y + 1;
|
||
|
|
size_t size = w * h * sizeof (Rgba);
|
||
|
|
|
||
|
|
memcpy (&image1.pixels()[0][0], &iptr1->pixels()[0][0], size);
|
||
|
|
}
|
||
|
|
}
|