Paranoia2_original/utils/maketex/sdf.cpp

661 lines
20 KiB
C++

/*
imagelib.cpp - simple loader\serializer for TGA & BMP
Copyright (C) 2015 Uncle Mike
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
*/
#include "conprint.h"
#include <windows.h>
#include <direct.h>
#include <fcntl.h>
#include <stdio.h>
#include <math.h>
#include "cmdlib.h"
#include "stringlib.h"
#include "imagelib.h"
#include "filesystem.h"
#include "mathlib.h"
#define DISTAA( c, xc, yc, xi, yi ) ( distaa3( img, gx, gy, w, c, xc, yc, xi, yi ))
#define SQRT2 1.4142136
/*
* Compute the local gradient at edge pixels using convolution filters.
* The gradient is computed only at edge pixels. At other places in the
* image, it is never used, and it's mostly zero anyway.
*/
void computegradient( double *img, int w, int h, double *gx, double *gy )
{
double glength;
for( int i = 1; i < h - 1; i++ )
{
// avoid edges where the kernels would spill over
for( int j = 1; j < w - 1; j++ )
{
int k = i*w + j;
if(( img[k] > 0.0 ) && ( img[k] < 1.0 ))
{
// compute gradient for edge pixels only
gx[k] = -img[k-w-1] - SQRT2 * img[k-1] - img[k+w-1] + img[k-w+1] + SQRT2 * img[k+1] + img[k+w+1];
gy[k] = -img[k-w-1] - SQRT2 * img[k-w] - img[k+w-1] + img[k-w+1] + SQRT2 * img[k+w] + img[k+w+1];
glength = gx[k] * gx[k] + gy[k] * gy[k];
if( glength > 0.0 )
{
// avoid division by zero
glength = sqrt( glength );
gx[k] = gx[k] / glength;
gy[k] = gy[k] / glength;
}
}
}
}
}
/*
* A somewhat tricky function to approximate the distance to an edge in a
* certain pixel, with consideration to either the local gradient (gx,gy)
* or the direction to the pixel (dx,dy) and the pixel greyscale value a.
* The latter alternative, using (dx,dy), is the metric used by edtaa2().
* Using a local estimate of the edge gradient (gx,gy) yields much better
* accuracy at and near edges, and reduces the error even at distant pixels
* provided that the gradient direction is accurately estimated.
*/
double edgedf( double gx, double gy, double a )
{
double df, glength, temp, a1;
if(( gx == 0 ) || ( gy == 0 ))
{
// Either A) gu or gv are zero, or B) both
df = 0.5 - a; // Linear approximation is A) correct or B) a fair guess
}
else
{
glength = sqrt( gx * gx + gy * gy );
if( glength > 0 )
{
gx = gx / glength;
gy = gy / glength;
}
/* Everything is symmetric wrt sign and transposition,
* so move to first octant (gx>=0, gy>=0, gx>=gy) to
* avoid handling all possible edge directions.
*/
gx = fabs(gx);
gy = fabs(gy);
if( gx < gy )
{
temp = gx;
gx = gy;
gy = temp;
}
a1 = 0.5 * gy / gx;
if( a < a1 )
{
// 0 <= a < a1
df = 0.5 * (gx + gy) - sqrt( 2.0 * gx * gy * a );
}
else if( a < ( 1.0 - a1 ))
{
// a1 <= a <= 1-a1
df = (0.5 - a) * gx;
}
else
{
// 1 - a1 < a <= 1
df = -0.5 * (gx + gy) + sqrt( 2.0 * gx * gy * ( 1.0 - a ));
}
}
return df;
}
double distaa3( double *img, double *gximg, double *gyimg, int w, int c, int xc, int yc, int xi, int yi )
{
double di, df, dx, dy, gx, gy, a;
int closest;
closest = c - xc - yc * w; // index to the edge pixel pointed to from c
a = img[closest]; // grayscale value at the edge pixel
gx = gximg[closest]; // X gradient component at the edge pixel
gy = gyimg[closest]; // Y gradient component at the edge pixel
a = bound( 0.0, a, 1.0 ); // clip grayscale values outside the range [0,1]
if( a == 0.0 )
return 1000000.0; // not an object pixel, return "very far" ("don't know yet")
dx = (double)xi;
dy = (double)yi;
di = sqrt( dx * dx + dy * dy ); // length of integer vector, like a traditional EDT
if( di == 0 )
{
// use local gradient only at edges
// Estimate based on local gradient only
df = edgedf( gx, gy, a );
}
else
{
// estimate gradient based on direction to edge (accurate for large di)
df = edgedf( dx, dy, a );
}
return di + df; // Same metric as edtaa2, except at edges (where di=0)
}
void edtaa3( double *img, double *gx, double *gy, int w, int h, short *distx, short *disty, double *dist )
{
double threshold = 1e-6;
double olddist, newdist;
int offset_u, offset_ur, offset_r, offset_rd, offset_d, offset_dl, offset_l, offset_lu;
int cdistx, cdisty, newdistx, newdisty;
int changed, x, y, i, c;
// initialize index offsets for the current image width
offset_u = -w;
offset_ur = -w + 1.0;
offset_r = 1.0;
offset_rd = w + 1.0;
offset_d = w;
offset_dl = w - 1.0;
offset_l = -1.0;
offset_lu = -w - 1.0;
// initialize the distance images
for( i = 0; i < w * h; i++ )
{
distx[i] = 0; // at first, all pixels point to
disty[i] = 0; // themselves as the closest known.
if( img[i] <= 0.0 )
{
// big value, means "not set yet"
dist[i] = 1000000.0;
}
else if( img[i] < 1.0 )
{
// gradient-assisted estimate
dist[i] = edgedf( gx[i], gy[i], img[i] );
}
else
{
// inside the object
dist[i]= 0.0;
}
}
// Perform the transformation
do
{
changed = 0;
// scan rows, except first row
for( y = 1; y < h; y++ )
{
// move index to leftmost pixel of current row
i = y * w;
// scan right, propagate distances from above & left
// leftmost pixel is special, has no left neighbors
olddist = dist[i];
// if non-zero distance or not set yet
if( olddist > 0 )
{
c = i + offset_u; // index of candidate for testing
cdistx = distx[c];
cdisty = disty[c];
newdistx = cdistx;
newdisty = cdisty+1;
newdist = DISTAA( c, cdistx, cdisty, newdistx, newdisty );
if( newdist < ( olddist - threshold ))
{
distx[i] = newdistx;
disty[i] = newdisty;
dist[i] = newdist;
olddist = newdist;
changed = 1;
}
c = i + offset_ur;
cdistx = distx[c];
cdisty = disty[c];
newdistx = cdistx - 1;
newdisty = cdisty + 1;
newdist = DISTAA( c, cdistx, cdisty, newdistx, newdisty );
if( newdist < ( olddist - threshold ))
{
distx[i] = newdistx;
disty[i] = newdisty;
dist[i] = newdist;
changed = 1;
}
}
i++;
// middle pixels have all neighbors
for( x = 1; x < w - 1; x++, i++ )
{
olddist = dist[i];
if( olddist <= 0 )
continue; // no need to update further
c = i + offset_l;
cdistx = distx[c];
cdisty = disty[c];
newdistx = cdistx + 1.0;
newdisty = cdisty;
newdist = DISTAA( c, cdistx, cdisty, newdistx, newdisty );
if( newdist < ( olddist - threshold ))
{
distx[i] = newdistx;
disty[i] = newdisty;
dist[i] = newdist;
olddist = newdist;
changed = 1;
}
c = i + offset_lu;
cdistx = distx[c];
cdisty = disty[c];
newdistx = cdistx+1;
newdisty = cdisty+1;
newdist = DISTAA(c, cdistx, cdisty, newdistx, newdisty);
if(newdist < (olddist-threshold))
{
distx[i]=newdistx;
disty[i]=newdisty;
dist[i]=newdist;
olddist=newdist;
changed = 1;
}
c = i+offset_u;
cdistx = distx[c];
cdisty = disty[c];
newdistx = cdistx;
newdisty = cdisty+1;
newdist = DISTAA(c, cdistx, cdisty, newdistx, newdisty);
if(newdist < (olddist-threshold))
{
distx[i]=newdistx;
disty[i]=newdisty;
dist[i]=newdist;
olddist=newdist;
changed = 1;
}
c = i+offset_ur;
cdistx = distx[c];
cdisty = disty[c];
newdistx = cdistx-1;
newdisty = cdisty+1;
newdist = DISTAA(c, cdistx, cdisty, newdistx, newdisty);
if(newdist < (olddist-threshold))
{
distx[i]=newdistx;
disty[i]=newdisty;
dist[i]=newdist;
changed = 1;
}
}
/* Rightmost pixel of row is special, has no right neighbors */
olddist = dist[i];
if(olddist > 0) // If not already zero distance
{
c = i+offset_l;
cdistx = distx[c];
cdisty = disty[c];
newdistx = cdistx+1;
newdisty = cdisty;
newdist = DISTAA(c, cdistx, cdisty, newdistx, newdisty);
if(newdist < (olddist-threshold))
{
distx[i]=newdistx;
disty[i]=newdisty;
dist[i]=newdist;
olddist=newdist;
changed = 1;
}
c = i+offset_lu;
cdistx = distx[c];
cdisty = disty[c];
newdistx = cdistx+1;
newdisty = cdisty+1;
newdist = DISTAA(c, cdistx, cdisty, newdistx, newdisty);
if(newdist < (olddist-threshold))
{
distx[i]=newdistx;
disty[i]=newdisty;
dist[i]=newdist;
olddist=newdist;
changed = 1;
}
c = i+offset_u;
cdistx = distx[c];
cdisty = disty[c];
newdistx = cdistx;
newdisty = cdisty+1;
newdist = DISTAA(c, cdistx, cdisty, newdistx, newdisty);
if(newdist < (olddist-threshold))
{
distx[i]=newdistx;
disty[i]=newdisty;
dist[i]=newdist;
changed = 1;
}
}
/* Move index to second rightmost pixel of current row. */
/* Rightmost pixel is skipped, it has no right neighbor. */
i = y*w + w-2;
/* scan left, propagate distance from right */
for(x=w-2; x>=0; x--, i--)
{
olddist = dist[i];
if(olddist <= 0) continue; // Already zero distance
c = i+offset_r;
cdistx = distx[c];
cdisty = disty[c];
newdistx = cdistx-1;
newdisty = cdisty;
newdist = DISTAA(c, cdistx, cdisty, newdistx, newdisty);
if(newdist < (olddist-threshold))
{
distx[i]=newdistx;
disty[i]=newdisty;
dist[i]=newdist;
changed = 1;
}
}
}
/* Scan rows in reverse order, except last row */
for(y=h-2; y>=0; y--)
{
/* move index to rightmost pixel of current row */
i = y*w + w-1;
/* Scan left, propagate distances from below & right */
/* Rightmost pixel is special, has no right neighbors */
olddist = dist[i];
if(olddist > 0) // If not already zero distance
{
c = i+offset_d;
cdistx = distx[c];
cdisty = disty[c];
newdistx = cdistx;
newdisty = cdisty-1;
newdist = DISTAA(c, cdistx, cdisty, newdistx, newdisty);
if(newdist < (olddist-threshold))
{
distx[i]=newdistx;
disty[i]=newdisty;
dist[i]=newdist;
olddist=newdist;
changed = 1;
}
c = i+offset_dl;
cdistx = distx[c];
cdisty = disty[c];
newdistx = cdistx+1;
newdisty = cdisty-1;
newdist = DISTAA(c, cdistx, cdisty, newdistx, newdisty);
if(newdist < (olddist-threshold))
{
distx[i]=newdistx;
disty[i]=newdisty;
dist[i]=newdist;
changed = 1;
}
}
i--;
/* Middle pixels have all neighbors */
for(x=w-2; x>0; x--, i--)
{
olddist = dist[i];
if(olddist <= 0) continue; // Already zero distance
c = i+offset_r;
cdistx = distx[c];
cdisty = disty[c];
newdistx = cdistx-1;
newdisty = cdisty;
newdist = DISTAA(c, cdistx, cdisty, newdistx, newdisty);
if(newdist < (olddist-threshold))
{
distx[i]=newdistx;
disty[i]=newdisty;
dist[i]=newdist;
olddist=newdist;
changed = 1;
}
c = i+offset_rd;
cdistx = distx[c];
cdisty = disty[c];
newdistx = cdistx-1;
newdisty = cdisty-1;
newdist = DISTAA(c, cdistx, cdisty, newdistx, newdisty);
if(newdist < (olddist-threshold))
{
distx[i]=newdistx;
disty[i]=newdisty;
dist[i]=newdist;
olddist=newdist;
changed = 1;
}
c = i+offset_d;
cdistx = distx[c];
cdisty = disty[c];
newdistx = cdistx;
newdisty = cdisty-1;
newdist = DISTAA(c, cdistx, cdisty, newdistx, newdisty);
if(newdist < (olddist-threshold))
{
distx[i]=newdistx;
disty[i]=newdisty;
dist[i]=newdist;
olddist=newdist;
changed = 1;
}
c = i+offset_dl;
cdistx = distx[c];
cdisty = disty[c];
newdistx = cdistx+1;
newdisty = cdisty-1;
newdist = DISTAA(c, cdistx, cdisty, newdistx, newdisty);
if(newdist < (olddist-threshold))
{
distx[i]=newdistx;
disty[i]=newdisty;
dist[i]=newdist;
changed = 1;
}
}
/* Leftmost pixel is special, has no left neighbors */
olddist = dist[i];
if(olddist > 0) // If not already zero distance
{
c = i+offset_r;
cdistx = distx[c];
cdisty = disty[c];
newdistx = cdistx-1;
newdisty = cdisty;
newdist = DISTAA(c, cdistx, cdisty, newdistx, newdisty);
if(newdist < (olddist-threshold))
{
distx[i]=newdistx;
disty[i]=newdisty;
dist[i]=newdist;
olddist=newdist;
changed = 1;
}
c = i+offset_rd;
cdistx = distx[c];
cdisty = disty[c];
newdistx = cdistx-1;
newdisty = cdisty-1;
newdist = DISTAA(c, cdistx, cdisty, newdistx, newdisty);
if(newdist < (olddist-threshold))
{
distx[i]=newdistx;
disty[i]=newdisty;
dist[i]=newdist;
olddist=newdist;
changed = 1;
}
c = i+offset_d;
cdistx = distx[c];
cdisty = disty[c];
newdistx = cdistx;
newdisty = cdisty-1;
newdist = DISTAA(c, cdistx, cdisty, newdistx, newdisty);
if(newdist < (olddist-threshold))
{
distx[i]=newdistx;
disty[i]=newdisty;
dist[i]=newdist;
changed = 1;
}
}
/* Move index to second leftmost pixel of current row. */
/* Leftmost pixel is skipped, it has no left neighbor. */
i = y*w + 1;
for(x=1; x<w; x++, i++)
{
/* scan right, propagate distance from left */
olddist = dist[i];
if(olddist <= 0) continue; // Already zero distance
c = i+offset_l;
cdistx = distx[c];
cdisty = disty[c];
newdistx = cdistx+1;
newdisty = cdisty;
newdist = DISTAA(c, cdistx, cdisty, newdistx, newdisty);
if(newdist < (olddist-threshold))
{
distx[i]=newdistx;
disty[i]=newdisty;
dist[i]=newdist;
changed = 1;
}
}
}
}
while(changed); // Sweep until no more updates are made
/* The transformation is completed. */
}
void Image_MakeSignedDistanceField( rgbdata_t *pic )
{
if( FBitSet( pic->flags, IMAGE_DXT_FORMAT ))
return; // can't merge compressed formats
if( !FBitSet( pic->flags, IMAGE_HAS_1BIT_ALPHA ))
return; // generate SDF from onebit alpha
short *xdist = (short *)Mem_Alloc( pic->width * pic->height * sizeof( short ));
short *ydist = (short *)Mem_Alloc( pic->width * pic->height * sizeof( short ));
double *gx = (double *)Mem_Alloc( pic->width * pic->height * sizeof( double ));
double *gy = (double *)Mem_Alloc( pic->width * pic->height * sizeof( double ));
double *data = (double *)Mem_Alloc( pic->width * pic->height * sizeof( double ));
double *outside = (double *)Mem_Alloc( pic->width * pic->height * sizeof( double ));
double *inside = (double *)Mem_Alloc( pic->width * pic->height * sizeof( double ));
double img_min = 255, img_max = -255;
int i;
// convert img into double (data)
for( i = 0; i < pic->width * pic->height; ++i )
{
data[i] = pic->buffer[i*4+3];
img_min = Q_min( data[i], img_min );
img_max = Q_max( data[i], img_max );
}
// rescale image levels between 0 and 1
for( i = 0; i < pic->width * pic->height; ++i )
{
data[i] = ( pic->buffer[i*4+3] - img_min ) / img_max;
}
// compute outside = edtaa3( bitmap ); % Transform background (0's)
computegradient( data, pic->height, pic->width, gx, gy );
edtaa3( data, gx, gy, pic->height, pic->width, xdist, ydist, outside );
for( i = 0; i < pic->width * pic->height; ++i )
outside[i] = Q_max( 0.0, outside[i] );
// compute inside = edtaa3( 1 - bitmap ); % Transform foreground (1's)
memset( gx, 0, pic->width * pic->height * sizeof( double ));
memset( gy, 0, pic->width * pic->height * sizeof( double ));
for( i = 0; i < pic->width * pic->height; ++i )
data[i] = 1.0 - data[i];
computegradient( data, pic->height, pic->width, gx, gy );
edtaa3( data, gx, gy, pic->height, pic->width, xdist, ydist, inside );
for( i = 0; i < pic->width * pic->height; ++i )
inside[i] = Q_max( 0.0, inside[i] );
// distmap = outside - inside; % Bipolar distance field
for( i = 0; i < pic->width * pic->height; ++i )
{
outside[i] -= inside[i];
outside[i] = 128 + outside[i] * 8;
outside[i] = bound( 0, outside[i], 255 );
pic->buffer[i*4+3] = 255 - (byte)outside[i];
}
ClearBits( pic->flags, IMAGE_HAS_1BIT_ALPHA );
ClearBits( pic->flags, IMAGE_HAS_8BIT_ALPHA );
SetBits( pic->flags, IMAGE_HAS_SDF_ALPHA );
Mem_Free( xdist );
Mem_Free( ydist );
Mem_Free( gx );
Mem_Free( gy );
Mem_Free( data );
Mem_Free( outside );
Mem_Free( inside );
}