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filters.im
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#define IMAGER_NO_CONTEXT
#include "imager.h"
#include "imageri.h"
#include <stdlib.h>
#include <math.h>
/*
=head1 NAME
filters.im - implements filters that operate on images
=head1 SYNOPSIS
i_contrast(im, 0.8);
i_hardinvert(im);
i_hardinvertall(im);
i_unsharp_mask(im, 2.0, 1.0);
... and more
=head1 DESCRIPTION
filters.c implements basic filters for Imager. These filters
should be accessible from the filter interface as defined in
the pod for Imager.
=head1 FUNCTION REFERENCE
Some of these functions are internal.
=over
=cut
*/
/*
=item saturate(in)
Clamps the input value between 0 and 255. (internal)
in - input integer
=cut
*/
static
unsigned char
saturate(int in) {
if (in>255) { return 255; }
else if (in>0) return in;
return 0;
}
/*
=item i_contrast(im, intensity)
Scales the pixel values by the amount specified.
im - image object
intensity - scalefactor
=cut
*/
void
i_contrast(i_img *im, float intensity) {
i_img_dim x, y;
int ch;
unsigned int new_color;
i_color rcolor;
dIMCTXim(im);
im_log((aIMCTX, 1,"i_contrast(im %p, intensity %f)\n", im, intensity));
if(intensity < 0) return;
for(y = 0; y < im->ysize; y++) for(x = 0; x < im->xsize; x++) {
i_gpix(im, x, y, &rcolor);
for(ch = 0; ch < im->channels; ch++) {
new_color = (unsigned int) rcolor.channel[ch];
new_color *= intensity;
if(new_color > 255) {
new_color = 255;
}
rcolor.channel[ch] = (unsigned char) new_color;
}
i_ppix(im, x, y, &rcolor);
}
}
static int
s_hardinvert_low(i_img *im, int all) {
i_img_dim x, y;
int ch;
int invert_channels = all ? im->channels : i_img_color_channels(im);
dIMCTXim(im);
im_log((aIMCTX,1,"i_hardinvert)low(im %p, all %d)\n", im, all));
#code im->bits <= 8
IM_COLOR *row, *entry;
/* always rooms to allocate a single line of i_color */
row = mymalloc(sizeof(IM_COLOR) * im->xsize); /* checked 17feb2005 tonyc */
for(y = 0; y < im->ysize; y++) {
IM_GLIN(im, 0, im->xsize, y, row);
entry = row;
for(x = 0; x < im->xsize; x++) {
for(ch = 0; ch < invert_channels; ch++) {
entry->channel[ch] = IM_SAMPLE_MAX - entry->channel[ch];
}
++entry;
}
IM_PLIN(im, 0, im->xsize, y, row);
}
myfree(row);
#/code
return 1;
}
/*
=item i_hardinvert(im)
Inverts the color channels of the input image.
im - image object
=cut
*/
void
i_hardinvert(i_img *im) {
s_hardinvert_low(im, 0);
}
/*
=item i_hardinvertall(im)
Inverts all channels of the input image.
im - image object
=cut
*/
void
i_hardinvertall(i_img *im) {
s_hardinvert_low(im, 1);
}
/*
=item i_noise(im, amount, type)
Adjusts the sample values randomly by the amount specified.
If type is 0, adjust all channels in a pixel by the same (random)
amount amount, if non-zero adjust each sample independently.
im - image object
amount - deviation in pixel values
type - noise individual for each channel if true
=cut
*/
#ifdef WIN32
/* random() is non-ASCII, even if it is better than rand() */
#define random() rand()
#endif
void
i_noise(i_img *im, float amount, unsigned char type) {
i_img_dim x, y;
int ch;
int new_color;
float damount = amount * 2;
i_color rcolor;
int color_inc = 0;
dIMCTXim(im);
im_log((aIMCTX, 1,"i_noise(im %p, intensity %.2f\n", im, amount));
if(amount < 0) return;
for(y = 0; y < im->ysize; y++) for(x = 0; x < im->xsize; x++) {
i_gpix(im, x, y, &rcolor);
if(type == 0) {
color_inc = (amount - (damount * ((double)random() / RAND_MAX)));
}
for(ch = 0; ch < im->channels; ch++) {
new_color = (int) rcolor.channel[ch];
if(type != 0) {
new_color += (amount - (damount * ((double)random() / RAND_MAX)));
} else {
new_color += color_inc;
}
if(new_color < 0) {
new_color = 0;
}
if(new_color > 255) {
new_color = 255;
}
rcolor.channel[ch] = (unsigned char) new_color;
}
i_ppix(im, x, y, &rcolor);
}
}
/*
=item i_bumpmap(im, bump, channel, light_x, light_y, st)
Makes a bumpmap on image im using the bump image as the elevation map.
im - target image
bump - image that contains the elevation info
channel - to take the elevation information from
light_x - x coordinate of light source
light_y - y coordinate of light source
st - length of shadow
=cut
*/
void
i_bumpmap(i_img *im, i_img *bump, int channel, i_img_dim light_x, i_img_dim light_y, i_img_dim st) {
i_img_dim x, y;
int ch;
i_img_dim mx, my;
i_color x1_color, y1_color, x2_color, y2_color, dst_color;
double nX, nY;
double tX, tY, tZ;
double aX, aY, aL;
double fZ;
unsigned char px1, px2, py1, py2;
dIMCTXim(im);
i_img new_im;
im_log((aIMCTX, 1, "i_bumpmap(im %p, add_im %p, channel %d, light(" i_DFp "), st %" i_DF ")\n",
im, bump, channel, i_DFcp(light_x, light_y), i_DFc(st)));
if(channel >= bump->channels) {
im_log((aIMCTX, 1, "i_bumpmap: channel = %d while bump image only has %d channels\n", channel, bump->channels));
return;
}
mx = (bump->xsize <= im->xsize) ? bump->xsize : im->xsize;
my = (bump->ysize <= im->ysize) ? bump->ysize : im->ysize;
i_img_empty_ch(&new_im, im->xsize, im->ysize, im->channels);
aX = (light_x > (mx >> 1)) ? light_x : mx - light_x;
aY = (light_y > (my >> 1)) ? light_y : my - light_y;
aL = sqrt((aX * aX) + (aY * aY));
for(y = 1; y < my - 1; y++) {
for(x = 1; x < mx - 1; x++) {
i_gpix(bump, x + st, y, &x1_color);
i_gpix(bump, x, y + st, &y1_color);
i_gpix(bump, x - st, y, &x2_color);
i_gpix(bump, x, y - st, &y2_color);
i_gpix(im, x, y, &dst_color);
px1 = x1_color.channel[channel];
py1 = y1_color.channel[channel];
px2 = x2_color.channel[channel];
py2 = y2_color.channel[channel];
nX = px1 - px2;
nY = py1 - py2;
nX += 128;
nY += 128;
fZ = (sqrt((nX * nX) + (nY * nY)) / aL);
tX = i_abs(x - light_x) / aL;
tY = i_abs(y - light_y) / aL;
tZ = 1 - (sqrt((tX * tX) + (tY * tY)) * fZ);
if(tZ < 0) tZ = 0;
if(tZ > 2) tZ = 2;
for(ch = 0; ch < im->channels; ch++)
dst_color.channel[ch] = (unsigned char) (float)(dst_color.channel[ch] * tZ);
i_ppix(&new_im, x, y, &dst_color);
}
}
i_copyto(im, &new_im, 0, 0, im->xsize, im->ysize, 0, 0);
i_img_exorcise(&new_im);
}
typedef struct {
double x,y,z;
} fvec;
static
float
dotp(fvec *a, fvec *b) {
return a->x*b->x+a->y*b->y+a->z*b->z;
}
static
void
normalize(fvec *a) {
double d = sqrt(dotp(a,a));
a->x /= d;
a->y /= d;
a->z /= d;
}
/*
positive directions:
x - right,
y - down
z - out of the plane
I = Ia + Ip*( cd*Scol(N.L) + cs*(R.V)^n )
Here, the variables are:
* Ia - ambient colour
* Ip - intensity of the point light source
* cd - diffuse coefficient
* Scol - surface colour
* cs - specular coefficient
* n - objects shinyness
* N - normal vector
* L - lighting vector
* R - reflection vector
* V - vision vector
static void fvec_dump(fvec *x) {
printf("(%.2f %.2f %.2f)", x->x, x->y, x->z);
}
*/
/* XXX: Should these return a code for success? */
/*
=item i_bumpmap_complex(im, bump, channel, tx, ty, Lx, Ly, Lz, Ip, cd, cs, n, Ia, Il, Is)
Makes a bumpmap on image im using the bump image as the elevation map.
im - target image
bump - image that contains the elevation info
channel - to take the elevation information from
tx - shift in x direction of where to start applying bumpmap
ty - shift in y direction of where to start applying bumpmap
Lx - x position/direction of light
Ly - y position/direction of light
Lz - z position/direction of light
Ip - light intensity
cd - diffuse coefficient
cs - specular coefficient
n - surface shinyness
Ia - ambient colour
Il - light colour
Is - specular colour
if z<0 then the L is taken to be the direction the light is shining in. Otherwise
the L is taken to be the position of the Light, Relative to the image.
=cut
*/
void
i_bumpmap_complex(i_img *im,
i_img *bump,
int channel,
i_img_dim tx,
i_img_dim ty,
double Lx,
double Ly,
double Lz,
float cd,
float cs,
float n,
i_color *Ia,
i_color *Il,
i_color *Is) {
i_img new_im;
i_img_dim x, y;
int ch;
i_img_dim mx, Mx, my, My;
float cdc[MAXCHANNELS];
float csc[MAXCHANNELS];
i_color x1_color, y1_color, x2_color, y2_color;
i_color Scol; /* Surface colour */
fvec L; /* Light vector */
fvec N; /* surface normal */
fvec R; /* Reflection vector */
fvec V; /* Vision vector */
dIMCTXim(im);
im_log((aIMCTX, 1, "i_bumpmap_complex(im %p, bump %p, channel %d, t(" i_DFp
"), Lx %.2f, Ly %.2f, Lz %.2f, cd %.2f, cs %.2f, n %.2f, Ia %p, Il %p, Is %p)\n",
im, bump, channel, i_DFcp(tx, ty), Lx, Ly, Lz, cd, cs, n, Ia, Il, Is));
if (channel >= bump->channels) {
im_log((aIMCTX, 1, "i_bumpmap_complex: channel = %d while bump image only has %d channels\n", channel, bump->channels));
return;
}
for(ch=0; ch<im->channels; ch++) {
cdc[ch] = (float)Il->channel[ch]*cd/255.f;
csc[ch] = (float)Is->channel[ch]*cs/255.f;
}
mx = 1;
my = 1;
Mx = bump->xsize-1;
My = bump->ysize-1;
V.x = 0;
V.y = 0;
V.z = 1;
if (Lz < 0) { /* Light specifies a direction vector, reverse it to get the vector from surface to light */
L.x = -Lx;
L.y = -Ly;
L.z = -Lz;
normalize(&L);
} else { /* Light is the position of the light source */
L.x = -0.2;
L.y = -0.4;
L.z = 1;
normalize(&L);
}
i_img_empty_ch(&new_im, im->xsize, im->ysize, im->channels);
for(y = 0; y < im->ysize; y++) {
for(x = 0; x < im->xsize; x++) {
double dp1, dp2;
double dx = 0, dy = 0;
/* Calculate surface normal */
if (mx<x && x<Mx && my<y && y<My) {
i_gpix(bump, x + 1, y, &x1_color);
i_gpix(bump, x - 1, y, &x2_color);
i_gpix(bump, x, y + 1, &y1_color);
i_gpix(bump, x, y - 1, &y2_color);
dx = x2_color.channel[channel] - x1_color.channel[channel];
dy = y2_color.channel[channel] - y1_color.channel[channel];
} else {
dx = 0;
dy = 0;
}
N.x = -dx * 0.015;
N.y = -dy * 0.015;
N.z = 1;
normalize(&N);
/* Calculate Light vector if needed */
if (Lz>=0) {
L.x = Lx - x;
L.y = Ly - y;
L.z = Lz;
normalize(&L);
}
dp1 = dotp(&L,&N);
R.x = -L.x + 2*dp1*N.x;
R.y = -L.y + 2*dp1*N.y;
R.z = -L.z + 2*dp1*N.z;
dp2 = dotp(&R,&V);
dp1 = dp1<0 ?0 : dp1;
dp2 = pow(dp2<0 ?0 : dp2,n);
i_gpix(im, x, y, &Scol);
for(ch = 0; ch < im->channels; ch++)
Scol.channel[ch] =
saturate( Ia->channel[ch] + cdc[ch]*Scol.channel[ch]*dp1 + csc[ch]*dp2 );
i_ppix(&new_im, x, y, &Scol);
}
}
i_copyto(im, &new_im, 0, 0, im->xsize, im->ysize, 0, 0);
i_img_exorcise(&new_im);
}
/*
=item i_postlevels(im, levels)
Quantizes Images to fewer levels.
im - target image
levels - number of levels
=cut
*/
void
i_postlevels(i_img *im, int levels) {
i_img_dim x, y;
int ch;
float pv;
int rv;
float av;
i_color rcolor;
rv = (int) ((float)(256 / levels));
av = (float)levels;
for(y = 0; y < im->ysize; y++) for(x = 0; x < im->xsize; x++) {
i_gpix(im, x, y, &rcolor);
for(ch = 0; ch < im->channels; ch++) {
pv = (((float)rcolor.channel[ch] / 255)) * av;
pv = (int) ((int)pv * rv);
if(pv < 0) pv = 0;
else if(pv > 255) pv = 255;
rcolor.channel[ch] = (unsigned char) pv;
}
i_ppix(im, x, y, &rcolor);
}
}
/*
=item i_mosaic(im, size)
Makes an image looks like a mosaic with tilesize of size
im - target image
size - size of tiles
=cut
*/
void
i_mosaic(i_img *im, i_img_dim size) {
i_img_dim x, y;
int ch, z;
i_img_dim lx, ly;
long sqrsize;
i_color rcolor;
long col[256];
sqrsize = size * size;
for(y = 0; y < im->ysize; y += size) for(x = 0; x < im->xsize; x += size) {
for(z = 0; z < 256; z++) col[z] = 0;
for(lx = 0; lx < size; lx++) {
for(ly = 0; ly < size; ly++) {
i_gpix(im, (x + lx), (y + ly), &rcolor);
for(ch = 0; ch < im->channels; ch++) {
col[ch] += rcolor.channel[ch];
}
}
}
for(ch = 0; ch < im->channels; ch++)
rcolor.channel[ch] = (int) ((float)col[ch] / sqrsize);
for(lx = 0; lx < size; lx++)
for(ly = 0; ly < size; ly++)
i_ppix(im, (x + lx), (y + ly), &rcolor);
}
}
/*
=item i_watermark(im, wmark, tx, ty, pixdiff)
Applies a watermark to the target image
im - target image
wmark - watermark image
tx - x coordinate of where watermark should be applied
ty - y coordinate of where watermark should be applied
pixdiff - the magnitude of the watermark, controls how visible it is
=cut
*/
void
i_watermark(i_img *im, i_img *wmark, i_img_dim tx, i_img_dim ty, int pixdiff) {
i_img_dim vx, vy;
int ch;
i_color val, wval;
i_img_dim mx = wmark->xsize;
i_img_dim my = wmark->ysize;
for(vx=0;vx<mx;vx++) for(vy=0;vy<my;vy++) {
i_gpix(im, tx+vx, ty+vy,&val );
i_gpix(wmark, vx, vy, &wval);
for(ch=0;ch<im->channels;ch++)
val.channel[ch] = saturate( val.channel[ch] + (pixdiff* (wval.channel[0]-128) )/128 );
i_ppix(im,tx+vx,ty+vy,&val);
}
}
/*
=item i_autolevels_mono(im, lsat, usat)
Do autolevels, but monochromatically.
=cut
*/
void
i_autolevels_mono(i_img *im, float lsat, float usat) {
i_color val;
i_img_dim i, x, y, hist[256];
i_img_dim sum_lum, min_lum, max_lum;
i_img_dim upper_accum, lower_accum;
i_color *row;
dIMCTXim(im);
int adapt_channels = im->channels == 4 ? 2 : 1;
int color_channels = i_img_color_channels(im);
i_img_dim color_samples = im->xsize * color_channels;
im_log((aIMCTX, 1,"i_autolevels_mono(im %p, lsat %f,usat %f)\n", im, lsat,usat));
/* build the histogram in 8-bits, unless the image has a very small
range it should make little difference to the result */
sum_lum = 0;
for (i = 0; i < 256; i++)
hist[i] = 0;
row = mymalloc(im->xsize * sizeof(i_color));
/* create histogram for each channel */
for (y = 0; y < im->ysize; y++) {
i_color *p = row;
i_glin(im, 0, im->xsize, y, row);
if (im->channels > 2)
i_adapt_colors(adapt_channels, im->channels, row, im->xsize);
for (x = 0; x < im->xsize; x++) {
hist[p->channel[0]]++;
++p;
}
}
myfree(row);
for(i = 0; i < 256; i++) {
sum_lum += hist[i];
}
min_lum = 0;
lower_accum = 0;
for (i = 0; i < 256; ++i) {
if (lower_accum < sum_lum * lsat)
min_lum = i;
lower_accum += hist[i];
}
max_lum = 255;
upper_accum = 0;
for(i = 255; i >= 0; i--) {
if (upper_accum < sum_lum * usat)
max_lum = i;
upper_accum += hist[i];
}
#code im->bits <= 8
IM_SAMPLE_T *srow = mymalloc(color_samples * sizeof(IM_SAMPLE_T));
#ifdef IM_EIGHT_BIT
IM_WORK_T low = min_lum;
i_sample_t lookup[256];
#else
IM_WORK_T low = min_lum / 255.0 * IM_SAMPLE_MAX;
#endif
double scale = 255.0 / (max_lum - min_lum);
#ifdef IM_EIGHT_BIT
for (i = 0; i < 256; ++i) {
IM_WORK_T tmp = (i - low) * scale;
lookup[i] = IM_LIMIT(tmp);
}
#endif
for(y = 0; y < im->ysize; y++) {
IM_GSAMP(im, 0, im->xsize, y, srow, NULL, color_channels);
for(i = 0; i < color_samples; ++i) {
#ifdef IM_EIGHT_BIT
srow[i] = lookup[srow[i]];
#else
IM_WORK_T tmp = (srow[i] - low) * scale;
srow[i] = IM_LIMIT(tmp);
#endif
}
IM_PSAMP(im, 0, im->xsize, y, srow, NULL, color_channels);
}
myfree(srow);
#/code
}
/*
=item i_autolevels(im, lsat, usat, skew)
Scales and translates each color such that it fills the range completely.
Skew is not implemented yet - purpose is to control the color skew that can
occur when changing the contrast.
im - target image
lsat - fraction of pixels that will be truncated at the lower end of the spectrum
usat - fraction of pixels that will be truncated at the higher end of the spectrum
skew - not used yet
Note: this code calculates levels and adjusts each channel separately,
which will typically cause a color shift.
=cut
*/
void
i_autolevels(i_img *im, float lsat, float usat, float skew) {
i_color val;
i_img_dim i, x, y, rhist[256], ghist[256], bhist[256];
i_img_dim rsum, rmin, rmax;
i_img_dim gsum, gmin, gmax;
i_img_dim bsum, bmin, bmax;
i_img_dim rcl, rcu, gcl, gcu, bcl, bcu;
dIMCTXim(im);
im_log((aIMCTX, 1,"i_autolevels(im %p, lsat %f,usat %f,skew %f)\n", im, lsat,usat,skew));
rsum=gsum=bsum=0;
for(i=0;i<256;i++) rhist[i]=ghist[i]=bhist[i] = 0;
/* create histogram for each channel */
for(y = 0; y < im->ysize; y++) for(x = 0; x < im->xsize; x++) {
i_gpix(im, x, y, &val);
rhist[val.channel[0]]++;
ghist[val.channel[1]]++;
bhist[val.channel[2]]++;
}
for(i=0;i<256;i++) {
rsum+=rhist[i];
gsum+=ghist[i];
bsum+=bhist[i];
}
rmin = gmin = bmin = 0;
rmax = gmax = bmax = 255;
rcu = rcl = gcu = gcl = bcu = bcl = 0;
for(i=0; i<256; i++) {
rcl += rhist[i]; if ( (rcl<rsum*lsat) ) rmin=i;
rcu += rhist[255-i]; if ( (rcu<rsum*usat) ) rmax=255-i;
gcl += ghist[i]; if ( (gcl<gsum*lsat) ) gmin=i;
gcu += ghist[255-i]; if ( (gcu<gsum*usat) ) gmax=255-i;
bcl += bhist[i]; if ( (bcl<bsum*lsat) ) bmin=i;
bcu += bhist[255-i]; if ( (bcu<bsum*usat) ) bmax=255-i;
}
for(y = 0; y < im->ysize; y++) for(x = 0; x < im->xsize; x++) {
i_gpix(im, x, y, &val);
val.channel[0]=saturate((val.channel[0]-rmin)*255/(rmax-rmin));
val.channel[1]=saturate((val.channel[1]-gmin)*255/(gmax-gmin));
val.channel[2]=saturate((val.channel[2]-bmin)*255/(bmax-bmin));
i_ppix(im, x, y, &val);
}
}
/*
=item Noise(x,y)
Pseudo noise utility function used to generate perlin noise. (internal)
x - x coordinate
y - y coordinate
=cut
*/
static
double
Noise(i_img_dim x, i_img_dim y) {
i_img_dim n = x + y * 57;
n = (n<<13) ^ n;
return ( 1.0 - ( (n * (n * n * 15731 + 789221) + 1376312589) & 0x7fffffff) / 1073741824.0);
}
/*
=item SmoothedNoise1(x,y)
Pseudo noise utility function used to generate perlin noise. (internal)
x - x coordinate
y - y coordinate
=cut
*/
static
double
SmoothedNoise1(double x, double y) {
double corners = ( Noise(x-1, y-1)+Noise(x+1, y-1)+Noise(x-1, y+1)+Noise(x+1, y+1) ) / 16;
double sides = ( Noise(x-1, y) +Noise(x+1, y) +Noise(x, y-1) +Noise(x, y+1) ) / 8;
double center = Noise(x, y) / 4;
return corners + sides + center;
}
/*
=item G_Interpolate(a, b, x)
Utility function used to generate perlin noise. (internal)
=cut
*/
static
double
C_Interpolate(double a, double b, double x) {
/* float ft = x * 3.1415927; */
double ft = x * PI;
double f = (1 - cos(ft)) * .5;
return a*(1-f) + b*f;
}
/*
=item InterpolatedNoise(x, y)
Utility function used to generate perlin noise. (internal)
=cut
*/
static
double
InterpolatedNoise(double x, double y) {
i_img_dim integer_X = x;
double fractional_X = x - integer_X;
i_img_dim integer_Y = y;
double fractional_Y = y - integer_Y;
double v1 = SmoothedNoise1(integer_X, integer_Y);
double v2 = SmoothedNoise1(integer_X + 1, integer_Y);
double v3 = SmoothedNoise1(integer_X, integer_Y + 1);
double v4 = SmoothedNoise1(integer_X + 1, integer_Y + 1);
double i1 = C_Interpolate(v1 , v2 , fractional_X);
double i2 = C_Interpolate(v3 , v4 , fractional_X);
return C_Interpolate(i1 , i2 , fractional_Y);
}
/*
=item PerlinNoise_2D(x, y)
Utility function used to generate perlin noise. (internal)
=cut
*/
static
float
PerlinNoise_2D(float x, float y) {
int i;
double frequency;
double amplitude;
double total = 0;
int Number_Of_Octaves=6;
int n = Number_Of_Octaves - 1;
for(i=0;i<n;i++) {
frequency = 2.0 * i;
amplitude = PI;
total = total + InterpolatedNoise(x * frequency, y * frequency) * amplitude;
}
return total;
}
/*
=item i_radnoise(im, xo, yo, rscale, ascale)
Perlin-like radial noise.
im - target image
xo - x coordinate of center
yo - y coordinate of center
rscale - radial scale
ascale - angular scale
=cut
*/
void
i_radnoise(i_img *im, i_img_dim xo, i_img_dim yo, double rscale, double ascale) {
i_img_dim x, y;
int ch;
i_color val;
unsigned char v;
double xc, yc, r;
double a;
for(y = 0; y < im->ysize; y++) for(x = 0; x < im->xsize; x++) {
xc = (double)x-xo+0.5;
yc = (double)y-yo+0.5;
r = rscale*sqrt(xc*xc+yc*yc)+1.2;
a = (PI+atan2(yc,xc))*ascale;
v = saturate(128+100*(PerlinNoise_2D(a,r)));
/* v=saturate(120+12*PerlinNoise_2D(xo+(float)x/scale,yo+(float)y/scale)); Good soft marble */
for(ch=0; ch<im->channels; ch++) val.channel[ch]=v;
i_ppix(im, x, y, &val);
}
}
/*
=item i_turbnoise(im, xo, yo, scale)
Perlin-like 2d noise noise.
im - target image
xo - x coordinate translation
yo - y coordinate translation
scale - scale of noise
=cut
*/
void
i_turbnoise(i_img *im, double xo, double yo, double scale) {
i_img_dim x,y;
int ch;
unsigned char v;
i_color val;
for(y = 0; y < im->ysize; y++) for(x = 0; x < im->xsize; x++) {
/* v=saturate(125*(1.0+PerlinNoise_2D(xo+(float)x/scale,yo+(float)y/scale))); */
v = saturate(120*(1.0+sin(xo+(double)x/scale+PerlinNoise_2D(xo+(double)x/scale,yo+(float)y/scale))));
for(ch=0; ch<im->channels; ch++) val.channel[ch] = v;
i_ppix(im, x, y, &val);
}
}