## -*- mode: tcl ; fill-column: 90 -*-
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## Generators -- Virtual Image - Test pattern
operator image::eye {
section generator virtual
example {width 256 height 256 factor 0.8}
note Returns image containing a test pattern with increasing spatial frequency \
from left to right, and increasing amplitude (i.e. black to white) \
from top to bottom.
uint width Width of the returned image
uint height Height of the returned image
double factor Maximum spatial frequency. Range 0..1.
state -fields {
double c ; // scaling factor
double h ;
} -setup {
aktive_geometry_set (domain, 0, 0, param->width, param->height, 1);
// MAX prevents divisions by zero.
aktive_uint maxx = MAX (param->width, 1);
aktive_uint maxy = MAX (param->height, 1);
state->c = param->factor * M_PI / (2. * maxx);
state->h = maxy * maxy;
}
blit eye {
{AH {y AY 1 up} {y SY 1 up}}
{AW {x AX 1 up} {x SX 1 up}}
{DD {z 0 1 up} {z 0 1 up}}
} {point {
y * y * cos (x * x * istate->c) / istate->h
}}
pixels {
#define SD (idomain->depth)
#define SH (idomain->height)
#define SW (idomain->width)
#define SX (request->x)
#define SY (request->y)
@@eye@@
}
}
##
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::return