diff options
| -rw-r--r-- | imagelerp.c | 99 | ||||
| -rw-r--r-- | mkfile | 1 |
2 files changed, 100 insertions, 0 deletions
diff --git a/imagelerp.c b/imagelerp.c new file mode 100644 index 0000000..c23bdad --- /dev/null +++ b/imagelerp.c @@ -0,0 +1,99 @@ +#include <u.h> +#include <libc.h> +#include <draw.h> +#include <memdraw.h> + +double +flerp(double a, double b, double t) +{ + return a + (b - a)*t; +} + +double +fclamp(double n, double min, double max) +{ + return n < min? min: n > max? max: n; +} + +Memimage* +lerpimages(Memimage *i0, Memimage *i1, double blendf) +{ + Memimage *ri; + Point p; + uchar *s0, *s1, *d; + int bpp; + + assert(i0->chan == i1->chan); + assert(Dx(i0->r) == Dx(i1->r) && Dy(i0->r) == Dy(i1->r)); + + ri = allocmemimage(i0->r, i0->chan); + if(ri == nil) + sysfatal("allocmemimage: %r"); + bpp = (i0->depth+7)/8; + + for(p.y = 0; p.y < i0->r.max.y; p.y++) + for(p.x = 0; p.x < i0->r.max.x; p.x++){ + s0 = byteaddr(i0, addpt(i0->r.min, p)); + s1 = byteaddr(i1, addpt(i1->r.min, p)); + d = byteaddr(ri, addpt(ri->r.min, p)); + switch(bpp){ + case 4: + d[3] = flerp(s0[3], s1[3], blendf); + case 3: + d[2] = flerp(s0[2], s1[2], blendf); + case 2: + d[1] = flerp(s0[1], s1[1], blendf); + case 1: + d[0] = flerp(s0[0], s1[0], blendf); + } + } + return ri; +} + +void +usage(void) +{ + fprint(2, "usage: %s [-f factor] image0 image1\n", argv0); + exits("usage"); +} + +void +main(int argc, char *argv[]) +{ + Memimage *m[2], *r; + char *s; + int fd; + double f; + + f = 0.5; + ARGBEGIN{ + case 'f': + f = strtod(EARGF(usage()), &s); + if(*s != 0) + sysfatal("wrong blending factor"); + break; + default: usage(); + }ARGEND; + if(argc != 2) + usage(); + + if(memimageinit() != 0) + sysfatal("memimageinit: %r"); + fd = open(argv[0], OREAD); + if(fd < 0) + sysfatal("open: %r"); + if((m[0] = readmemimage(fd)) == nil) + sysfatal("readmemimage: %r"); + close(fd); + fd = open(argv[1], OREAD); + if(fd < 0) + sysfatal("open: %r"); + if((m[1] = readmemimage(fd)) == nil) + sysfatal("readmemimage: %r"); + close(fd); + r = lerpimages(m[0], m[1], fclamp(f, 0, 1)); + if(writememimage(1, r) < 0) + sysfatal("writememimage: %r"); + exits(nil); +} + @@ -9,6 +9,7 @@ TARG=\ isometric\ ptinline\ chain\ + imagelerp\ HFILES=\ libgeometry/geometry.h\ |