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/* See LICENSE file for copyright and license details. */
#include "arg.h"
#include "stream.h"
#include "util.h"
#include <fcntl.h>
#include <inttypes.h>
#include <string.h>
#include <unistd.h>
static void
process_xyza(struct stream *streams, size_t n_streams, size_t n)
{
double x1, y1, z1, a1;
double x2, y2, z2, a2;
size_t i, j;
for (i = 0; i < n; i += streams->pixel_size) {
x1 = ((double *)(streams[0].buf + i))[0];
y1 = ((double *)(streams[0].buf + i))[1];
z1 = ((double *)(streams[0].buf + i))[2];
a1 = ((double *)(streams[0].buf + i))[3];
for (j = 1; j < n_streams; j++) {
x2 = ((double *)(streams[j].buf + i))[0];
y2 = ((double *)(streams[j].buf + i))[1];
z2 = ((double *)(streams[j].buf + i))[2];
a2 = ((double *)(streams[j].buf + i))[3];
x1 = x1 * a1 * (1 - a2) + x2 * a2;
y1 = y1 * a1 * (1 - a2) + y2 * a2;
z1 = z1 * a1 * (1 - a2) + z2 * a2;
a1 = a1 * (1 - a2) + a2;
}
((double *)(streams[0].buf + i))[0] = x1;
((double *)(streams[0].buf + i))[1] = y1;
((double *)(streams[0].buf + i))[2] = z1;
((double *)(streams[0].buf + i))[3] = a1;
}
}
static void
process_xyza_b(struct stream *streams, size_t n_streams, size_t n)
{
double x1, y1, z1, a1;
double x2, y2, z2, a2;
size_t i, j;
for (i = 0; i < n; i += streams->pixel_size) {
x1 = ((double *)(streams[0].buf + i))[0];
y1 = ((double *)(streams[0].buf + i))[1];
z1 = ((double *)(streams[0].buf + i))[2];
a1 = ((double *)(streams[0].buf + i))[3];
for (j = 1; j < n_streams;) {
x2 = ((double *)(streams[j].buf + i))[0];
y2 = ((double *)(streams[j].buf + i))[1];
z2 = ((double *)(streams[j].buf + i))[2];
a2 = ((double *)(streams[j].buf + i))[3];
a2 /= ++j;
x1 = x1 * a1 * (1 - a2) + x2 * a2;
y1 = y1 * a1 * (1 - a2) + y2 * a2;
z1 = z1 * a1 * (1 - a2) + z2 * a2;
a1 = a1 * (1 - a2) + a2;
}
((double *)(streams[0].buf + i))[0] = x1;
((double *)(streams[0].buf + i))[1] = y1;
((double *)(streams[0].buf + i))[2] = z1;
((double *)(streams[0].buf + i))[3] = a1;
}
}
static void
usage(void)
{
eprintf("usage: %s [-b] bottom-stream ... top-stream\n", argv0);
}
int
main(int argc, char *argv[])
{
struct stream *streams;
size_t n_streams;
int blend = 0;
size_t i, j, n;
ssize_t r;
size_t closed;
void (*process)(struct stream *streams, size_t n_streams, size_t n) = NULL;
ARGBEGIN {
case 'b':
blend = 1;
break;
default:
usage();
} ARGEND;
if (argc < 2)
usage();
n_streams = (size_t)argc;
streams = calloc(n_streams, sizeof(*streams));
if (!streams)
eprintf("calloc:");
for (i = 0; i < n_streams; i++) {
streams[i].file = argv[i];
streams[i].fd = open(streams[i].file, O_RDONLY);
if (streams[i].fd < 0)
eprintf("open %s:", streams[i].file);
if (i) {
if (streams[i].width != streams->width || streams[i].height != streams->height)
eprintf("videos do not have the same geometry\n");
if (strcmp(streams[i].pixfmt, streams->pixfmt))
eprintf("videos use incompatible pixel formats\n");
}
}
if (!strcmp(streams->pixfmt, "xyza"))
process = blend ? process_xyza_b : process_xyza;
else
eprintf("pixel format %s is not supported, try xyza\n", streams->pixfmt);
while (n_streams) {
n = SIZE_MAX;
for (i = 0; i < n_streams; i++) {
if (streams[i].ptr < sizeof(streams->buf) && !eread_stream(streams + i, SIZE_MAX)) {
close(streams[i].fd);
streams[i].fd = -1;
}
if (streams[i].ptr && streams[i].ptr < n)
n = streams[i].ptr;
}
n -= n % streams->pixel_size;
process(streams, n_streams, n);
for (j = 0; j < n;) {
r = write(STDOUT_FILENO, streams->buf + j, n - j);
if (r < 0)
eprintf("write <stdout>:");
j += (size_t)r;
}
closed = SIZE_MAX;
for (i = 0; i < n_streams; i++) {
memmove(streams[i].buf, streams[i].buf + n, streams[i].ptr -= n);
if (streams[i].ptr < streams->pixel_size && streams[i].fd < 0 && closed == SIZE_MAX)
closed = i;
}
if (closed != SIZE_MAX) {
for (i = (j = closed) + 1; i < n_streams; i++)
if (streams[i].ptr < streams->pixel_size && streams[i].fd < 0)
streams[j++] = streams[i];
n_streams = j;
}
}
free(streams);
return 0;
}
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