1 files changed, 92 insertions, 0 deletions
diff --git a/src/blind-chroma-key.c b/src/blind-chroma-key.c
new file mode 100644
index 0000000..e7b1448
--- /dev/null
+++ b/src/blind-chroma-key.c
@@ -0,0 +1,92 @@
+/* See LICENSE file for copyright and license details. */
+#include "common.h"
+
+USAGE("key-stream")
+
+
+#define PROCESS(TYPE, SUFFIX)\
+	static void\
+	process_##SUFFIX(struct stream *stream, struct stream *key)\
+	{\
+		size_t i, n, m = 0;\
+		TYPE x1, y1, z1, a1, a2, variance2, *keyxyza;\
+		TYPE x, y, z, d;\
+		do {\
+			if (!m) {\
+				m = stream->frame_size;\
+				while (key->ptr < key->frame_size)\
+					if (!eread_stream(key, key->frame_size - key->ptr))\
+						return;\
+				keyxyza = (TYPE *)(key->buf);\
+				x1 = keyxyza[0];\
+				y1 = keyxyza[1];\
+				z1 = keyxyza[2];\
+				a1 = keyxyza[3];\
+				x = x1 - keyxyza[4];\
+				y = y1 - keyxyza[5];\
+				z = z1 - keyxyza[6];\
+				a2 = keyxyza[7];\
+				variance2 = x * x + y * y + z * z;\
+				if (a2 > a1) {\
+					a1 = 1 - a1;\
+					a2 = 1 - a2;\
+				}\
+				memmove(key->buf, key->buf + key->frame_size,\
+					key->ptr -= key->frame_size);\
+			}\
+			n = MIN(stream->ptr, m) / stream->pixel_size;\
+			for (i = 0; i < n; i++) {\
+				x = ((TYPE *)(stream->buf))[4 * i + 0] - x1;\
+				y = ((TYPE *)(stream->buf))[4 * i + 1] - y1;\
+				z = ((TYPE *)(stream->buf))[4 * i + 2] - z1;\
+				d = x * x + y * y + z * z;\
+				if (d <= variance2) {\
+					if (a1 == a2)\
+						d = 0;\
+					else\
+						d = sqrt(d / variance2) * (a1 - a2) + a2;\
+					((TYPE *)(stream->buf))[4 * i + 3] *= d;\
+				}\
+			}\
+			n *= stream->pixel_size;\
+			m -= n;\
+			ewriteall(STDOUT_FILENO, stream->buf, n, "<stdout>");\
+			memmove(stream->buf, stream->buf + n, stream->ptr -= n);\
+		} while (eread_stream(stream, SIZE_MAX));\
+		if (stream->ptr)\
+			eprintf("%s: incomplete frame\n", stream->file);\
+	}
+
+PROCESS(double, lf)
+PROCESS(float, f)
+
+
+int
+main(int argc, char *argv[])
+{
+	struct stream stream, key;
+	void (*process)(struct stream *stream, struct stream *key);
+
+	UNOFLAGS(argc != 1);
+
+	eopen_stream(&stream, NULL);
+	eopen_stream(&key, argv[0]);
+
+	if (!strcmp(stream.pixfmt, "xyza"))
+		process = process_lf;
+	else if (!strcmp(stream.pixfmt, "xyza f"))
+		process = process_f;
+	else
+		eprintf("pixel format %s is not supported, try xyza\n", stream.pixfmt);
+
+	if (strcmp(stream.pixfmt, key.pixfmt))
+		eprintf("videos use incompatible pixel formats\n");
+
+	if (key.width > 2 || key.height > 2 || key.width * key.height != 2)
+		eprintf("%s: each frame must contain exactly 2 pixels\n", key.file);
+
+	fprint_stream_head(stdout, &stream);
+	efflush(stdout, "<stdout>");
+	process(&stream, &key);
+	return 0;
+}