1 files changed, 78 insertions, 0 deletions
diff --git a/src/blind-unpremultiply.c b/src/blind-unpremultiply.c
new file mode 100644
index 0000000..d0639c8
--- /dev/null
+++ b/src/blind-unpremultiply.c
@@ -0,0 +1,78 @@
+/* See LICENSE file for copyright and license details. */
+#include "common.h"
+
+USAGE("[-xyz]")
+
+static int skip_x = 0;
+static int skip_y = 0;
+static int skip_z = 0;
+
+
+#define PROCESS(TYPE, SUFFIX)\
+	static void\
+	process_##SUFFIX(struct stream *stream)\
+	{\
+		size_t i, n;\
+		TYPE a;\
+		do {\
+			n = stream->ptr / stream->pixel_size;\
+			for (i = 0; i < n; i++) {\
+				a = ((TYPE *)(stream->buf))[4 * i + 3];\
+				if (!a)\
+					continue;\
+				if (!skip_x)\
+					((TYPE *)(stream->buf))[4 * i + 0] /= a;\
+				if (!skip_y)\
+					((TYPE *)(stream->buf))[4 * i + 1] /= a;\
+				if (!skip_z)\
+					((TYPE *)(stream->buf))[4 * i + 2] /= a;\
+			}\
+			n *= stream->pixel_size;\
+			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;
+	void (*process)(struct stream *stream);
+
+	ARGBEGIN {
+	case 'x':
+		skip_x = 1;
+		break;
+	case 'y':
+		skip_y = 1;
+		break;
+	case 'z':
+		skip_z = 1;
+		break;
+	default:
+		usage();
+	} ARGEND;
+
+	if (argc)
+		usage();
+
+	eopen_stream(&stream, NULL);
+
+	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);
+
+	fprint_stream_head(stdout, &stream);
+	efflush(stdout, "<stdout>");
+	process(&stream);
+	return 0;
+}