test: add tests for zimg RGB repacking

This tests the RGB repacker code in zimg, which deserves to be tested
because it's tricky and there will be more formats.

scale_test.c contains some code that can be used to test any scaler. Or
at least that would be great; currently it can only test repacking of
some byte-aligned-component RGB formats. It should be called
repack_test.c, but I'm too lazy to change the filename now.

The idea is that libswscale is used to cross-check the conversions
performed by the zimg wrapper. This is why it's "OK" that scale_test.c
does libswscale calls.

scale_sws.c is the equivalent to scale_zimg.c, and is of course
worthless (because it tests libswscale by comparing the results with
libswscale), but still might help with finding bugs in scale_test.c.

This borrows a sorted list of image formats from test/img_format.c, for
the same reason that file sorts them.

There's a slight possibility that this can be used to test vo_gpu.c too
some times in the future.

1 files changed, 28 insertions, 0 deletions

diff --git a/test/scale_test.h b/test/scale_test.h
new file mode 100644
index 0000000000..f49b456ecb
--- /dev/null
+++ b/test/scale_test.h
@@ -0,0 +1,28 @@
+#pragma once
+
+#include "tests.h"
+#include "video/mp_image.h"
+
+struct scale_test_fns {
+    bool (*scale)(void *ctx, struct mp_image *dst, struct mp_image *src);
+    bool (*supports_fmts)(void *ctx, int imgfmt_dst, int imgfmt_src);
+};
+
+struct scale_test {
+    // To be filled in by user.
+    const struct scale_test_fns *fns;
+    void *fns_priv;
+    const char *test_name;
+    struct test_ctx *ctx;
+
+    // Private.
+    struct mp_image *img_repack_rgb8;
+    struct mp_image *img_repack_rgba8;
+    struct mp_image *img_repack_rgb16;
+    struct mp_image *img_repack_rgba16;
+    struct mp_sws_context *sws;
+    int fail;
+};
+
+// Test color repacking between packed formats (typically RGB).
+void repack_test_run(struct scale_test *stest);