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, 5 insertions, 4 deletions

diff --git a/test/img_format.c b/test/img_format.c
index ff3af4c005..cf5bbb3af2 100644
--- a/test/img_format.c
+++ b/test/img_format.c
@@ -7,8 +7,9 @@
 #include "video/mp_image.h"
 #include "video/sws_utils.h"
 
-static int imgfmts[IMGFMT_AVPIXFMT_END - IMGFMT_AVPIXFMT_START + 100];
-static int num_imgfmts;
+int imgfmts[IMGFMT_AVPIXFMT_END - IMGFMT_AVPIXFMT_START + 100];
+int num_imgfmts;
+
 static enum AVPixelFormat pixfmt_unsup[100];
 static int num_pixfmt_unsup;
 static bool imgfmts_initialized;
@@ -21,7 +22,7 @@ static int cmp_imgfmt_name(const void *a, const void *b)
     return strcmp(name_a, name_b);
 }
 
-static void find_all_imgfmts(void)
+void init_imgfmts_list(void)
 {
     if (imgfmts_initialized)
         return;
@@ -61,7 +62,7 @@ static const char *comp_type(enum mp_component_type type)
 
 static void run(struct test_ctx *ctx)
 {
-    find_all_imgfmts();
+    init_imgfmts_list();
 
     FILE *f = test_open_out(ctx, "img_formats.txt");