[gimp] plug-ins: set blue channel of BC5 dds images to 0 instead of 255.

[Jacob Boerema <jboerema src gnome org>]

commit 691548579ac40eb7fc2d116a878eef0bfd6bfe77
Author: Jacob Boerema <jgboerema gmail com>
Date:   Tue Jan 5 17:56:24 2021 -0500

    plug-ins: set blue channel of BC5 dds images to 0 instead of 255.
    
    Information in issue #6200 revealed that 0 as default value for
    the blue channel is a lot more common than 255 so let's use
    that instead. The discussion and testing revealed no negative
    effects for the other formats that use the same code to
    initialize the memory to read blocks of image data.

 plug-ins/file-dds/dxt.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/plug-ins/file-dds/dxt.c b/plug-ins/file-dds/dxt.c
index bbea32b271..28d407a00f 100644
--- a/plug-ins/file-dds/dxt.c
+++ b/plug-ins/file-dds/dxt.c
@@ -1484,7 +1484,7 @@ dxt_decompress (unsigned char *dst,
     {
       for (x = 0; x < width; x += 4)
         {
-          memset(block, 255, 16 * 4);
+          memset(block, 0, 16 * 4);
 
           if (format == DDS_COMPRESS_BC1)
             {