Add some high bit-depth pixel formats

These are not fully supported yet, just preparing for future work.

include/SDL3/SDL_pixels.h

@@ -129,9 +129,11 @@ typedef enum
 {
     SDL_ARRAYORDER_NONE,
     SDL_ARRAYORDER_RGB,
-    SDL_ARRAYORDER_UNUSED1, /* Left for compatibility with SDL2 */
-    SDL_ARRAYORDER_UNUSED2, /* Left for compatibility with SDL2 */
-    SDL_ARRAYORDER_BGR
+    SDL_ARRAYORDER_RGBA,
+    SDL_ARRAYORDER_ARGB,
+    SDL_ARRAYORDER_BGR,
+    SDL_ARRAYORDER_BGRA,
+    SDL_ARRAYORDER_ABGR
 } SDL_ArrayOrder;
 
 /** Packed component layout. */
@@ -316,6 +318,42 @@ typedef enum
     SDL_PIXELFORMAT_ABGR2101010 =
         SDL_DEFINE_PIXELFORMAT(SDL_PIXELTYPE_PACKED32, SDL_PACKEDORDER_ABGR,
                                SDL_PACKEDLAYOUT_2101010, 32, 4),
+    SDL_PIXELFORMAT_R16G16B16 =
+        SDL_DEFINE_PIXELFORMAT(SDL_PIXELTYPE_ARRAYU16, SDL_ARRAYORDER_RGB, 0,
+                               48, 3),
+    SDL_PIXELFORMAT_B16G16R16 =
+        SDL_DEFINE_PIXELFORMAT(SDL_PIXELTYPE_ARRAYU16, SDL_ARRAYORDER_BGR, 0,
+                               48, 3),
+    SDL_PIXELFORMAT_R16G16B16A16 =
+        SDL_DEFINE_PIXELFORMAT(SDL_PIXELTYPE_ARRAYU16, SDL_ARRAYORDER_RGBA, 0,
+                               64, 4),
+    SDL_PIXELFORMAT_A16R16G16B16 =
+        SDL_DEFINE_PIXELFORMAT(SDL_PIXELTYPE_ARRAYU16, SDL_ARRAYORDER_ARGB, 0,
+                               64, 4),
+    SDL_PIXELFORMAT_B16G16R16A16 =
+        SDL_DEFINE_PIXELFORMAT(SDL_PIXELTYPE_ARRAYU16, SDL_ARRAYORDER_BGRA, 0,
+                               64, 4),
+    SDL_PIXELFORMAT_A16B16G16R16 =
+        SDL_DEFINE_PIXELFORMAT(SDL_PIXELTYPE_ARRAYU16, SDL_ARRAYORDER_ABGR, 0,
+                               64, 4),
+    SDL_PIXELFORMAT_R16G16B16_F16 =
+        SDL_DEFINE_PIXELFORMAT(SDL_PIXELTYPE_ARRAYF16, SDL_ARRAYORDER_RGB, 0,
+                               48, 3),
+    SDL_PIXELFORMAT_B16G16R16_F16 =
+        SDL_DEFINE_PIXELFORMAT(SDL_PIXELTYPE_ARRAYF16, SDL_ARRAYORDER_BGR, 0,
+                               48, 3),
+    SDL_PIXELFORMAT_R16G16B16A16_F16 =
+        SDL_DEFINE_PIXELFORMAT(SDL_PIXELTYPE_ARRAYF16, SDL_ARRAYORDER_RGBA, 0,
+                               64, 4),
+    SDL_PIXELFORMAT_A16R16G16B16_F16 =
+        SDL_DEFINE_PIXELFORMAT(SDL_PIXELTYPE_ARRAYF16, SDL_ARRAYORDER_ARGB, 0,
+                               64, 4),
+    SDL_PIXELFORMAT_B16G16R16A16_F16 =
+        SDL_DEFINE_PIXELFORMAT(SDL_PIXELTYPE_ARRAYF16, SDL_ARRAYORDER_BGRA, 0,
+                               64, 4),
+    SDL_PIXELFORMAT_A16B16G16R16_F16 =
+        SDL_DEFINE_PIXELFORMAT(SDL_PIXELTYPE_ARRAYF16, SDL_ARRAYORDER_ABGR, 0,
+                               64, 4),
 
     /* Aliases for RGBA byte arrays of color data, for the current platform */
 #if SDL_BYTEORDER == SDL_BIG_ENDIAN