Added SDL_CreateSurfacePalette()

src/dynapi/SDL_dynapi.sym

@@ -79,6 +79,7 @@ SDL3_0.0.0 {
     SDL_CreateStorageDirectory;
     SDL_CreateSurface;
     SDL_CreateSurfaceFrom;
+    SDL_CreateSurfacePalette;
     SDL_CreateSystemCursor;
     SDL_CreateTLS;
     SDL_CreateTexture;

src/dynapi/SDL_dynapi_overrides.h

@@ -104,6 +104,7 @@
 #define SDL_CreateStorageDirectory SDL_CreateStorageDirectory_REAL
 #define SDL_CreateSurface SDL_CreateSurface_REAL
 #define SDL_CreateSurfaceFrom SDL_CreateSurfaceFrom_REAL
+#define SDL_CreateSurfacePalette SDL_CreateSurfacePalette_REAL
 #define SDL_CreateSystemCursor SDL_CreateSystemCursor_REAL
 #define SDL_CreateTLS SDL_CreateTLS_REAL
 #define SDL_CreateTexture SDL_CreateTexture_REAL

src/dynapi/SDL_dynapi_procs.h

@@ -124,6 +124,7 @@ SDL_DYNAPI_PROC(SDL_Renderer*,SDL_CreateSoftwareRenderer,(SDL_Surface *a),(a),re
 SDL_DYNAPI_PROC(int,SDL_CreateStorageDirectory,(SDL_Storage *a, const char *b),(a,b),return)
 SDL_DYNAPI_PROC(SDL_Surface*,SDL_CreateSurface,(int a, int b, SDL_PixelFormat c),(a,b,c),return)
 SDL_DYNAPI_PROC(SDL_Surface*,SDL_CreateSurfaceFrom,(int a, int b, SDL_PixelFormat c, void *d, int e),(a,b,c,d,e),return)
+SDL_DYNAPI_PROC(SDL_Palette*,SDL_CreateSurfacePalette,(SDL_Surface *a),(a),return)
 SDL_DYNAPI_PROC(SDL_Cursor*,SDL_CreateSystemCursor,(SDL_SystemCursor a),(a),return)
 SDL_DYNAPI_PROC(SDL_TLSID,SDL_CreateTLS,(void),(),return)
 SDL_DYNAPI_PROC(SDL_Texture*,SDL_CreateTexture,(SDL_Renderer *a, SDL_PixelFormat b, int c, int d, int e),(a,b,c,d,e),return)

src/video/SDL_bmp.c

@@ -439,8 +439,10 @@ SDL_Surface *SDL_LoadBMP_IO(SDL_IOStream *src, SDL_bool closeio)
 
     /* Load the palette, if any */
     if (SDL_ISPIXELFORMAT_INDEXED(surface->format)) {
-        int max_colors = (1 << SDL_BITSPERPIXEL(surface->format));
-        SDL_Palette *palette;
+        SDL_Palette *palette = SDL_CreateSurfacePalette(surface);
+        if (!palette) {
+            goto done;
+        }
 
         if (SDL_SeekIO(src, fp_offset + 14 + biSize, SDL_IO_SEEK_SET) < 0) {
             SDL_SetError("Error seeking in datastream");
@@ -456,21 +458,17 @@ SDL_Surface *SDL_LoadBMP_IO(SDL_IOStream *src, SDL_bool closeio)
             biClrUsed = 1 << biBitCount;
         }
 
-        if (biClrUsed > (Uint32)max_colors) {
+        if (biClrUsed > (Uint32)palette->ncolors) {
             biClrUsed = 1 << biBitCount; /* try forcing it? */
-            if (biClrUsed > (Uint32)max_colors) {
+            if (biClrUsed > (Uint32)palette->ncolors) {
                 SDL_SetError("Unsupported or incorrect biClrUsed field");
                 goto done;
             }
         }
-
-        palette = SDL_CreatePalette(biClrUsed);
-        if (!palette) {
-            goto done;
-        }
+        palette->ncolors = biClrUsed;
 
         if (biSize == 12) {
-            for (i = 0; i < (int)biClrUsed; ++i) {
+            for (i = 0; i < palette->ncolors; ++i) {
                 if (!SDL_ReadU8(src, &palette->colors[i].b) ||
                     !SDL_ReadU8(src, &palette->colors[i].g) ||
                     !SDL_ReadU8(src, &palette->colors[i].r)) {
@@ -479,7 +477,7 @@ SDL_Surface *SDL_LoadBMP_IO(SDL_IOStream *src, SDL_bool closeio)
                 palette->colors[i].a = SDL_ALPHA_OPAQUE;
             }
         } else {
-            for (i = 0; i < (int)biClrUsed; ++i) {
+            for (i = 0; i < palette->ncolors; ++i) {
                 if (!SDL_ReadU8(src, &palette->colors[i].b) ||
                     !SDL_ReadU8(src, &palette->colors[i].g) ||
                     !SDL_ReadU8(src, &palette->colors[i].r) ||
@@ -494,9 +492,6 @@ SDL_Surface *SDL_LoadBMP_IO(SDL_IOStream *src, SDL_bool closeio)
                 palette->colors[i].a = SDL_ALPHA_OPAQUE;
             }
         }
-
-        SDL_SetSurfacePalette(surface, palette);
-        SDL_DestroyPalette(palette);
     }
 
     /* Read the surface pixels.  Note that the bmp image is upside down */

src/video/SDL_surface.c

@@ -367,6 +367,46 @@ float SDL_GetSurfaceHDRHeadroom(SDL_Surface *surface, SDL_Colorspace colorspace)
     return 1.0f;
 }
 
+SDL_Palette *SDL_CreateSurfacePalette(SDL_Surface *surface)
+{
+    SDL_Palette *palette;
+
+    if (!SDL_SurfaceValid(surface)) {
+        SDL_InvalidParamError("surface");
+        return NULL;
+    }
+
+    if (!SDL_ISPIXELFORMAT_INDEXED(surface->format)) {
+        SDL_SetError("The surface is not indexed format");
+        return NULL;
+    }
+
+    palette = SDL_CreatePalette((1 << SDL_BITSPERPIXEL(surface->format)));
+    if (!palette) {
+        return NULL;
+    }
+
+    if (palette->ncolors == 2) {
+        /* Create a black and white bitmap palette */
+        palette->colors[0].r = 0xFF;
+        palette->colors[0].g = 0xFF;
+        palette->colors[0].b = 0xFF;
+        palette->colors[1].r = 0x00;
+        palette->colors[1].g = 0x00;
+        palette->colors[1].b = 0x00;
+    }
+
+    if (SDL_SetSurfacePalette(surface, palette) < 0) {
+        SDL_DestroyPalette(palette);
+        return NULL;
+    }
+
+    /* The surface has retained the palette, we can remove the reference here */
+    SDL_assert(palette->refcount == 2);
+    SDL_DestroyPalette(palette);
+    return palette;
+}
+
 int SDL_SetSurfacePalette(SDL_Surface *surface, SDL_Palette *palette)
 {
     if (!SDL_SurfaceValid(surface)) {