SDL: Fixed compiler warning

From a01aaf053cbf91f627d4b55848ece14709888b81 Mon Sep 17 00:00:00 2001
From: Sam Lantinga <[EMAIL REDACTED]>
Date: Sat, 30 Oct 2021 21:42:07 -0700
Subject: [PATCH] Fixed compiler warning

---
 src/video/SDL_pixels.c | 13 ++++++-------
 1 file changed, 6 insertions(+), 7 deletions(-)

diff --git a/src/video/SDL_pixels.c b/src/video/SDL_pixels.c
index c7b4d32912..8015e02134 100644
--- a/src/video/SDL_pixels.c
+++ b/src/video/SDL_pixels.c
@@ -1238,19 +1238,18 @@ SDL_PremultiplySurfaceAlphaToARGB8888(SDL_Surface *src, Uint32 *dst)
         SDL_LockSurface(src);
 
     for (y = 0; y < src->h; ++y) {
-        Uint8 *src_px = (Uint8*)(src->pixels) + (y * src->pitch);
+        Uint32 *src_px = (Uint32*)((Uint8 *)src->pixels + (y * src->pitch));
         for (x = 0; x < src->w; ++x) {
             /* Component bytes extraction. */
-            SDL_GetRGBA(*(Uint32*)src_px, src->format, &R, &G, &B, &A);
-            src_px += src->format->BytesPerPixel;
+            SDL_GetRGBA(*src_px++, src->format, &R, &G, &B, &A);
 
             /* Alpha pre-multiplication of each component. */
-            R = (float)A * ((float)R /255);
-            G = (float)A * ((float)G /255);
-            B = (float)A * ((float)B /255);
+            R = ((Uint32)A * R) / 255;
+            G = ((Uint32)A * G) / 255;
+            B = ((Uint32)A * B) / 255;
 
             /* ARGB8888 pixel recomposition. */
-            (*dst++) = (((Uint32)A << 24) | ((Uint32)R << 16) | ((Uint32)G << 8)) | ((Uint32)B << 0);
+            *dst++ = (((Uint32)A << 24) | ((Uint32)R << 16) | ((Uint32)G << 8) | (B << 0));
         }
     }
     if (SDL_MUSTLOCK(src))