SDL: render: Fix texture format selection for color-keyed indexed surfaces

SDL Commits
1 
From 2ffabb51500346bb0a7e621ebf4f0463b1b420b5 Mon Sep 17 00:00:00 2001
From: nmlgc <[EMAIL REDACTED]>
Date: Tue, 14 Oct 2025 23:34:32 +0200
Subject: [PATCH] render: Fix texture format selection for color-keyed indexed
 surfaces

015cc6a broke texture format selection for this kind of surface if the
renderer's first texture format doesn't happen to have an alpha
channel. This happens for on-screen software renderers on Windows,
whose preferred format is the window's own `SDL_PIXELFORMAT_XRGB8888`.
This fixed check also cover the intent behind 015cc6a, assuming that
indexed and alpha formats are mutually exclusive.
---
 src/render/SDL_render.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/src/render/SDL_render.c b/src/render/SDL_render.c
index 4a8b10772e3fc..b5726feb57500 100644
--- a/src/render/SDL_render.c
+++ b/src/render/SDL_render.c
@@ -1844,10 +1844,13 @@ SDL_Texture *SDL_CreateTextureFromSurface(SDL_Renderer *renderer, SDL_Surface *s
             }
         }
 
+        // Indexed formats don't support the transparency needed for color-keyed surfaces
+        bool preferIndexed = SDL_ISPIXELFORMAT_INDEXED(surface->format) && !needAlpha;
+
         for (i = 0; i < renderer->num_texture_formats; ++i) {
             if (!SDL_ISPIXELFORMAT_FOURCC(renderer->texture_formats[i]) &&
                 SDL_ISPIXELFORMAT_ALPHA(renderer->texture_formats[i]) == needAlpha &&
-                SDL_ISPIXELFORMAT_INDEXED(renderer->texture_formats[i]) == SDL_ISPIXELFORMAT_INDEXED(surface->format)) {
+                SDL_ISPIXELFORMAT_INDEXED(renderer->texture_formats[i]) == preferIndexed) {
                 format = renderer->texture_formats[i];
                 break;
             }