SDL: renderer: Check the surface validity flag when re-acquiring the surface in the software renderer (2a53e)

SDL Commits
1 
From 2a53eed783e966a1d55ecad6a93c9835e522c166 Mon Sep 17 00:00:00 2001
From: Frank Praznik <[EMAIL REDACTED]>
Date: Mon, 27 Apr 2026 12:29:55 -0400
Subject: [PATCH] renderer: Check the surface validity flag when re-acquiring
 the surface in the software renderer

If a size change occurs, the sdl2-compat event handler will flush the renderer, which will cause the software renderer to re-acquire a surface that was invalidated due to the size change. However, if the OnWindowPixelSizeChanged handler is called afterward, the invalid flag will be set on the surface, causing presentation to fail.

Check both for a null surface pointer and an invalid surface flag when checking surface validity in the software renderer.

(cherry picked from commit 73fc274ef7f96e181ec217f54ed74e0dca91b771)
---
 src/render/software/SDL_render_sw.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/src/render/software/SDL_render_sw.c b/src/render/software/SDL_render_sw.c
index 160e2a10beeb2..ce3a3f5165b6e 100644
--- a/src/render/software/SDL_render_sw.c
+++ b/src/render/software/SDL_render_sw.c
@@ -34,6 +34,7 @@
 #include "SDL_triangle.h"
 #include "../../video/SDL_pixels_c.h"
 #include "../../video/SDL_rotate.h"
+#include "../../video/SDL_sysvideo.h"
 
 // SDL surface based renderer implementation
 
@@ -54,12 +55,13 @@ typedef struct
 static SDL_Surface *SW_ActivateRenderer(SDL_Renderer *renderer)
 {
     SW_RenderData *data = (SW_RenderData *)renderer->internal;
+    SDL_Window *window = renderer->window;
 
     if (!data->surface) {
         data->surface = data->window;
     }
-    if (!data->surface) {
-        SDL_Surface *surface = SDL_GetWindowSurface(renderer->window);
+    if (window && (!data->surface || !window->surface_valid)) {
+        SDL_Surface *surface = SDL_GetWindowSurface(window);
         if (surface) {
             data->surface = data->window = surface;
         }