From e84299fd3f1bf3f58e7aeddc017d2b6dc835f676 Mon Sep 17 00:00:00 2001
From: "Dmitry D. Chernov" <blackdoomer@yandex.ru>
Date: Fri, 24 Mar 2023 04:02:48 +1000
Subject: [PATCH] Game: Fixed missing check for the availability of stencil
 buffer This fixes experimental dynamic light effects ('light_enabled 1' and
 'light_player_halo') which were broken by
 0e101bd452c40da601236aaa2dd4106be47ddce1. It's worth noting that they even
 work on my laptop's integrated video if I just set 'gwin_has_stencil' to
 True, even though the driver says it doesn't support stencils. The discrete
 GPU on the same laptop reports it correctly.

---
 src/game/sdl/g_system.pas  | 10 ++++++++++
 src/game/sdl2/g_system.pas | 10 ++++++++++
 2 files changed, 20 insertions(+)

diff --git a/src/game/sdl/g_system.pas b/src/game/sdl/g_system.pas
index 0fcad1a..cc8704c 100644
--- a/src/game/sdl/g_system.pas
+++ b/src/game/sdl/g_system.pas
@@ -78,12 +78,22 @@ implementation
   (* --------- Graphics --------- *)
 
   function LoadGL: Boolean;
+  {$IFNDEF NOGL_INIT}
+  var
+    ltmp: Integer;
+  {$ENDIF}
   begin
     result := true;
     {$IFDEF NOGL_INIT}
     nogl_Init;
     if glRenderToFBO and (not nogl_ExtensionSupported('GL_OES_framebuffer_object')) then
     {$ELSE}
+    if SDL_GL_GetAttribute(SDL_GL_STENCIL_SIZE, @ltmp) = 0 then
+    begin
+      e_LogWritefln('stencil buffer size: %s', [ltmp]);
+      gwin_has_stencil := (ltmp > 0);
+    end;
+
     if glRenderToFBO and (not Load_GL_ARB_framebuffer_object) then
     {$ENDIF}
     begin
diff --git a/src/game/sdl2/g_system.pas b/src/game/sdl2/g_system.pas
index 9cd1ee1..b3005d5 100644
--- a/src/game/sdl2/g_system.pas
+++ b/src/game/sdl2/g_system.pas
@@ -75,12 +75,22 @@ implementation
   (* --------- Graphics --------- *)
 
   function LoadGL: Boolean;
+  {$IFNDEF NOGL_INIT}
+  var
+    ltmp: Integer;
+  {$ENDIF}
   begin
     result := true;
     {$IFDEF NOGL_INIT}
     nogl_Init;
     if glRenderToFBO and (not nogl_ExtensionSupported('GL_OES_framebuffer_object')) then
     {$ELSE}
+    if SDL_GL_GetAttribute(SDL_GL_STENCIL_SIZE, @ltmp) = 0 then
+    begin
+      e_LogWritefln('stencil buffer size: %s', [ltmp]);
+      gwin_has_stencil := (ltmp > 0);
+    end;
+
     if glRenderToFBO and (not Load_GL_ARB_framebuffer_object) then
     {$ENDIF}
     begin
-- 
2.29.2