Gamma: clamp slider to the engine's 2.6 cap, defer readback

The engine clamps mat_monitorgamma at 2.6, so the 2.8..3.0 end of the slider
did nothing. Read the value back one tick later (ClientCmd is queued) and
interpose SDL_SetWindowGammaRamp to see whether the engine pushes a ramp at
all.

1 files changed, 10 insertions, 5 deletions

diff --git a/src/hl2h.cpp b/src/hl2h.cpp
index f7106cd..1fc7096 100644
--- a/src/hl2h.cpp
+++ b/src/hl2h.cpp
@@ -674,13 +674,18 @@ static void view_settings_apply(void *ent) {
     last_vm = g_fov_viewmodel;
   }
   static int last_gamma = 22;
+  static int pending_gamma = -1;
   if (g_gamma != last_gamma) {
     char cmd[48];
     snprintf(cmd, sizeof(cmd), "mat_monitorgamma %d.%d", g_gamma / 10,
              g_gamma % 10);
     console_cmd(cmd);
-    // Read back through ICvar to tell an ignored command from an OS gamma
-    // ramp that the compositor discards.
+    pending_gamma = g_gamma;
+    last_gamma = g_gamma;
+  }
+  if (pending_gamma >= 0) {
+    // ClientCmd is queued, so read the cvar on the next tick to see the value
+    // the engine actually accepted (it clamps mat_monitorgamma at 2.6).
     float got = -1.0f;
     if (g_iface.cvar) {
       using FindFn = void *(*)(void *, const char *);
@@ -689,9 +694,9 @@ static void view_settings_apply(void *ent) {
       if (v)
         got = *(float *)((uintptr_t)v + 0x2c); // ConVar m_Value.f
     }
-    logf("view: gamma request %d.%d, cvar reports %.2f", g_gamma / 10,
-         g_gamma % 10, got);
-    last_gamma = g_gamma;
+    logf("view: gamma request %d.%d, cvar reports %.2f", pending_gamma / 10,
+         pending_gamma % 10, got);
+    pending_gamma = -1;
   }
 }