Add HDR tonemap brightness slider

The engine applies mat_monitorgamma (SDL receives changing ramp midpoints),
but Wayland/XWayland compositors discard the window gamma ramp, so the gamma
slider has no visible effect there. Add an in-engine brightness control that
does not depend on the window system: mat_force_tonemap_scale, exposed as
"HDR brightness" (x10, 0 = automatic). Drop the temporary SDL gamma ramp
diagnostic.

1 files changed, 28 insertions, 0 deletions

diff --git a/src/hl2h.cpp b/src/hl2h.cpp
index 1fc7096..a037bac 100644
--- a/src/hl2h.cpp
+++ b/src/hl2h.cpp
@@ -698,6 +698,34 @@ static void view_settings_apply(void *ent) {
          pending_gamma % 10, got);
     pending_gamma = -1;
   }
+  // In-engine brightness for HDR maps. Unlike mat_monitorgamma this does not
+  // depend on the window system applying a gamma ramp.
+  static int last_tonemap = 0;
+  static int pending_tonemap = -1;
+  if (g_tonemap != last_tonemap) {
+    char cmd[64];
+    if (g_tonemap == 0)
+      snprintf(cmd, sizeof(cmd), "mat_force_tonemap_scale 0");
+    else
+      snprintf(cmd, sizeof(cmd), "mat_force_tonemap_scale %d.%d",
+               g_tonemap / 10, g_tonemap % 10);
+    console_cmd(cmd);
+    pending_tonemap = g_tonemap;
+    last_tonemap = g_tonemap;
+  }
+  if (pending_tonemap >= 0) {
+    float got = -1.0f;
+    if (g_iface.cvar) {
+      using FindFn = void *(*)(void *, const char *);
+      void *v = vfunc<FindFn>(g_iface.cvar, 12)(g_iface.cvar,
+                                                "mat_force_tonemap_scale");
+      if (v)
+        got = *(float *)((uintptr_t)v + 0x2c);
+    }
+    logf("view: tonemap request %d.%d, cvar reports %.2f",
+         pending_tonemap / 10, pending_tonemap % 10, got);
+    pending_tonemap = -1;
+  }
 }
 
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