[client] egl: add options for maximum NV level and initial level

Adds options:

 * egl:nvGain
 * egl:nvGainMax

Fixes #153

VERSION

@@ -1 +1 @@
-a12-216-g666a6a218f+1
+a12-217-gf946117dac+1

client/renderers/EGL/desktop.c

@@ -19,6 +19,7 @@ Place, Suite 330, Boston, MA 02111-1307 USA
 
 #include "desktop.h"
 #include "common/debug.h"
+#include "common/option.h"
 #include "utils.h"
 
 #include "texture.h"
@@ -63,7 +64,7 @@ struct EGL_Desktop
 
   // night vision
   KeybindHandle kbNV;
-  bool  nv;
+  int   nvMax;
   int   nvGain;
 };
 
@@ -141,6 +142,9 @@ bool egl_desktop_init(EGL_Desktop ** desktop)
 
   (*desktop)->kbNV = app_register_keybind(SDL_SCANCODE_N, egl_desktop_toggle_nv, *desktop);
 
+  (*desktop)->nvMax  = option_get_int("egl", "nvGainMax");
+  (*desktop)->nvGain = option_get_int("egl", "nvGain"   );
+
   return true;
 }
 
@@ -148,7 +152,7 @@ bool egl_desktop_init(EGL_Desktop ** desktop)
 void egl_desktop_toggle_nv(SDL_Scancode key, void * opaque)
 {
   EGL_Desktop * desktop = (EGL_Desktop *)opaque;
-  if (++desktop->nvGain == 4)
+  if (desktop->nvGain++ == desktop->nvMax)
     desktop->nvGain = 0;
 
        if (desktop->nvGain == 0) app_alert(LG_ALERT_INFO, "NV Disabled");

client/renderers/EGL/egl.c

@@ -101,6 +101,20 @@ static struct Option egl_options[] =
     .type         = OPTION_TYPE_BOOL,
     .value.x_bool = false
   },
+  {
+    .module       = "egl",
+    .name         = "nvGainMax",
+    .description  = "The maximum night vision gain",
+    .type         = OPTION_TYPE_INT,
+    .value.x_int  = 1
+  },
+  {
+    .module       = "egl",
+    .name         = "nvGain",
+    .description  = "The initial night vision gain at startup",
+    .type         = OPTION_TYPE_INT,
+    .value.x_int  = 0
+  },
   {0}
 };