fix(render): dark parts of a cab and of the running gear are no longer crushed to black, as the AgX look raises its contrast power from 1.0 in the shadows up to 1.6 only from the middle tones on, which keeps the bright tones, the outside view and the night as they were but leaves black knobs, levers and lettering visible on a black desk; the light of a cab can be scaled with gfx.cab.ambient, 1.0 by default

rendering/opengl33renderer.cpp

@@ -3939,6 +3939,8 @@ bool opengl33_renderer::Render_cab(TDynamicObject const *Dynamic, float const Li
             }
 
             auto const old_ambient { light_ubs.ambient };
+            light_ubs.ambient *= Global.gfx_cab_ambient;
+            light_ubo->update( light_ubs );
             auto const luminance { Global.fLuminance * ( Dynamic->fShade > 0.0f ? Dynamic->fShade : 1.0f ) };
             if( Lightlevel > 0.f ) {
                 // crude way to light the cabin, until we have something more complete in place

shaders/tonemapping.glsl

@@ -109,7 +109,7 @@ vec3 AgxLook(vec3 val)
 
     vec3 offset = vec3(0.0);
     vec3 slope = vec3(1.0);
-    vec3 power = vec3(1.6);
+    vec3 power = mix(vec3(1.0), vec3(1.6), smoothstep(0.0, 0.4, luma));
     float sat = 0.9;
 
 #if AGX_LOOK == 1

utilities/Globals.cpp

@@ -1335,6 +1335,11 @@ global_settings::ConfigParse_gfx( cParser &Parser, std::string_view const Token
         Parser.getTokens();
         Parser >> RenderCabShadowsRange;
     }
+    else if (Token == "gfx.cab.ambient")
+    {
+        Parser.getTokens();
+        Parser >> gfx_cab_ambient;
+    }
     else if (Token == "gfx.smoke")
     {
         // smoke visualization toggle
@@ -1600,6 +1605,7 @@ global_settings::export_as_text( std::ostream &Output ) const {
         << shadowtune.range << " "
         << 0 << "\n";
     export_as_text( Output, "gfx.shadows.cab.range", RenderCabShadowsRange );
+    export_as_text( Output, "gfx.cab.ambient", gfx_cab_ambient );
     export_as_text( Output, "gfx.smoke", Smoke );
     export_as_text( Output, "gfx.smoke.fidelity", SmokeFidelity );
     export_as_text( Output, "smoothtraction", bSmoothTraction );

utilities/Globals.h

@@ -159,6 +159,7 @@ struct global_settings {
     bool RenderShadows{ true };
 	bool applicationQuitOrder{false};
     int RenderCabShadowsRange{ 0 };
+    float gfx_cab_ambient{ 1.0f };
     struct shadowtune_t {
         unsigned int map_size{ 2048 };
         float range{ 250.f };