Add a bit of ambient to the sectorview spheres

data/shaders/gl2/billboard_sphereimpostor.frag

@@ -5,13 +5,15 @@ varying vec4 color;
 varying vec2 uv;
 varying vec3 lightDir;
 
+uniform Scene scene;
+
 void main(void)
 {
 	float len = dot(uv, uv);
 	if (len > 1.0)
 		discard;
 	vec3 normal = vec3(uv.x, uv.y, sqrt(1.0 - len));
 	float diff = dot(normal, lightDir);
-	gl_FragColor = color * diff;
+	gl_FragColor = color * diff + scene.ambient;
 	SetFragDepth();
 }

src/SectorView.cpp

@@ -471,6 +471,7 @@ void SectorView::Draw3D()
 	m_renderer->SetTransform(matrix4x4f::Identity());
 
 	//draw star billboards in one go
+	m_renderer->SetAmbientColor(Color(30));
 	m_renderer->DrawTriangles(m_starVerts.get(), m_solidState, m_starMaterial.Get());
 
 	//draw sector legs in one go

src/graphics/gl2/SphereImpostorMaterial.h

@@ -17,6 +17,11 @@ namespace Graphics {
 			Program *CreateProgram(const MaterialDescriptor &) {
 				return new Program("billboard_sphereimpostor", "");
 			}
+
+			virtual void Apply() override {
+				GL2::Material::Apply();
+				m_program->sceneAmbient.Set(m_renderer->GetAmbientColor());
+			}
 		};
 	}
 }