Merge pull request #4416 from The-E/fix/4415_several_lab_issues

Two minor lab fixes

Author: The-E

code/lab/manager/lab_manager.cpp

@@ -224,7 +224,9 @@ void LabManager::onFrame(float frametime) {
 				break;
 
 			case KEY_M:
-				gr_dump_envmap(Renderer->currentMissionBackground.c_str());
+				// Dumping the environment map only makes sense if we actually have a background set
+				if (Renderer->currentMissionBackground != LAB_MISSION_NONE_STRING)
+					gr_dump_envmap(Renderer->currentMissionBackground.c_str());
 				break;
 
 				// bail...

code/lab/renderer/lab_renderer.cpp

@@ -63,7 +63,8 @@ void LabRenderer::renderModel(float frametime) {
 		Ships[obj->instance].flags.set(Ship::Ship_Flags::Subsystem_movement_locked, !renderFlags[LabRenderFlag::RotateSubsystems]);
 		Ships[obj->instance].flags.set(Ship::Ship_Flags::Draw_as_wireframe, renderFlags[LabRenderFlag::ShowWireframe]);
 		Ships[obj->instance].flags.set(Ship::Ship_Flags::Render_full_detail, renderFlags[LabRenderFlag::ShowFullDetail]);
-		Ships[obj->instance].flags.set(Ship::Ship_Flags::Render_without_light, renderFlags[LabRenderFlag::NoLighting] || currentMissionBackground == "None");
+		Ships[obj->instance].flags.set(Ship::Ship_Flags::Render_without_light,
+			renderFlags[LabRenderFlag::NoLighting] || currentMissionBackground == LAB_MISSION_NONE_STRING);
 		Ships[obj->instance].flags.set(Ship::Ship_Flags::Render_without_diffuse, renderFlags[LabRenderFlag::NoDiffuseMap]);
 		Ships[obj->instance].flags.set(Ship::Ship_Flags::Render_without_glowmap, renderFlags[LabRenderFlag::NoGlowMap]);
 		Ships[obj->instance].flags.set(Ship::Ship_Flags::Render_without_normalmap, renderFlags[LabRenderFlag::NoNormalMap]);
@@ -218,7 +219,7 @@ void LabRenderer::renderHud(float) {
 	}
 
 	//Print current Team Color setting, if any
-	if (currentTeamColor != "<none>") {
+	if (currentTeamColor != LAB_TEAM_COLOR_NONE) {
 		gr_printf_no_resize(gr_screen.center_offset_x + 2,
 			gr_screen.center_offset_y + gr_screen.center_h - (gr_get_font_height() * 3) - 3,
 			"Use T and Y to cycle through available Team Color settings. Current: %s",

code/lab/renderer/lab_renderer.h

@@ -67,6 +67,9 @@ enum class TextureOverride {
 	Specular
 };
 
+constexpr auto LAB_MISSION_NONE_STRING = "None";
+constexpr auto LAB_TEAM_COLOR_NONE = "<none>";
+
 class LabRenderer {
 public:
 	LabRenderer() {
@@ -75,8 +78,8 @@ class LabRenderer {
 		directionalFactor = static_light_factor;
 		textureQuality = TextureQuality::Maximum;
 		cameraDistance = 100.0f;
-		currentTeamColor = "<none>";
-		useBackground("None");
+		currentTeamColor = LAB_TEAM_COLOR_NONE;
+		useBackground(LAB_MISSION_NONE_STRING);
 
 		labCamera.reset(new OrbitCamera());
 
@@ -110,25 +113,28 @@ class LabRenderer {
 	}
 
 	void useNextTeamColorPreset() {
-		auto color_itr = Team_Colors.find(currentTeamColor);
-
-		if (color_itr == Team_Colors.begin()) {
-			color_itr = --Team_Colors.end();
-			currentTeamColor = color_itr->first;
-		}
-		else {
-			--color_itr;
-			currentTeamColor = color_itr->first;
+		if (!Team_Colors.empty()) {
+			auto color_itr = Team_Colors.find(currentTeamColor);
+
+			if (color_itr == Team_Colors.begin()) {
+				color_itr = --Team_Colors.end();
+				currentTeamColor = color_itr->first;
+			} else {
+				--color_itr;
+				currentTeamColor = color_itr->first;
+			}
 		}
 	}
 
 	void usePreviousTeamColorPreset() {
-		auto color_itr = Team_Colors.find(currentTeamColor);
+		if (!Team_Colors.empty()) {
+			auto color_itr = Team_Colors.find(currentTeamColor);
 
-		++color_itr;
-		if (color_itr == Team_Colors.end())
-			color_itr = Team_Colors.begin();
-		currentTeamColor = color_itr->first;
+			++color_itr;
+			if (color_itr == Team_Colors.end())
+				color_itr = Team_Colors.begin();
+			currentTeamColor = color_itr->first;
+		}
 	}
 
 	void setTeamColor(SCP_string teamColor) {