Fix r_lazyShaders behaviors

1. Don't build everything on map load if mode 2 is used.
   GLSL_InitWorldShadersOrError is called before EndRegistration so
   it's not necessary to request building shaders therie.
2. Do rebuild everything on glsl_restart if mode 1 is used.
   This fixes the broken fallback-to-builtin-shaders behavior.

Author: slipher

src/engine/renderer/tr_bsp.cpp

@@ -7034,5 +7034,5 @@ void RE_LoadWorldMap( const char *name )
 	}
 
 	tr.worldLoaded = true;
-	GLSL_InitWorldShadersOrError();
+	GLSL_InitWorldShaders();
 }

src/engine/renderer/tr_init.cpp

@@ -93,7 +93,18 @@ Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 	cvar_t      *r_exportTextures;
 	cvar_t      *r_heatHaze;
 	cvar_t      *r_noMarksOnTrisurfs;
-	cvar_t      *r_lazyShaders;
+
+	/* Default value is 1: Delay GLSL shader build until first map load.
+
+	This makes possible for the user to quickly reach the game main menu
+	without building all GLSL shaders and set a low graphics preset before
+	joining a game and loading a map.
+
+	Doing so prevents building unwanted or unsupported GLSL shaders on slow
+	and/or old hardware and drastically reduce first startup time. */
+	Cvar::Range<Cvar::Cvar<int>> r_lazyShaders(
+		"r_lazyShaders", "build GLSL shaders (0) on startup, (1) on map load or (2) when used",
+		Cvar::NONE, 1, 0, 2);
 
 	cvar_t      *r_checkGLErrors;
 	cvar_t      *r_logFile;
@@ -1122,16 +1133,6 @@ ScreenshotCmd screenshotPNGRegistration("screenshotPNG", ssFormat_t::SSF_PNG, "p
 		r_heatHaze = Cvar_Get( "r_heatHaze", "1", CVAR_LATCH | CVAR_ARCHIVE );
 		r_noMarksOnTrisurfs = Cvar_Get( "r_noMarksOnTrisurfs", "1", CVAR_CHEAT );
 
-		/* 1: Delay GLSL shader build until first map load.
-
-		This makes possible for the user to quickly reach the game main menu
-		without building all GLSL shaders and set a low graphics preset before
-		joining a game and loading a map.
-
-		Doing so prevents building unwanted or unsupported GLSL shaders on slow
-		and/or old hardware and drastically reduce first startup time. */
-		r_lazyShaders = Cvar_Get( "r_lazyShaders", "1", 0 );
-
 		r_wolfFog = Cvar_Get( "r_wolfFog", "1", CVAR_CHEAT );
 		r_noFog = Cvar_Get( "r_noFog", "0", CVAR_CHEAT );
 
@@ -1556,7 +1557,7 @@ ScreenshotCmd screenshotPNGRegistration("screenshotPNG", ssFormat_t::SSF_PNG, "p
 	void RE_EndRegistration()
 	{
 		R_SyncRenderThread();
-		if ( r_lazyShaders->integer == 1 )
+		if ( r_lazyShaders.Get() == 1 )
 		{
 			GLSL_FinishGPUShaders();
 		}

src/engine/renderer/tr_local.h

@@ -2837,7 +2837,7 @@ enum class realtimeLightingRenderer_t { LEGACY, TILED };
 	extern cvar_t *r_exportTextures;
 	extern cvar_t *r_heatHaze;
 	extern cvar_t *r_noMarksOnTrisurfs;
-	extern cvar_t *r_lazyShaders; // 0: build all shaders on program start 1: delay shader build until first map load 2: delay shader build until needed
+	extern Cvar::Range<Cvar::Cvar<int>> r_lazyShaders; // 0: build all shaders on program start 1: delay shader build until first map load 2: delay shader build until needed
 
 	extern cvar_t *r_norefresh; // bypasses the ref rendering
 	extern cvar_t *r_drawentities; // disable/enable entity rendering
@@ -3378,7 +3378,7 @@ inline bool checkGLErrors()
 	alignas(16) extern shaderCommands_t tess;
 
 	void                    GLSL_InitGPUShaders();
-	void                    GLSL_InitWorldShadersOrError();
+	void                    GLSL_InitWorldShaders();
 	void                    GLSL_ShutdownGPUShaders();
 	void                    GLSL_FinishGPUShaders();
 

src/engine/renderer/tr_shade.cpp

@@ -143,7 +143,7 @@ static void EnableAvailableFeatures()
 }
 
 // For shaders that require map data for compile-time values 
-void GLSL_InitWorldShadersOrError() {
+void GLSL_InitWorldShaders() {
 	// make sure the render thread is stopped
 	R_SyncRenderThread();
 
@@ -155,8 +155,6 @@ void GLSL_InitWorldShadersOrError() {
 	if ( glConfig2.materialSystemAvailable ) {
 		gl_shaderManager.load( gl_cullShader );
 	}
-
-	gl_shaderManager.buildAll();
 }
 
 static void GLSL_InitGPUShadersOrError()
@@ -350,7 +348,7 @@ static void GLSL_InitGPUShadersOrError()
 		gl_shaderManager.load( gl_fxaaShader );
 	}
 
-	if ( !r_lazyShaders->integer )
+	if ( r_lazyShaders.Get() == 0 )
 	{
 		gl_shaderManager.buildAll();
 	}
@@ -369,9 +367,10 @@ void GLSL_InitGPUShaders()
 	 is set on the command line, the cycle is:
 	 1. Start the app.
 	 2. Change shader file(s)
-	 3. Do /glsl_restart at the app console to reload them. If there is a problem the app will
-	    revert to the last working changes in shaders.cpp, so no need to restart the app.
-	    FIXME: this doesn't work, actually it kills the app!
+	 3. Do /glsl_restart at the app console to reload them. If there is a problem and
+	    r_lazyShaders < 2, the app will revert to the last working changes in shaders.cpp, so no need
+	    to restart the app. OTOH if r_lazyShaders = 2 you can iterate really fast, but
+	    you die if you make a typo.
 	 4. If further changes are needed, repeat from step 3.
 
 	 Note that Daemon will respond by listing the files it thinks are different.
@@ -391,6 +390,10 @@ void GLSL_InitGPUShaders()
 		{
 			Log::Warn("Loading external shaders.");
 			GLSL_InitGPUShadersOrError();
+			if ( r_lazyShaders.Get() == 1 && tr.world != nullptr )
+			{
+				gl_shaderManager.buildAll();
+			}
 			Log::Warn("External shaders in use.");
 		}
 		catch (const ShaderException& e)
@@ -426,6 +429,7 @@ void GLSL_ShutdownGPUShaders()
 
 	gl_shaderManager.freeAll();
 
+	gl_generic2DShader = nullptr;
 	gl_genericShader = nullptr;
 	gl_genericShaderMaterial = nullptr;
 	gl_cullShader = nullptr;