Add menu option for disabling shadow maps and detecting if storage buffers are available or not

src/gl/dynlights/gl_dynlight1.cpp

@@ -59,6 +59,7 @@ CVAR (Bool, gl_attachedlights, true, CVAR_ARCHIVE | CVAR_GLOBALCONFIG);
 CVAR (Bool, gl_lights_checkside, true, CVAR_ARCHIVE | CVAR_GLOBALCONFIG);
 CVAR (Bool, gl_light_sprites, true, CVAR_ARCHIVE | CVAR_GLOBALCONFIG);
 CVAR (Bool, gl_light_particles, true, CVAR_ARCHIVE | CVAR_GLOBALCONFIG);
+CVAR (Bool, gl_light_shadowmap, true, CVAR_ARCHIVE | CVAR_GLOBALCONFIG);
 
 //==========================================================================
 //

src/gl/dynlights/gl_shadowmap.cpp

@@ -26,6 +26,7 @@
 #include "gl/dynlights/gl_dynlight.h"
 #include "gl/system/gl_interface.h"
 #include "gl/system/gl_debug.h"
+#include "gl/system/gl_cvars.h"
 #include "gl/renderer/gl_renderer.h"
 #include "gl/renderer/gl_postprocessstate.h"
 #include "gl/renderer/gl_renderbuffers.h"
@@ -67,6 +68,9 @@
 
 void FShadowMap::Update()
 {
+	if (!IsEnabled())
+		return;
+
 	UploadAABBTree();
 	UploadLights();
 
@@ -97,12 +101,25 @@ void FShadowMap::Update()
 
 bool FShadowMap::ShadowTest(ADynamicLight *light, const DVector3 &pos)
 {
-	if (mAABBTree)
+	if (IsEnabled() && mAABBTree)
 		return mAABBTree->RayTest(light->Pos(), pos) >= 1.0f;
 	else
 		return true;
 }
 
+bool FShadowMap::IsEnabled() const
+{
+	return gl_light_shadowmap && !!(gl.flags & RFL_SHADER_STORAGE_BUFFER);
+}
+
+int FShadowMap::ShadowMapIndex(ADynamicLight *light)
+{
+	if (IsEnabled())
+		return mLightToShadowmap[light];
+	else
+		return 1024;
+}
+
 void FShadowMap::UploadLights()
 {
 	mLights.Clear();

src/gl/dynlights/gl_shadowmap.h

@@ -20,11 +20,14 @@ public:
 	void Update();
 
 	// Return the assigned shadow map index for a given light
-	int ShadowMapIndex(ADynamicLight *light) { return mLightToShadowmap[light]; }
+	int ShadowMapIndex(ADynamicLight *light);
 
 	// Test if a world position is in shadow relative to the specified light and returns false if it is
 	bool ShadowTest(ADynamicLight *light, const DVector3 &pos);
 
+	// Returns true if gl_light_shadowmap is enabled and supported by the hardware
+	bool IsEnabled() const;
+
 private:
 	// Upload the AABB-tree to the GPU
 	void UploadAABBTree();

src/gl/shaders/gl_shader.cpp

@@ -105,6 +105,11 @@ bool FShader::Load(const char * name, const char * vert_prog_lump, const char *
 		vp_comb << "#define USE_QUAD_DRAWER\n";
 	}
 
+	if (!!(gl.flags & RFL_SHADER_STORAGE_BUFFER))
+	{
+		vp_comb << "#define SUPPORTS_SHADOWMAPS\n";
+	}
+
 	vp_comb << defines << i_data.GetString().GetChars();
 	FString fp_comb = vp_comb;
 

src/gl/system/gl_cvars.h

@@ -26,6 +26,7 @@ EXTERN_CVAR (Bool, gl_attachedlights);
 EXTERN_CVAR (Bool, gl_lights_checkside);
 EXTERN_CVAR (Bool, gl_light_sprites);
 EXTERN_CVAR (Bool, gl_light_particles);
+EXTERN_CVAR (Bool, gl_light_shadowmap);
 
 EXTERN_CVAR(Int, gl_fogmode)
 EXTERN_CVAR(Int, gl_lightmode)

wadsrc/static/language.enu

@@ -2656,6 +2656,7 @@ GLLIGHTMNU_LIGHTDEFS		= "Enable light definitions";
 GLLIGHTMNU_CLIPLIGHTS 		= "Clip lights";
 GLLIGHTMNU_LIGHTSPRITES 	= "Lights affect sprites";
 GLLIGHTMNU_LIGHTPARTICLES 	= "Lights affect particles";
+GLLIGHTMNU_LIGHTSHADOWMAP 	= "Light shadowmaps";
 
 // OpenGL Preferences
 GLPREFMNU_TITLE 				= "OPENGL PREFERENCES";

wadsrc/static/menudef.zz

@@ -226,6 +226,7 @@ OptionMenu "GLLightOptions"
 	Option "$GLLIGHTMNU_CLIPLIGHTS",		gl_lights_checkside,			"YesNo"
 	Option "$GLLIGHTMNU_LIGHTSPRITES",		gl_light_sprites,				"YesNo"
 	Option "$GLLIGHTMNU_LIGHTPARTICLES",	gl_light_particles,				"YesNo"
+	Option "$GLLIGHTMNU_LIGHTSHADOWMAP",	gl_light_shadowmap,				"YesNo"
 }
 
 OptionMenu "GLPrefOptions"

wadsrc/static/shaders/glsl/main.fp

@@ -139,6 +139,8 @@ float R_DoomLightingEquation(float light)
 //
 //===========================================================================
 
+#ifdef SUPPORTS_SHADOWMAPS
+
 float sampleShadowmap(vec2 lightpos, vec2 testpos, float v)
 {
 	float u;
@@ -173,6 +175,9 @@ float sampleShadowmap(vec2 lightpos, vec2 testpos, float v)
 
 float shadowmapAttenuation(vec4 lightpos, float shadowIndex)
 {
+	if (shadowIndex <= -1024.0 || shadowIndex >= 1024.0)
+		return 1.0; // No shadowmap available for this light
+
 	float v = (abs(shadowIndex) + 0.5) / 1024.0;
 	vec2 dir = (pixelpos.xz - lightpos.xz);
 	vec2 normal = normalize(vec2(-dir.y, dir.x));
@@ -184,6 +189,8 @@ float shadowmapAttenuation(vec4 lightpos, float shadowIndex)
 	return sum / PCF_COUNT;
 }
 
+#endif
+
 //===========================================================================
 //
 // Standard lambertian diffuse light calculation
@@ -206,7 +213,9 @@ float diffuseContribution(vec3 lightDirection, vec3 normal)
 float pointLightAttenuation(vec4 lightpos, float shadowIndex)
 {
 	float attenuation = max(lightpos.w - distance(pixelpos.xyz, lightpos.xyz),0.0) / lightpos.w;
+#ifdef SUPPORTS_SHADOWMAPS
 	attenuation *= shadowmapAttenuation(lightpos, shadowIndex);
+#endif
 	if (shadowIndex >= 0.0) // Sign bit is the attenuated light flag
 	{
 		return attenuation;