Allow setting light attenuation mode from mapinfo

src/common/rendering/hwrenderer/data/hw_renderstate.h

@@ -647,6 +647,7 @@ public:
 		matrices.mClipLine.X = -10000000.0f;
 		matrices.mShadowFilter = gl_light_shadow_filter;
 		matrices.mLightBlendMode = 0;
+		matrices.mLightAttenuationMode = 0;
 		matrices.mProjectionMatrix.ortho(0, (float)width, (float)height, 0, -1.0f, 1.0f);
 		matrices.CalcDependencies();
 		return SetViewpoint(matrices);

src/common/rendering/hwrenderer/data/hw_viewpointuniforms.h

@@ -13,6 +13,14 @@ enum class ELightBlendMode : uint8_t
 	DEFAULT = CLAMP,
 };
 
+enum class ELightAttenuationMode : uint8_t
+{
+	LINEAR = 0,
+	INVERSE_SQUARE = 1,
+
+	DEFAULT = LINEAR,
+};
+
 struct HWViewpointUniforms
 {
 	VSMatrix mProjectionMatrix;
@@ -35,6 +43,8 @@ struct HWViewpointUniforms
 
 	int mLightTilesWidth = 0;
 
+	int mLightAttenuationMode = 0;
+
 	void CalcDependencies()
 	{
 		mNormalViewMatrix.computeNormalMatrix(mViewMatrix);

src/gamedata/g_mapinfo.cpp

@@ -325,6 +325,7 @@ void level_info_t::Reset()
 	skyrotatevector = FVector3(0, 0, 1);
 	skyrotatevector2 = FVector3(0, 0, 1);
 	lightblendmode = ELightBlendMode::DEFAULT;
+	lightattenuationmode = ELightAttenuationMode::DEFAULT;
 	tonemap = ETonemapMode::None;
 }
 
@@ -1596,10 +1597,14 @@ DEFINE_MAP_OPTION(lightblendmode, false)
 	parse.ParseAssign();
 	parse.sc.MustGetString();
 
-	if (parse.sc.Compare("Default") || parse.sc.Compare("Clamp"))
+	if (parse.sc.Compare("Default"))
 	{
 		info->lightblendmode = ELightBlendMode::DEFAULT;
 	}
+	else if (parse.sc.Compare("Clamp"))
+	{
+		info->lightblendmode = ELightBlendMode::CLAMP;
+	}
 	else if (parse.sc.Compare("ColoredClamp"))
 	{
 		info->lightblendmode = ELightBlendMode::CLAMP_COLOR;
@@ -1642,6 +1647,29 @@ DEFINE_MAP_OPTION(lightblendmode, false)
 	}
 }
 
+DEFINE_MAP_OPTION(lightattenuationmode, false)
+{
+	parse.ParseAssign();
+	parse.sc.MustGetString();
+
+	if (parse.sc.Compare("Default"))
+	{
+		info->lightattenuationmode = ELightAttenuationMode::DEFAULT;
+	}
+	else if (parse.sc.Compare("Linear"))
+	{
+		info->lightattenuationmode = ELightAttenuationMode::LINEAR;
+	}
+	else if (parse.sc.Compare("InverseSquare"))
+	{
+		info->lightattenuationmode = ELightAttenuationMode::INVERSE_SQUARE;
+	}
+	else
+	{
+		parse.sc.ScriptMessage("Invalid light attenuation mode %s", parse.sc.String);
+	}
+}
+
 DEFINE_MAP_OPTION(notexturefill, false)
 {
 	if (parse.CheckAssign())

src/gamedata/g_mapinfo.h

@@ -431,6 +431,7 @@ struct level_info_t
 	FString		acsName;
 	bool		fs_nocheckposition;
 	ELightBlendMode lightblendmode;
+	ELightAttenuationMode lightattenuationmode;
 	ETonemapMode tonemap;
 	
 	CutsceneDef intro, outro;

src/rendering/hwrenderer/scene/hw_drawinfo.cpp

@@ -127,7 +127,8 @@ void HWDrawInfo::StartScene(FRenderViewpoint &parentvp, HWViewpointUniforms *uni
 		}
 		VPUniforms.mClipLine.X = -10000000.0f;
 		VPUniforms.mShadowFilter = static_cast<int>(gl_light_shadow_filter);
-		VPUniforms.mLightBlendMode = (level.info ? (int)level.info->lightblendmode : 0);
+		VPUniforms.mLightBlendMode = (level.info ? static_cast<int>(level.info->lightblendmode) : 0);
+		VPUniforms.mLightAttenuationMode = (level.info ? static_cast<int>(level.info->lightattenuationmode) : 0);
 	}
 	mClipper->SetViewpoint(Viewpoint);
 	vClipper->SetViewpoint(Viewpoint);

wadsrc/static/shaders/scene/binding_rsbuffers.glsl

@@ -21,6 +21,8 @@ layout(set = 1, binding = 0, std140) uniform ViewpointUBO
 	int uLightBlendMode;
 
 	int uLightTilesWidth;	// Levelmesh light tiles
+    
+    int uLightAttenuationMode;
 };
 
 layout(set = 1, binding = 1, std140) uniform MatricesUBO

wadsrc/static/shaders/scene/lightmodel_normal.glsl

@@ -1,3 +1,28 @@
+float linearDistanceAttenuation(vec4 lightpos, float d)
+{
+	return clamp((lightpos.w - d) / lightpos.w, 0.0, 1.0);
+}
+
+float inverseSquareDistanceAttenuation(vec4 lightpos, float d)
+{
+	float strength = 1500.0;
+	float r = lightpos.w;
+	float a = d / r;
+	float b = clamp(1.0 - a * a * a * a, 0.0, 1.0);
+	return (b * b) / (d * d + 1.0) * strength;
+}
+
+float distanceAttenuation(vec4 lightpos, float d)
+{
+    if ( uLightAttenuationMode == 1 )
+    {
+        return inverseSquareDistanceAttenuation(lightpos, d);
+    }
+    else
+    {
+        return linearDistanceAttenuation(lightpos, d);
+    }
+}
 
 vec3 lightContribution(int i, vec3 normal)
 {
@@ -14,7 +39,7 @@ vec3 lightContribution(int i, vec3 normal)
 	float dotprod = dot(normal, lightdir);
 	if (dotprod < -0.0001) return vec3(0.0);	// light hits from the backside. This can happen with full sector light lists and must be rejected for all cases. Note that this can cause precision issues.
 
-	float attenuation = clamp((lightpos.w - lightdistance) / lightpos.w, 0.0, 1.0);
+	float attenuation = distanceAttenuation(lightpos, lightdistance);
 
 	if (lightspot1.w == 1.0)
 		attenuation *= spotLightAttenuation(lightpos, lightspot1.xyz, lightspot2.x, lightspot2.y);

wadsrc/static/shaders/scene/lightmodel_pbr.glsl

@@ -61,6 +61,18 @@ float inverseSquareDistanceAttenuation(vec4 lightpos)
 	return (b * b) / (d * d + 1.0) * strength;
 }
 
+float distanceAttenuation(vec4 lightpos)
+{
+    if ( uLightAttenuationMode == 1 )
+    {
+        return inverseSquareDistanceAttenuation(lightpos);
+    }
+    else
+    {
+        return linearDistanceAttenuation(lightpos);
+    }
+}
+
 vec3 ProcessMaterialLight(Material material, vec3 ambientLight)
 {
 	vec3 worldpos = pixelpos.xyz;
@@ -96,7 +108,7 @@ vec3 ProcessMaterialLight(Material material, vec3 ambientLight)
 				vec3 L = normalize(lightpos.xyz - worldpos);
 				vec3 H = normalize(V + L);
 
-				float attenuation = inverseSquareDistanceAttenuation(lightpos);
+				float attenuation = distanceAttenuation(lightpos);
 				if (lightspot1.w == 1.0)
 					attenuation *= spotLightAttenuation(lightpos, lightspot1.xyz, lightspot2.x, lightspot2.y);
 				if (lightcolor.a < 0.0)
@@ -136,7 +148,7 @@ vec3 ProcessMaterialLight(Material material, vec3 ambientLight)
 				vec3 L = normalize(lightpos.xyz - worldpos);
 				vec3 H = normalize(V + L);
 
-				float attenuation = linearDistanceAttenuation(lightpos);
+				float attenuation = distanceAttenuation(lightpos);
 				if (lightspot1.w == 1.0)
 					attenuation *= spotLightAttenuation(lightpos, lightspot1.xyz, lightspot2.x, lightspot2.y);
 				if (lightcolor.a < 0.0)

wadsrc/static/shaders/scene/lightmodel_specular.glsl

@@ -1,3 +1,28 @@
+float linearDistanceAttenuation(vec4 lightpos, float d)
+{
+	return clamp((lightpos.w - d) / lightpos.w, 0.0, 1.0);
+}
+
+float inverseSquareDistanceAttenuation(vec4 lightpos, float d)
+{
+	float strength = 1500.0;
+	float r = lightpos.w;
+	float a = d / r;
+	float b = clamp(1.0 - a * a * a * a, 0.0, 1.0);
+	return (b * b) / (d * d + 1.0) * strength;
+}
+
+float distanceAttenuation(vec4 lightpos, float d)
+{
+    if ( uLightAttenuationMode == 1 )
+    {
+        return inverseSquareDistanceAttenuation(lightpos, d);
+    }
+    else
+    {
+        return linearDistanceAttenuation(lightpos, d);
+    }
+}
 
 vec2 lightAttenuation(int i, vec3 normal, vec3 viewdir, float lightcolorA, float glossiness, float specularLevel)
 {
@@ -9,7 +34,7 @@ vec2 lightAttenuation(int i, vec3 normal, vec3 viewdir, float lightcolorA, float
 	if (lightpos.w < lightdistance)
 		return vec2(0.0); // Early out lights touching surface but not this fragment
 
-	float attenuation = clamp((lightpos.w - lightdistance) / lightpos.w, 0.0, 1.0);
+	float attenuation = distanceAttenuation(lightpos, lightdistance);
 
 	if (lightspot1.w == 1.0)
 		attenuation *= spotLightAttenuation(lightpos, lightspot1.xyz, lightspot2.x, lightspot2.y);