materials: Make fallback radiance (used when no BSP radiance given) a…

…n explicit attribute

src/refresh/vkpt/bsp_mesh.c

@@ -135,15 +135,9 @@ compute_emissive(mtexinfo_t *texinfo)
 
 	const float bsp_emissive = (float)texinfo->radiance * cvar_pt_bsp_radiance_scale->value;
 
-	const qboolean is_emissive_fake = texinfo->material->image_emissive && ((texinfo->material->image_emissive->flags & IF_FAKE_EMISSIVE) != 0);
-
-	// If emissive is "fake", treat absence of SURF_LIGHT flag as "not emissive"
-	// If emissive is not "fake" (ie explicit image), treat absence of SURF_LIGHT flag as "fully emissive"
-	const float fallback_emissive = is_emissive_fake ? 0.f : 1.f;
-
 	return ((texinfo->c.flags & SURF_LIGHT) && texinfo->material->bsp_radiance)
 		? bsp_emissive
-		: fallback_emissive;
+		: texinfo->material->default_radiance;
 }
 
 #define DUMP_WORLD_MESH_TO_OBJ 0
@@ -2029,7 +2023,12 @@ bsp_mesh_register_textures(bsp_t *bsp)
 				synth_surface_material &= !is_warp_surface;
 
 			if (synth_surface_material)
+			{
 				MAT_SynthesizeEmissive(mat);
+				/* If emissive is "fake", treat absence of BSP radiance flag as "not emissive":
+				* The assumption is that this is closer to the author's intention */
+				mat->default_radiance = 0.0f;
+			}
 		}
 
 		info->material = mat;

src/refresh/vkpt/material.c

@@ -168,6 +168,9 @@ static void MAT_Reset(pbr_material_t * mat)
 	mat->base_factor = 1.f;
 	mat->light_styles = true;
 	mat->bsp_radiance = true;
+	/* Treat absence of SURF_LIGHT flag as "fully emissive" by default.
+	 * Typically works well with explicit emissive image. */
+	mat->default_radiance = 1.f;
 	mat->flags = MATERIAL_KIND_REGULAR;
 	mat->num_frames = 1;
 	mat->emissive_threshold = cvar_pt_surface_lights_threshold->integer;
@@ -292,6 +295,7 @@ enum AttributeIndex
 	MAT_TEXTURE_EMISSIVE,
 	MAT_LIGHT_STYLES,
 	MAT_BSP_RADIANCE,
+	MAT_DEFAULT_RADIANCE,
 	MAT_TEXTURE_MASK,
 	MAT_SYNTH_EMISSIVE,
 	MAT_EMISSIVE_THRESHOLD,
@@ -316,6 +320,7 @@ static struct MaterialAttribute {
 	{MAT_TEXTURE_EMISSIVE, "texture_emissive", ATTR_STRING},
 	{MAT_LIGHT_STYLES, "light_styles", ATTR_BOOL},
 	{MAT_BSP_RADIANCE, "bsp_radiance", ATTR_BOOL},
+	{MAT_DEFAULT_RADIANCE, "default_radiance", ATTR_FLOAT},
 	{MAT_TEXTURE_MASK, "texture_mask", ATTR_STRING},
 	{MAT_SYNTH_EMISSIVE, "synth_emissive", ATTR_BOOL},
 	{MAT_EMISSIVE_THRESHOLD, "emissive_threshold", ATTR_INT},
@@ -449,6 +454,10 @@ static int set_material_attribute(pbr_material_t* mat, const char* attribute, co
 		mat->bsp_radiance = bvalue;
 		if (reload_flags) *reload_flags |= RELOAD_MAP;
 		break;
+	case MAT_DEFAULT_RADIANCE:
+		mat->default_radiance = fvalue;
+		if (reload_flags) *reload_flags |= RELOAD_MAP;
+		break;
 	case MAT_TEXTURE_MASK:
 		set_material_texture(mat, svalue, mat->filename_mask, &mat->image_mask, IF_NONE, !sourceFile);
 		if (reload_flags) *reload_flags |= RELOAD_MAP;
@@ -684,6 +693,9 @@ static void save_materials(const char* file_name, bool save_all, bool force)
 		if (!mat->bsp_radiance)
 			FS_FPrintf(file, "\tbsp_radiance 0\n");
 
+		if (mat->default_radiance != 1.f)
+			FS_FPrintf(file, "\tdefault_radiance %f\n", mat->default_radiance);
+
 		if (mat->synth_emissive)
 			FS_FPrintf(file, "\tsynth_emissive 1\n");
 
@@ -980,6 +992,7 @@ void MAT_Print(pbr_material_t const * mat)
 	Com_Printf("    is_light %d\n", (mat->flags & MATERIAL_FLAG_LIGHT) != 0);
 	Com_Printf("    light_styles %d\n", mat->light_styles ? 1 : 0);
 	Com_Printf("    bsp_radiance %d\n", mat->bsp_radiance ? 1 : 0);
+	Com_Printf("    default_radiance %f\n", mat->default_radiance);
 	Com_Printf("    synth_emissive %d\n", mat->synth_emissive ? 1 : 0);
 	Com_Printf("    emissive_threshold %d\n", mat->emissive_threshold);
 }

src/refresh/vkpt/material.h

@@ -57,6 +57,7 @@ typedef struct pbr_material_s {
 	int next_frame;
 	bool light_styles;
 	bool bsp_radiance;
+	float default_radiance;
 	imageflags_t image_flags;
 	imagetype_t image_type;
 	bool synth_emissive;