X-Ray: Added a slider for the alpha

- will not render when set to 0.0 for speed reasons. so when user sets
transparency to hide everything the bigger passes will be skipped.

release/scripts/startup/bl_ui/space_view3d.py

@@ -3538,6 +3538,9 @@ class VIEW3D_PT_shading(Panel):
 
             row = col.row()
             row.prop(shading, "show_xray")
+            sub = row.row()
+            sub.active = shading.show_xray
+            sub.prop(shading, "xray_alpha", text="")
 
             row = col.row()
             row.active = not shading.show_xray

source/blender/blenloader/intern/versioning_280.c

@@ -1522,5 +1522,18 @@ void blo_do_versions_280(FileData *fd, Library *UNUSED(lib), Main *main)
 				}
 			}
 		}
+
+		if (!DNA_struct_elem_find(fd->filesdna, "View3DShading", "float", "xray_alpha")) {
+			for (bScreen *screen = main->screen.first; screen; screen = screen->id.next) {
+				for (ScrArea *sa = screen->areabase.first; sa; sa = sa->next) {
+					for (SpaceLink *sl = sa->spacedata.first; sl; sl = sl->next) {
+						if (sl->spacetype == SPACE_VIEW3D) {
+							View3D *v3d = (View3D *)sl;
+							v3d->shading.xray_alpha = 0.5f;
+						}
+					}
+				}
+			}
+		}
 	}
 }

source/blender/draw/engines/workbench/shaders/workbench_forward_composite_frag.glsl

@@ -21,18 +21,20 @@ void main()
 	float transparent_revealage = texelFetch(transparentRevealage, texel, 0).r;
 #endif
 	vec4 color;
+	vec4 bg_color;
 
 #ifdef V3D_SHADING_OBJECT_OUTLINE
 	float outline = calculate_object_outline(objectId, texel, object_id);
 #else /* V3D_SHADING_OBJECT_OUTLINE */
 	float outline = 1.0;
 #endif /* V3D_SHADING_OBJECT_OUTLINE */
-
+	bg_color = vec4(background_color(world_data, uv_viewport.y), 0.0);
 	if (object_id == NO_OBJECT_ID) {
-		color = vec4(background_color(world_data, uv_viewport.y), 0.0);
+		color = bg_color;
 	} else {
 #ifdef WORKBENCH_REVEALAGE_ENABLED
 		color = vec4((transparent_accum.xyz / max(transparent_accum.a, EPSILON)) * (1.0 - transparent_revealage), 1.0);
+		color = mix(bg_color, color, clamp(1.0 - transparent_revealage, 0.0, 1.0));
 #else
 		color = vec4(transparent_accum.xyz / max(transparent_accum.a, EPSILON), 1.0);
 #endif

source/blender/draw/engines/workbench/shaders/workbench_forward_transparent_accum_frag.glsl

@@ -2,6 +2,7 @@
 uniform sampler2D image;
 #endif
 uniform mat3 normalWorldMatrix;
+uniform float alpha = 0.5;
 
 #ifdef NORMAL_VIEWPORT_PASS_ENABLED
 in vec3 normal_viewport;
@@ -53,7 +54,6 @@ void main()
 
 #endif /* V3D_LIGHTING_STUDIO */
 
-	float alpha = 0.5	;
 	vec4 premultiplied = vec4(shaded_color.rgb * alpha, alpha);
 	transparentAccum = calculate_transparent_accum(premultiplied);
 }

source/blender/draw/engines/workbench/shaders/workbench_forward_transparent_revealage_frag.glsl

@@ -1,7 +1,7 @@
 layout(location=0) out float transparentRevealage;
-
+uniform float alpha = 0.5;
 void main()
 {
-	transparentRevealage = 0.5;
+	transparentRevealage = alpha;
 }
 

source/blender/draw/engines/workbench/workbench_forward.c

@@ -178,6 +178,7 @@ static WORKBENCH_MaterialData *get_or_create_material_data(
 		        drawtype == OB_SOLID ? wpd->transparent_accum_sh : wpd->transparent_accum_texture_sh,
 		        psl->transparent_accum_pass);
 		DRW_shgroup_uniform_block(grp, "world_block", wpd->world_ubo);
+		DRW_shgroup_uniform_float(grp, "alpha", &wpd->shading.xray_alpha, 1);
 		workbench_material_set_normal_world_matrix(grp, wpd, e_data.normal_world_matrix);
 		material->object_id = engine_object_data->object_id;
 		copy_v4_v4(material->material_data.diffuse_color, material_template.material_data.diffuse_color);
@@ -343,6 +344,7 @@ void workbench_forward_engine_init(WORKBENCH_Data *vedata)
 		int state = DRW_STATE_WRITE_COLOR | DRW_STATE_TRANSPARENT_REVEALAGE;
 		psl->transparent_revealage_pass = DRW_pass_create("Transparent Revealage", state);
 		grp = DRW_shgroup_create(e_data.transparent_revealage_sh, psl->transparent_revealage_pass);
+		DRW_shgroup_uniform_float(grp, "alpha", &wpd->shading.xray_alpha, 1);
 		wpd->transparent_revealage_shgrp = grp;
 	}
 #endif
@@ -546,14 +548,17 @@ void workbench_forward_draw_scene(WORKBENCH_Data *vedata)
 	/* Write Depth + Object ID */
 	GPU_framebuffer_bind(fbl->object_outline_fb);
 	DRW_draw_pass(psl->object_outline_pass);
-
-	/* Shade */
-	GPU_framebuffer_bind(fbl->transparent_accum_fb);
-	DRW_draw_pass(psl->transparent_accum_pass);
+	
+	if (wpd->shading.xray_alpha > 0.0) {
+		/* Shade */
+		GPU_framebuffer_bind(fbl->transparent_accum_fb);
+		DRW_draw_pass(psl->transparent_accum_pass);
 #ifdef WORKBENCH_REVEALAGE_ENABLED
-	GPU_framebuffer_bind(fbl->transparent_revealage_fb);
-	DRW_draw_pass(psl->transparent_revealage_pass);
+		GPU_framebuffer_bind(fbl->transparent_revealage_fb);
+		DRW_draw_pass(psl->transparent_revealage_pass);
 #endif
+	}
+
 	/* Composite */
 	GPU_framebuffer_bind(fbl->composite_fb);
 	DRW_draw_pass(psl->composite_pass);

source/blender/editors/space_view3d/space_view3d.c

@@ -325,7 +325,8 @@ static SpaceLink *view3d_new(const ScrArea *UNUSED(sa), const Scene *scene)
 	v3d->drawtype = OB_SOLID;
 	v3d->shading.flag = V3D_SHADING_SPECULAR_HIGHLIGHT;
 	v3d->shading.light = V3D_LIGHTING_STUDIO;
-	v3d->shading.shadow_intensity = 0.5;
+	v3d->shading.shadow_intensity = 0.5f;
+	v3d->shading.xray_alpha = 0.5f;
 	copy_v3_fl(v3d->shading.single_color, 0.8f);
 
 	v3d->overlay.flag = V3D_OVERLAY_LOOK_DEV;

source/blender/makesdna/DNA_view3d_types.h

@@ -148,7 +148,7 @@ typedef struct View3DShading {
 	float studiolight_background;
 
 	float object_outline_color[3];
-	float pad2;
+	float xray_alpha;
 } View3DShading;
 
 /* 3D Viewport Overlay setings */

source/blender/makesrna/intern/rna_space.c

@@ -2342,6 +2342,15 @@ static void rna_def_space_view3d_shading(BlenderRNA *brna)
 	RNA_def_property_ui_text(prop, "X-Ray", "Show whole scene transparent");
 	RNA_def_property_update(prop, NC_SPACE | ND_SPACE_VIEW3D, NULL);
 
+	prop = RNA_def_property(srna, "xray_alpha", PROP_FLOAT, PROP_FACTOR);
+	RNA_def_property_float_sdna(prop, NULL, "shading.xray_alpha");
+	RNA_def_property_float_default(prop, 0.5);
+	RNA_def_property_ui_text(prop, "X-Ray Alpha", "Amount of alpha to use");
+	RNA_def_property_range(prop, 0.0f, 1.0f);
+	RNA_def_property_ui_range(prop, 0.04f, 1.0f, 1, 1);
+	RNA_def_property_clear_flag(prop, PROP_ANIMATABLE);
+	RNA_def_property_update(prop, NC_SPACE | ND_SPACE_VIEW3D, NULL);
+
 	prop = RNA_def_property(srna, "use_scene_light", PROP_BOOLEAN, PROP_NONE);
 	RNA_def_property_boolean_sdna(prop, NULL, "shading.flag", V3D_SHADING_SCENE_LIGHT);
 	RNA_def_property_clear_flag(prop, PROP_ANIMATABLE);