3D View: x-ray support for depth picking

Selection loop would draw the selection ignoring xray.
Now draw in a separate pass after clearing the depth buffer,
as with regular drawing.

Also disable depth sorting,
caller can sort the hit-list by depth if needed.

source/blender/editors/space_view3d/drawobject.c

@@ -8174,6 +8174,50 @@ void draw_object(Scene *scene, ARegion *ar, View3D *v3d, Base *base, const short
 	ED_view3d_clear_mats_rv3d(rv3d);
 }
 
+
+/**
+ * Drawing for selection picking,
+ * caller must have called 'GPU_select_load_id(base->selcode)' first.
+ */
+void draw_object_select(Scene *scene, ARegion *ar, View3D *v3d, Base *base, const short dflag)
+{
+	BLI_assert(dflag & DRAW_PICKING && dflag & DRAW_CONSTCOLOR);
+	draw_object(scene, ar, v3d, base, dflag);
+
+	/* we draw duplicators for selection too */
+	if ((base->object->transflag & OB_DUPLI)) {
+		ListBase *lb;
+		DupliObject *dob;
+		Base tbase;
+
+		tbase.flag = OB_FROMDUPLI;
+		lb = object_duplilist(G.main->eval_ctx, scene, base->object);
+
+		for (dob = lb->first; dob; dob = dob->next) {
+			float omat[4][4];
+			char dt;
+			short dtx;
+
+			tbase.object = dob->ob;
+			copy_m4_m4(omat, dob->ob->obmat);
+			copy_m4_m4(dob->ob->obmat, dob->mat);
+
+			/* extra service: draw the duplicator in drawtype of parent */
+			/* MIN2 for the drawtype to allow bounding box objects in groups for lods */
+			dt = tbase.object->dt;   tbase.object->dt = MIN2(tbase.object->dt, base->object->dt);
+			dtx = tbase.object->dtx; tbase.object->dtx = base->object->dtx;
+
+			draw_object(scene, ar, v3d, &tbase, dflag);
+
+			tbase.object->dt = dt;
+			tbase.object->dtx = dtx;
+
+			copy_m4_m4(dob->ob->obmat, omat);
+		}
+		free_object_duplilist(lb);
+	}
+}
+
 /* ***************** BACKBUF SEL (BBS) ********* */
 
 static void bbs_obmode_mesh_verts__mapFunc(void *userData, int index, const float co[3],

source/blender/editors/space_view3d/view3d_draw.c

@@ -100,6 +100,7 @@
 #include "GPU_material.h"
 #include "GPU_compositing.h"
 #include "GPU_extensions.h"
+#include "GPU_select.h"
 
 #include "view3d_intern.h"  /* own include */
 
@@ -2023,6 +2024,35 @@ static void view3d_draw_xraytransp(Scene *scene, ARegion *ar, View3D *v3d, const
 	glDepthMask(GL_TRUE);
 }
 
+/* clears zbuffer and draws it over,
+ * note that in the select version we don't care about transparent flag as with regular drawing */
+static void view3d_draw_xray_select(Scene *scene, ARegion *ar, View3D *v3d, bool *clear)
+{
+	/* Not ideal, but we need to read from the previous depths before clearing
+	 * otherwise we could have a function to load the depths after drawing.
+	 *
+	 * Clearing the depth buffer isn't all that common between drawing objects so accept this for now.
+	 */
+	if (U.gpu_select_pick_deph) {
+		GPU_select_load_id(-1);
+	}
+
+	View3DAfter *v3da;
+	if (*clear && v3d->zbuf) {
+		glClear(GL_DEPTH_BUFFER_BIT);
+		*clear = false;
+	}
+
+	v3d->xray = true;
+	while ((v3da = BLI_pophead(&v3d->afterdraw_xray))) {
+		if (GPU_select_load_id(v3da->base->selcol)) {
+			draw_object_select(scene, ar, v3d, v3da->base, v3da->dflag);
+		}
+		MEM_freeN(v3da);
+	}
+	v3d->xray = false;
+}
+
 /* *********************** */
 
 /*
@@ -2487,6 +2517,58 @@ void ED_view3d_draw_depth(Scene *scene, ARegion *ar, View3D *v3d, bool alphaover
 	U.obcenter_dia = obcenter_dia;
 }
 
+void ED_view3d_draw_select_loop(
+        ViewContext *vc, Scene *scene, View3D *v3d, ARegion *ar,
+        bool use_obedit_skip, bool use_nearest)
+{
+	short code = 1;
+	const short dflag = DRAW_PICKING | DRAW_CONSTCOLOR;
+
+	if (vc->obedit && vc->obedit->type == OB_MBALL) {
+		draw_object(scene, ar, v3d, BASACT, dflag);
+	}
+	else if ((vc->obedit && vc->obedit->type == OB_ARMATURE)) {
+		/* if not drawing sketch, draw bones */
+		if (!BDR_drawSketchNames(vc)) {
+			draw_object(scene, ar, v3d, BASACT, dflag);
+		}
+	}
+	else {
+		Base *base;
+
+		for (base = scene->base.first; base; base = base->next) {
+			if (base->lay & v3d->lay) {
+
+				if ((base->object->restrictflag & OB_RESTRICT_SELECT) ||
+				    (use_obedit_skip && (scene->obedit->data == base->object->data)))
+				{
+					base->selcol = 0;
+				}
+				else {
+					base->selcol = code;
+
+					if (use_nearest && (base->object->dtx & OB_DRAWXRAY)) {
+						ED_view3d_after_add(&v3d->afterdraw_xray, base, dflag);
+					}
+					else {
+						if (GPU_select_load_id(code)) {
+							draw_object_select(scene, ar, v3d, base, dflag);
+						}
+					}
+					code++;
+				}
+			}
+		}
+
+		if (use_nearest) {
+			bool xrayclear = true;
+			if (v3d->afterdraw_xray.first) {
+				view3d_draw_xray_select(scene, ar, v3d, &xrayclear);
+			}
+		}
+	}
+}
+
 typedef struct View3DShadow {
 	struct View3DShadow *next, *prev;
 	GPULamp *lamp;

source/blender/editors/space_view3d/view3d_intern.h

@@ -143,6 +143,8 @@ void draw_motion_paths_cleanup(View3D *v3d);
 
 /* drawobject.c */
 void draw_object(Scene *scene, struct ARegion *ar, View3D *v3d, Base *base, const short dflag);
+void draw_object_select(Scene *scene, ARegion *ar, View3D *v3d, Base *base, const short dflag);
+
 bool draw_glsl_material(Scene *scene, struct Object *ob, View3D *v3d, const char dt);
 void draw_object_instance(Scene *scene, View3D *v3d, RegionView3D *rv3d, struct Object *ob, const char dt, int outline);
 void draw_object_backbufsel(Scene *scene, View3D *v3d, RegionView3D *rv3d, struct Object *ob);
@@ -195,7 +197,11 @@ void draw_sim_debug_data(Scene *scene, View3D *v3d, ARegion *ar);
 void view3d_main_region_draw(const struct bContext *C, struct ARegion *ar);
 void ED_view3d_draw_depth(Scene *scene, struct ARegion *ar, View3D *v3d, bool alphaoverride);
 void ED_view3d_draw_depth_gpencil(Scene *scene, ARegion *ar, View3D *v3d);
-void ED_view3d_after_add(ListBase *lb, Base *base, const short dflag);
+void ED_view3d_draw_select_loop(
+        ViewContext *vc, Scene *scene, View3D *v3d, ARegion *ar,
+        bool use_obedit_skip, bool use_nearest);
+
+void ED_view3d_after_add(ListBase *lb, Base *base, const short dflag);\
 
 void circf(float x, float y, float rad);
 void circ(float x, float y, float rad);

source/blender/editors/space_view3d/view3d_view.c

@@ -1091,78 +1091,6 @@ void view3d_viewmatrix_set(Scene *scene, const View3D *v3d, RegionView3D *rv3d)
 	}
 }
 
-static void view3d_select_loop(ViewContext *vc, Scene *scene, View3D *v3d, ARegion *ar, bool use_obedit_skip)
-{
-	short code = 1;
-	char dt;
-	short dtx;
-
-	if (vc->obedit && vc->obedit->type == OB_MBALL) {
-		draw_object(scene, ar, v3d, BASACT, DRAW_PICKING | DRAW_CONSTCOLOR);
-	}
-	else if ((vc->obedit && vc->obedit->type == OB_ARMATURE)) {
-		/* if not drawing sketch, draw bones */
-		if (!BDR_drawSketchNames(vc)) {
-			draw_object(scene, ar, v3d, BASACT, DRAW_PICKING | DRAW_CONSTCOLOR);
-		}
-	}
-	else {
-		Base *base;
-
-		v3d->xray = true;  /* otherwise it postpones drawing */
-		for (base = scene->base.first; base; base = base->next) {
-			if (base->lay & v3d->lay) {
-
-				if ((base->object->restrictflag & OB_RESTRICT_SELECT) ||
-				    (use_obedit_skip && (scene->obedit->data == base->object->data)))
-				{
-					base->selcol = 0;
-				}
-				else {
-					base->selcol = code;
-
-					if (GPU_select_load_id(code)) {
-						draw_object(scene, ar, v3d, base, DRAW_PICKING | DRAW_CONSTCOLOR);
-
-						/* we draw duplicators for selection too */
-						if ((base->object->transflag & OB_DUPLI)) {
-							ListBase *lb;
-							DupliObject *dob;
-							Base tbase;
-
-							tbase.flag = OB_FROMDUPLI;
-							lb = object_duplilist(G.main->eval_ctx, scene, base->object);
-
-							for (dob = lb->first; dob; dob = dob->next) {
-								float omat[4][4];
-
-								tbase.object = dob->ob;
-								copy_m4_m4(omat, dob->ob->obmat);
-								copy_m4_m4(dob->ob->obmat, dob->mat);
-
-								/* extra service: draw the duplicator in drawtype of parent */
-								/* MIN2 for the drawtype to allow bounding box objects in groups for lods */
-								dt = tbase.object->dt;   tbase.object->dt = MIN2(tbase.object->dt, base->object->dt);
-								dtx = tbase.object->dtx; tbase.object->dtx = base->object->dtx;
-
-								draw_object(scene, ar, v3d, &tbase, DRAW_PICKING | DRAW_CONSTCOLOR);
-
-								tbase.object->dt = dt;
-								tbase.object->dtx = dtx;
-
-								copy_m4_m4(dob->ob->obmat, omat);
-							}
-							free_object_duplilist(lb);
-						}
-					}
-					code++;
-				}
-			}
-		}
-		v3d->xray = false;  /* restore */
-	}
-}
-
 /**
  * Optionally cache data for multiple calls to #view3d_opengl_select
  *
@@ -1200,6 +1128,7 @@ int view3d_opengl_select(
 	        (is_pick_select == false) &&
 	        (select_mode == VIEW3D_SELECT_PICK_NEAREST) &&
 	        GPU_select_query_check_active());
+	const bool use_nearest = (is_pick_select && select_mode == VIEW3D_SELECT_PICK_NEAREST);
 
 	char gpu_select_mode;
 
@@ -1256,7 +1185,7 @@ int view3d_opengl_select(
 	
 	GPU_select_begin(buffer, bufsize, &rect, gpu_select_mode, 0);
 
-	view3d_select_loop(vc, scene, v3d, ar, use_obedit_skip);
+	ED_view3d_draw_select_loop(vc, scene, v3d, ar, use_obedit_skip, use_nearest);
 
 	hits = GPU_select_end();
 	
@@ -1264,7 +1193,7 @@ int view3d_opengl_select(
 	if (do_passes) {
 		GPU_select_begin(buffer, bufsize, &rect, GPU_SELECT_NEAREST_SECOND_PASS, hits);
 
-		view3d_select_loop(vc, scene, v3d, ar, use_obedit_skip);
+		ED_view3d_draw_select_loop(vc, scene, v3d, ar, use_obedit_skip, use_nearest);
 
 		GPU_select_end();
 	}

source/blender/gpu/intern/gpu_select_pick.c

@@ -91,6 +91,15 @@ static void rect_subregion_stride_calc(const rcti *src, const rcti *dst, SubRect
 	r_sub->skip = src_x - dst_x;
 }
 
+/**
+ * Ignore depth clearing as a change,
+ * only check if its been changed _and_ filled in (ignore clearing since XRAY does this).
+ */
+BLI_INLINE bool depth_is_filled(const depth_t *prev, const depth_t *curr)
+{
+	return (*prev != *curr) && (*curr != DEPTH_MAX);
+}
+
 /* ----------------------------------------------------------------------------
  * DepthBufCache
  *
@@ -142,17 +151,28 @@ static bool depth_buf_subrect_depth_any(
 	return false;
 }
 
-static bool depth_buf_rect_not_equal(
-        const DepthBufCache *rect_depth_a, const DepthBufCache *rect_depth_b,
+static bool depth_buf_rect_depth_any_filled(
+        const DepthBufCache *rect_prev, const DepthBufCache *rect_curr,
         unsigned int rect_len)
 {
+#if 0
 	return memcmp(rect_depth_a->buf, rect_depth_b->buf, rect_len * sizeof(depth_t)) != 0;
+#else
+	const depth_t *prev = rect_prev->buf;
+	const depth_t *curr = rect_curr->buf;
+	for (unsigned int i = 0; i < rect_len; i++, curr++, prev++) {
+		if (depth_is_filled(prev, curr)) {
+			return true;
+		}
+	}
+	return false;
+#endif
 }
 
 /**
  * Both buffers are the same size, just check if the sub-rect contains any differences.
  */
-static bool depth_buf_subrect_not_equal(
+static bool depth_buf_subrect_depth_any_filled(
         const DepthBufCache *rect_src, const DepthBufCache *rect_dst,
         const SubRectStride *sub_rect)
 {
@@ -162,7 +182,7 @@ static bool depth_buf_subrect_not_equal(
 	for (unsigned int i = 0; i < sub_rect->span_len; i++) {
 		const depth_t *curr_end = curr + sub_rect->span;
 		for (; curr < curr_end; prev++, curr++) {
-			if (*prev != *curr) {
+			if (depth_is_filled(prev, curr)) {
 				return true;
 			}
 		}
@@ -422,8 +442,11 @@ static void gpu_select_load_id_pass_nearest(const DepthBufCache *rect_prev, cons
 	if (id != SELECT_ID_NONE) {
 		unsigned int *id_ptr = ps->nearest.rect_id;
 
+		/* Check against DEPTH_MAX because XRAY will clear the buffer,
+		 * so previously set values will become unset.
+		 * In this case just leave those id's left as-is. */
 #define EVAL_TEST() \
-		if (*curr != *prev) { \
+		if (depth_is_filled(prev, curr)) { \
 			*id_ptr = id; \
 		} ((void)0)
 
@@ -472,7 +495,7 @@ bool gpu_select_pick_load_id(unsigned int id)
 			}
 		}
 		else {
-			if (depth_buf_rect_not_equal(ps->gl.rect_depth, ps->gl.rect_depth_test, rect_len)) {
+			if (depth_buf_rect_depth_any_filled(ps->gl.rect_depth, ps->gl.rect_depth_test, rect_len)) {
 				ps->gl.rect_depth_test->id = ps->gl.prev_id;
 				gpu_select_load_id_pass_nearest(ps->gl.rect_depth, ps->gl.rect_depth_test);
 				do_pass = true;
@@ -623,16 +646,17 @@ unsigned int gpu_select_pick_end(void)
 		hits = -1;
 	}
 	else {
+		/* leave sorting up to the caller */
 		qsort(depth_data, depth_data_len, sizeof(DepthID), depth_cmp);
 
 		for (unsigned int i = 0; i < depth_data_len; i++) {
 #ifdef DEBUG_PRINT
-			printf("  hit: %d: depth %u\n", depth_data[i].id,  depth_data[i].depth);
+			printf("  hit: %u: depth %u\n", depth_data[i].id,  depth_data[i].depth);
 #endif
 			/* first 3 are dummy values */
 			g_pick_state.buffer[hits][0] = 1;
-			g_pick_state.buffer[hits][1] = 0x0;
-			g_pick_state.buffer[hits][2] = 0x0;
+			g_pick_state.buffer[hits][1] = 0x0;  /* depth_data[i].depth; */ /* unused */
+			g_pick_state.buffer[hits][2] = 0x0;  /* z-far is currently never used. */
 			g_pick_state.buffer[hits][3] = depth_data[i].id;
 			hits++;
 		}
@@ -709,7 +733,7 @@ void gpu_select_pick_cache_load_id(void)
 				}
 			}
 			else {
-				if (depth_buf_subrect_not_equal(rect_depth, rect_depth->next, &ps->cache.sub_rect)) {
+				if (depth_buf_subrect_depth_any_filled(rect_depth, rect_depth->next, &ps->cache.sub_rect)) {
 					gpu_select_load_id_pass_nearest(rect_depth, rect_depth->next);
 				}
 			}