T54983: Bone selection overlay

Bone selection overlay is only available in pose mode.
and when active overrules the selection buffer.

This is currently `tricked` by switching the draw engines, but this is
an exception. Not sure how to solve this in a better way.

After this is solved we can look at how to localize the dim effect to only the objects connected to the active armatures. Currently it dims the whole screen (including background).

@campbellbarton I added you as reviewer as it you have done a lot in the DRW_draw_select_loop

Reviewers: campbellbarton, fclem

Reviewed By: fclem

Subscribers: campbellbarton

Tags: #bf_blender_2.8, #code_quest

Maniphest Tasks: T54983

Differential Revision: https://developer.blender.org/D3241

2 files changed, 94 insertions, 6 deletions

diff --git a/source/blender/draw/intern/draw_manager.c b/source/blender/draw/intern/draw_manager.c
index f18e2d119dc..98fe737410f 100644
--- a/source/blender/draw/intern/draw_manager.c
+++ b/source/blender/draw/intern/draw_manager.c
@@ -1570,6 +1570,15 @@ void DRW_draw_select_loop(
 			obedit_mode = CTX_MODE_EDIT_ARMATURE;
 		}
 	}
+	bool use_bone_selection_overlay = false;
+	if (v3d->overlay.flag &= V3D_OVERLAY_BONE_SELECTION) {
+		if (!(v3d->flag2 &= V3D_RENDER_OVERRIDE)) {
+			Object *obpose = OBPOSE_FROM_OBACT(obact);
+			if (obpose) {
+				use_bone_selection_overlay = true;
+			}
+		}
+	}
 
 	struct GPUViewport *viewport = GPU_viewport_create();
 	GPU_viewport_size_set(viewport, (const int[2]){BLI_rcti_size_x(rect), BLI_rcti_size_y(rect)});
@@ -1584,8 +1593,17 @@ void DRW_draw_select_loop(
 		drw_engines_enable_from_mode(obedit_mode);
 	}
 	else {
-		drw_engines_enable_basic();
-		drw_engines_enable_from_object_mode();
+		/* when in pose mode and overlays enable and bone selection overlay
+		   active, switch order as the bone selection must have more precedence
+		   than the rest of the scene */
+		if (use_bone_selection_overlay) {
+			drw_engines_enable_from_object_mode();
+			drw_engines_enable_basic();
+		}
+		else {
+			drw_engines_enable_basic();
+			drw_engines_enable_from_object_mode();
+		}
 	}
 
 	/* Setup viewport */
diff --git a/source/blender/draw/modes/pose_mode.c b/source/blender/draw/modes/pose_mode.c
index a7fc1da959b..19a93c8c52d 100644
--- a/source/blender/draw/modes/pose_mode.c
+++ b/source/blender/draw/modes/pose_mode.c
@@ -22,10 +22,13 @@
 /** \file blender/draw/modes/pose_mode.c
  *  \ingroup draw
  */
+#include "BKE_modifier.h"
+
+#include "DNA_modifier_types.h"
+#include "DNA_view3d_types.h"
 
 #include "DRW_engine.h"
 #include "DRW_render.h"
-#include "DNA_view3d_types.h"
 
 /* If builtin shaders are needed */
 #include "GPU_shader.h"
@@ -50,6 +53,7 @@ typedef struct POSE_PassList {
 	struct DRWPass *bone_envelope;
 	struct DRWPass *bone_axes;
 	struct DRWPass *relationship;
+	struct DRWPass *bone_selection;
 } POSE_PassList;
 
 typedef struct POSE_StorageList {
@@ -67,10 +71,33 @@ typedef struct POSE_Data {
 /* *********** STATIC *********** */
 
 typedef struct POSE_PrivateData {
-	char pad; /* UNUSED */
+	DRWShadingGroup *bone_selection_shgrp;
 } POSE_PrivateData; /* Transient data */
 
+static struct {
+	struct GPUShader *bone_selection_sh;
+} e_data = {NULL};
+
+static float blend_color[4] = {0.0, 0.0, 0.0, 0.5};
+
 /* *********** FUNCTIONS *********** */
+static bool POSE_is_bone_selection_overlay_active(void)
+{
+	const DRWContextState *dcs = DRW_context_state_get();
+	const View3D *v3d = dcs->v3d;
+	return v3d && (v3d->overlay.flag & V3D_OVERLAY_BONE_SELECTION);
+}
+
+static void POSE_engine_init(void *UNUSED(vedata))
+{
+	if (!e_data.bone_selection_sh) {
+		e_data.bone_selection_sh = GPU_shader_get_builtin_shader(GPU_SHADER_3D_UNIFORM_COLOR);
+	}
+}
+
+static void POSE_engine_free(void)
+{
+}
 
 /* Here init all passes and shading groups
  * Assume that all Passes are NULL */
@@ -120,12 +147,42 @@ static void POSE_cache_init(void *vedata)
 		        DRW_STATE_BLEND | DRW_STATE_WIRE;
 		psl->relationship = DRW_pass_create("Bone Relationship Pass", state);
 	}
+
+	{
+		if (POSE_is_bone_selection_overlay_active()) {
+			DRWShadingGroup *grp;
+			psl->bone_selection = DRW_pass_create("Bone Selection", DRW_STATE_WRITE_COLOR | DRW_STATE_DEPTH_EQUAL | DRW_STATE_BLEND);
+			grp = DRW_shgroup_create(e_data.bone_selection_sh, psl->bone_selection);
+			DRW_shgroup_uniform_vec4(grp, "color", blend_color, 1);
+			stl->g_data->bone_selection_shgrp = grp;
+		}
+	}
+}
+
+static bool POSE_is_driven_by_active_armature(Object *ob)
+{
+	Object *armature = modifiers_isDeformedByArmature(ob);
+	if (armature) {
+		const DRWContextState *draw_ctx = DRW_context_state_get();
+		bool is_active = DRW_pose_mode_armature(armature, draw_ctx->obact);
+		if (!is_active && armature->proxy_from) {
+			is_active = DRW_pose_mode_armature(armature->proxy_from, draw_ctx->obact);
+		}
+		return is_active;
+	} else {
+		Object *meshDeform = modifiers_isDeformedByMeshDeform(ob);
+		if (meshDeform) {
+			return POSE_is_driven_by_active_armature(meshDeform);
+		}
+	}
+	return false;
 }
 
 /* Add geometry to shading groups. Execute for each objects */
 static void POSE_cache_populate(void *vedata, Object *ob)
 {
 	POSE_PassList *psl = ((POSE_Data *)vedata)->psl;
+	POSE_StorageList *stl = ((POSE_Data *)vedata)->stl;
 	const DRWContextState *draw_ctx = DRW_context_state_get();
 
 	/* In the future this will allow us to implement face manipulators,
@@ -143,6 +200,11 @@ static void POSE_cache_populate(void *vedata, Object *ob)
 			};
 			DRW_shgroup_armature_pose(ob, passes);
 		}
+	} else if (ob->type == OB_MESH && POSE_is_bone_selection_overlay_active() && POSE_is_driven_by_active_armature(ob)) {
+		struct Gwn_Batch *geom = DRW_cache_object_surface_get(ob);
+		if (geom) {
+			DRW_shgroup_call_object_add(stl->g_data->bone_selection_shgrp, geom, ob);
+		}
 	}
 }
 
@@ -178,6 +240,14 @@ static void POSE_draw_scene(void *vedata)
 	DefaultTextureList *dtxl = DRW_viewport_texture_list_get();
 	const DRWContextState *draw_ctx = DRW_context_state_get();
 	const bool transparent_bones = (draw_ctx->v3d->overlay.arm_flag & V3D_OVERLAY_ARM_TRANSP_BONES) != 0;
+	const bool bone_selection_overlay = POSE_is_bone_selection_overlay_active();
+
+	if(bone_selection_overlay) {
+		GPU_framebuffer_bind(dfbl->default_fb);
+		DRW_draw_pass(psl->bone_selection);
+		GPU_framebuffer_clear_depth(dfbl->depth_only_fb, 1.0);
+		GPU_framebuffer_bind(dfbl->default_fb);
+	}
 
 	DRW_draw_pass(psl->bone_envelope);
 
@@ -228,8 +298,8 @@ DrawEngineType draw_engine_pose_type = {
 	NULL, NULL,
 	N_("PoseMode"),
 	&POSE_data_size,
-	NULL,
-	NULL,
+	&POSE_engine_init,
+	&POSE_engine_free,
 	&POSE_cache_init,
 	&POSE_cache_populate,
 	NULL,