BGE: New Draw debug shadow box for sun lamp

New Check option "Show Shadow Box" in shadow panel of sun lamp to get
feedback about which objects project shadows.

Minor tweaks by Campbell Barton and Jorge Bernal

Reviewers: moguri, sybren, kupoman, dfelinto, lordloki, campbellbarton

Reviewed By: lordloki, campbellbarton

Subscribers: sergey, lordloki

Projects: #game_engine

Differential Revision: https://developer.blender.org/D1149

3 files changed, 104 insertions, 17 deletions

diff --git a/source/blender/editors/space_view3d/drawobject.c b/source/blender/editors/space_view3d/drawobject.c
index ecc2499a63f..ece195aa22b 100644
--- a/source/blender/editors/space_view3d/drawobject.c
+++ b/source/blender/editors/space_view3d/drawobject.c
@@ -214,6 +214,7 @@ static void drawcube_size(float size);
 static void drawcircle_size(float size);
 static void draw_empty_sphere(float size);
 static void draw_empty_cone(float size);
+static void draw_box(float vec[8][3], bool solid);
 
 static void ob_wire_color_blend_theme_id(const unsigned char ob_wire_col[4], const int theme_id, float fac)
 {
@@ -1144,6 +1145,52 @@ static void draw_transp_spot_volume(Lamp *la, float x, float z)
 	glCullFace(GL_BACK);
 }
 
+#ifdef WITH_GAMEENGINE
+static void draw_transp_sun_volume(Lamp *la)
+{
+	float box[8][3];
+
+	/* construct box */
+	box[0][0] = box[1][0] = box[2][0] = box[3][0] = -la->shadow_frustum_size;
+	box[4][0] = box[5][0] = box[6][0] = box[7][0] = +la->shadow_frustum_size;
+	box[0][1] = box[1][1] = box[4][1] = box[5][1] = -la->shadow_frustum_size;
+	box[2][1] = box[3][1] = box[6][1] = box[7][1] = +la->shadow_frustum_size;
+	box[0][2] = box[3][2] = box[4][2] = box[7][2] = -la->clipend;
+	box[1][2] = box[2][2] = box[5][2] = box[6][2] = -la->clipsta;
+
+	/* draw edges */
+	draw_box(box, false);
+
+	/* draw faces */
+	glEnable(GL_CULL_FACE);
+	glEnable(GL_BLEND);
+	glDepthMask(0);
+
+	/* draw backside darkening */
+	glCullFace(GL_FRONT);
+
+	glBlendFunc(GL_ZERO, GL_SRC_ALPHA);
+	glColor4f(0.0f, 0.0f, 0.0f, 0.4f);
+
+	draw_box(box, true);
+
+	/* draw front side lighting */
+	glCullFace(GL_BACK);
+
+	glBlendFunc(GL_ONE, GL_ONE);
+	glColor4f(0.2f, 0.2f, 0.2f, 1.0f);
+
+	draw_box(box, true);
+
+	/* restore state */
+	glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
+	glDisable(GL_BLEND);
+	glDepthMask(1);
+	glDisable(GL_CULL_FACE);
+	glCullFace(GL_BACK);
+}
+#endif
+
 static void drawlamp(View3D *v3d, RegionView3D *rv3d, Base *base,
                      const char dt, const short dflag, const unsigned char ob_wire_col[4], const bool is_obact)
 {
@@ -1166,7 +1213,22 @@ static void drawlamp(View3D *v3d, RegionView3D *rv3d, Base *base,
 	                       !(base->flag & OB_FROMDUPLI) &&
 	                       !is_view);
 
-	if (drawcone && !v3d->transp) {
+#ifdef WITH_GAMEENGINE
+	const bool drawshadowbox = (
+	        (rv3d->rflag & RV3D_IS_GAME_ENGINE) &&
+	        (dt > OB_WIRE) &&
+	        !(G.f & G_PICKSEL) &&
+	        (la->type == LA_SUN) &&
+	        ((la->mode & LA_SHAD_BUF) || 
+	        (la->mode & LA_SHAD_RAY)) &&
+	        (la->mode & LA_SHOW_SHADOW_BOX) &&
+	        !(base->flag & OB_FROMDUPLI) &&
+	        !is_view);
+#else
+	const bool drawshadowbox = false;
+#endif
+
+	if ((drawcone || drawshadowbox) && !v3d->transp) {
 		/* in this case we need to draw delayed */
 		ED_view3d_after_add(&v3d->afterdraw_transp, base, dflag);
 		return;
@@ -1411,6 +1473,13 @@ static void drawlamp(View3D *v3d, RegionView3D *rv3d, Base *base,
 				dir = -dir;
 			}
 		}
+
+#ifdef WITH_GAMEENGINE
+		if (drawshadowbox) {
+			draw_transp_sun_volume(la);
+		}
+#endif
+
 	}
 	else if (la->type == LA_AREA) {
 		setlinestyle(3);
@@ -7037,19 +7106,31 @@ static void draw_forcefield(Object *ob, RegionView3D *rv3d,
 	setlinestyle(0);
 }
 
-static void draw_box(float vec[8][3])
+static void draw_box(float vec[8][3], bool solid)
 {
-	glBegin(GL_LINE_STRIP);
-	glVertex3fv(vec[0]); glVertex3fv(vec[1]); glVertex3fv(vec[2]); glVertex3fv(vec[3]);
-	glVertex3fv(vec[0]); glVertex3fv(vec[4]); glVertex3fv(vec[5]); glVertex3fv(vec[6]);
-	glVertex3fv(vec[7]); glVertex3fv(vec[4]);
-	glEnd();
+	if (!solid) {
+		glBegin(GL_LINE_STRIP);
+		glVertex3fv(vec[0]); glVertex3fv(vec[1]); glVertex3fv(vec[2]); glVertex3fv(vec[3]);
+		glVertex3fv(vec[0]); glVertex3fv(vec[4]); glVertex3fv(vec[5]); glVertex3fv(vec[6]);
+		glVertex3fv(vec[7]); glVertex3fv(vec[4]);
+		glEnd();
 
-	glBegin(GL_LINES);
-	glVertex3fv(vec[1]); glVertex3fv(vec[5]);
-	glVertex3fv(vec[2]); glVertex3fv(vec[6]);
-	glVertex3fv(vec[3]); glVertex3fv(vec[7]);
-	glEnd();
+		glBegin(GL_LINES);
+		glVertex3fv(vec[1]); glVertex3fv(vec[5]);
+		glVertex3fv(vec[2]); glVertex3fv(vec[6]);
+		glVertex3fv(vec[3]); glVertex3fv(vec[7]);
+		glEnd();
+	}
+	else {
+		glBegin(GL_QUADS);
+		glVertex3fv(vec[0]); glVertex3fv(vec[1]); glVertex3fv(vec[2]); glVertex3fv(vec[3]);
+		glVertex3fv(vec[7]); glVertex3fv(vec[6]); glVertex3fv(vec[5]); glVertex3fv(vec[4]);
+		glVertex3fv(vec[4]); glVertex3fv(vec[5]); glVertex3fv(vec[1]); glVertex3fv(vec[0]);
+		glVertex3fv(vec[3]); glVertex3fv(vec[2]); glVertex3fv(vec[6]); glVertex3fv(vec[7]);
+		glVertex3fv(vec[3]); glVertex3fv(vec[7]); glVertex3fv(vec[4]); glVertex3fv(vec[0]);
+		glVertex3fv(vec[1]); glVertex3fv(vec[5]); glVertex3fv(vec[6]); glVertex3fv(vec[2]);
+		glEnd();
+	}
 }
 
 static void draw_bb_quadric(BoundBox *bb, char type, bool around_origin)
@@ -7143,7 +7224,7 @@ static void draw_bounding_volume(Object *ob, char type)
 			vec[0][2] = vec[3][2] = vec[4][2] = vec[7][2] = -size[2];
 			vec[1][2] = vec[2][2] = vec[5][2] = vec[6][2] = +size[2];
 			
-			draw_box(vec);
+			draw_box(vec, false);
 		}
 		else {
 			draw_bb_quadric(bb, type, true);
@@ -7151,7 +7232,7 @@ static void draw_bounding_volume(Object *ob, char type)
 	}
 	else {
 		if (type == OB_BOUND_BOX)
-			draw_box(bb->vec);
+			draw_box(bb->vec, false);
 		else
 			draw_bb_quadric(bb, type, false);
 	}
@@ -7187,7 +7268,7 @@ static void drawtexspace(Object *ob)
 	
 	setlinestyle(2);
 
-	draw_box(vec);
+	draw_box(vec, false);
 
 	setlinestyle(0);
 }
@@ -7464,7 +7545,7 @@ static void draw_rigidbody_shape(Object *ob)
 			vec[0][2] = vec[3][2] = vec[4][2] = vec[7][2] = -size[2];
 			vec[1][2] = vec[2][2] = vec[5][2] = vec[6][2] = +size[2];
 			
-			draw_box(vec);
+			draw_box(vec, false);
 			break;
 		case RB_SHAPE_SPHERE:
 			draw_bb_quadric(bb, OB_BOUND_SPHERE, true);
@@ -7928,7 +8009,7 @@ void draw_object(Scene *scene, ARegion *ar, View3D *v3d, Base *base, const short
 				VECSUBFAC(p0, sds->p0, sds->cell_size, sds->adapt_res);
 				VECADDFAC(p1, sds->p1, sds->cell_size, sds->adapt_res);
 				BKE_boundbox_init_from_minmax(&bb, p0, p1);
-				draw_box(bb.vec);
+				draw_box(bb.vec, false);
 
 #if 0
 				/* draw base resolution bounds */
diff --git a/source/blender/makesdna/DNA_lamp_types.h b/source/blender/makesdna/DNA_lamp_types.h
index a920182d5a3..ce8e86cb512 100644
--- a/source/blender/makesdna/DNA_lamp_types.h
+++ b/source/blender/makesdna/DNA_lamp_types.h
@@ -151,6 +151,7 @@ typedef struct Lamp {
 #define LA_LAYER_SHADOW	(1 << 15)
 #define LA_SHAD_TEX     (1 << 16)
 #define LA_SHOW_CONE    (1 << 17)
+#define LA_SHOW_SHADOW_BOX (1 << 18)
 
 /* layer_shadow */
 #define LA_LAYER_SHADOW_BOTH	0
diff --git a/source/blender/makesrna/intern/rna_lamp.c b/source/blender/makesrna/intern/rna_lamp.c
index c915acdeeac..481d139a9de 100644
--- a/source/blender/makesrna/intern/rna_lamp.c
+++ b/source/blender/makesrna/intern/rna_lamp.c
@@ -825,6 +825,11 @@ static void rna_def_sun_lamp(BlenderRNA *brna)
 	RNA_def_property_ui_range(prop, 0.001, 100.0, 2, 1);
 	RNA_def_property_ui_text(prop, "Frustum Size", "Size of the frustum used for creating the shadow map");
 	RNA_def_property_update(prop, 0, "rna_Lamp_draw_update");
+
+	prop = RNA_def_property(srna, "show_shadow_box", PROP_BOOLEAN, PROP_NONE);
+	RNA_def_property_boolean_sdna(prop, NULL, "mode", LA_SHOW_SHADOW_BOX);
+	RNA_def_property_ui_text(prop, "Show Shadow Box", "Draw box in 3D view to visualize which object are contained in it");
+	RNA_def_property_update(prop, 0, "rna_Lamp_draw_update");
 }
 
 static void rna_def_hemi_lamp(BlenderRNA *brna)