Armature: Envelope Bones: Change drawing method.

We now use a more pleasant and efficient way to display enveloppe bones
and their radius.

For this we use a capsule geometry that is displaced (in the vertex shader)
to a signed distance field that represents the bone shape.

The bone distance radius are now drawn in 3D using a "pseudo-fresnel" effect.
This gives a better understanding of what is inside the radius of influence.

When capsules are not needed, we switch to default raytraced points.
The capsules are not distorded by the bone's matrix (same as their actual
influence radius) and are correctly displayed even with complex scaled
parents hierarchy.

1 files changed, 45 insertions, 97 deletions

diff --git a/source/blender/draw/intern/draw_cache.c b/source/blender/draw/intern/draw_cache.c
index 1dd588afc9f..1b41ff311a8 100644
--- a/source/blender/draw/intern/draw_cache.c
+++ b/source/blender/draw/intern/draw_cache.c
@@ -1878,43 +1878,24 @@ Gwn_Batch *DRW_cache_bone_wire_wire_outline_get(void)
 	return SHC.drw_bone_wire_wire;
 }
 
-
 /* Helpers for envelope bone's solid sphere-with-hidden-equatorial-cylinder.
  * Note that here we only encode head/tail in forth component of the vector. */
 static void benv_lat_lon_to_co(const float lat, const float lon, float r_nor[3])
 {
 	/* Poles are along Y axis. */
 	r_nor[0] = sinf(lat) * cosf(lon);
-	r_nor[1] = cosf(lat);
+	r_nor[1] = -cosf(lat);
 	r_nor[2] = sinf(lat) * sinf(lon);
 }
 
-static void benv_add_tri(Gwn_VertBuf *vbo, uint pos_id, uint *v_idx, float *co1, float *co2, float *co3)
-{
-	/* Given tri and its seven other mirrors along X/Y/Z axes. */
-	for (int x = -1; x <= 1; x += 2) {
-		for (int y = -1; y <= 1; y += 2) {
-			const float head_tail = (y == -1) ? 0.0f : 1.0f;
-			for (int z = -1; z <= 1; z += 2) {
-				GWN_vertbuf_attr_set(vbo, pos_id, (*v_idx)++,
-				                     (const float[4]){co1[0] * x, co1[1] * y, co1[2] * z, head_tail});
-				GWN_vertbuf_attr_set(vbo, pos_id, (*v_idx)++,
-				                     (const float[4]){co2[0] * x, co2[1] * y, co2[2] * z, head_tail});
-				GWN_vertbuf_attr_set(vbo, pos_id, (*v_idx)++,
-				                     (const float[4]){co3[0] * x, co3[1] * y, co3[2] * z, head_tail});
-			}
-		}
-	}
-}
-
 Gwn_Batch *DRW_cache_bone_envelope_solid_get(void)
 {
-#define CIRCLE_RESOL 32  /* Must be multiple of 4 */
 	if (!SHC.drw_bone_envelope) {
-		const int lon_res = CIRCLE_RESOL / 4;
-		const int lat_res = CIRCLE_RESOL / 4;
-		const float lon_inc = M_PI_2 / lon_res;
-		const float lat_inc = M_PI_2 / lat_res;
+		const int lon_res = 24;
+		const int lat_res = 16;
+		const float lon_inc = 2.0f * M_PI / lon_res;
+		const float lat_inc = M_PI / lat_res;
+		const float eps = 0.02f;
 		unsigned int v_idx = 0;
 
 		static Gwn_VertFormat format = { 0 };
@@ -1925,92 +1906,59 @@ Gwn_Batch *DRW_cache_bone_envelope_solid_get(void)
 
 		/* Vertices */
 		Gwn_VertBuf *vbo = GWN_vertbuf_create_with_format(&format);
-		GWN_vertbuf_data_alloc(vbo, lat_res * lon_res * 8 * 6);
+		GWN_vertbuf_data_alloc(vbo, ((lat_res + 1) * 2) * lon_res * 2);
 
-		float lon = 0.0f;
+		float lon = lon_inc;
 		for (int i = 0; i < lon_res; i++, lon += lon_inc) {
 			float lat = 0.0f;
-			float co1[3], co2[3], co3[3], co4[3];
+			float co1[4], co2[4];
+			co1[3] = co2[3] = 0.0f;
 
+			/* 1st sphere */
 			for (int j = 0; j < lat_res; j++, lat += lat_inc) {
-				benv_lat_lon_to_co(lat,           lon,           co1);
-				benv_lat_lon_to_co(lat,           lon + lon_inc, co2);
-				benv_lat_lon_to_co(lat + lat_inc, lon + lon_inc, co3);
-				benv_lat_lon_to_co(lat + lat_inc, lon,           co4);
+				benv_lat_lon_to_co(lat, lon,           co1);
+				benv_lat_lon_to_co(lat, lon + lon_inc, co2);
 
-				if (j != 0) {  /* At pole, n1 and n2 are identical. */
-					benv_add_tri(vbo, attr_id.pos, &v_idx, co1, co2, co3);
-				}
-				benv_add_tri(vbo, attr_id.pos, &v_idx, co1, co3, co4);
+				GWN_vertbuf_attr_set(vbo, attr_id.pos, v_idx++, co1);
+				GWN_vertbuf_attr_set(vbo, attr_id.pos, v_idx++, co2);
 			}
-
-			/* lat is at equator (i.e. lat == pi / 2). */
-			/* We need to add 'cylinder' part between the equators (along XZ plane). */
-			for (int x = -1; x <= 1; x += 2) {
-				for (int z = -1; z <= 1; z += 2) {
-					GWN_vertbuf_attr_set(vbo, attr_id.pos, v_idx++,
-					                     (const float[4]){co3[0] * x, co3[1], co3[2] * z, 0.0f});
-					GWN_vertbuf_attr_set(vbo, attr_id.pos, v_idx++,
-					                     (const float[4]){co4[0] * x, co4[1], co4[2] * z, 0.0f});
-					GWN_vertbuf_attr_set(vbo, attr_id.pos, v_idx++,
-					                     (const float[4]){co4[0] * x, co4[1], co4[2] * z, 1.0f});
-
-					GWN_vertbuf_attr_set(vbo, attr_id.pos, v_idx++,
-					                     (const float[4]){co3[0] * x, co3[1], co3[2] * z, 0.0f});
-					GWN_vertbuf_attr_set(vbo, attr_id.pos, v_idx++,
-					                     (const float[4]){co4[0] * x, co4[1], co4[2] * z, 1.0f});
-					GWN_vertbuf_attr_set(vbo, attr_id.pos, v_idx++,
-					                     (const float[4]){co3[0] * x, co3[1], co3[2] * z, 1.0f});
-				}
+			/* Need to close the sphere, but add a small gap to be able
+			 * to distinguish the verts in the vertex shader. */
+			benv_lat_lon_to_co(M_PI - eps, lon,           co1);
+			benv_lat_lon_to_co(M_PI - eps, lon + lon_inc, co2);
+			GWN_vertbuf_attr_set(vbo, attr_id.pos, v_idx++, co1);
+			GWN_vertbuf_attr_set(vbo, attr_id.pos, v_idx++, co2);
+
+			/* Add some precision to the middle part */
+			// co1[3] = co2[3] = 0.5f;
+			// co1[1] = co2[1] = 0.0f;
+			// GWN_vertbuf_attr_set(vbo, attr_id.pos, v_idx++, co1);
+			// GWN_vertbuf_attr_set(vbo, attr_id.pos, v_idx++, co2);
+
+			/* 2nd sphere */
+			co1[3] = co2[3] = 1.0f;
+
+			/* Need to open the sphere */
+			benv_lat_lon_to_co(eps, lon,           co1);
+			benv_lat_lon_to_co(eps, lon + lon_inc, co2);
+			GWN_vertbuf_attr_set(vbo, attr_id.pos, v_idx++, co1);
+			GWN_vertbuf_attr_set(vbo, attr_id.pos, v_idx++, co2);
+
+			lat = lat_inc;
+			for (int j = 1; j < lat_res + 1; j++, lat += lat_inc) {
+				benv_lat_lon_to_co(lat, lon,           co1);
+				benv_lat_lon_to_co(lat, lon + lon_inc, co2);
+
+				GWN_vertbuf_attr_set(vbo, attr_id.pos, v_idx++, co1);
+				GWN_vertbuf_attr_set(vbo, attr_id.pos, v_idx++, co2);
 			}
 		}
 
-		SHC.drw_bone_envelope = GWN_batch_create_ex(GWN_PRIM_TRIS, vbo, NULL, GWN_BATCH_OWNS_VBO);
+		SHC.drw_bone_envelope = GWN_batch_create_ex(GWN_PRIM_TRI_STRIP, vbo, NULL, GWN_BATCH_OWNS_VBO);
 	}
 	return SHC.drw_bone_envelope;
 }
 
-
-Gwn_Batch *DRW_cache_bone_envelope_distance_outline_get(void)
-{
-#define CIRCLE_RESOL 32  /* Must be multiple of 2 */
-	if (!SHC.drw_bone_envelope_distance) {
-		unsigned int v_idx = 0;
-
-		static Gwn_VertFormat format = { 0 };
-		static unsigned int pos_id;
-		if (format.attrib_ct == 0) {
-			pos_id = GWN_vertformat_attr_add(&format, "pos", GWN_COMP_F32, 4, GWN_FETCH_FLOAT);
-		}
-
-		/* Vertices */
-		Gwn_VertBuf *vbo = GWN_vertbuf_create_with_format(&format);
-		GWN_vertbuf_data_alloc(vbo, CIRCLE_RESOL * 2 + 6);
-
-		/* Encoded triangle strip, vertex shader gives them final correct value. */
-		for (int i = 0; i < CIRCLE_RESOL + 1; i++) {
-			const bool is_headtail_transition = ELEM(i, CIRCLE_RESOL / 2, CIRCLE_RESOL);
-			const float head_tail = (i > CIRCLE_RESOL / 2) ? 1.0f : 0.0f;
-			const float alpha = 2.0f * M_PI * i / CIRCLE_RESOL;
-			const float x = cosf(alpha);
-			const float y = -sinf(alpha);
-
-			/*                                                        { X, Y, head/tail, inner/outer border } */
-			GWN_vertbuf_attr_set(vbo, pos_id, v_idx++, (const float[4]){x, y, head_tail, 0.0f});
-			GWN_vertbuf_attr_set(vbo, pos_id, v_idx++, (const float[4]){x, y, head_tail, 1.0f});
-			if (is_headtail_transition) {
-				GWN_vertbuf_attr_set(vbo, pos_id, v_idx++, (const float[4]){x, y, 1.0f - head_tail, 0.0f});
-				GWN_vertbuf_attr_set(vbo, pos_id, v_idx++, (const float[4]){x, y, 1.0f - head_tail, 1.0f});
-			}
-		}
-
-		SHC.drw_bone_envelope_distance = GWN_batch_create_ex(GWN_PRIM_TRI_STRIP, vbo, NULL, GWN_BATCH_OWNS_VBO);
-	}
-	return SHC.drw_bone_envelope_distance;
-#undef CIRCLE_RESOL
-}
-
-
 /* Bone body. */
 Gwn_Batch *DRW_cache_bone_envelope_wire_outline_get(void)
 {