+/*
+ * Free a segment from the UI bar to be reused later
+ */
+VG_STATIC void world_routes_ui_popfirst( struct route_ui_bar *pui )
+{
+ if( pui->segment_count )
+ {
+ pui->segment_start ++;
+
+ if( pui->segment_start == 32 )
+ pui->segment_start = 0;
+
+ pui->segment_count --;
+ }
+}
+
+/*
+ * Reset ui bar completely
+ */
+VG_STATIC void world_routes_ui_clear( struct route_ui_bar *pui )
+{
+ pui->segment_start = (pui->segment_start + pui->segment_count) %
+ k_max_ui_segments;
+ pui->segment_count = 0;
+}
+
+/*
+ * Break a index range into two pieces over the edge of the maximum it can
+ * store. s1 is 0 always, so its a ring buffer.
+ */
+VG_STATIC void world_routes_ui_split_indices( u32 s0, u32 count,
+ u32 *c0, u32 *c1 )
+{
+ *c0 = (VG_MIN( s0+count, k_route_ui_max_indices )) - s0;
+ *c1 = count-(*c0);
+}
+
+/*
+ * Place a set of indices into gpu array automatically splits
+ * across bounds
+ */
+VG_STATIC void world_routes_ui_set_indices( struct route_ui_bar *pui,
+ u16 *indices, u32 count )
+{
+ u32 c0, c1;
+ world_routes_ui_split_indices( pui->indices_head, count, &c0, &c1 );
+
+ glBindBuffer( GL_ELEMENT_ARRAY_BUFFER, pui->ebo );
+
+ if( c0 )
+ {
+ glBufferSubData( GL_ELEMENT_ARRAY_BUFFER, pui->indices_head*sizeof(u16),
+ c0*sizeof(u16), indices );
+ }
+
+ if( c1 )
+ {
+ glBufferSubData( GL_ELEMENT_ARRAY_BUFFER, 0, c1*sizeof(u16), indices+c0 );
+ pui->indices_head = c1;
+ }
+ else
+ pui->indices_head += c0;
+}
+
+/*
+ * Place a set of vertices into gpu array
+ */
+VG_STATIC u32 world_routes_ui_set_verts( struct route_ui_bar *pui,
+ v2f *verts, u32 count )
+{
+ if( pui->vertex_head + count >= k_route_ui_max_verts )
+ pui->vertex_head = 0;
+
+ u32 vert_start = pui->vertex_head;
+ pui->vertex_head += count;
+
+ glBindBuffer( GL_ARRAY_BUFFER, pui->vbo );
+ glBufferSubData( GL_ARRAY_BUFFER, (GLintptr)(vert_start*sizeof(v2f)),
+ sizeof(v2f)*count, verts );
+
+ return vert_start;
+}
+
+/*
+ * Update the last (count) vertices positions, does not add any.
+ * Data must already be written to, and not cross either array boundaries.
+ */
+VG_STATIC u32 world_routes_ui_update_verts( struct route_ui_bar *pui,
+ v2f *verts, u32 count )
+{
+ u32 vert_start = pui->vertex_head-count;
+
+ glBindBuffer( GL_ARRAY_BUFFER, pui->vbo );
+ glBufferSubData( GL_ARRAY_BUFFER, (GLintptr)(vert_start*sizeof(v2f)),
+ sizeof(v2f)*count, verts );
+
+ return vert_start;
+}
+
+/*
+ * Current/active segment of this UI bar
+ */
+VG_STATIC struct route_ui_segment *world_routes_ui_curseg(
+ struct route_ui_bar *pui )
+{
+ u32 index = (pui->segment_start+pui->segment_count-1)%k_max_ui_segments;
+ return &pui->segments[ index ];
+}
+
+/*
+ * Start a new segment in the UI bar, will create a split on the last one if
+ * there is one active currently. (api)
+ */
+VG_STATIC void world_routes_ui_newseg( u32 route )
+{
+ struct route_ui_bar *pui = &world.ui_bars[route];
+
+ glBindVertexArray( pui->vao );
+ if( pui->segment_count )
+ {
+ float const k_gap_width = 1.0f;
+
+ struct route_ui_segment *cseg = world_routes_ui_curseg( pui );
+
+ v2f verts[2];
+ verts[0][0] = cseg->length-k_gap_width;
+ verts[0][1] = 0.5f;
+ verts[1][0] = cseg->length-k_gap_width;
+ verts[1][1] = -0.5f;
+
+ world_routes_ui_update_verts( pui, verts, 2 );
+ }
+
+ pui->segment_count ++;
+ struct route_ui_segment *segment = world_routes_ui_curseg( pui );
+
+ v2f verts[4];
+ verts[0][0] = 0.0f;
+ verts[0][1] = 0.5f;
+ verts[1][0] = 0.0f;
+ verts[1][1] = -0.5f;
+ verts[2][0] = 0.0f;
+ verts[2][1] = 0.5f;
+ verts[3][0] = 0.0f;
+ verts[3][1] = -0.5f;
+
+ u32 vert_start = world_routes_ui_set_verts( pui, verts, 4 );
+
+ u16 indices[6];
+ indices[0] = vert_start + 0;
+ indices[1] = vert_start + 1;
+ indices[2] = vert_start + 3;
+ indices[3] = vert_start + 0;
+ indices[4] = vert_start + 3;
+ indices[5] = vert_start + 2;
+
+ segment->vertex_start = vert_start;
+ segment->vertex_count = 4;
+ segment->index_start = pui->indices_head;
+ segment->index_count = 6;
+ segment->notches = 0;
+
+ world_routes_ui_set_indices( pui, indices, 6 );
+}
+
+/*
+ * Extend the end of the bar
+ */
+VG_STATIC void world_routes_ui_updatetime( u32 route, float time )