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diff --git a/player_walkgrid.h b/player_walkgrid.h
new file mode 100644
index 0000000..937c305
--- /dev/null
+++ b/player_walkgrid.h
@@ -0,0 +1,963 @@
+#ifndef PLAYER_WALKGRID_H
+#define PLAYER_WALKGRID_H
+
+#include "common.h"
+#include "player.h"
+
+/*
+ * Walkgrid implementation,
+ *  loosely based of cmuratoris youtube video 'Killing the Walkmonster'
+ */
+
+#define WALKGRID_SIZE 16
+struct walkgrid
+{
+   struct grid_sample
+   {
+      enum sample_type
+      {
+         k_sample_type_air,      /* Nothing was hit. */
+         k_sample_type_invalid,  /* The point is invalid, but there is a sample
+                                    underneath that can be used */
+         k_sample_type_valid,    /* This point is good */
+      }
+      type;
+
+      v3f clip[2];
+      v3f pos;
+
+      enum traverse_state
+      {
+         k_traverse_none = 0x00,
+         k_traverse_h    = 0x01,
+         k_traverse_v    = 0x02
+      }
+      state;
+   }
+   samples[WALKGRID_SIZE][WALKGRID_SIZE];
+
+   boxf region;
+
+   float move; /* Current amount of movement we have left to apply */
+   v2f dir;    /* The movement delta */
+   v2i cell_id;/* Current cell */
+   v2f pos;    /* Local position (in cell) */
+   float h;
+};
+
+static int player_walkgrid_tri_walkable( u32 tri[3] )
+{
+   return tri[0] > world.sm_geo_std_oob.vertex_count;
+}
+
+/*
+ * Get a sample at this pole location, will return 1 if the sample is valid,
+ * and pos will be updated to be the intersection location.
+ */
+static void player_walkgrid_samplepole( struct grid_sample *s )
+{
+   boxf region = {{ s->pos[0] -0.01f, s->pos[1] - 4.0f, s->pos[2] -0.01f},
+                  { s->pos[0] +0.01f, s->pos[1] + 4.0f, s->pos[2] +0.01f}};
+
+   u32 geo[256];
+   v3f tri[3];
+   int len = bh_select( &world.geo.bhtris, region, geo, 256 );
+   
+   const float k_minworld_y = -2000.0f;
+
+   float walk_height = k_minworld_y,
+         block_height = k_minworld_y;
+
+   s->type = k_sample_type_air;
+
+   for( int i=0; i<len; i++ )
+   {
+      u32 *ptri = &world.geo.indices[ geo[i]*3 ];
+
+      for( int j=0; j<3; j++ )
+         v3_copy( world.geo.verts[ptri[j]].co, tri[j] );
+      
+      v3f vdown = {0.0f,-1.0f,0.0f};
+      v3f sample_from;
+      v3_copy( s->pos, sample_from );
+      sample_from[1] = region[1][1];
+      
+      float dist;
+      if( ray_tri( tri, sample_from, vdown, &dist ))
+      {
+         v3f p0;
+         v3_muladds( sample_from, vdown, dist, p0 );
+
+         if( player_walkgrid_tri_walkable(ptri) )
+         {
+            if( p0[1] > walk_height )
+            {
+               walk_height = p0[1];
+            }
+         }
+         else
+         {
+            if( p0[1] > block_height )
+               block_height = p0[1];
+         }
+      }
+   }
+
+   s->pos[1] = walk_height;
+
+   if( walk_height > k_minworld_y )
+      if( block_height > walk_height )
+         s->type = k_sample_type_invalid;
+      else
+         s->type = k_sample_type_valid;
+   else
+      s->type = k_sample_type_air;
+}
+
+float const k_gridscale = 0.5f;
+
+enum eclipdir
+{
+   k_eclipdir_h = 0,
+   k_eclipdir_v = 1
+};
+
+static void player_walkgrid_clip_blocker( struct grid_sample *sa,
+                                          struct grid_sample *sb,
+                                          struct grid_sample *st,
+                                          enum eclipdir dir )
+{
+   v3f clipdir, pos;
+   int valid_a = sa->type == k_sample_type_valid,
+       valid_b = sb->type == k_sample_type_valid;
+   struct grid_sample *target = valid_a? sa: sb,
+                      *other  = valid_a? sb: sa;
+   v3_copy( target->pos, pos );
+   v3_sub( other->pos, target->pos, clipdir );
+
+   boxf cell_region;
+   v3_muladds( pos, (v3f){1.0f,1.0f,1.0f}, -k_gridscale*2.1f, cell_region[0]);
+   v3_muladds( pos, (v3f){1.0f,1.0f,1.0f},  k_gridscale*2.1f, cell_region[1]);
+
+   u32 geo[256];
+   v3f tri[3];
+   int len = bh_select( &world.geo.bhtris, cell_region, geo, 256 );
+   
+   float start_time = v3_length( clipdir ),
+         min_time = start_time;
+   v3_normalize( clipdir );
+   v3_muls( clipdir, 0.0001f, st->clip[dir] );
+
+   for( int i=0; i<len; i++ )
+   {
+      u32 *ptri = &world.geo.indices[ geo[i]*3 ];
+      for( int j=0; j<3; j++ )
+         v3_copy( world.geo.verts[ptri[j]].co, tri[j] );
+
+      if( player_walkgrid_tri_walkable(ptri) )
+         continue;
+
+      float dist;
+      if(ray_tri( tri, pos, clipdir, &dist ))
+      {
+         if( dist > 0.0f && dist < min_time )
+         {
+            min_time = dist;
+            sb->type = k_sample_type_air;
+         }
+      }
+   }
+
+   if( !(min_time < start_time) )
+      min_time = 0.5f * k_gridscale;
+
+   min_time = vg_clampf( min_time/k_gridscale, 0.01f, 0.99f );
+
+   v3_muls( clipdir, min_time, st->clip[dir] );
+
+   v3f p0;
+   v3_muladds( target->pos, st->clip[dir], k_gridscale, p0 );
+}
+
+static void player_walkgrid_clip_edge( struct grid_sample *sa,
+                                       struct grid_sample *sb,
+                                       struct grid_sample *st, /* data store */
+                                       enum eclipdir dir )
+{
+   v3f clipdir = { 0.0f, 0.0f, 0.0f }, pos;
+   int valid_a = sa->type == k_sample_type_valid,
+       valid_b = sb->type == k_sample_type_valid;
+
+   struct grid_sample *target = valid_a? sa: sb,
+                      *other  = valid_a? sb: sa;
+   
+   v3_sub( other->pos, target->pos, clipdir );
+   clipdir[1] = 0.0f;
+
+   v3_copy( target->pos, pos );
+
+   boxf cell_region;
+   v3_muladds( pos, (v3f){1.0f,1.0f,1.0f}, -k_gridscale*1.1f, cell_region[0]);
+   v3_muladds( pos, (v3f){1.0f,1.0f,1.0f},  k_gridscale*1.1f, cell_region[1]);
+
+   u32 geo[256];
+   int len = bh_select( &world.geo.bhtris, cell_region, geo, 256 );
+
+   float max_dist = 0.0f;
+   v3f tri[3];
+   v3f perp;
+   v3_cross( clipdir,(v3f){0.0f,1.0f,0.0f},perp );
+   v3_muls( clipdir, 0.001f, st->clip[dir] );
+
+   for( int i=0; i<len; i++ )
+   {
+      u32 *ptri = &world.geo.indices[ geo[i]*3 ];
+      for( int j=0; j<3; j++ )
+         v3_copy( world.geo.verts[ptri[j]].co, tri[j] );
+      
+      if( !player_walkgrid_tri_walkable(ptri) )
+         continue;
+
+      for( int k=0; k<3; k++ )
+      {
+         int ia = k,
+             ib = (k+1)%3;
+         
+         v3f v0, v1;
+         v3_sub( tri[ia], pos, v0 );
+         v3_sub( tri[ib], pos, v1 );
+
+         if( (clipdir[2]*v0[0] - clipdir[0]*v0[2]) *
+             (clipdir[2]*v1[0] - clipdir[0]*v1[2]) < 0.0f )
+         {
+            float da = v3_dot(v0,perp),
+                  db = v3_dot(v1,perp),
+                  d  = da-db,
+                  qa = da/d;
+
+            v3f p0;
+            v3_muls( v1, qa, p0 );
+            v3_muladds( p0, v0, 1.0f-qa, p0 );
+            
+            float h = v3_dot(p0,clipdir)/v3_dot(clipdir,clipdir);
+
+            if( h >= max_dist && h <= 1.0f )
+            {
+               max_dist = h;
+               float l = 1.0f/v3_length(clipdir);
+               v3_muls( p0, l, st->clip[dir] );
+            }
+         }
+      }
+   }
+}
+
+static const struct conf
+{
+   struct confedge
+   {  
+      /* i: sample index
+       * d: data index
+       * a: axis index
+       * o: the 'other' point to do a A/B test with
+       *       if its -1, all AB is done.
+       */
+      int i0, i1, 
+          d0, d1,
+          a0, a1,
+          o0, o1;
+   }
+   edges[2];
+   int edge_count;
+}
+k_walkgrid_configs[16] = {
+   {{},0},
+   {{{ 3,3, 3,0, 1,0, -1,-1 }}, 1},
+   {{{ 2,2, 1,3, 0,1, -1,-1 }}, 1},
+   {{{ 2,3, 1,0, 0,0,  3,-1 }}, 1},
+
+   {{{ 1,1, 0,1, 1,0, -1,-1 }}, 1},
+   {{{ 3,3, 3,0, 1,0, -1,-1 },
+     { 1,1, 0,1, 1,0, -1,-1 }}, 2},
+   {{{ 1,2, 0,3, 1,1,  2,-1 }}, 1},
+   {{{ 1,3, 0,0, 1,0,  2, 2 }}, 1},
+
+   {{{ 0,0, 0,0, 0,1, -1,-1 }}, 1},
+   {{{ 3,0, 3,0, 1,1,  0,-1 }}, 1},
+   {{{ 2,2, 1,3, 0,1, -1,-1 },
+     { 0,0, 0,0, 0,1, -1,-1 }}, 2},
+   {{{ 2,0, 1,0, 0,1,  3, 3 }}, 1},
+
+   {{{ 0,1, 0,1, 0,0,  1,-1 }}, 1},
+   {{{ 3,1, 3,1, 1,0,  0, 0 }}, 1},
+   {{{ 0,2, 0,3, 0,1,  1, 1 }}, 1},
+   {{},0},
+};
+
+/* 
+ * Get a buffer of edges from cell location
+ */
+static const struct conf *player_walkgrid_conf( struct walkgrid *wg, 
+      v2i cell,
+      struct grid_sample *corners[4] )
+{
+   corners[0] = &wg->samples[cell[1]  ][cell[0]  ];
+   corners[1] = &wg->samples[cell[1]+1][cell[0]  ];
+   corners[2] = &wg->samples[cell[1]+1][cell[0]+1];
+   corners[3] = &wg->samples[cell[1]  ][cell[0]+1];
+
+   u32 vd0 = corners[0]->type == k_sample_type_valid,
+       vd1 = corners[1]->type == k_sample_type_valid,
+       vd2 = corners[2]->type == k_sample_type_valid,
+       vd3 = corners[3]->type == k_sample_type_valid,
+       config = (vd0<<3) | (vd1<<2) | (vd2<<1) | vd3;
+
+   return &k_walkgrid_configs[ config ];
+}
+
+static void player_walkgrid_floor(v3f pos)
+{
+   v3_muls( pos, 1.0f/k_gridscale, pos );
+   v3_floor( pos, pos );
+   v3_muls( pos, k_gridscale, pos );
+}
+
+/* 
+ * Computes the barycentric coordinate of location on a triangle (vertical),
+ * then sets the Y position to the interpolation of the three points
+ */
+static void player_walkgrid_stand_tri( v3f a, v3f b, v3f c, v3f pos )
+{
+   v3f v0,v1,v2; 
+   v3_sub( b, a, v0 );
+   v3_sub( c, a, v1 );
+   v3_sub( pos, a, v2 );
+
+   float d = v0[0]*v1[2] - v1[0]*v0[2],
+         v = (v2[0]*v1[2] - v1[0]*v2[2]) / d,
+         w = (v0[0]*v2[2] - v2[0]*v0[2]) / d,
+         u = 1.0f - v - w;
+
+   vg_line( pos, a, 0xffff0000 );
+   vg_line( pos, b, 0xff00ff00 );
+   vg_line( pos, c, 0xff0000ff );
+   pos[1] = u*a[1] + v*b[1] + w*c[1];
+}
+
+/*
+ * Get the minimum time value of pos+dir until a cell edge
+ *
+ * t[0] -> t[3] are the individual time values
+ * t[5] & t[6]  are the maximum axis values
+ * t[6] is the minimum value
+ *
+ */
+static void player_walkgrid_min_cell( float t[7], v2f pos, v2f dir )
+{
+   v2f frac = { 1.0f/dir[0], 1.0f/dir[1] };
+
+   t[0] = 999.9f;
+   t[1] = 999.9f;
+   t[2] = 999.9f;
+   t[3] = 999.9f;
+   
+   if( fabsf(dir[0]) > 0.0001f )
+   {
+      t[0] = (0.0f-pos[0]) * frac[0];
+      t[1] = (1.0f-pos[0]) * frac[0];
+   }
+   if( fabsf(dir[1]) > 0.0001f )
+   {
+      t[2] = (0.0f-pos[1]) * frac[1];
+      t[3] = (1.0f-pos[1]) * frac[1];
+   }
+
+   t[4] = vg_maxf(t[0],t[1]);
+   t[5] = vg_maxf(t[2],t[3]);
+   t[6] = vg_minf(t[4],t[5]);
+}
+
+static void player_walkgrid_iter(struct walkgrid *wg, int iter)
+{
+
+   /*
+    * For each walkgrid iteration we are stepping through cells and determining
+    * the intersections with the grid, and any edges that are present
+    */
+
+   u32 icolours[] = { 0xffff00ff, 0xff00ffff, 0xffffff00 };
+   
+   v3f pa, pb, pc, pd, pl0, pl1;
+   pa[0] = wg->region[0][0] + (float)wg->cell_id[0] *k_gridscale;
+   pa[1] = (wg->region[0][1] + wg->region[1][1]) * 0.5f + k_gridscale;
+   pa[2] = wg->region[0][2] + (float)wg->cell_id[1] *k_gridscale;
+#if 0
+   pb[0] = pa[0];
+   pb[1] = pa[1];
+   pb[2] = pa[2] + k_gridscale;
+   pc[0] = pa[0] + k_gridscale;
+   pc[1] = pa[1];
+   pc[2] = pa[2] + k_gridscale;
+   pd[0] = pa[0] + k_gridscale;
+   pd[1] = pa[1];
+   pd[2] = pa[2];
+   /* if you want to draw the current cell */
+   vg_line( pa, pb, 0xff00ffff );
+   vg_line( pb, pc, 0xff00ffff );
+   vg_line( pc, pd, 0xff00ffff );
+   vg_line( pd, pa, 0xff00ffff );
+#endif
+   pl0[0] = pa[0] + wg->pos[0]*k_gridscale;
+   pl0[1] = pa[1];
+   pl0[2] = pa[2] + wg->pos[1]*k_gridscale;
+
+   /* 
+    * If there are edges present, we need to create a 'substep' event, where
+    * we find the intersection point, find the fully resolved position,
+    * then the new pos dir is the intersection->resolution
+    *
+    * the resolution is applied in non-discretized space in order to create a 
+    * suitable vector for finding outflow, we want it to leave the cell so it 
+    * can be used by the quad
+    */
+
+   v2f pos, dir;
+   v2_copy( wg->pos, pos );
+   v2_muls( wg->dir, wg->move, dir );
+
+   struct grid_sample *corners[4];
+   v2f corners2d[4] = {{0.0f,0.0f},{0.0f,1.0f},{1.0f,1.0f},{1.0f,0.0f}};
+   const struct conf *conf = player_walkgrid_conf( wg, wg->cell_id, corners );
+   
+   float t[7];
+   player_walkgrid_min_cell( t, pos, dir );
+
+   for( int i=0; i<conf->edge_count; i++ )
+   {
+      const struct confedge *edge = &conf->edges[i];
+
+      v2f e0, e1, n, r, target, res, tangent;
+      e0[0] = corners2d[edge->i0][0] + corners[edge->d0]->clip[edge->a0][0];
+      e0[1] = corners2d[edge->i0][1] + corners[edge->d0]->clip[edge->a0][2];
+      e1[0] = corners2d[edge->i1][0] + corners[edge->d1]->clip[edge->a1][0];
+      e1[1] = corners2d[edge->i1][1] + corners[edge->d1]->clip[edge->a1][2];
+      
+      v3f pe0 = { pa[0] + e0[0]*k_gridscale,
+                  pa[1],
+                  pa[2] + e0[1]*k_gridscale };
+      v3f pe1 = { pa[0] + e1[0]*k_gridscale,
+                  pa[1],
+                  pa[2] + e1[1]*k_gridscale };
+
+      v2_sub( e1, e0, tangent );
+      n[0] = -tangent[1];
+      n[1] =  tangent[0];
+      v2_normalize( n );
+
+      /*
+       * If we find ourselfs already penetrating the edge, move back out a
+       * little
+       */
+      v2_sub( e0, pos, r );
+      float p1 = v2_dot(r,n);
+
+      if( -p1 < 0.0001f )
+      {
+         v2_muladds( pos, n, p1+0.0001f, pos );
+         v2_copy( pos, wg->pos );
+         v3f p_new = { pa[0] + pos[0]*k_gridscale,
+                       pa[1],
+                       pa[2] + pos[1]*k_gridscale };
+         v3_copy( p_new, pl0 );
+      }
+      
+      v2_add( pos, dir, target );
+
+      v2f v1, v2, v3;
+      v2_sub( e0, pos, v1 );
+      v2_sub( target, pos, v2 );
+
+      v2_copy( n, v3 );
+
+      v2_sub( e0, target, r );
+      float p = v2_dot(r,n),
+            t1 = v2_dot(v1,v3)/v2_dot(v2,v3);
+
+      if( t1 < t[6] && t1 > 0.0f && -p < 0.001f )
+      {
+         v2_muladds( target, n, p+0.0001f, res );
+
+         v2f intersect;
+         v2_muladds( pos, dir, t1, intersect );
+         v2_copy( intersect, pos );
+         v2_sub( res, intersect, dir );
+
+         v3f p_res = { pa[0] + res[0]*k_gridscale,
+                       pa[1],
+                       pa[2] + res[1]*k_gridscale };
+         v3f p_int = { pa[0] + intersect[0]*k_gridscale,
+                       pa[1],
+                       pa[2] + intersect[1]*k_gridscale };
+
+         vg_line( pl0, p_int, icolours[iter%3] );
+         v3_copy( p_int, pl0 );
+         v2_copy( pos, wg->pos );
+
+         player_walkgrid_min_cell( t, pos, dir );
+      }
+   }
+
+   /* 
+    * Compute intersection with grid cell moving outwards
+    */
+   t[6] = vg_minf( t[6], 1.0f );
+   
+   pl1[0] = pl0[0] + dir[0]*k_gridscale*t[6];
+   pl1[1] = pl0[1];
+   pl1[2] = pl0[2] + dir[1]*k_gridscale*t[6];
+   vg_line( pl0, pl1, icolours[iter%3] );
+   
+   if( t[6] < 1.0f )
+   {
+      /*
+       * To figure out what t value created the clip so we know which edge 
+       * to wrap around
+       */
+
+      if( t[4] < t[5] )
+      {
+         wg->pos[1] = pos[1] + dir[1]*t[6];
+
+         if( t[0] > t[1] ) /* left edge */
+         {
+            wg->pos[0] = 0.9999f;
+            wg->cell_id[0] --;
+
+            if( wg->cell_id[0] == 0 )
+               wg->move = -1.0f;
+         }
+         else /* Right edge */
+         {
+            wg->pos[0] = 0.0001f;
+            wg->cell_id[0] ++;
+
+            if( wg->cell_id[0] == WALKGRID_SIZE-2 )
+               wg->move = -1.0f;
+         }
+      }
+      else
+      {
+         wg->pos[0] = pos[0] + dir[0]*t[6];
+
+         if( t[2] > t[3] ) /* bottom edge */
+         {
+            wg->pos[1] = 0.9999f;
+            wg->cell_id[1] --;
+
+            if( wg->cell_id[1] == 0 )
+               wg->move = -1.0f;
+         }
+         else /* top edge */
+         {
+            wg->pos[1] = 0.0001f;
+            wg->cell_id[1] ++;
+
+            if( wg->cell_id[1] == WALKGRID_SIZE-2 )
+               wg->move = -1.0f;
+         }
+      }
+
+      wg->move -= t[6];
+   }
+   else
+   {
+      v2_muladds( wg->pos, dir, wg->move, wg->pos );
+      wg->move = 0.0f;
+   }
+}
+
+static void player_walkgrid_stand_cell(struct walkgrid *wg)
+{
+   /*
+    * NOTE: as opposed to the other function which is done in discretized space
+    *       this use a combination of both.
+    */
+
+   v3f world;
+   world[0] = wg->region[0][0]+((float)wg->cell_id[0]+wg->pos[0])*k_gridscale;
+   world[1] = player.rb.co[1];
+   world[2] = wg->region[0][2]+((float)wg->cell_id[1]+wg->pos[1])*k_gridscale;
+
+   struct grid_sample *corners[4];
+   const struct conf *conf = player_walkgrid_conf( wg, wg->cell_id, corners );
+
+   if( conf != k_walkgrid_configs )
+   {
+      if( conf->edge_count == 0 )
+      {
+         v3f v0;
+
+         /* Split the basic quad along the shortest diagonal */
+         if( fabsf(corners[2]->pos[1] - corners[0]->pos[1]) < 
+             fabsf(corners[3]->pos[1] - corners[1]->pos[1]) )
+         {
+            vg_line( corners[2]->pos, corners[0]->pos, 0xffaaaaaa );
+            
+            if( wg->pos[0] > wg->pos[1] )
+               player_walkgrid_stand_tri( corners[0]->pos,
+                                          corners[3]->pos,
+                                          corners[2]->pos, world );
+            else
+               player_walkgrid_stand_tri( corners[0]->pos,
+                                          corners[2]->pos,
+                                          corners[1]->pos, world );
+         }
+         else
+         {
+            vg_line( corners[3]->pos, corners[1]->pos, 0xffaaaaaa );
+
+            if( wg->pos[0] < 1.0f-wg->pos[1] )
+               player_walkgrid_stand_tri( corners[0]->pos,
+                                          corners[3]->pos,
+                                          corners[1]->pos, world );
+            else
+               player_walkgrid_stand_tri( corners[3]->pos,
+                                          corners[2]->pos,
+                                          corners[1]->pos, world );
+         }
+      }
+      else
+      {
+         for( int i=0; i<conf->edge_count; i++ )
+         {
+            const struct confedge *edge = &conf->edges[i];
+
+            v3f p0, p1;
+            v3_muladds( corners[edge->i0]->pos, 
+                        corners[edge->d0]->clip[edge->a0], k_gridscale, p0 );
+            v3_muladds( corners[edge->i1]->pos, 
+                        corners[edge->d1]->clip[edge->a1], k_gridscale, p1 );
+
+            /* 
+             * Find penetration distance between player position and the edge
+             */
+
+            v2f normal = { -(p1[2]-p0[2]), p1[0]-p0[0] },
+                   rel = { world[0]-p0[0], world[2]-p0[2] };
+
+            if( edge->o0 == -1 )
+            {
+               /* No subregions (default case), just use triangle created by
+                * i0, e0, e1 */
+               player_walkgrid_stand_tri( corners[edge->i0]->pos,
+                                          p0,
+                                          p1, world );
+            }
+            else
+            {
+               /* 
+                * Test if we are in the first region, which is
+                * edge.i0, edge.e0, edge.o0,
+                */
+               v3f v0, ref;
+               v3_sub( p0, corners[edge->o0]->pos, ref );
+               v3_sub( world, corners[edge->o0]->pos, v0 );
+
+               vg_line( corners[edge->o0]->pos, p0, 0xffffff00 );
+               vg_line( corners[edge->o0]->pos, world, 0xff000000 );
+               
+               if( ref[0]*v0[2] - ref[2]*v0[0] < 0.0f )
+               {
+                  player_walkgrid_stand_tri( corners[edge->i0]->pos,
+                                             p0,
+                                             corners[edge->o0]->pos, world );
+               }
+               else
+               {
+                  if( edge->o1 == -1 )
+                  {
+                     /*
+                      * No other edges mean we just need to use the opposite
+                      *
+                      * e0, e1, o0 (in our case, also i1)
+                      */
+                     player_walkgrid_stand_tri( p0,
+                                                p1,
+                                                corners[edge->o0]->pos, world );
+                  }
+                  else
+                  {
+                     /*
+                      * Note: this v0 calculation can be ommited with the 
+                      *       current tileset.
+                      *
+                      *       the last two triangles we have are:
+                      *         e0, e1, o1
+                      *       and
+                      *         e1, i1, o1
+                      */
+                     v3_sub( p1, corners[edge->o1]->pos, ref );
+                     v3_sub( world, corners[edge->o1]->pos, v0 );
+                     vg_line( corners[edge->o1]->pos, p1, 0xff00ffff );
+
+                     if( ref[0]*v0[2] - ref[2]*v0[0] < 0.0f )
+                     {
+                        player_walkgrid_stand_tri( p0,
+                                                   p1,
+                                                   corners[edge->o1]->pos,
+                                                   world );
+                     }
+                     else
+                     {
+                        player_walkgrid_stand_tri( p1,
+                                                   corners[edge->i1]->pos,
+                                                   corners[edge->o1]->pos,
+                                                   world );
+                     }
+                  }
+               }
+            }
+         }
+      }
+   }
+
+   v3_copy( world, player.rb.co );
+}
+
+static void player_walkgrid_getsurface(void)
+{
+   float const k_stepheight = 0.5f;
+   float const k_miny = 0.6f;
+   float const k_height = 1.78f;
+   float const k_region_size = (float)WALKGRID_SIZE/2.0f * k_gridscale;
+
+   static struct walkgrid wg;
+
+   v3f cell;
+   v3_copy( player.rb.co, cell );
+   player_walkgrid_floor( cell );
+
+   v3_muladds( cell, (v3f){-1.0f,-1.0f,-1.0f}, k_region_size, wg.region[0] );
+   v3_muladds( cell, (v3f){ 1.0f, 1.0f, 1.0f}, k_region_size, wg.region[1] );
+
+   
+   /* 
+    * Create player input vector
+    */
+   v3f delta = {0.0f,0.0f,0.0f};
+   v3f fwd = { -sinf(-player.angles[0]), 0.0f, -cosf(-player.angles[0]) },
+       side = { -fwd[2], 0.0f, fwd[0] };
+
+   /* Temp */
+   if( !vg_console_enabled() )
+   {
+      if( glfwGetKey( vg_window, GLFW_KEY_W ) )
+         v3_muladds( delta, fwd,  ktimestep*k_walkspeed, delta );
+      if( glfwGetKey( vg_window, GLFW_KEY_S ) )
+         v3_muladds( delta, fwd, -ktimestep*k_walkspeed, delta );
+
+      if( glfwGetKey( vg_window, GLFW_KEY_A ) )
+         v3_muladds( delta, side, -ktimestep*k_walkspeed, delta );
+      if( glfwGetKey( vg_window, GLFW_KEY_D ) )
+         v3_muladds( delta, side,  ktimestep*k_walkspeed, delta );
+
+      v3_muladds( delta, fwd, 
+            vg_get_axis("vertical")*-ktimestep*k_walkspeed, delta );
+      v3_muladds( delta, side, 
+            vg_get_axis("horizontal")*ktimestep*k_walkspeed, delta );
+   }
+
+   /* 
+    * Create our move in grid space
+    */
+   wg.dir[0] = delta[0] * (1.0f/k_gridscale);
+   wg.dir[1] = delta[2] * (1.0f/k_gridscale);
+   wg.move = 1.0f;
+
+   v2f region_pos = 
+   {
+      (player.rb.co[0] - wg.region[0][0]) * (1.0f/k_gridscale),
+      (player.rb.co[2] - wg.region[0][2]) * (1.0f/k_gridscale)
+   };
+   v2f region_cell_pos;
+   v2_floor( region_pos, region_cell_pos );
+   v2_sub( region_pos, region_cell_pos, wg.pos );
+
+   wg.cell_id[0] = region_cell_pos[0];
+   wg.cell_id[1] = region_cell_pos[1];
+
+   for(int y=0; y<WALKGRID_SIZE; y++ )
+   {
+      for(int x=0; x<WALKGRID_SIZE; x++ )
+      {
+         struct grid_sample *s = &wg.samples[y][x];
+         v3_muladds( wg.region[0], (v3f){ x, 0, y }, k_gridscale, s->pos );
+         s->state = k_traverse_none;
+         s->type = k_sample_type_air;
+         v3_zero( s->clip[0] );
+         v3_zero( s->clip[1] );
+      }
+   }
+
+   v2i border[WALKGRID_SIZE*WALKGRID_SIZE];
+   v2i *cborder = border;
+   u32 border_length = 1;
+
+   struct grid_sample *base = NULL; 
+
+   v2i starters[] = {{0,0},{1,1},{0,1},{1,0}};
+
+   for( int i=0;i<4;i++ )
+   {
+      v2i test;
+      v2i_add( wg.cell_id, starters[i], test );
+      v2i_copy( test, border[0] );
+      base = &wg.samples[test[1]][test[0]];
+
+      base->pos[1] = cell[1];
+      player_walkgrid_samplepole( base );
+
+      if( base->type == k_sample_type_valid )
+         break;
+      else
+         base->type = k_sample_type_air;
+   }
+   
+   vg_line_pt3( base->pos, 0.1f, 0xffffffff );
+
+   int iter = 0;
+
+   while( border_length )
+   {
+      v2i directions[] = {{1,0},{0,1},{-1,0},{0,-1}};
+
+      v2i *old_border = cborder;
+      int  len = border_length;
+
+      border_length = 0;
+      cborder = old_border+len;
+
+      for( int i=0; i<len; i++ )
+      {
+         v2i co;
+         v2i_copy( old_border[i], co );
+         struct grid_sample *sa = &wg.samples[co[1]][co[0]];
+
+         for( int j=0; j<4; j++ )
+         {
+            v2i newp;
+            v2i_add( co, directions[j], newp );
+
+            if( newp[0] < 0 || newp[1] < 0 || 
+                newp[0] == WALKGRID_SIZE || newp[1] == WALKGRID_SIZE )
+               continue;
+
+            struct grid_sample *sb = &wg.samples[newp[1]][newp[0]];
+            enum traverse_state thismove = j%2==0? 1: 2;
+
+            if( (sb->state & thismove) == 0x00 || 
+                  sb->type == k_sample_type_air )
+            {
+               sb->pos[1] = sa->pos[1];
+
+               player_walkgrid_samplepole( sb );
+
+               if( sb->type != k_sample_type_air )
+               {
+                  /* 
+                   * Need to do a blocker pass
+                   */
+
+                  struct grid_sample *store = (j>>1 == 0)? sa: sb;
+                  player_walkgrid_clip_blocker( sa, sb, store, j%2 );
+                  
+
+                  if( sb->type != k_sample_type_air )
+                  {
+                     vg_line( sa->pos, sb->pos, 0xffffffff );
+                  
+                     if( sb->state == k_traverse_none )
+                        v2i_copy( newp, cborder[ border_length ++ ] );
+                  }
+                  else
+                  {
+                     v3f p1;
+                     v3_muladds( sa->pos, store->clip[j%2], k_gridscale, p1 );
+                     vg_line( sa->pos, p1, 0xffffffff );
+                  }
+               }
+               else
+               {
+                  /* 
+                   * A clipping pass is now done on the edge of the walkable
+                   * surface
+                   */
+                  
+                  struct grid_sample *store = (j>>1 == 0)? sa: sb;
+                  player_walkgrid_clip_edge( sa, sb, store, j%2 );
+
+                  v3f p1;
+                  v3_muladds( sa->pos, store->clip[j%2], k_gridscale, p1 );
+                  vg_line( sa->pos, p1, 0xffffffff );
+               }
+
+               sb->state |= thismove;
+            }
+         }
+
+         sa->state = k_traverse_h|k_traverse_v;
+      }
+
+      iter ++;
+      if( iter == walk_grid_iterations )
+         break;
+   }
+
+   /* Draw connections */
+   struct grid_sample *corners[4];
+   for( int x=0; x<WALKGRID_SIZE-1; x++ )
+   {
+      for( int z=0; z<WALKGRID_SIZE-1; z++ )
+      {
+         const struct conf *conf = 
+            player_walkgrid_conf( &wg, (v2i){x,z}, corners );
+
+         for( int i=0; i<conf->edge_count; i++ )
+         {
+            const struct confedge *edge = &conf->edges[i];
+
+            v3f p0, p1;
+            v3_muladds( corners[edge->i0]->pos, 
+                    corners[edge->d0]->clip[edge->a0], k_gridscale, p0 );
+            v3_muladds( corners[edge->i1]->pos, 
+                    corners[edge->d1]->clip[edge->a1], k_gridscale, p1 );
+
+            vg_line( p0, p1, 0xff0000ff );
+         }
+      }
+   }
+
+   /*
+    * Commit player movement into the grid 
+    */
+   
+   if( v3_length2(delta) <= 0.00001f )
+      return;
+   
+   int i=0;
+   for(; i<8 && wg.move > 0.001f; i++ )
+      player_walkgrid_iter( &wg, i );
+
+   player_walkgrid_stand_cell( &wg );
+}
+
+static void player_walkgrid(void)
+{
+   player_walkgrid_getsurface();
+   
+   m4x3_mulv( player.rb.to_world, (v3f){0.0f,1.8f,0.0f}, player.camera_pos );
+   player_mouseview();
+   rb_update_transform( &player.rb );
+}
+
+#endif /* PLAYER_WALKGRID_H */