diff --git a/overviewer_core/src/iterate.c b/overviewer_core/src/iterate.c
index 6516237..00a6ace 100644
--- a/overviewer_core/src/iterate.c
+++ b/overviewer_core/src/iterate.c
@@ -666,7 +666,7 @@ chunk_render(PyObject *self, PyObject *args) {
                 state.imgy -= 12;
                 /* get blockid */
                 state.block = getArrayShort3D(blocks_py, state.x, state.y, state.z);
-                if (state.block == 0 || render_mode_hidden(rendermode, state.x, state.y, state.z)) {
+                if (state.block == block_air || render_mode_hidden(rendermode, state.x, state.y, state.z)) {
                     continue;
                 }
                 
diff --git a/overviewer_core/src/primitives/base.c b/overviewer_core/src/primitives/base.c
index 3a955e2..099cdd8 100644
--- a/overviewer_core/src/primitives/base.c
+++ b/overviewer_core/src/primitives/base.c
@@ -16,6 +16,7 @@
  */
 
 #include "../overviewer.h"
+#include "../mc_id.h"
 #include "biomes.h"
 
 typedef struct {
@@ -93,24 +94,24 @@ base_draw(void *data, RenderState *state, PyObject *src, PyObject *mask, PyObjec
      * biome-compliant ones! The tinting is now all done here.
      */
     if (/* grass, but not snowgrass */
-        (state->block == 2 && get_data(state, BLOCKS, state->x, state->y+1, state->z) != 78) ||
+        (state->block == block_grass && get_data(state, BLOCKS, state->x, state->y+1, state->z) != 78) ||
         /* water */
-        state->block == 8 || state->block == 9 ||
+        state->block == block_flowing_water || state->block == block_water ||
         /* leaves */
-        state->block == 18 || state->block == 161 ||
+        state->block == block_leaves || state->block == block_leaves2 ||
         /* tallgrass, but not dead shrubs */
-        (state->block == 31 && state->block_data != 0) ||
+        (state->block == block_tallgrass && state->block_data != 0) ||
         /* pumpkin/melon stem, not fully grown. Fully grown stems
          * get constant brown color (see textures.py) */
-        (((state->block == 104) || (state->block == 105)) && (state->block_data != 7)) ||
+        (((state->block == block_pumpkin_stem) || (state->block == block_melon_stem)) && (state->block_data != 7)) ||
         /* vines */
-        state->block == 106 ||
+        state->block == block_vine ||
         /* lily pads */
-        state->block == 111 ||
+        state->block == block_waterlily ||
         /* doublePlant grass & ferns */
-        (state->block == 175 && (state->block_data == 2 || state->block_data == 3)) ||
+        (state->block == block_double_plant && (state->block_data == 2 || state->block_data == 3)) ||
         /* doublePlant grass & ferns tops */
-        (state->block == 175 && below_block == 175 && (below_data == 2 || below_data == 3)) )
+        (state->block == block_double_plant && below_block == block_double_plant && (below_data == 2 || below_data == 3)) )
     {
         /* do the biome stuff! */
         PyObject *facemask = mask;
@@ -118,7 +119,7 @@ base_draw(void *data, RenderState *state, PyObject *src, PyObject *mask, PyObjec
         PyObject *color_table = NULL;
         unsigned char flip_xy = 0;
         
-        if (state->block == 2) {
+        if (state->block == block_grass) {
             /* grass needs a special facemask */
             facemask = self->grass_texture;
         }
diff --git a/overviewer_core/src/primitives/edge-lines.c b/overviewer_core/src/primitives/edge-lines.c
index a82624f..1f2e948 100644
--- a/overviewer_core/src/primitives/edge-lines.c
+++ b/overviewer_core/src/primitives/edge-lines.c
@@ -16,6 +16,7 @@
  */
 
 #include "../overviewer.h"
+#include "../mc_id.h"
 
 typedef struct {
     float opacity;
@@ -34,16 +35,16 @@ edge_lines_draw(void *data, RenderState *state, PyObject *src, PyObject *mask, P
     PrimitiveEdgeLines *self = (PrimitiveEdgeLines *)data;
 
     /* Draw some edge lines! */
-    if (state->block == 44 || state->block == 78 || !is_transparent(state->block)) {
+    if (state->block == block_stone_slab || state->block == block_snow_layer || !is_transparent(state->block)) {
         Imaging img_i = imaging_python_to_c(state->img);
         unsigned char ink[] = {0, 0, 0, 255 * self->opacity};
         unsigned short side_block;
         int x = state->x, y = state->y, z = state->z;
 
         int increment=0;
-        if ((state->block == 44 || state->block == 126) && ((state->block_data & 0x8) == 0 ))  // half-steps BUT no upsidown half-steps
+        if ((state->block == block_stone_slab || state->block == block_wooden_slab) && ((state->block_data & 0x8) == 0 ))  // half-steps BUT no upsidown half-steps
             increment=6;
-        else if ((state->block == 78) || (state->block == 93) || (state->block == 94)) // snow, redstone repeaters (on and off)
+        else if ((state->block == block_snow_layer) || (state->block == block_unpowered_repeater) || (state->block == block_powered_repeater)) // snow, redstone repeaters (on and off)
             increment=9;
         
         /* +X side */
@@ -51,9 +52,9 @@ edge_lines_draw(void *data, RenderState *state, PyObject *src, PyObject *mask, P
         if (side_block != state->block && (is_transparent(side_block) || render_mode_hidden(state->rendermode, x+1, y, z)) && 
             /* WARNING: ugly special case approaching */
             /* if the block is a slab and the side block is a stair don't draw anything, it can give very ugly results */
-            !((state->block == 44 || state->block == 126) && ((side_block == 53) || (side_block == 67) || (side_block == 108) ||
-            (side_block == 109) || (side_block == 114) || (side_block == 128) || (side_block == 134) || (side_block == 135) ||
-            (side_block == 136)))) {
+            !((state->block == block_stone_slab || state->block == block_wooden_slab) && ((side_block == block_oak_stairs) || (side_block == block_stone_stairs) || (side_block == block_brick_stairs) ||
+            (side_block == block_stone_brick_stairs) || (side_block == block_nether_brick_stairs) || (side_block == block_sandstone_stairs) || (side_block == block_spruce_stairs) || (side_block == block_birch_stairs) ||
+            (side_block == block_jungle_stairs)))) {
             ImagingDrawLine(img_i, state->imgx+12, state->imgy+1+increment, state->imgx+22+1, state->imgy+5+1+increment, &ink, 1);
             ImagingDrawLine(img_i, state->imgx+12, state->imgy+increment, state->imgx+22+1, state->imgy+5+increment, &ink, 1);
         }
@@ -63,9 +64,9 @@ edge_lines_draw(void *data, RenderState *state, PyObject *src, PyObject *mask, P
         if (side_block != state->block && (is_transparent(side_block) || render_mode_hidden(state->rendermode, x, y, z-1)) &&
             /* WARNING: ugly special case approaching */
             /* if the block is a slab and the side block is a stair don't draw anything, it can give very ugly results */
-            !((state->block == 44 || state->block == 126) && ((side_block == 53) || (side_block == 67) || (side_block == 108) ||
-            (side_block == 109) || (side_block == 114) || (side_block == 128) || (side_block == 134) || (side_block == 135) ||
-            (side_block == 136)))) {
+            !((state->block == block_stone_slab || state->block == block_wooden_slab) && ((side_block == block_oak_stairs) || (side_block == block_stone_stairs) || (side_block == block_brick_stairs) ||
+            (side_block == block_stone_brick_stairs) || (side_block == block_nether_brick_stairs) || (side_block == block_sandstone_stairs) || (side_block == block_spruce_stairs) || (side_block == block_birch_stairs) ||
+            (side_block == block_jungle_stairs)))) {
             ImagingDrawLine(img_i, state->imgx, state->imgy+6+1+increment, state->imgx+12+1, state->imgy+1+increment, &ink, 1);
             ImagingDrawLine(img_i, state->imgx, state->imgy+6+increment, state->imgx+12+1, state->imgy+increment, &ink, 1);
         }
diff --git a/overviewer_core/src/primitives/hide.c b/overviewer_core/src/primitives/hide.c
index cdb24e8..bc39c2e 100644
--- a/overviewer_core/src/primitives/hide.c
+++ b/overviewer_core/src/primitives/hide.c
@@ -16,6 +16,7 @@
  */
 
 #include "../overviewer.h"
+#include "../mc_id.h"
 
 struct HideRule {
     unsigned short blockid;
diff --git a/overviewer_core/src/primitives/lighting.c b/overviewer_core/src/primitives/lighting.c
index 97f7f0a..9539368 100644
--- a/overviewer_core/src/primitives/lighting.c
+++ b/overviewer_core/src/primitives/lighting.c
@@ -16,6 +16,7 @@
  */
 
 #include "../overviewer.h"
+#include "../mc_id.h"
 #include "lighting.h"
 #include <math.h>
 
@@ -138,7 +139,7 @@ estimate_blocklevel(RenderPrimitiveLighting *self, RenderState *state,
     blocklevel = get_data(state, BLOCKLIGHT, x, y, z);
     
     /* no longer a guess */
-    if (!(block == 44 || block == 53 || block == 67 || block == 108 || block == 109 || block == 180 || block == 182 || block == 205) && authoratative) {
+    if (!(block == block_stone_slab || block == block_oak_stairs || block == block_stone_stairs || block == block_brick_stairs || block == block_stone_brick_stairs || block == block_red_sandstone_stairs || block == block_stone_slab2 || block == block_purpur_slab ) && authoratative) {
         *authoratative = 1;
     }
     
@@ -159,9 +160,9 @@ get_lighting_color(RenderPrimitiveLighting *self, RenderState *state,
 
     /* special half-step handling, stairs handling */
     /* Anvil also needs to be here, blockid 145 */
-    if (block == 44 || block == 53 || block == 67 || block == 108 || block == 109 || block == 114 ||
-        block == 128 || block == 134 || block == 135 || block == 136 || block == 145 || block == 156 ||
-        block == 163 || block == 164 || block == 180 || block == 182 || block == 203 || block == 205) {
+    if (block == block_stone_slab || block == block_oak_stairs || block == block_stone_stairs || block == block_brick_stairs || block == block_stone_brick_stairs || block == block_nether_brick_stairs ||
+        block == block_sandstone_stairs || block == block_spruce_stairs || block == block_birch_stairs || block == block_jungle_stairs || block == block_anvil || block == block_quartz_stairs ||
+        block == block_acacia_stairs || block == block_dark_oak_stairs || block == block_red_sandstone_stairs || block == block_stone_slab2 || block == block_purpur_stairs || block == block_purpur_slab ) {
         unsigned int upper_block;
         
         /* stairs and half-blocks take the skylevel from the upper block if it's transparent */
@@ -170,10 +171,10 @@ get_lighting_color(RenderPrimitiveLighting *self, RenderState *state,
         do {
             upper_counter++; 
             upper_block = get_data(state, BLOCKS, x, y + upper_counter, z);
-        } while (upper_block == 44 || upper_block == 53 || upper_block == 67 || upper_block == 108 ||
-                 upper_block == 109 || upper_block == 114 || upper_block == 128 || upper_block == 134 ||
-                 upper_block == 135 || upper_block == 136 || upper_block == 156 || upper_block == 163 ||
-                 upper_block == 164 || upper_block == 180 || upper_block == 182 || upper_block == 203 || upper_block == 205);
+        } while (upper_block == block_stone_slab || upper_block == block_oak_stairs || upper_block == block_stone_stairs || upper_block == block_brick_stairs ||
+                 upper_block == block_stone_brick_stairs || upper_block == block_nether_brick_stairs || upper_block == block_sandstone_stairs || upper_block == block_spruce_stairs ||
+                 upper_block == block_birch_stairs || upper_block == block_jungle_stairs || upper_block == block_quartz_stairs || upper_block == block_acacia_stairs ||
+                 upper_block == block_dark_oak_stairs || upper_block == block_red_sandstone_stairs || upper_block == block_stone_slab2 || upper_block == block_purpur_stairs || upper_block == block_purpur_slab );
         if (is_transparent(upper_block)) {
             skylevel = get_data(state, SKYLIGHT, x, y + upper_counter, z);
         } else {
@@ -186,7 +187,7 @@ get_lighting_color(RenderPrimitiveLighting *self, RenderState *state,
 
     }
     
-    if (block == 10 || block == 11) {
+    if (block == block_flowing_lava || block == block_lava) {
         /* lava blocks should always be lit! */
         *r = 255;
         *g = 255;
@@ -305,7 +306,7 @@ lighting_draw(void *data, RenderState *state, PyObject *src, PyObject *mask, PyO
     self = (RenderPrimitiveLighting *)data;
     x = state->x, y = state->y, z = state->z;
     
-    if ((state->block == 8) || (state->block == 9)) { /* special case for water */
+    if ((state->block == block_flowing_water) || (state->block == block_water)) { /* special case for water */
         /* looks like we need a new case for lighting, there are
          * blocks that are transparent for occlusion calculations and
          * need per-face shading if the face is drawn. */
diff --git a/overviewer_core/src/primitives/overlay-structure.c b/overviewer_core/src/primitives/overlay-structure.c
index b0292cb..bc4a7cf 100644
--- a/overviewer_core/src/primitives/overlay-structure.c
+++ b/overviewer_core/src/primitives/overlay-structure.c
@@ -16,6 +16,7 @@
  */
 
 #include "overlay.h"
+#include "../mc_id.h"
 
 typedef enum { false, true } bool;
 
diff --git a/overviewer_core/src/primitives/overlay.c b/overviewer_core/src/primitives/overlay.c
index ff7ce75..8fce0bc 100644
--- a/overviewer_core/src/primitives/overlay.c
+++ b/overviewer_core/src/primitives/overlay.c
@@ -16,6 +16,7 @@
  */
 
 #include "overlay.h"
+#include "../mc_id.h"
 
 static void get_color(void *data, RenderState *state,
                       unsigned char *r, unsigned char *g, unsigned char *b, unsigned char *a) {
@@ -85,9 +86,9 @@ overlay_draw(void *data, RenderState *state, PyObject *src, PyObject *mask, PyOb
 
     // exactly analogous to edge-line code for these special blocks
     int increment=0;
-    if (state->block == 44)  // half-step
+    if (state->block == block_stone_slab)  // half-step
         increment=6;
-    else if (state->block == 78) // snow
+    else if (state->block == block_snow_layer) // snow
         increment=9;
     
     /* skip rendering the overlay if we can't see it */
diff --git a/overviewer_core/src/primitives/smooth-lighting.c b/overviewer_core/src/primitives/smooth-lighting.c
index e8cd369..05e9351 100644
--- a/overviewer_core/src/primitives/smooth-lighting.c
+++ b/overviewer_core/src/primitives/smooth-lighting.c
@@ -16,6 +16,7 @@
  */
 
 #include "../overviewer.h"
+#include "../mc_id.h"
 #include "lighting.h"
 #include <math.h>
 
@@ -228,7 +229,7 @@ smooth_lighting_draw(void *data, RenderState *state, PyObject *src, PyObject *ma
     /* non-transparent blocks get the special smooth treatment */
     
     /* special code for water */
-    if (state->block == 9)
+    if (state->block == block_water)
     {
         if (!(state->block_pdata & (1 << 4)))
             light_top = 0;