From 2377b3cd523535bfa6bb171d8ed11eefcc6a7a22 Mon Sep 17 00:00:00 2001
From: Andrew Chin <achin@eminence32.net>
Date: Thu, 7 Feb 2013 19:44:56 -0500
Subject: [PATCH] Fixed nether rendering crash

The nether rendering mode was not properly handling x and z values
outside of the range 0 to 15.  This was causing an out-of-bounds
segfault when accessing the remove_block array.

Fixes #881
Fixes #851
Fixes #852
---
 overviewer_core/src/overviewer.h        |  2 +-
 overviewer_core/src/primitives/nether.c | 12 ++++++------
 overviewer_core/src/primitives/nether.h |  4 +++-
 3 files changed, 10 insertions(+), 8 deletions(-)

diff --git a/overviewer_core/src/overviewer.h b/overviewer_core/src/overviewer.h
index 23ff5fa..e20c15f 100644
--- a/overviewer_core/src/overviewer.h
+++ b/overviewer_core/src/overviewer.h
@@ -26,7 +26,7 @@
 
 // increment this value if you've made a change to the c extesion
 // and want to force users to rebuild
-#define OVERVIEWER_EXTENSION_VERSION 41
+#define OVERVIEWER_EXTENSION_VERSION 42
 
 /* Python PIL, and numpy headers */
 #include <Python.h>
diff --git a/overviewer_core/src/primitives/nether.c b/overviewer_core/src/primitives/nether.c
index 0cc6706..671fd5f 100644
--- a/overviewer_core/src/primitives/nether.c
+++ b/overviewer_core/src/primitives/nether.c
@@ -23,20 +23,20 @@ walk_chunk(RenderState *state, RenderPrimitiveNether *data) {
     int x, y, z;
     int id;
 
-    for (x = 0; x < WIDTH; x++) {
-        for (z = 0; z < DEPTH; z++) {
+    for (x = -1; x < WIDTH + 1; x++) {
+        for (z = -1; z < DEPTH + 1; z++) {
             id = get_data(state, BLOCKS, x, NETHER_ROOF - (state->chunky * 16), z);
             if (id == 7) {
-                data->remove_block[x][NETHER_ROOF][z] = 1;
+                data->remove_block[x+1][NETHER_ROOF][z+1] = 1;
                 id = get_data(state, BLOCKS, x, (NETHER_ROOF + 1) - (state->chunky * 16), z);
                 if (id == 39 || id == 40)
-                    data->remove_block[x][NETHER_ROOF + 1][z] = 1;
+                    data->remove_block[x+1][NETHER_ROOF + 1][z+1] = 1;
             }
 
             for (y = NETHER_ROOF-1; y>=0; y--) {
                 id = get_data(state, BLOCKS, x, y - (state->chunky * 16), z);
                 if (id == 7 || id == 87)
-                    data->remove_block[x][y][z] = 1;
+                    data->remove_block[x+1][y][z+1] = 1;
                 else
                     break;
             }
@@ -56,7 +56,7 @@ nether_hidden(void *data, RenderState *state, int x, int y, int z) {
         walk_chunk(state, self);
 
     real_y = y + (state->chunky * 16);
-    return self->remove_block[x][real_y][z];
+    return self->remove_block[x+1][real_y][z+1];
 }
 
 RenderPrimitiveInterface primitive_nether = {
diff --git a/overviewer_core/src/primitives/nether.h b/overviewer_core/src/primitives/nether.h
index 73ae26e..72c898f 100644
--- a/overviewer_core/src/primitives/nether.h
+++ b/overviewer_core/src/primitives/nether.h
@@ -22,9 +22,11 @@
 #define DEPTH 16
 #define HEIGHT 256
 
+// add two to these because the primative functions should expect to
+// deal with x and z values of -1 and 16
 typedef struct {
     int walked_chunk;
 
-    int remove_block[WIDTH][HEIGHT][DEPTH];
+    int remove_block[WIDTH+2][HEIGHT][DEPTH+2];
     
 } RenderPrimitiveNether;