broke out nether, heightfading, depth, and edgelines from base primitive

overviewer_core/src/primitives/nether.c

@@ -0,0 +1,42 @@
+/* 
+ * This file is part of the Minecraft Overviewer.
+ *
+ * Minecraft Overviewer is free software: you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as published
+ * by the Free Software Foundation, either version 3 of the License, or (at
+ * your option) any later version.
+ *
+ * Minecraft Overviewer is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General
+ * Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with the Overviewer.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "../overviewer.h"
+
+static int
+nether_hidden(void *data, RenderState *state, int x, int y, int z) {
+    /* hide all blocks above all air blocks */
+    while (z < 128)
+    {
+        if (getArrayByte3D(state->blocks, x, y, z) == 0)
+        {
+            return 0;
+            break;
+        }
+        z++;
+    }
+    return 1;
+}
+
+RenderPrimitiveInterface primitive_nether = {
+    "nether", 0,
+    NULL,
+    NULL,
+    NULL,
+    nether_hidden,
+    NULL,
+};