added a Hide() render primitive

docs/config.rst

@@ -560,6 +560,15 @@ Cave
     only_lit
         Only render lit caves. Default: False
 
+Hide
+    Hide blocks based on blockid. Blocks hidden in this way will be
+    treated exactly the same as air.
+
+    **Options**
+
+    minerals
+        A list of block ids, or (blockid, data) tuples to hide.
+
 DepthTinting
     Tint blocks a color according to their depth (height) from bedrock. Useful
     mainly for cave renders.

overviewer_core/rendermodes.py

@@ -188,6 +188,12 @@ class MineralOverlay(Overlay):
         'minerals' : ('a list of (blockid, (r, g, b)) tuples for coloring minerals', None),
     }
 
+class Hide(RenderPrimitive):
+    name = "hide"
+    options = {
+        'blocks' : ('a list of blockids or (blockid, data) tuples of blocks to hide', []),
+    }
+
 # Built-in rendermodes for your convenience!
 normal = [Base(), EdgeLines()]
 lighting = [Base(), EdgeLines(), Lighting()]

overviewer_core/src/primitives/hide.c

@@ -0,0 +1,111 @@
+/*
+ * 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"
+
+struct HideRule {
+    unsigned short blockid;
+    unsigned char has_data;
+    unsigned char data;
+};
+
+typedef struct {
+    struct HideRule* rules;
+} RenderPrimitiveHide;
+
+static int
+hide_start(void *data, RenderState *state, PyObject *support) {
+    PyObject *opt;
+    RenderPrimitiveHide* self = (RenderPrimitiveHide *)data;
+    self->rules = NULL;
+    
+    if (!render_mode_parse_option(support, "blocks", "O", &(opt)))
+        return 1;
+    if (opt && opt != Py_None) {
+        Py_ssize_t blocks_size = 0, i;
+        
+        if (!PyList_Check(opt)) {
+            PyErr_SetString(PyExc_TypeError, "'blocks' must be a list");
+            return 1;
+        }
+        
+        blocks_size = PyList_GET_SIZE(opt);
+        self->rules = calloc(blocks_size + 1, sizeof(struct HideRule));
+        if (self->rules == NULL) {
+            return 1;
+        }
+
+        for (i = 0; i < blocks_size; i++) {
+            PyObject *block = PyList_GET_ITEM(opt, i);
+            
+            if (PyInt_Check(block)) {
+                /* format 1: just a block id */
+                self->rules[i].blockid = PyInt_AsLong(block);
+                self->rules[i].has_data = 0;
+            } else if (PyArg_ParseTuple(block, "Hb", &(self->rules[i].blockid), &(self->rules[i].data))) {
+                /* format 2: (blockid, data) */
+                self->rules[i].has_data = 1;
+            } else {
+                /* format not recognized */
+                free(self->rules);
+                self->rules = NULL;
+                return 1;
+            }
+        }
+    }
+    
+    return 0;
+}
+
+static void
+hide_finish(void *data, RenderState *state) {
+    RenderPrimitiveHide *self = (RenderPrimitiveHide *)data;
+    
+    if (self->rules) {
+        free(self->rules);
+    }
+}
+
+static int
+hide_hidden(void *data, RenderState *state, int x, int y, int z) {
+    RenderPrimitiveHide *self = (RenderPrimitiveHide *)data;
+    unsigned int i;
+    
+    if (self->rules == NULL)
+        return 0;
+    
+    for (i = 0; self->rules[i].blockid != 0; i++) {
+        if (state->block == self->rules[i].blockid) {
+            if (!(self->rules[i].has_data))
+                return 1;
+            if (state->block_data == self->rules[i].data)
+                return 1;
+        }
+    }
+    
+    return 0;
+}
+
+RenderPrimitiveInterface primitive_hide = {
+    "hide",
+    sizeof(RenderPrimitiveHide),
+    hide_start,
+    hide_finish,
+    NULL,
+    hide_hidden,
+    NULL,
+};