Added ReadBlend, a data extraction API for Blender's .blend files

This can come in handy, to author physics data for Bullet from Blender, and directly get the physics data straight from the .blend file

Thanks a lot to Adam D. Moss, to digg up this code and make it available under the MIT license
It was mentioned several years ago in this thread:
http://archives.seul.org/linuxgames/Apr-2005/msg00002.html

Extras/readblend/testblend.c

@@ -0,0 +1,110 @@
+#include <stdlib.h>
+#include <stdio.h>
+
+#include "abs-file.h"
+
+#include "readblend.h"
+
+void crawl(BlendFile* blend_file,
+	   BlendObject obj)
+{
+  BlendObject data_obj;
+
+  if (blend_object_structure_getfield(blend_file, &data_obj, obj, "totvert")) {
+    if (blend_object_type(blend_file, data_obj) == BLEND_OBJ_LONG32) {
+      long data1 = 123456;
+      if (blend_object_getdata(blend_file, &data1, data_obj)) {
+	fprintf(stderr, "TOTVERT=(%ld) ", data1);
+      } else {
+	fprintf(stderr, "FETCH ERROR\n");
+      }
+    }
+  }
+
+  if (blend_object_structure_getfield(blend_file, &data_obj, obj, "co")) {
+    if (blend_object_type(blend_file, data_obj) == BLEND_OBJ_FLOAT) {
+      float data1 = 123456.7;
+      float data2 = 123456.8;
+      float data3 = 123456.9;
+      if (blend_object_array_getdata(blend_file, &data1, data_obj, 0,0) &&
+	  blend_object_array_getdata(blend_file, &data2, data_obj, 0,1) &&
+	  blend_object_array_getdata(blend_file, &data3, data_obj, 0,2)) {
+	fprintf(stderr, "CO=(%f,%f,%f) ", data1, data2, data3);
+      } else {
+	fprintf(stderr, "FETCH ERROR\n");
+      }
+    }
+  }
+
+}
+
+static BLENDBLOCKCALLBACK_RETURN
+blockiter(BLENDBLOCKCALLBACK_ARGS) {
+  int i;
+  int entry_count = blend_block_get_entry_count(blend_file, block);
+#if 0
+  const char* tagname = blend_block_get_tagname(blend_file, block);
+  const char* typename = blend_block_get_typename(blend_file, block);
+  fprintf(stderr, "block: tag=%s type=%s entries=%d ",
+	  tagname, typename, entry_count);
+#endif
+  for (i=0; i<entry_count; ++i) {
+    BlendObject obj = blend_block_get_object(blend_file, block, i);
+    crawl(blend_file, obj);
+  }
+  //fprintf(stderr, "\n");
+  return 1;
+}
+
+
+int
+main(int argc, char *argv[])
+{
+  MY_FILETYPE *file;
+  BlendFile *bf;
+  int rtn = 0;
+
+  if (argc <= 1) {
+    fprintf(stderr, "specify filename on command line.\n");
+    return -1;
+  }
+
+  file = MY_OPEN_FOR_READ(argv[1]);
+
+  if (!file) {
+    fprintf(stderr, "couldn't open file. :(\n");
+    return -1;
+  }
+
+  bf = blend_read(file);
+
+  if (!bf) {
+    fprintf(stderr, "couldn't read blender file. :(\n");
+    rtn = -1;
+    goto closeit;
+  }
+
+  blend_dump_typedefs(bf);
+
+  blend_dump_blocks(bf);
+
+  fflush(stdout);
+
+  blend_foreach_block(bf, blockiter, NULL);
+
+
+  {
+    BlendObject obj;
+    char want_name[] = "IMmetalrock.jpg";
+    if (blend_object_get_by_IDname(bf,&obj, want_name)) {
+      fprintf(stderr, "got %s.\n", want_name);
+    }
+  }
+
+
+  blend_free(bf);
+
+ closeit:
+  MY_CLOSE(file);
+  return rtn;
+}