add 'fixed' joint for btMultiBody

improve btMultiBody version of URDF reader (still work-in-progress)
enabled planar joint for btMultiBody (untested)
enable loading from relative path for .stl meshes

src/Bullet3Common/b3FileUtils.h

@@ -0,0 +1,105 @@
+#ifndef B3_FILE_UTILS_H
+#define B3_FILE_UTILS_H
+
+#include <stdio.h>
+#include "b3Scalar.h"
+
+struct b3FileUtils
+{
+	b3FileUtils()
+	{
+	}
+	virtual ~b3FileUtils()
+	{
+	}
+
+	bool findFile(const char* orgFileName, char* relativeFileName, int maxRelativeFileNameMaxLen)
+	{
+		
+			const char* prefix[]={"","./","./data/","../data/","../../data/","../../../data/","../../../../data/"};
+			int numPrefixes = sizeof(prefix)/sizeof(const char*);
+	
+			FILE* f=0;
+			bool fileFound = false;
+			int result = 0;
+
+			for (int i=0;!f && i<numPrefixes;i++)
+			{
+#ifdef _WIN32
+				sprintf_s(relativeFileName,maxRelativeFileNameMaxLen,"%s%s",prefix[i],orgFileName);
+#else
+				sprintf(relativeFileName,"%s%s",prefix[i],orgFileName);
+#endif
+				f = fopen(relativeFileName,"rb");
+				if (f)
+				{
+					fileFound = true;
+					break;
+				}
+			}
+			if (f)
+			{
+				fclose(f);
+			}
+	
+		return fileFound;
+	}
+
+	static const char* strip2(const char* name, const char* pattern)
+	{
+		size_t const patlen = strlen(pattern);
+		size_t patcnt = 0;
+		const char * oriptr;
+		const char * patloc;
+		// find how many times the pattern occurs in the original string
+		for (oriptr = name; patloc = strstr(oriptr, pattern); oriptr = patloc + patlen)
+		{
+			patcnt++;
+		}
+		return oriptr;
+	}
+
+
+	void extractPath(const char* fileName, char* path, int maxPathLength)
+	{
+		const char* stripped = strip2(fileName, "/");
+		stripped = strip2(stripped, "\\");
+
+		ptrdiff_t len = stripped-fileName;
+		b3Assert((len+1)<maxPathLength);
+
+		if (len && ((len+1)<maxPathLength))
+		{
+
+			for (int i=0;i<len;i++)
+			{
+				path[i] = fileName[i];
+			}
+			path[len]=0;
+		} else
+		{
+#ifdef _WIN32
+			sprintf_s(path, maxPathLength,"");
+#else
+			sprintf(path, maxPathLength,"");
+#endif
+		}
+	}
+
+	/*static const char* strip2(const char* name, const char* pattern)
+	{
+		size_t const patlen = strlen(pattern);
+		size_t patcnt = 0;
+		const char * oriptr;
+		const char * patloc;
+		// find how many times the pattern occurs in the original string
+		for (oriptr = name; patloc = strstr(oriptr, pattern); oriptr = patloc + patlen)
+		{
+			patcnt++;
+		}
+		return oriptr;
+	}
+	*/
+
+};
+#endif //B3_FILE_UTILS_H