diff --git a/examples/Importers/ImportObjDemo/Wavefront2GLInstanceGraphicsShape.cpp b/examples/Importers/ImportObjDemo/Wavefront2GLInstanceGraphicsShape.cpp
index 08fa521ae..f44030f21 100644
--- a/examples/Importers/ImportObjDemo/Wavefront2GLInstanceGraphicsShape.cpp
+++ b/examples/Importers/ImportObjDemo/Wavefront2GLInstanceGraphicsShape.cpp
@@ -111,7 +111,7 @@ GLInstanceGraphicsShape* btgCreateGraphicsShapeFromWavefrontObj(const tinyobj::a
 						}
 						else
 						{
-							b3Warning("obj texture coordinate out-of-range!");
+							//b3Warning("obj texture coordinate out-of-range!");
 							vtx2.uv[0] = 0;
 							vtx2.uv[1] = 0;
 						}
diff --git a/examples/ThirdPartyLibs/glad/glad/gl.h b/examples/ThirdPartyLibs/glad/glad/gl.h
index 3d08b2d45..0dfb4d9c8 100644
--- a/examples/ThirdPartyLibs/glad/glad/gl.h
+++ b/examples/ThirdPartyLibs/glad/glad/gl.h
@@ -2007,12 +2007,16 @@ typedef khronos_ssize_t GLsizeiptr;
 #if defined(__ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__) && (__ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__ > 1060)
 	typedef long GLintptrARB;
 #else
+#ifndef __gltypes_h_
 typedef ptrdiff_t GLintptrARB;
 #endif
+#endif
 #if defined(__ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__) && (__ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__ > 1060)
 	typedef long GLsizeiptrARB;
 #else
+#ifndef __gltypes_h_
 typedef ptrdiff_t GLsizeiptrARB;
+#endif
 #endif
 	typedef int64_t GLint64EXT;
 	typedef uint64_t GLuint64EXT;
diff --git a/examples/TinyRenderer/TinyRenderer.cpp b/examples/TinyRenderer/TinyRenderer.cpp
index f98362d96..2880eb254 100644
--- a/examples/TinyRenderer/TinyRenderer.cpp
+++ b/examples/TinyRenderer/TinyRenderer.cpp
@@ -156,8 +156,11 @@ struct Shader : public IShader
 		float index_x = b3Max(float(0.0), b3Min(float(m_width - 1), p[0]));
 		float index_y = b3Max(float(0.0), b3Min(float(m_height - 1), p[1]));
 		int idx = int(index_x) + int(index_y) * m_width;                       // index in the shadowbuffer array
-		float shadow = 0.8 + 0.2 * (m_shadowBuffer->at(idx) < -depth + 0.05);  // magic coeff to avoid z-fighting
-
+		float shadow = 1.0;
+		if (m_shadowBuffer && idx >=0 && idx <m_shadowBuffer->size())
+		{
+			shadow = 0.8 + 0.2 * (m_shadowBuffer->at(idx) < -depth + 0.05);  // magic coeff to avoid z-fighting
+		}
 		Vec3f bn = (varying_nrm * bar).normalize();
 		Vec2f uv = varying_uv * bar;
 
@@ -174,7 +177,13 @@ struct Shader : public IShader
 
 		for (int i = 0; i < 3; ++i)
 		{
-			color[i] = b3Min(int(m_ambient_coefficient * color[i] + shadow * (m_diffuse_coefficient * diffuse + m_specular_coefficient * specular) * color[i] * m_light_color[i]), 255);
+			int orgColor = 0;
+			float floatColor = (m_ambient_coefficient * color[i] + shadow * (m_diffuse_coefficient * diffuse + m_specular_coefficient * specular) * color[i] * m_light_color[i]);
+			if (floatColor==floatColor)
+			{
+				orgColor=int(floatColor);
+			}
+			color[i] = b3Min(orgColor, 255);
 		}
 
 		return false;
diff --git a/setup.py b/setup.py
index b661d632a..4d2212767 100644
--- a/setup.py
+++ b/setup.py
@@ -50,7 +50,7 @@ def parallelCCompile(self,
     newcc_args = cc_args
     if _platform == "darwin":
       if src.endswith('.cpp'):
-        newcc_args = cc_args + ["-stdlib=libc++"]
+        newcc_args = cc_args + ["-mmacosx-version-min=10.7", "-stdlib=libc++"]
     self._compile(obj, src, ext, newcc_args, extra_postargs, pp_opts)
 
   # convert to list, imap is evaluated on-demand
@@ -418,7 +418,7 @@ elif _platform == "win32":
   +["examples/ThirdPartyLibs/glad/gl.c"]
 elif _platform == "darwin":
   print("darwin!")
-  os.environ['LDFLAGS'] = '-framework Cocoa -stdlib=libc++ -framework OpenGL'
+  os.environ['LDFLAGS'] = '-framework Cocoa -mmacosx-version-min=10.7 -stdlib=libc++ -framework OpenGL'
   CXX_FLAGS += '-DB3_NO_PYTHON_FRAMEWORK '
   CXX_FLAGS += '-DHAS_SOCKLEN_T '
   CXX_FLAGS += '-D_DARWIN '
@@ -491,7 +491,7 @@ if 'BT_USE_EGL' in EGL_CXX_FLAGS:
 
 setup(
     name='pybullet',
-    version='2.5.5',
+    version='2.5.6',
     description=
     'Official Python Interface for the Bullet Physics SDK specialized for Robotics Simulation and Reinforcement Learning',
     long_description=
diff --git a/src/LinearMath/btMatrixX.h b/src/LinearMath/btMatrixX.h
index 388c57c2d..961c94dc6 100644
--- a/src/LinearMath/btMatrixX.h
+++ b/src/LinearMath/btMatrixX.h
@@ -338,24 +338,23 @@ struct btMatrixX
 		btMatrixX res(rows(), other.cols());
 		res.setZero();
 		//		BT_PROFILE("btMatrixX mul");
-		for (int j = 0; j < res.cols(); ++j)
+		for (int i = 0; i < rows(); ++i)
 		{
 			{
-				for (int i = 0; i < res.rows(); ++i)
+				for (int j = 0; j < other.cols(); ++j)
 				{
 					T dotProd = 0;
-					//					T dotProd2=0;
-					//int waste=0,waste2=0;
-
 					{
-						//						bool useOtherCol = true;
 						{
-							for (int v = 0; v < rows(); v++)
+							int r = rows();
+							int c = cols();
+
+							for (int k = 0; k < cols(); k++)
 							{
-								T w = (*this)(i, v);
-								if (other(v, j) != 0.f)
+								T w = (*this)(i, k);
+								if (other(k, j) != 0.f)
 								{
-									dotProd += w * other(v, j);
+									dotProd += w * other(k, j);
 								}
 							}
 						}