export btHeightfieldTerrainShape to PyBullet. Note that tinyrenderer doesn't support rendering it (it would be too slow on CPU)

fix rare getKeyboardEvents threading issue
change texture color to default plane.urdf blue

examples/Heightfield/HeightfieldExample.cpp

@@ -485,13 +485,16 @@ getRawHeightfieldData
                 btAssert(raw && "out of memory");
 
                 byte_t * p = raw;
-                for (int i = 0; i < width; ++i)
+                
+				for (int j = 0; j < width; ++j)
                 {
-                    float x = i * s_gridSpacing;
-                    for (int j = 0; j < width; ++j)
+                    
+					for (int i = 0; i < width; ++i)
                     {
+						float x = i * s_gridSpacing;
                         float y = j * s_gridSpacing;
-                        float z = double(image[i*3+width*j*3])*(14./256.);
+						float heightScaling = (14. / 256.);
+						float z = double(image[(width - 1 - i) * 3 + width*j * 3]) * heightScaling;
                         convertFromFloat(p, z, type);
 						// update min/max
 						if (!i && !j) {