Fixed lines drawn using the 'none' line join mode having missing sections of each line segment.

src/modules/graphics/opengl/Polyline.cpp

@@ -349,6 +349,7 @@ void Polyline::draw()
 		}
 
 		// Fill the index array to make 2 triangles from each quad.
+		// NOTE: The triangle vertex ordering here is important!
 		for (size_t i = 0; i < numindices / 6; i++)
 		{
 			// First triangle.
@@ -357,8 +358,8 @@ void Polyline::draw()
 			indices[i * 6 + 2] = GLushort(i * 4 + 2);
 
 			// Second triangle.
-			indices[i * 6 + 3] = GLushort(i * 4 + 2);
-			indices[i * 6 + 4] = GLushort(i * 4 + 1);
+			indices[i * 6 + 3] = GLushort(i * 4 + 0);
+			indices[i * 6 + 4] = GLushort(i * 4 + 2);
 			indices[i * 6 + 5] = GLushort(i * 4 + 3);
 		}
 	}