Code re-work and content update: lighting.

src/1.getting_started/5.1.transformations/transformations.cpp

@@ -169,11 +169,11 @@ int main()
         transform = glm::rotate(transform, (float)glfwGetTime(), glm::vec3(0.0f, 0.0f, 1.0f));
 
         // get matrix's uniform location and set matrix
+        ourShader.use();
         unsigned int transformLoc = glGetUniformLocation(ourShader.ID, "transform");
         glUniformMatrix4fv(transformLoc, 1, GL_FALSE, glm::value_ptr(transform));
 
         // render container
-        ourShader.use();
         glBindVertexArray(VAO);
         glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, 0);