Update GLM to latest version (0.9.9.3). This includes GLM's change of matrices no longer default initializing to the identity matrix. This commit thus also includes the update of all of LearnOpenGL's code to reflect this: all matrices are now constructor-initialized to the identity matrix where relevant.

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

@@ -167,7 +167,7 @@ int main()
         glBindTexture(GL_TEXTURE_2D, texture2);
 
         // create transformations
-        glm::mat4 transform;
+        glm::mat4 transform = glm::mat4(1.0f); // make sure to initialize matrix to identity matrix first
         transform = glm::translate(transform, glm::vec3(0.5f, -0.5f, 0.0f));
         transform = glm::rotate(transform, (float)glfwGetTime(), glm::vec3(0.0f, 0.0f, 1.0f));
 

src/1.getting_started/5.2.transformations_exercise2/transformations_exercise2.cpp

@@ -167,7 +167,7 @@ int main()
         glBindTexture(GL_TEXTURE_2D, texture2);
 
 
-        glm::mat4 transform;
+        glm::mat4 transform = glm::mat4(1.0f); // make sure to initialize matrix to identity matrix first
         // first container
         // ---------------
         transform = glm::translate(transform, glm::vec3(0.5f, -0.5f, 0.0f));
@@ -182,7 +182,7 @@ int main()
 
         // second transformation
         // ---------------------
-        transform = glm::mat4(); // reset it to an identity matrix
+        transform = glm::mat4(1.0f); // reset it to identity matrix
         transform = glm::translate(transform, glm::vec3(-0.5f, 0.5f, 0.0f));
         float scaleAmount = sin(glfwGetTime());
         transform = glm::scale(transform, glm::vec3(scaleAmount, scaleAmount, scaleAmount));

src/1.getting_started/6.1.coordinate_systems/coordinate_systems.cpp

@@ -170,9 +170,9 @@ int main()
         ourShader.use();
       
         // create transformations
-        glm::mat4 model;
-        glm::mat4 view;
-        glm::mat4 projection;
+        glm::mat4 model         = glm::mat4(1.0f); // make sure to initialize matrix to identity matrix first
+        glm::mat4 view          = glm::mat4(1.0f);
+        glm::mat4 projection    = glm::mat4(1.0f);
         model = glm::rotate(model, glm::radians(-55.0f), glm::vec3(1.0f, 0.0f, 0.0f));
         view  = glm::translate(view, glm::vec3(0.0f, 0.0f, -3.0f));
         projection = glm::perspective(glm::radians(45.0f), (float)SCR_WIDTH / (float)SCR_HEIGHT, 0.1f, 100.0f);

src/1.getting_started/6.2.coordinate_systems_depth/coordinate_systems_depth.cpp

@@ -202,9 +202,9 @@ int main()
         ourShader.use();
 
         // create transformations
-        glm::mat4 model;
-        glm::mat4 view;
-        glm::mat4 projection;
+        glm::mat4 model         = glm::mat4(1.0f); // make sure to initialize matrix to identity matrix first
+        glm::mat4 view          = glm::mat4(1.0f);
+        glm::mat4 projection    = glm::mat4(1.0f);
         model = glm::rotate(model, (float)glfwGetTime(), glm::vec3(0.5f, 1.0f, 0.0f));
         view  = glm::translate(view, glm::vec3(0.0f, 0.0f, -3.0f));
         projection = glm::perspective(glm::radians(45.0f), (float)SCR_WIDTH / (float)SCR_HEIGHT, 0.1f, 100.0f);

src/1.getting_started/6.3.coordinate_systems_multiple/coordinate_systems_multiple.cpp

@@ -215,8 +215,8 @@ int main()
         ourShader.use();
 
         // create transformations
-        glm::mat4 view;
-        glm::mat4 projection;
+        glm::mat4 view          = glm::mat4(1.0f); // make sure to initialize matrix to identity matrix first
+        glm::mat4 projection    = glm::mat4(1.0f);
         projection = glm::perspective(glm::radians(45.0f), (float)SCR_WIDTH / (float)SCR_HEIGHT, 0.1f, 100.0f);
         view       = glm::translate(view, glm::vec3(0.0f, 0.0f, -3.0f));
         // pass transformation matrices to the shader
@@ -228,7 +228,7 @@ int main()
         for (unsigned int i = 0; i < 10; i++)
         {
             // calculate the model matrix for each object and pass it to shader before drawing
-            glm::mat4 model;
+            glm::mat4 model = glm::mat4(1.0f);
             model = glm::translate(model, cubePositions[i]);
             float angle = 20.0f * i;
             model = glm::rotate(model, glm::radians(angle), glm::vec3(1.0f, 0.3f, 0.5f));

src/1.getting_started/7.1.camera_circle/camera_circle.cpp

@@ -220,7 +220,7 @@ int main()
         ourShader.use();
 
         // camera/view transformation
-        glm::mat4 view;
+        glm::mat4 view = glm::mat4(1.0f); // make sure to initialize matrix to identity matrix first
         float radius = 10.0f;
         float camX   = sin(glfwGetTime()) * radius;
         float camZ   = cos(glfwGetTime()) * radius;
@@ -232,7 +232,7 @@ int main()
         for (unsigned int i = 0; i < 10; i++)
         {
             // calculate the model matrix for each object and pass it to shader before drawing
-            glm::mat4 model;
+            glm::mat4 model = glm::mat4(1.0f);
             model = glm::translate(model, cubePositions[i]);
             float angle = 20.0f * i;
             model = glm::rotate(model, glm::radians(angle), glm::vec3(1.0f, 0.3f, 0.5f));

src/1.getting_started/7.2.camera_keyboard_dt/camera_keyboard_dt.cpp

@@ -243,7 +243,7 @@ int main()
         for (unsigned int i = 0; i < 10; i++)
         {
             // calculate the model matrix for each object and pass it to shader before drawing
-            glm::mat4 model;
+            glm::mat4 model = glm::mat4(1.0f); // make sure to initialize matrix to identity matrix first
             model = glm::translate(model, cubePositions[i]);
             float angle = 20.0f * i;
             model = glm::rotate(model, glm::radians(angle), glm::vec3(1.0f, 0.3f, 0.5f));

src/1.getting_started/7.3.camera_mouse_zoom/camera_mouse_zoom.cpp

@@ -256,7 +256,7 @@ int main()
         for (unsigned int i = 0; i < 10; i++)
         {
             // calculate the model matrix for each object and pass it to shader before drawing
-            glm::mat4 model;
+            glm::mat4 model = glm::mat4(1.0f); // make sure to initialize matrix to identity matrix first
             model = glm::translate(model, cubePositions[i]);
             float angle = 20.0f * i;
             model = glm::rotate(model, glm::radians(angle), glm::vec3(1.0f, 0.3f, 0.5f));

src/1.getting_started/7.4.camera_class/camera_class.cpp

@@ -251,7 +251,7 @@ int main()
         for (unsigned int i = 0; i < 10; i++)
         {
             // calculate the model matrix for each object and pass it to shader before drawing
-            glm::mat4 model;
+            glm::mat4 model = glm::mat4(1.0f); // make sure to initialize matrix to identity matrix first
             model = glm::translate(model, cubePositions[i]);
             float angle = 20.0f * i;
             model = glm::rotate(model, glm::radians(angle), glm::vec3(1.0f, 0.3f, 0.5f));