feat: add uniform transform matrix with modifiable elements in main.rs

src/main.rs

@@ -236,6 +236,8 @@ fn main() {
                 .attach_file("./shaders/simple.frag")
                 .link()
         };
+        // get uniform location for the matrix (named `transform` in your vertex shader)
+        let transform_loc = unsafe { simple_shader.get_uniform_location("transform") };
 
         // Used to demonstrate keyboard handling for exercise 2.
         let mut _arbitrary_number = 0.0; // feel free to remove
@@ -298,6 +300,11 @@ fn main() {
 
                 // == // Issue the necessary gl:: commands to draw your scene here
                 simple_shader.activate();
+                // build and send the transform matrix (start from identity)
+                let mut transform = glm::identity();
+                // modify element (0,0) here; change indices to test a, b, c, d, e, f, etc.
+                transform[(0,0)] = elapsed.sin(); 
+                gl::UniformMatrix4fv(transform_loc, 1, gl::FALSE, transform.as_ptr());
                 gl::BindVertexArray(my_vao);
                 gl::DrawElements(
                     gl::TRIANGLES,