From d1eab0d16fadb572f797f345df26fef8d1d1a0a6 Mon Sep 17 00:00:00 2001
From: Michael Zhang <mail@mzhang.io>
Date: Sat, 8 Apr 2023 17:46:57 -0500
Subject: [PATCH] Implement the arrow keys controlling the scaling

---
 assignment-2a/src/HW2a.cpp | 34 +++++++++++++++++++++++++++++-----
 1 file changed, 29 insertions(+), 5 deletions(-)

diff --git a/assignment-2a/src/HW2a.cpp b/assignment-2a/src/HW2a.cpp
index a83bf5e..795e668 100755
--- a/assignment-2a/src/HW2a.cpp
+++ b/assignment-2a/src/HW2a.cpp
@@ -59,6 +59,10 @@ GLint window_width = 500;
 GLint window_height = 500;
 GLdouble pi = 4.0 * atan(1.0);
 
+// Added state
+GLdouble scale_x = 1.0, scale_y = 1.0;
+const GLdouble SCALE_DELTA = 0.05;
+
 GLFWcursor *hand_cursor, *arrow_cursor; // some different cursors
 
 GLint NVERTICES = 9; // part of the hard-coded model
@@ -74,9 +78,25 @@ static void error_callback(int error, const char *description) {
 // keyboard input will be handled
 static void key_callback(GLFWwindow *window, int key, int scancode, int action,
                          int mods) {
-  if (key == GLFW_KEY_ESCAPE &&
-      action == GLFW_PRESS) // checks to see if the escape key was pressed
-    glfwSetWindowShouldClose(window, GL_TRUE); // closes the window
+  // checks to see if the escape key was pressed
+  if ((key == GLFW_KEY_ESCAPE || key == GLFW_KEY_Q) && action == GLFW_PRESS)
+    // closes the window
+    glfwSetWindowShouldClose(window, GL_TRUE);
+
+  // arrow keys control the scaling of the object
+  if (action == GLFW_PRESS || action == GLFW_REPEAT) {
+    if (key == GLFW_KEY_LEFT || key == GLFW_KEY_A)
+      scale_x -= SCALE_DELTA;
+
+    else if (key == GLFW_KEY_RIGHT || key == GLFW_KEY_D)
+      scale_x += SCALE_DELTA;
+
+    else if (key == GLFW_KEY_UP || key == GLFW_KEY_W)
+      scale_y += SCALE_DELTA;
+
+    else if (key == GLFW_KEY_DOWN || key == GLFW_KEY_S)
+      scale_y -= SCALE_DELTA;
+  }
 }
 
 //----------------------------------------------------------------------------
@@ -240,9 +260,13 @@ int main(int argc, char **argv) {
     // define/re-define the modelview matrix. In this template, we define M to
     // be the identity matrix; you will need define M according to the user's
     // actions.
-    for (i = 0; i < 16; i++) {
+    /* for (i = 0; i < 16; i++) {
       M[i] = (i % 5 == 0);
-    }
+    }*/
+    M[0] = scale_x;
+    M[5] = scale_y;
+    M[10] = 1.0;
+    M[15] = 1.0;
 
     // sanity check that your matrix contents are what you expect them to be
     if (DEBUG_ON)