From e415b62a2e85f44e6ff285e08b16525605d2fc0f Mon Sep 17 00:00:00 2001
From: Johnny Richard <johnny@johnnyrichard.com>
Date: Sun, 14 Nov 2021 01:27:15 +0100
Subject: controller_t: Reduce memory usage using bitwise

---
 src/controller.c | 72 ++++++++++++++++++++++++++++++++++++--------------------
 src/controller.h | 22 +++++++++--------
 src/main.c       | 12 +++++-----
 3 files changed, 64 insertions(+), 42 deletions(-)

(limited to 'src')

diff --git a/src/controller.c b/src/controller.c
index 09757c4..4e488e9 100644
--- a/src/controller.c
+++ b/src/controller.c
@@ -38,39 +38,59 @@ controller_update(controller_t *self,
 {
   if (event->type == SDL_KEYDOWN) {
     switch (event->key.keysym.sym) {
-      case SDLK_UP:
-        self->up = true;
-        break;
-      case SDLK_DOWN:
-        self->down = true;
-        break;
-      case SDLK_LEFT:
-        self->left = true;
-        break;
-      case SDLK_RIGHT:
-        self->right = true;
-        break;
+    case SDLK_UP:
+      self->pressed_buttons |= BTN_UP;
+      break;
+    case SDLK_DOWN:
+      self->pressed_buttons |= BTN_DOWN;
+      break;
+    case SDLK_LEFT:
+      self->pressed_buttons |= BTN_LEFT;
+      break;
+    case SDLK_RIGHT:
+      self->pressed_buttons |= BTN_RIGHT;
+      break;
     }
   }
 
   if (event->type == SDL_KEYUP) {
     switch (event->key.keysym.sym) {
-      case SDLK_UP:
-        self->up = false;
-        break;
+    case SDLK_UP:
+      self->pressed_buttons ^= BTN_UP;
+      break;
+    case SDLK_DOWN:
+      self->pressed_buttons ^= BTN_DOWN;
+      break;
+    case SDLK_LEFT:
+      self->pressed_buttons ^= BTN_LEFT;
+      break;
+    case SDLK_RIGHT:
+      self->pressed_buttons ^= BTN_RIGHT;
+      break;
+    }
+  }
+}
 
-      case SDLK_DOWN:
-        self->down = false;
-        break;
+bool
+controller_is_up_pressed(controller_t *self)
+{
+  return self->pressed_buttons & BTN_UP;
+}
 
-      case SDLK_LEFT:
-        self->left = false;
-        break;
+bool
+controller_is_down_pressed(controller_t *self)
+{
+  return self->pressed_buttons & BTN_DOWN;
+}
 
-      case SDLK_RIGHT:
-        self->right = false;
-        break;
-    }
-  }
+bool
+controller_is_right_pressed(controller_t *self)
+{
+  return self->pressed_buttons & BTN_RIGHT;
 }
 
+bool
+controller_is_left_pressed(controller_t *self)
+{
+  return self->pressed_buttons & BTN_LEFT;
+}
diff --git a/src/controller.h b/src/controller.h
index 736b9e6..ecc0389 100644
--- a/src/controller.h
+++ b/src/controller.h
@@ -33,23 +33,25 @@
 
 #include <SDL.h>
 #include <stdbool.h>
+#include <stdint.h>
 
-#ifdef __cplusplus
-extern "C" {
-#endif
+enum btn_t {
+  BTN_UP    = 1 << 0,
+  BTN_DOWN  = 1 << 1,
+  BTN_RIGHT = 1 << 2,
+  BTN_LEFT  = 1 << 3
+};
 
 typedef struct controller_t {
-  bool up;
-  bool down;
-  bool left;
-  bool right;
+  uint8_t pressed_buttons;
 } controller_t;
 
 void controller_update(controller_t *self,
                        SDL_Event    *event);
 
-#ifdef __cplusplus
-}
-#endif
+bool controller_is_up_pressed(controller_t *self);
+bool controller_is_down_pressed(controller_t *self);
+bool controller_is_right_pressed(controller_t *self);
+bool controller_is_left_pressed(controller_t *self);
 
 #endif /* CONTROLLER_H */
diff --git a/src/main.c b/src/main.c
index 2c71864..b8e723b 100644
--- a/src/main.c
+++ b/src/main.c
@@ -74,7 +74,7 @@ main (int   argc,
   SDL_Rect rect = { .x = 0, .y = 0, .w = 20, .h = 20 };
 
   bool quit = false;
-  controller_t controller = {0};
+  controller_t ctrl = {0};
 
   while (!quit) {
     screenSurface = SDL_GetWindowSurface(window);
@@ -89,13 +89,13 @@ main (int   argc,
       if (event.type == SDL_QUIT) {
         quit = true;
       }
-      controller_update(&controller, &event);
+      controller_update(&ctrl, &event);
     }
 
-    if (controller.up)    rect.y -= 1;
-    if (controller.down)  rect.y += 1;
-    if (controller.left)  rect.x -= 1;
-    if (controller.right) rect.x += 1;
+    if (controller_is_up_pressed(&ctrl))    rect.y -= 1;
+    if (controller_is_down_pressed(&ctrl))  rect.y += 1;
+    if (controller_is_left_pressed(&ctrl))  rect.x -= 1;
+    if (controller_is_right_pressed(&ctrl)) rect.x += 1;
 
     SDL_FillRect(
         screenSurface,
-- 
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