From efcf9cfffefd62cac875537024d0029a72a56b76 Mon Sep 17 00:00:00 2001
From: Gregory Eremin <g@erem.in>
Date: Wed, 30 Sep 2015 17:55:40 +0300
Subject: [PATCH] Implement a basic scene class

---
 Makefile                     |  2 +-
 main.cpp => src/breakout.cpp | 61 ++++++++----------------------------
 src/breakout.h               |  6 ++++
 src/scene.cpp                | 38 ++++++++++++++++++++++
 src/scene.h                  | 21 +++++++++++++
 5 files changed, 79 insertions(+), 49 deletions(-)
 rename main.cpp => src/breakout.cpp (53%)
 create mode 100644 src/breakout.h
 create mode 100644 src/scene.cpp
 create mode 100644 src/scene.h

diff --git a/Makefile b/Makefile
index 59fa52c..d8fcb54 100644
--- a/Makefile
+++ b/Makefile
@@ -3,7 +3,7 @@ CC=clang++
 all: build run
 
 build:
-	$(CC) -lSDL2 main.cpp -o breakout
+	$(CC) -lSDL2 src/scene.cpp src/breakout.cpp -o breakout
 
 run:
 	./breakout
diff --git a/main.cpp b/src/breakout.cpp
similarity index 53%
rename from main.cpp
rename to src/breakout.cpp
index 1736d33..f6bebab 100644
--- a/main.cpp
+++ b/src/breakout.cpp
@@ -1,17 +1,7 @@
 #include <iostream>
 #include "SDL2/SDL.h"
-
-#define SCREEN_X 100
-#define SCREEN_Y 100
-#define SCREEN_WIDTH 640
-#define SCREEN_HEIGHT 480
-#define PAD_WIDTH 200
-#define PAD_HEIGHT 20
-
-#define KEY_MOVE_STEP 5
-
-#define BG_COLOR 0, 0, 0, 255
-#define PAD_COLOR 0, 0, 255, 255
+#include "breakout.h"
+#include "scene.h"
 
 int main(int argc, char const *argv[]) {
     if (SDL_Init(SDL_INIT_VIDEO) != 0) {
@@ -43,31 +33,14 @@ int main(int argc, char const *argv[]) {
         return 1;
     }
 
-    // Setting background color to black
-    SDL_SetRenderDrawColor(renderer, BG_COLOR);
-    SDL_RenderClear(renderer);
-
-    // Creat a rect at pos ( 50, 50 ) that's 50 pixels wide and 50 pixels high.
-    SDL_Rect pad = {
-        .x = (SCREEN_WIDTH - PAD_WIDTH) / 2,
-        .y = (SCREEN_HEIGHT - PAD_HEIGHT),
-        .w = PAD_WIDTH,
-        .h = PAD_HEIGHT
-    };
-
-    // Set render color to blue ( rect will be rendered in this color )
-    SDL_SetRenderDrawColor(renderer, PAD_COLOR);
-
-    // Render rect
-    SDL_RenderFillRect(renderer, &pad);
-
-    // Render the rect to the screen
-    SDL_RenderPresent(renderer);
+    Scene scene(window, renderer);
 
     SDL_Event e;
     bool quit = false;
     while (!quit) {
+        bool has_event = false;
         while (SDL_PollEvent(&e)) {
+            has_event = true;
             if (e.type == SDL_QUIT) {
                 quit = true;
             }
@@ -77,31 +50,23 @@ int main(int argc, char const *argv[]) {
                     quit = true;
                     break;
                 case SDLK_LEFT:
-                    pad.x -= KEY_MOVE_STEP;
+                    scene.move_pad_relative(-KEY_MOVE_STEP);
                     break;
                 case SDLK_RIGHT:
-                    pad.x += KEY_MOVE_STEP;
+                    scene.move_pad_relative(KEY_MOVE_STEP);
                     break;
                 }
             }
             if (e.type == SDL_MOUSEMOTION) {
-                pad.x = e.motion.x - PAD_WIDTH / 2;
-            }
-
-            if (pad.x < 0) {
-                pad.x = 0;
-            } else if (pad.x > SCREEN_WIDTH - PAD_WIDTH) {
-                pad.x = SCREEN_WIDTH - PAD_WIDTH;
+                scene.move_pad(e.motion.x - PAD_WIDTH / 2);
             }
         }
 
-        // Re-rendering
-        SDL_SetRenderDrawColor(renderer, BG_COLOR);
-        SDL_RenderClear(renderer);
-        SDL_SetRenderDrawColor(renderer, PAD_COLOR);
-        SDL_RenderFillRect(renderer, &pad);
-        SDL_RenderPresent(renderer);
-        SDL_Delay(1);
+        if (has_event) {
+            scene.render();
+        } else {
+            SDL_Delay(1);
+        }
     }
 
     SDL_DestroyWindow(window);
diff --git a/src/breakout.h b/src/breakout.h
new file mode 100644
index 0000000..7f46f95
--- /dev/null
+++ b/src/breakout.h
@@ -0,0 +1,6 @@
+#define SCREEN_X 300
+#define SCREEN_Y 100
+#define SCREEN_WIDTH 400
+#define SCREEN_HEIGHT 600
+
+#define KEY_MOVE_STEP 5
diff --git a/src/scene.cpp b/src/scene.cpp
new file mode 100644
index 0000000..93bbbbc
--- /dev/null
+++ b/src/scene.cpp
@@ -0,0 +1,38 @@
+#include <iostream>
+#include "SDL2/SDL.h"
+#include "breakout.h"
+#include "scene.h"
+
+Scene::Scene(SDL_Window *w, SDL_Renderer *r) {
+    window = w;
+    renderer = r;
+
+    pad.x = (SCREEN_WIDTH - PAD_WIDTH) / 2;
+    pad.y = (SCREEN_HEIGHT - PAD_HEIGHT);
+    pad.w = PAD_WIDTH;
+    pad.h = PAD_HEIGHT;
+}
+
+Scene::~Scene() {}
+
+void Scene::render() {
+    SDL_SetRenderDrawColor(renderer, BG_COLOR);
+    SDL_RenderClear(renderer);
+    SDL_SetRenderDrawColor(renderer, PAD_COLOR);
+    SDL_RenderFillRect(renderer, &pad);
+    SDL_RenderPresent(renderer);
+}
+
+void Scene::move_pad(int x) {
+    pad.x = x;
+
+    if (pad.x < 0) {
+        pad.x = 0;
+    } else if (pad.x > SCREEN_WIDTH - PAD_WIDTH) {
+        pad.x = SCREEN_WIDTH - PAD_WIDTH;
+    }
+}
+
+void Scene::move_pad_relative(int delta) {
+    move_pad(pad.x + delta);
+}
diff --git a/src/scene.h b/src/scene.h
new file mode 100644
index 0000000..8dfd520
--- /dev/null
+++ b/src/scene.h
@@ -0,0 +1,21 @@
+#define PAD_WIDTH 200
+#define PAD_HEIGHT 20
+
+#define BG_COLOR 0, 0, 0, 255
+#define PAD_COLOR 0, 0, 255, 255
+
+class Scene {
+public:
+    Scene(SDL_Window *w, SDL_Renderer *r);
+    ~Scene();
+
+    void render();
+    void move_pad(int x);
+    void move_pad_relative(int delta);
+private:
+    SDL_Window *window;
+    SDL_Renderer *renderer;
+
+    SDL_Rect pad;
+    SDL_Rect blocks[10];
+};