更新：02 - UI State - 完成UIState的测试。

Author: zeroxer

src/main.cpp

@@ -8,6 +8,17 @@ SDL_Surface *screen;
 int screen_width = 640;
 int screen_height = 480;
 
+struct UIState
+{
+    int mousex;
+    int mousey;
+    int mousedown;
+
+    int hotitem;
+    int activeitem;
+}
+uistate = {0, 0, 0, 0, 0};
+
 // Simplified interface to SDL_
 void drawrect(int x, int y, int w, int h, int color)
 {
@@ -27,8 +38,9 @@ void render()
     // Clear the screen.
     drawrect(0, 0, screen_width, screen_height, 0);
 
-    // Draw a rectangle.
-    drawrect(64, 48, 64, 48, 0xff);
+    // Test the uistate is working.
+    drawrect(uistate.mousex - 32, uistate.mousey - 24, 
+            64, 48, 0xff << (uistate.mousedown * 8));
 
     // Tell SDL to update the whole screen
     SDL_UpdateWindowSurface(window);
@@ -78,17 +90,45 @@ int main(int argc, char *argv[])
         {
             switch (event.type)
             {
+                // Update mouse position.
+                case SDL_MOUSEMOTION:
+                {
+                    uistate.mousex = event.motion.x;
+                    uistate.mousey = event.motion.y;
+                } break;
+
+                // Update button down state if left-clicking.
+                case SDL_MOUSEBUTTONDOWN:
+                {
+                    if (event.button.button == 1 )
+                    {
+                        uistate.mousedown = 1;
+                    }
+                } break;
+
+                // Update button down state if left-clicking.
+                case SDL_MOUSEBUTTONUP:
+                {
+                    if (event.button.button == 1)
+                    {
+                        uistate.mousedown = 0;
+                    }
+                } break;
+
                 case SDL_KEYDOWN:
                 {
 
                 } break;
 
                 case SDL_KEYUP:
                 {
-                    // If escape is pressed, return (and thus, quit)
-                    if (event.key.keysym.sym == SDLK_ESCAPE)
+                    switch (event.key.keysym.sym)
                     {
-                        return 0;
+                        // If escape is pressed, return (and thus, quit)
+                        case SDLK_ESCAPE:
+                        {
+                            return 0;
+                        }
                     }
                 } break;