當SDL不具備焦點時，SDL不停止移動鼠標 - SDL C++

Question

我希望我的遊戲引擎能夠停止將鼠標移動到中心（用於偏航和俯仰相機計算）。我寫了一些應該照顧它的代碼，但鼠標在最小化時仍然移動。

void mainLoop() 
{ 
    // This is the main logic portion of the engine 
    bool done = false; 
    bool visible = true; 
    SDL_Event event; 

    // Check to make sure we are supposed to quit 
    while(! done) 
    { 
     // Check for SDL events 
     while(SDL_PollEvent(& event)) 
     { 
      // Figure out which event the user has triggered 
      switch (event.type) 
      { 
       case SDL_QUIT : 
        done = true; 
        break; 
       case SDL_ACTIVEEVENT: 
        if(event.active.state & SDL_APPACTIVE) 
        { 
         //If the application is no longer active 
         if(event.active.gain == 0) 
         { 
          visible = false; 
         } 
         else 
         { 
          visible = true; 
         } 
        } 
       case SDL_KEYDOWN : 

        // Check for user input 
        switch(event.key.keysym.sym) 
        { 
         // Escape - end the program 
         case SDLK_ESCAPE : 
          done = true; 
          break; 
         // Plus key - increase the speed of the camera 
         case SDLK_PLUS : 
         case SDLK_KP_PLUS : 
          if(camera.walkSpeed < 20.0f) { camera.walkSpeed += 1.0f; } 
          break; 
         // Minus key - decrease the speed of the camera 
         case SDLK_KP_MINUS : 
         case SDLK_MINUS : 
          if(camera.walkSpeed > 2.0f) {camera.walkSpeed -= 1.0f; } 
          break; 
         // F1 - save a TGA screenshot 
         case SDLK_F1: 
          saveScreenshot(); 
          break; 
         // All other unassigned keys 
         default: 
          break; 
        } 
      } 
     } 
     // All events have been handled, now handle logic and rendering 
     if(visible) 
     { 
      updateFrame(); 
      renderFrame(); 
     } 
    } 
} 

當應用程序失去焦點時，它應該將可見標誌設置爲false，從而停止更新和渲染功能。有任何想法嗎？

Answer 1

試試這個：

#include <SDL.h> 
#include <iostream> 

using namespace std; 

int main(int argc, char** argv) 
{ 
    SDL_Init(SDL_INIT_EVERYTHING); 
    SDL_SetVideoMode(640, 480, 32, SDL_ANYFORMAT); 

    bool visible = true; 
    bool done = false; 
    while(!done) 
    { 
     SDL_Event event; 
     while(SDL_PollEvent(& event)) 
     { 
      switch (event.type) 
      { 
      case SDL_QUIT : 
       done = true; 
       break; 
      case SDL_ACTIVEEVENT: 
       if(event.active.state & SDL_APPACTIVE || 
        event.active.state & SDL_APPINPUTFOCUS) 
       { 
        visible = (event.active.gain == 1); 
       } 
      } 
     } 

     if(visible) 
     { 
      static unsigned int frame = 0; 
      frame++; 
      cout << "frame: " << frame << endl; 
     } 

     SDL_Delay(10); 
    } 

    SDL_Quit(); 
    return 0; 
} 

您需要的除了檢查SDL_APPINPUTFOCUS到SDL_APPACTIVE。