Keypressing at the same time
Author
Hi, I'm just trying to make a box move with gdi and c++. I want to make it so when I push up and left to go diagonal. I have it now it the Window procedure. I saw a thread here just the other day about that but I can't find it. I was thinking about using direct input but I can't find any good tutorials. If anyone has any good info it will be greatly appreciated, thanks.
Author
Is there a better way than to check if the keys are pressed than putting it in the Window Procedure. It seems once I press a key and then press another one the first one isn't pressed anymore. And what about calling the WM_PAINT message after a key has been pressed with InvalidateRect(), is there a better way of doing this?
You could store the keypresses in a char keys[256] array, so that the WM_KEYDOWN/UP message sets the byte to 1 or 0 respectively. This way, you process the key states after the message loop, essentially keeping your own buffer of input. You can query any of the buffered states by checking the array; so if (keys[VK_DOWN] && keys[VK_RIGHT]) should report a diagonal press.
As the other guy said, look up GetKeyState or GetAsyncKeyState on MSDN. Both functions will return 1 in the high-word if the key is down and 0 if it's up. It's as easy as that!
Of course, an array of bool keys[?] and updating in WM_KEYDOWN are better if you want to check the keystate every frame.
Of course, an array of bool keys[?] and updating in WM_KEYDOWN are better if you want to check the keystate every frame.
Author
This is how I am doing it, but it seems when I press a key and hold it down, and then press another one the first key isnt pressed any more. If I made an array wouldn't that do the same thing?
void CheckKeys(void){ if(GetAsyncKeyState(VK_UP)){ BoxY -= 1; BoxHeight -= 1; } if(GetAsyncKeyState(VK_DOWN)){ BoxY += 1; BoxHeight += 1; } if(GetAsyncKeyState(VK_LEFT)){ BoxX -= 1; BoxWidth -= 1; } if(GetAsyncKeyState(VK_RIGHT)){ BoxX += 1; BoxWidth += 1; }}case WM_PAINT: HDC hdc; PAINTSTRUCT ps; RECT Client; hdc = BeginPaint(hWnd, &ps); GetClientRect(hWnd, &Client); FillRect(hdc, &Client, (HBRUSH) (COLOR_WINDOW+1)); Rectangle(hdc, BoxX, BoxY, BoxWidth, BoxHeight); char buf[256]; sprintf(buf, "X=%d \n Y=%d", BoxX, BoxY); TextOut(hdc, 10, 10, buf, strlen(buf)); EndPaint(hWnd, &ps); return 0; break; case WM_KEYDOWN: CheckKeys(); InvalidateRect(hWnd, NULL, NULL); return 0; break;
Here's a simplified snippet of code from Manta-X
I get full motion with that - I can hold keys down together and it works fine.
///// From WndProccase WM_KEYDOWN:{ m_gameData->keys[wParam] = true;return 0;}case WM_KEYUP:{ m_gameData->keys[wParam] = false; return 0;}/////// In game loopif (m_gameData->keys[ VK_RIGHT ] == true){ m_gameData->playerShip->position.x += 1;}if (m_gameData->keys[ VK_UP ] == true){ m_gameData->playerShip->position.z -= 1;}I get full motion with that - I can hold keys down together and it works fine.
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