在DirectX中簡單剪裁9

Question

我對Directx9中的簡單剪裁感興趣。 在最上面的圖片，你看到我得到。 我想在不改變座標和/或視口的情況下獲取底部圖片上的內容。 意思是說，我會繪製整個圓圈，但DirectX9會將其剪下。

剪輯矩形會在WINDOW座標中給出，所以它不會受到當前狀態轉換的影響。 此外，它應該影響從現在開始到窗口的所有內容，包括多邊形，精靈，紋理，文本等。

somone可以建議如何做到這一點？

Answer 1

你正在描述一種內置於directx設備中的剪刀測試。

見Scissor Test

更具體地說，您只需設置在屏幕的矩形座標使用SetScissorRect

，然後通過調用

device->SetRenderState(D3DRS_SCISSORTESTENABLE , TRUE); 

Answer 2

我一個月前有同樣的問題，我試圖找到一個裁剪方法後，想出了一個解決辦法我自己，所以我不得不開發自己的...這應該工作：

void Clip(LPDIRECT3DDEVICE9 device, LPDIRECT3DSURFACE9 surface, LPDIRECT3DSURFACE9 backbuffer, int x, int y, int width, int height, int destX, int destY, int destWidth, int destHeight) 
{ 
    RECT source; 

    if (x >= destX && (x+width) <= (destX+destWidth)) 
    { 
     source.left = 0; 
     source.right = width; 
    } 
    else if ((x >= destX && x <= (destX+destWidth)) && ((x+width) > (destX+destWidth))) 
    { 
     source.left = 0; 
     source.right = width - ((x+width) - (destX+destWidth)); 
     source.right = abs(source.right); 
    } 
    else if (x < destX && (x+width) < (destX+destWidth)) 
    { 
     source.left = abs(x); 
     source.right = width; 
    } 
    else if ((x < destX) && ((x+width) > (destX+destWidth))) 
    { 
     source.left = abs(x); 
     source.right = source.left + (destWidth); 
    } 
    else 
    { 
     return; 
    } 


    if (y >= destY && (y+height) <= (destY+destHeight)) 
    { 
     source.top = 0; 
     source.bottom = height; 
    } 
    else if ((y >= destY && y <= (destY+destHeight)) && ((y+height) > (destY+destHeight))) 
    { 
     source.top = 0; 
     source.bottom = height - ((y+height) - (destY+destHeight)); 
     source.bottom = abs(source.bottom); 
    } 
    else if (y < destY && (y+height) > destY && (y+height) <= (destY+destHeight)) 
    { 
     source.top = abs(y); 
     source.bottom = height; 
    } 
    else if ((y < destY) && ((y+height) > (destY+destHeight))) 
    { 
     source.top = abs(y);  
     source.bottom = source.top + (destHeight); 
    } 
    else 
    { 
     return; 
    } 


    RECT destination; 

    if (x >= destX && (x+width) <= (destX+destWidth)) 
    { 
     destination.left = x; 
     destination.right = x + width; 
    } 
    else if ((x >= destX && x <= (destX+destWidth)) && ((x+width) > (destX+destWidth))) 
    { 
     destination.left = x; 
     destination.right = (destX+destWidth); 
    } 
    else if ((x < destX) && ((x+width) < (destX+destWidth)) && ((x+width) >= x)) 
    { 
     destination.left = destX; 
     destination.right = width - abs(x); 
    } 
    else if ((x < destX) && ((x+width) > (destX+destWidth))) 
    { 
     destination.left = destX; 
     destination.right = (destX+destWidth); 
    } 
    else 
    { 
     return; 
    } 

    if (y >= destY && (y+height) <= (destY+destHeight)) 
    { 
     destination.top = y; 
     destination.bottom = y + height; 
    } 
    else if ((y >= destY && y <= (destY+destHeight)) && (y+height) > (destY+destHeight)) 
    { 
     destination.top = y; 
     destination.bottom = (destY+destHeight); 
    } 
    else if (y < destY && (y+height) > destY && (y+height) <= (destY+destHeight)) 
    { 
     destination.top = destY; 
     destination.bottom = height - abs(y); 
    } 
    else if ((y < destY) && ((y+height) > (destY+destHeight))) 
    { 
     destination.top = destY; 
     destination.bottom = (destY+destHeight); 
    } 
    else 
    { 
     return; 
    } 

    device->StretchRect(surface, &source, backbuffer, &destination, D3DTEXF_NONE);  

    DeleteObject(&source); 
    DeleteObject(&destination); 
};