无法在D2D1中旋转对象

Question

我是新来的直接2D和有点迷失。我试图旋转一个物体，但我所做的方式，它是旋转整个游戏屏幕，而不是仅仅一个物体。我不知道如何接近旋转只是特定的物体。我希望我已经提供了足够的信息，但如果没有，请告诉我。如果这是个愚蠢的简单问题，我很抱歉。任何帮助都将不胜感激。

void SpriteSheet::Draw(bool rotate)
{

ID2D1Effect *chromakeyEffect = NULL;
ID2D1Effect *scaleit = NULL;
ID2D1Effect * rotation = NULL;

D2D1_POINT_2F ptss = { 50, 50 };
D2D1_VECTOR_3F vec{ -5.0f, -500.0f, 100.0f };


D2D1_VECTOR_3F vector{ 0.0f, 1.0f, 0.0f };

// this is the rotating part
if (rotate)
{
    //D2D1::Matrix3x2F::Identity()._11;
    gfx->GetRenderTarget()->SetTransform(
        D2D1::Matrix3x2F::Rotation(20, D2D1::Point2F(100, 100)));
}



gfx->GetDeviceContext()->CreateEffect(CLSID_D2D1ChromaKey, &chromakeyEffect);
gfx->GetDeviceContext()->CreateEffect(CLSID_D2D1Scale, &scaleit);
gfx->GetDeviceContext()->CreateEffect(CLSID_D2D12DAffineTransform, &rotation);

// applying chroma key
chromakeyEffect->SetInput(0, bmp);
chromakeyEffect->SetValue(D2D1_CHROMAKEY_PROP_COLOR, vector);
chromakeyEffect->SetValue(D2D1_CHROMAKEY_PROP_TOLERANCE, 0.8f);
chromakeyEffect->SetValue(D2D1_CHROMAKEY_PROP_INVERT_ALPHA, false);
chromakeyEffect->SetValue(D2D1_CHROMAKEY_PROP_FEATHER, false);

// scale the object
scaleit->SetInputEffect(0, chromakeyEffect);
//scaleit->SetValue(D2D1_SCALE_PROP_BORDER_MODE, vec);
//scaleit->SetValue(D2D1_SCALE_PROP_CENTER_POINT, D2D1::Vector2F(1.0f, 1.0f));
scaleit->SetValue(D2D1_SCALE_PROP_SCALE, D2D1::Vector2F(0.50f, 0.50f));

// draw it on screen
gfx->GetDeviceContext()->DrawImage(scaleit, ptss);

if (chromakeyEffect) chromakeyEffect->Release();        
}

Answer 1

刚刚遇到了旋转矩阵，这解决了这个问题。我采用了比例效应，并对其进行旋转。

if(rotate)
{
    rotation->SetInputEffect(0, scaleit);
    D2D1_MATRIX_3X2_F matrix = D2D1::Matrix3x2F::Rotation(98, D2D1::Point2F(50, 40));

    rotation->SetValue(D2D1_2DAFFINETRANSFORM_PROP_TRANSFORM_MATRIX, matrix);
}