DirectX:绘制位图图像在视口中放大导致低质量?
问题描述:
我使用DirectX在缓冲区中绘制带有RGB数据的图像。下面是简码:DirectX:绘制位图图像在视口中放大导致低质量?
// create the vertex buffer
D3D11_BUFFER_DESC bd;
ZeroMemory(&bd, sizeof(bd));
bd.Usage = D3D11_USAGE_DYNAMIC; // write access access by CPU and GPU
bd.ByteWidth = sizeOfOurVertices; // size is the VERTEX struct * pW*pH
bd.BindFlags = D3D11_BIND_VERTEX_BUFFER; // use as a vertex buffer
bd.CPUAccessFlags = D3D11_CPU_ACCESS_WRITE; // allow CPU to write in buffer
dev->CreateBuffer(&bd, NULL, &pVBuffer); // create the buffer
//Create Sample for texture
D3D11_SAMPLER_DESC desc;
desc.Filter = D3D11_FILTER_ANISOTROPIC;
desc.MaxAnisotropy = 16;
ID3D11SamplerState *ppSamplerState = NULL;
dev->CreateSamplerState(&desc, &ppSamplerState);
devcon->PSSetSamplers(0, 1, &ppSamplerState);
//Create list vertices from RGB data buffer
pW = bitmapSource->PixelWidth;
pH = bitmapSource->PixelHeight;
OurVertices = new VERTEX[pW*pH];
vIndex = 0;
unsigned char* curP = rgbPixelsBuff;
for (y = 0; y < pH; y++)
{
for (x = 0; x < pW; x++)
{
OurVertices[vIndex].Color.b = *curP++;
OurVertices[vIndex].Color.g = *curP++;
OurVertices[vIndex].Color.r = *curP++;
OurVertices[vIndex].Color.a = *curP++;
OurVertices[vIndex].X = x;
OurVertices[vIndex].Y = y;
OurVertices[vIndex].Z = 0.0f;
vIndex++;
}
}
sizeOfOurVertices = sizeof(VERTEX)* pW*pH;
// copy the vertices into the buffer
D3D11_MAPPED_SUBRESOURCE ms;
devcon->Map(pVBuffer, NULL, D3D11_MAP_WRITE_DISCARD, NULL, &ms); // map the buffer
memcpy(ms.pData, OurVertices, sizeOfOurVertices); // copy the data
devcon->Unmap(pVBuffer, NULL);
// unmap the buffer
// clear the back buffer to a deep blue
devcon->ClearRenderTargetView(backbuffer, D3DXCOLOR(0.0f, 0.2f, 0.4f, 1.0f));
// select which vertex buffer to display
UINT stride = sizeof(VERTEX);
UINT offset = 0;
devcon->IASetVertexBuffers(0, 1, &pVBuffer, &stride, &offset);
// select which primtive type we are using
devcon->IASetPrimitiveTopology(D3D11_PRIMITIVE_TOPOLOGY_POINTLIST);
// draw the vertex buffer to the back buffer
devcon->Draw(pW*pH, 0);
// switch the back buffer and the front buffer
swapchain->Present(0, 0);
当视口的大小小于或等于图像的大小=>一切正常。但是,当视口尺寸较大时,图像的质量非常差。
我已经搜索并尝试使用desc.Filter = D3D11_FILTER_ANISOTROPIC;
作为上述代码(我试图使用D3D11_FILTER_MIN_POINT_MAG_MIP_LINEAR
或D3D11_FILTER_MIN_LINEAR_MAG_MIP_POINT
太),但结果并不会更好。以下图像是显示结果:
非常感谢!
答
您正在使用DirectX将每个像素绘制为一个点。正常情况下,当屏幕尺寸变大时,您的积分会分开,质量会变差。您应该使用填充RGB数据和像素着色器的纹理来绘制纹理四边形。
什么是缩放值?很明显,如果你高档的形象,那么它会看起来模糊。您可能想要使用mipmap? – Asesh
@Asesh:我也尝试过使用D3D11_FILTER_MIN_POINT_MAG_MIP_LINEAR或D3D11_FILTER_MIN_LINEAR_MAG_MIP_POINT,但并不是更好。缩放值为1.2,1.5或任何值,它们总是使图像像上述图像那样出现交叉线。它通常不会看起来模糊。 – TTGroup
你的纹理支持mipmap吗? DDS文件支持mipmap。只使用该过滤器是不够的,你的纹理也应该支持mipmap,否则你将不得不在运行时生成它们。无论如何,应该没有那么多与您使用的缩放比例值截图中所显示的差异。一定有什么问题。 – Asesh