我在DirectX 11中渲染样条线,但我遇到了一个问题,它似乎被卡在屏幕空间中,我不能说服它在世界空间中。
样条曲线最初定义为控制点的std::vector<DirectX::XMFLOAT3>
,它被扩展为样条曲线上称为linePoints
的实际点的矢量。然后在此函数中创建顶点、索引和常量缓冲区:
void Spline::createBuffers(ID3D11Device* device)
{
Vertex vertices[100];
for (int i = 0; i < 100; i++)
{
Vertex v;
v.position = linePoints.at(i);
v.colour = XMFLOAT4(0, 0, 0, 1.0);
vertices[i] = v;
}
D3D11_BUFFER_DESC bd;
ZeroMemory(&bd, sizeof(D3D11_BUFFER_DESC));
bd.Usage = D3D11_USAGE_DEFAULT;
bd.ByteWidth = sizeof(Vertex) * linePoints.size();
bd.BindFlags = D3D11_BIND_VERTEX_BUFFER;
bd.CPUAccessFlags = 0;
D3D11_SUBRESOURCE_DATA InitData;
ZeroMemory(&InitData, sizeof(InitData));
InitData.pSysMem = vertices;
device->CreateBuffer(&bd, &InitData, &vertexBuffer);
ZeroMemory(&bd, sizeof(D3D11_BUFFER_DESC));
bd.Usage = D3D11_USAGE_DEFAULT;
bd.CPUAccessFlags = 0;
bd.ByteWidth = sizeof(WORD) * linePoints.size();
bd.BindFlags = D3D11_BIND_INDEX_BUFFER;
WORD indices[200];
int count = 0;
for (WORD i = 0; i < 100; i++)
{
indices[count] = i;
indices[count + 1] = i + 1;
count += 2;
}
ZeroMemory(&InitData, sizeof(InitData));
InitData.pSysMem = indices;
device->CreateBuffer(&bd, &InitData, &indexBuffer);
ZeroMemory(&bd, sizeof(bd));
bd.Usage = D3D11_USAGE_DEFAULT;
bd.ByteWidth = sizeof(LineCBuffer);
bd.BindFlags = D3D11_BIND_CONSTANT_BUFFER;
bd.CPUAccessFlags = 0;
device->CreateBuffer(&bd, nullptr, &constBuffer);
}
绘制函数为:
void Spline::Draw(ID3D11PixelShader* pShader, ID3D11VertexShader* vShader, Camera& cam)
{
context->IASetPrimitiveTopology(D3D11_PRIMITIVE_TOPOLOGY_LINESTRIP);
context->VSSetShader(vShader, nullptr, 0);
context->PSSetShader(pShader, nullptr, 0);
LineCBuffer lCB;
lCB.world = XMMatrixIdentity();
lCB.view = XMMatrixTranspose(cam.getView());
lCB.projection = XMMatrixTranspose(cam.getProjection());
context->UpdateSubresource(constBuffer, 0, nullptr, &lCB, 0, 0);
context->VSSetConstantBuffers(0, 1, &constBuffer);
UINT stride = sizeof(Vertex);
UINT offset = 0;
context->IASetVertexBuffers(0, 1, &vertexBuffer, &stride, &offset);
context->IASetIndexBuffer(indexBuffer, DXGI_FORMAT_R16_UINT, 0);
context->DrawIndexed(100, 0, 0);
context->IASetPrimitiveTopology(D3D11_PRIMITIVE_TOPOLOGY_TRIANGLELIST);
}
整个着色器文件是:
cbuffer lineCBuffer : register(b0)
{
matrix World;
matrix View;
matrix Projection;
};
struct VS_IN
{
float3 position : POSITION;
float4 colour : COLOUR;
};
struct VS_OUT
{
float4 pos : SV_POSITION;
float4 colour : COLOUR;
};
VS_OUT lineVertexShader(float3 position : POSITION, float4 colour : COLOUR)
{
VS_OUT output = (VS_OUT)0;
output.pos = mul(position, World);
output.pos = mul(output.pos, View);
output.pos = mul(output.pos, Projection);
output.pos.w = 1.0f;
output.colour = colour;
return output;
}
float4 linePixelShader(VS_OUT input) : SV_TARGET
{
return input.colour;
}
问题是线的起点(尤其是设置为(0,0,0)时)被锚定到视口。当开始时,如果线位于(0,0,0),它将不会离开屏幕的中心,即使它应该在屏幕外。
1条答案
按热度按时间ny6fqffe1#
我想你的乘法运算出了问题。
使用float 3作为位置输入。位置是Point,所以应该使用
作为3D空间中的点。如果你的float 3是一个向量,你创建一个
所以你的顶点着色器应该看起来像下面这样:
还有一件事不要将位置w设置为1!光栅化器自动对SV_POSITION值进行透视分割。然后将同质值传递到像素着色器。有时你真的想设置z和w为1,也许你的立方体贴图渲染在最大距离。但我认为这是另一个错误。
当你不需要在额外的乘法中使用世界、视图和投影时,为什么不在CPU上预先计算它,然后将最终的worldViewProj矩阵推送到你的着色器?
祝你好运