我是DirectX的新手。我现在在某种程度上有一个愚蠢的问题。
我使用的是Windows 8.1 DirectX 11.2，我使用的是右手坐标系。
我尝试将纹理应用于x-y平面中的等边三角形，并以（0,0,0）为中心。 但输出形状是扭曲的（它看起来不像等边三角形！）。理论上，如果从x轴看，我什么也看不见，因为等边三角形位于x-y平面。但事实证明，我可以看到三角形。另外，如果我改变法向量的值，输出形状也会改变！我不明白为什么，请帮忙！
以下是视图矩阵配置：
static const XMVECTORF32 eye = { 0.0f, 0.0f, 1.5f, 0.0f };
static const XMVECTORF32 at = { 0.0f, 0.0f, 0.0f, 0.0f };
static const XMVECTORF32 up = { 0.0f, 1.0f, 0.0f, 0.0f };
这是顶点着色器：
cbuffer ModelViewProjectionConstantBuffer : register(b0)
{
matrix model;
matrix view;
matrix projection;
};
struct VertexShaderInput
{
float3 pos : POSITION;
float3 norm : NORMAL;
float2 tex : TEXCOORD0;
};
struct PixelShaderInput
{
float4 pos : SV_POSITION;
float3 norm : NORMAL;
float2 tex : TEXCOORD0;
};
PixelShaderInput main(VertexShaderInput input)
{
PixelShaderInput vertexShaderOutput;
float4 pos = float4(input.pos, 1.0f);
pos = mul(pos, model);
pos = mul(pos, view);
pos = mul(pos, projection);
vertexShaderOutput.pos = pos;
vertexShaderOutput.tex = input.tex;
vertexShaderOutput.norm = mul(float4(normalize(input.norm), 0.0f), model).xyz;
return vertexShaderOutput;
}
这是pixelshader：
Texture2D Texture : register(t0);
SamplerState Sampler : register(s0);
struct PixelShaderInput
{
float4 pos : SV_POSITION;
float3 norm : NORMAL;
float2 tex : TEXCOORD0;
};
float4 main(PixelShaderInput input) : SV_TARGET
{
float3 lightDirection = normalize(float3(0, 0, -1));
return Texture.Sample(Sampler, input.tex); //* (0.8f * saturate(dot(normalize(input.norm), -lightDirection)) + 0.2f);
}
这是坐标：
VertexPositionTexture vertexPositionTexture[] =
{
{ XMFLOAT3(-1.5, -0.5*sqrtf(3), 0.0f), XMFLOAT3(0.0f, 0.0f, 0.4f), XMFLOAT2(0.0, 1.0) },
{ XMFLOAT3(0.0f, sqrtf(3), 0.0f), XMFLOAT3(0.0f, 0.0f, 0.4f), XMFLOAT2(0.5, 0.0) },
{ XMFLOAT3(1.5, -0.5*sqrtf(3), 0.0f), XMFLOAT3(0.0f, 0.0f, 0.4f), XMFLOAT2(1.0, 1.0) },
}
索引数组按顺时针顺序只是{0,1,2}。
因此，如果我将vertexPositionTexture XMFLOAT3（0.0,0.0,0.4）中的法线向量值更改为XMFLOAT3（0.0,0.0，-1），则形状肯定会发生变化。我不知道为什么？
以下是我创建DeviceDependentResources的方法：
void TextureSceneRenderer::CreateDeviceDependentResources()
{
// Load shaders asynchronously.
auto loadVSTask = DX::ReadDataAsync(L"TextureVertexShader.cso");
auto loadPSTask = DX::ReadDataAsync(L"TexturePixelShader.cso");
BasicLoader^ loader = ref new BasicLoader(m_deviceResources->GetD3DDevice());
loader->LoadTexture(
L"cat.dds",
&m_texture,
&m_textureSRV
);
// create the sampler
D3D11_SAMPLER_DESC samplerDesc;
ZeroMemory(&samplerDesc, sizeof(D3D11_SAMPLER_DESC));
samplerDesc.Filter = D3D11_FILTER_ANISOTROPIC;
samplerDesc.AddressU = D3D11_TEXTURE_ADDRESS_WRAP;
samplerDesc.AddressV = D3D11_TEXTURE_ADDRESS_WRAP;
samplerDesc.AddressW = D3D11_TEXTURE_ADDRESS_WRAP;
samplerDesc.MipLODBias = 0.0f;
// use 4x on feature level 9.2 and above, otherwise use only 2x
samplerDesc.MaxAnisotropy = 8;
samplerDesc.ComparisonFunc = D3D11_COMPARISON_NEVER;
samplerDesc.BorderColor[0] = 0.0f;
samplerDesc.BorderColor[1] = 0.0f;
samplerDesc.BorderColor[2] = 0.0f;
samplerDesc.BorderColor[3] = 0.0f;
// allow use of all mip levels
samplerDesc.MinLOD = 0;
samplerDesc.MaxLOD = D3D11_FLOAT32_MAX;
DX::ThrowIfFailed(
m_deviceResources->GetD3DDevice()->CreateSamplerState(
&samplerDesc,
&m_sampler)
);
// After the vertex shader file is loaded, create the shader and input layout.
auto createVSTask = loadVSTask.then([this](const std::vector<byte>& fileData) {
DX::ThrowIfFailed(
m_deviceResources->GetD3DDevice()->CreateVertexShader(
&fileData[0],
fileData.size(),
nullptr,
&m_vertexShader
)
);
static const D3D11_INPUT_ELEMENT_DESC vertexDesc[] =
{
{ "POSITION", 0, DXGI_FORMAT_R32G32B32_FLOAT, 0, 0, D3D11_INPUT_PER_VERTEX_DATA, 0 },
{ "NORMAL", 0, DXGI_FORMAT_R32G32B32_FLOAT, 0, 12, D3D11_INPUT_PER_VERTEX_DATA, 0 },
{ "TEXCOORD", 0, DXGI_FORMAT_R32G32_FLOAT, 0, 24, D3D11_INPUT_PER_VERTEX_DATA, 0 },
};
DX::ThrowIfFailed(
m_deviceResources->GetD3DDevice()->CreateInputLayout(
vertexDesc,
ARRAYSIZE(vertexDesc),
&fileData[0],
fileData.size(),
&m_inputLayout
)
);
});
// After the pixel shader file is loaded, create the shader and constant buffer.
auto createPSTask = loadPSTask.then([this](const std::vector<byte>& fileData) {
DX::ThrowIfFailed(
m_deviceResources->GetD3DDevice()->CreatePixelShader(
&fileData[0],
fileData.size(),
nullptr,
&m_pixelShader
)
);
CD3D11_BUFFER_DESC constantBufferDesc(sizeof(ModelViewProjectionConstantBuffer), D3D11_BIND_CONSTANT_BUFFER);
DX::ThrowIfFailed(
m_deviceResources->GetD3DDevice()->CreateBuffer(
&constantBufferDesc,
nullptr,
&m_constantBuffer
)
);
});
// Once both shaders are loaded, create the mesh.
auto createCubeTask = (createPSTask && createVSTask).then([this]() {
D3D11_SUBRESOURCE_DATA vertexBufferData = { 0 };
vertexBufferData.pSysMem = this->model->getVertexPositionTexture();
vertexBufferData.SysMemPitch = 0;
vertexBufferData.SysMemSlicePitch = 0;
CD3D11_BUFFER_DESC vertexBufferDesc(sizeof(this->model- >getVertexPositionTexture()[0])*this->model->n_texture_vertex, D3D11_BIND_VERTEX_BUFFER);
DX::ThrowIfFailed(
m_deviceResources->GetD3DDevice()->CreateBuffer(
&vertexBufferDesc,
&vertexBufferData,
&m_vertexBuffer
)
);
m_indexCount = this->model->n_mesh;//ARRAYSIZE(cubeIndices);
D3D11_SUBRESOURCE_DATA indexBufferData = { 0 };
indexBufferData.pSysMem = this->model->getMeshTextureIndex();
indexBufferData.SysMemPitch = 0;
indexBufferData.SysMemSlicePitch = 0;
CD3D11_BUFFER_DESC indexBufferDesc(sizeof(this->model->getMeshTextureIndex()[0])*m_indexCount, D3D11_BIND_INDEX_BUFFER);
DX::ThrowIfFailed(
m_deviceResources->GetD3DDevice()->CreateBuffer(
&indexBufferDesc,
&indexBufferData,
&m_indexBuffer
)
);
});
// Once the cube is loaded, the object is ready to be rendered.
createCubeTask.then([this]() {
m_loadingComplete = true;
});
}
这是渲染功能：
void TextureSceneRenderer::Render()
{
// Loading is asynchronous. Only draw geometry after it's loaded.
if (!m_loadingComplete)
{
return;
}
auto context = m_deviceResources->GetD3DDeviceContext();
// Set render targets to the screen.
ID3D11RenderTargetView *const targets[1] = { m_deviceResources->GetBackBufferRenderTargetView() };
context->OMSetRenderTargets(1, targets, m_deviceResources->GetDepthStencilView());
// Prepare the constant buffer to send it to the graphics device.
context->UpdateSubresource(
m_constantBuffer.Get(),
0,
NULL,
&m_constantBufferData,
0,
0
);
// Each vertex is one instance of the VertexPositionColor struct.
UINT stride = sizeof(VertexPositionColor);
UINT offset = 0;
context->IASetVertexBuffers(
0,
1,
m_vertexBuffer.GetAddressOf(),
&stride,
&offset
);
context->IASetIndexBuffer(
m_indexBuffer.Get(),
DXGI_FORMAT_R16_UINT, // Each index is one 16-bit unsigned integer (short).
0
);
context->IASetPrimitiveTopology(D3D11_PRIMITIVE_TOPOLOGY_TRIANGLELIST);
context->IASetInputLayout(m_inputLayout.Get());
// Attach our vertex shader.
context->VSSetShader(
m_vertexShader.Get(),
nullptr,
0
);
// Send the constant buffer to the graphics device.
context->VSSetConstantBuffers(
0,
1,
m_constantBuffer.GetAddressOf()
);
// Attach our pixel shader.
context->PSSetShader(
m_pixelShader.Get(),
nullptr,
0
);
context->PSSetShaderResources(
0,
1,
m_textureSRV.GetAddressOf()
);
context->PSSetSamplers(
0, // starting at the first sampler slot
1, // set one sampler binding
m_sampler.GetAddressOf()
);
// Draw the objects.
context->DrawIndexed(
m_indexCount,
0,
0
);
}