Directx11学习笔记【十二】 画一个旋转的彩色立方体

上一次我们学习了如何画一个2D三角形，现在让我们进一步学习如何画一个旋转的彩色立方体吧。

具体流程同画三角形类似，因此不再给出完整代码了，不同的部分会再说明。

 

由于我们要画彩色的立方体，所以顶点结构体中加入颜色变量

struct Vertex
{
    XMFLOAT3 pos;
    XMFLOAT4 color;
};

着色器代码 

 1 cbuffer cbPerObject
 2 {
 3     float4x4 gWorldViewProj; 
 4 };
 5 
 6 struct VertexIn
 7 {
 8     float3 PosL  : POSITION;
 9         float4 Color : COLOR;
10 };
11 
12 struct VertexOut
13 {
14     float4 PosH  : SV_POSITION;
15         float4 Color : COLOR;
16 };
17 
18 VertexOut VS(VertexIn vin)
19 {
20     VertexOut vout;
21     
22     // Transform to homogeneous clip space.
23     vout.PosH = mul(float4(vin.PosL, 1.0f), gWorldViewProj);
24     
25     // Just pass vertex color into the pixel shader.
26         vout.Color = vin.Color;
27     
28         return vout;
29 }
30 
31 float4 PS(VertexOut pin) : SV_Target
32 {
33     return pin.Color;
34 }
35 
36 technique11 ColorTech
37 {
38     pass P0
39     {
40         SetVertexShader( CompileShader( vs_5_0, VS() ) );
41         SetGeometryShader( NULL );
42         SetPixelShader( CompileShader( ps_5_0, PS() ) );
43     }
44 }

定义了一个矩阵gWorldViewProj，后面我们会利用它进行旋转立方体

 

BoxDemo.h

 1 #pragma once
 2 
 3 #include "Dx11DemoBase.h"
 4 #include "d3dx11effect.h"
 5 
 6 class BoxDemo : public Dx11DemoBase
 7 {
 8 public:
 9     BoxDemo();
10     ~BoxDemo();
11 
12     bool LoadContent() override;
13     void UnLoadContent() override;
14 
15     void Update(float dt) override;
16     void Render() override;
17 
18 private:
19     ID3D11Buffer *m_pVertexBuffer;
20     ID3D11Buffer *m_pIndexBuffer;//新增
21     ID3D11InputLayout *m_pInputLayout;
22 
23     ID3DX11Effect *m_pFx;
24     ID3DX11EffectTechnique *m_pTechnique;
25     ID3DX11EffectMatrixVariable *m_pFxWorldViewProj;
26     XMFLOAT4X4 m_world;
27     XMFLOAT4X4 m_view;
28     XMFLOAT4X4 m_proj;
29 
30 };

 

LoadContent()函数

顶点信息及缓冲的创建

 1 Vertex vertices[] =
 2     {        
 3         { XMFLOAT3(-0.5f, -0.5f, -0.5f), XMFLOAT4(255, 255, 255, 1) },//white
 4         { XMFLOAT3(-0.5f, +0.5f, -0.5f), XMFLOAT4(0, 0, 0, 1) },//black
 5         { XMFLOAT3(+0.5f, +0.5f, -0.5f), XMFLOAT4(255, 0, 0, 1) },//red
 6         { XMFLOAT3(+0.5f, -0.5f, -0.5f), XMFLOAT4(0, 255, 0, 1) },//green
 7         { XMFLOAT3(-0.5f, -0.5f, +0.5f), XMFLOAT4(0, 0, 255, 1) },//blue
 8         { XMFLOAT3(-0.5f, +0.5f, +0.5f), XMFLOAT4(255, 255, 0, 1) },//yellow
 9         { XMFLOAT3(+0.5f, +0.5f, +0.5f), XMFLOAT4(0, 255, 255, 1) },//cyan
10         { XMFLOAT3(+0.5f, -0.5f, +0.5f), XMFLOAT4(255, 0, 255, 1) }//magenta
11     };
12 
13 
14     D3D11_BUFFER_DESC vertexDesc;
15     ZeroMemory(&vertexDesc, sizeof(vertexDesc));
16     vertexDesc.Usage = D3D11_USAGE_DEFAULT;
17     vertexDesc.BindFlags = D3D11_BIND_VERTEX_BUFFER;
18     vertexDesc.ByteWidth = sizeof(Vertex)* 8;
19 
20     D3D11_SUBRESOURCE_DATA resourceData;
21     ZeroMemory(&resourceData, sizeof(resourceData));
22     resourceData.pSysMem = vertices;
23     result = m_pd3dDevice->CreateBuffer(&vertexDesc, &resourceData, &m_pVertexBuffer);
24     if (FAILED(result))
25     {
26         return false;
27     }

 

相比三角形，立方体还要定义Index信息，来确定立方体的六个面

 1 UINT indices[] = {
 2         // front face
 3         0, 1, 2,
 4         0, 2, 3,
 5 
 6         // back face
 7         4, 6, 5,
 8         4, 7, 6,
 9 
10         // left face
11         4, 5, 1,
12         4, 1, 0,
13 
14         // right face
15         3, 2, 6,
16         3, 6, 7,
17 
18         // top face
19         1, 5, 6,
20         1, 6, 2,
21 
22         // bottom face
23         4, 0, 3,
24         4, 3, 7
25     };
26 
27     D3D11_BUFFER_DESC indexDesc;
28     ZeroMemory(&indexDesc, sizeof(indexDesc));
29     indexDesc.Usage = D3D11_USAGE_IMMUTABLE;
30     indexDesc.BindFlags = D3D11_BIND_INDEX_BUFFER;
31     indexDesc.ByteWidth = sizeof(UINT)* 36;
32 
33     D3D11_SUBRESOURCE_DATA indexData;
34     ZeroMemory(&indexData, sizeof(indexData));
35     indexData.pSysMem = indices;
36     result = m_pd3dDevice->CreateBuffer(&indexDesc, &indexData, &m_pIndexBuffer);
37     if (FAILED(result))
38     {
39         return false;
40     }

 

定义输入布局

 1 D3D11_INPUT_ELEMENT_DESC solidColorLayout[] =
 2     {
 3         { "POSITION", 0, DXGI_FORMAT_R32G32B32_FLOAT, 0, 0, D3D11_INPUT_PER_VERTEX_DATA, 0 },
 4         { "COLOR", 0, DXGI_FORMAT_R32G32B32_FLOAT, 0, 0, D3D11_INPUT_PER_VERTEX_DATA, 0 }
 5     };
 6     UINT numLayoutElements = ARRAYSIZE(solidColorLayout);
 7     D3DX11_PASS_DESC passDesc;
 8     m_pTechnique->GetPassByIndex(0)->GetDesc(&passDesc);
 9 
10     result = m_pd3dDevice->CreateInputLayout(solidColorLayout, numLayoutElements, passDesc.pIAInputSignature,
11         passDesc.IAInputSignatureSize, &m_pInputLayout);

 

Update()函数----实现旋转

怎么实现立方体的旋转呢？我们之前不是给出了 world,view,proj三个矩阵吗，实现旋转的一种方式就是根据游戏时间旋转相应矩阵(例如world矩阵)。

可以定义一个静态变量表示游戏时间，每一帧运行时更新t值，同时对矩阵作相应旋转即可。

 1 static float t = 0.0f;
 2     t += (float)XM_PI * 0.0125f;
 3     static DWORD dwTimeStart = 0;
 4     DWORD dwTimeCur = GetTickCount();
 5     if (dwTimeStart == 0)
 6         dwTimeStart = dwTimeCur;
 7     t = (dwTimeCur - dwTimeStart) / 1000.0f;
 8 
 9     XMVECTOR pos = XMVectorSet(2.0f, 0.0f, 0.0f, 1.0f);
10     XMVECTOR target = XMVectorSet(0.0f, 0.0f, 0.0f, 1.0f);
11     XMVECTOR up = XMVectorSet(0.0f, 1.0f, 0.0f, 0.0f);
12 
13     XMMATRIX V = XMMatrixLookAtLH(pos, target, up);
14     XMStoreFloat4x4(&m_view, V);
15     XMMATRIX T = XMMatrixPerspectiveFovLH(XM_PIDIV2, m_width / static_cast<float>(m_height),
16         0.01f, 100.0f);
17     XMStoreFloat4x4(&m_proj, T);
18     //根据时间旋转world矩阵
19     XMMATRIX P = XMMatrixRotationY(t);
20     XMStoreFloat4x4(&m_world, P);

 

Render()函数

和之前的代码大部分一样，不同的是要设置IndexBuffer，绘制的时候要用DrawIndexed()而不是Draw().

 1 if (m_pImmediateContext == 0)
 2         return;
 3     //清除渲染目标视图
 4     float clearColor[4] = { 1.0f, 1.0f, 1.0f, 1.0f };//背景颜色
 5     m_pImmediateContext->ClearRenderTargetView(m_pRenderTargetView, clearColor);
 6 
 7     UINT stride = sizeof(Vertex);
 8     UINT offset = 0;
 9     //设置数据信息格式控制信息
10     m_pImmediateContext->IASetInputLayout(m_pInputLayout);
11     //设置要绘制的几何体信息
12     m_pImmediateContext->IASetVertexBuffers(0,1,&m_pVertexBuffer,&stride,&offset);
13     m_pImmediateContext->IASetIndexBuffer(m_pIndexBuffer, DXGI_FORMAT_R32_UINT, 0);
14     //指明如何绘制
15     m_pImmediateContext->IASetPrimitiveTopology(D3D11_PRIMITIVE_TOPOLOGY_TRIANGLELIST);
16 
17     //设置常量 
18     XMMATRIX world = XMLoadFloat4x4(&m_world);
19     XMMATRIX view = XMLoadFloat4x4(&m_view);
20     XMMATRIX proj = XMLoadFloat4x4(&m_proj);
21     XMMATRIX worldViewProj = world*view*proj;
22     m_pFxWorldViewProj->SetMatrix(reinterpret_cast<float*>(&worldViewProj));
23 
24     D3DX11_TECHNIQUE_DESC techDesc;
25     m_pTechnique->GetDesc(&techDesc);
26     for (UINT i = 0; i < techDesc.Passes; ++i)
27     {
28         m_pTechnique->GetPassByIndex(i)->Apply(0, m_pImmediateContext);
29         m_pImmediateContext->DrawIndexed(36, 0, 0);
30     }
31     //马上输出
32     m_pSwapChain->Present(0, 0);

 

这样我们的工作都完成了，运行便可以得到一个旋转的彩色立方体了.

下面是运行的一个截图