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
cbuffer cbPerObject
{
float4x4 gWorldViewProj;
}; struct VertexIn
{
float3 PosL : POSITION;
float4 Color : COLOR;
}; struct VertexOut
{
float4 PosH : SV_POSITION;
float4 Color : COLOR;
}; VertexOut VS(VertexIn vin)
{
VertexOut vout; // Transform to homogeneous clip space.
vout.PosH = mul(float4(vin.PosL, 1.0f), gWorldViewProj); // Just pass vertex color into the pixel shader.
vout.Color = vin.Color; return vout;
} float4 PS(VertexOut pin) : SV_Target
{
return pin.Color;
} technique11 ColorTech
{
pass P0
{
SetVertexShader( CompileShader( vs_5_0, VS() ) );
SetGeometryShader( NULL );
SetPixelShader( CompileShader( ps_5_0, PS() ) );
}
}
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
#pragma once #include "Dx11DemoBase.h"
#include "d3dx11effect.h" class BoxDemo : public Dx11DemoBase
{
public:
BoxDemo();
~BoxDemo(); bool LoadContent() override;
void UnLoadContent() override; void Update(float dt) override;
void Render() override; private:
ID3D11Buffer *m_pVertexBuffer;
ID3D11Buffer *m_pIndexBuffer;//新增
ID3D11InputLayout *m_pInputLayout; ID3DX11Effect *m_pFx;
ID3DX11EffectTechnique *m_pTechnique;
ID3DX11EffectMatrixVariable *m_pFxWorldViewProj;
XMFLOAT4X4 m_world;
XMFLOAT4X4 m_view;
XMFLOAT4X4 m_proj; };
LoadContent()函数
顶点信息及缓冲的创建
Vertex vertices[] =
{
{ XMFLOAT3(-0.5f, -0.5f, -0.5f), XMFLOAT4(, , , ) },//white
{ XMFLOAT3(-0.5f, +0.5f, -0.5f), XMFLOAT4(, , , ) },//black
{ XMFLOAT3(+0.5f, +0.5f, -0.5f), XMFLOAT4(, , , ) },//red
{ XMFLOAT3(+0.5f, -0.5f, -0.5f), XMFLOAT4(, , , ) },//green
{ XMFLOAT3(-0.5f, -0.5f, +0.5f), XMFLOAT4(, , , ) },//blue
{ XMFLOAT3(-0.5f, +0.5f, +0.5f), XMFLOAT4(, , , ) },//yellow
{ XMFLOAT3(+0.5f, +0.5f, +0.5f), XMFLOAT4(, , , ) },//cyan
{ XMFLOAT3(+0.5f, -0.5f, +0.5f), XMFLOAT4(, , , ) }//magenta
}; D3D11_BUFFER_DESC vertexDesc;
ZeroMemory(&vertexDesc, sizeof(vertexDesc));
vertexDesc.Usage = D3D11_USAGE_DEFAULT;
vertexDesc.BindFlags = D3D11_BIND_VERTEX_BUFFER;
vertexDesc.ByteWidth = sizeof(Vertex)* ; D3D11_SUBRESOURCE_DATA resourceData;
ZeroMemory(&resourceData, sizeof(resourceData));
resourceData.pSysMem = vertices;
result = m_pd3dDevice->CreateBuffer(&vertexDesc, &resourceData, &m_pVertexBuffer);
if (FAILED(result))
{
return false;
}
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
UINT indices[] = {
// front face
, , ,
, , ,
// back face
, , ,
, , ,
// left face
, , ,
, , ,
// right face
, , ,
, , ,
// top face
, , ,
, , ,
// bottom face
, , ,
, ,
};
D3D11_BUFFER_DESC indexDesc;
ZeroMemory(&indexDesc, sizeof(indexDesc));
indexDesc.Usage = D3D11_USAGE_IMMUTABLE;
indexDesc.BindFlags = D3D11_BIND_INDEX_BUFFER;
indexDesc.ByteWidth = sizeof(UINT)* ;
D3D11_SUBRESOURCE_DATA indexData;
ZeroMemory(&indexData, sizeof(indexData));
indexData.pSysMem = indices;
result = m_pd3dDevice->CreateBuffer(&indexDesc, &indexData, &m_pIndexBuffer);
if (FAILED(result))
{
return false;
}
定义输入布局
D3D11_INPUT_ELEMENT_DESC solidColorLayout[] =
{
{ "POSITION", , DXGI_FORMAT_R32G32B32_FLOAT, , , D3D11_INPUT_PER_VERTEX_DATA, },
{ "COLOR", , DXGI_FORMAT_R32G32B32_FLOAT, , , D3D11_INPUT_PER_VERTEX_DATA, }
};
UINT numLayoutElements = ARRAYSIZE(solidColorLayout);
D3DX11_PASS_DESC passDesc;
m_pTechnique->GetPassByIndex()->GetDesc(&passDesc); result = m_pd3dDevice->CreateInputLayout(solidColorLayout, numLayoutElements, passDesc.pIAInputSignature,
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。
static float t = 0.0f;
t += (float)XM_PI * 0.0125f;
static DWORD dwTimeStart = ;
DWORD dwTimeCur = GetTickCount();
if (dwTimeStart == )
dwTimeStart = dwTimeCur;
t = (dwTimeCur - dwTimeStart) / 1000.0f; XMVECTOR pos = XMVectorSet(2.0f, 0.0f, 0.0f, 1.0f);
XMVECTOR target = XMVectorSet(0.0f, 0.0f, 0.0f, 1.0f);
XMVECTOR up = XMVectorSet(0.0f, 1.0f, 0.0f, 0.0f); XMMATRIX V = XMMatrixLookAtLH(pos, target, up);
XMStoreFloat4x4(&m_view, V);
XMMATRIX T = XMMatrixPerspectiveFovLH(XM_PIDIV2, m_width / static_cast<float>(m_height),
0.01f, 100.0f);
XMStoreFloat4x4(&m_proj, T);
//根据时间旋转world矩阵
XMMATRIX P = XMMatrixRotationY(t);
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().
if (m_pImmediateContext == )
return;
//清除渲染目标视图
float clearColor[] = { 1.0f, 1.0f, 1.0f, 1.0f };//背景颜色
m_pImmediateContext->ClearRenderTargetView(m_pRenderTargetView, clearColor); UINT stride = sizeof(Vertex);
UINT offset = ;
//设置数据信息格式控制信息
m_pImmediateContext->IASetInputLayout(m_pInputLayout);
//设置要绘制的几何体信息
m_pImmediateContext->IASetVertexBuffers(,,&m_pVertexBuffer,&stride,&offset);
m_pImmediateContext->IASetIndexBuffer(m_pIndexBuffer, DXGI_FORMAT_R32_UINT, );
//指明如何绘制
m_pImmediateContext->IASetPrimitiveTopology(D3D11_PRIMITIVE_TOPOLOGY_TRIANGLELIST); //设置常量
XMMATRIX world = XMLoadFloat4x4(&m_world);
XMMATRIX view = XMLoadFloat4x4(&m_view);
XMMATRIX proj = XMLoadFloat4x4(&m_proj);
XMMATRIX worldViewProj = world*view*proj;
m_pFxWorldViewProj->SetMatrix(reinterpret_cast<float*>(&worldViewProj)); D3DX11_TECHNIQUE_DESC techDesc;
m_pTechnique->GetDesc(&techDesc);
for (UINT i = ; i < techDesc.Passes; ++i)
{
m_pTechnique->GetPassByIndex(i)->Apply(, m_pImmediateContext);
m_pImmediateContext->DrawIndexed(, , );
}
//马上输出
m_pSwapChain->Present(, );
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
