《dx12 龙书》第一部分学习笔记（三）

1、设置XMVECTOR类型中的数据：
示例工程说明：

#include <Windows.h>
#include <iostream>
#include <DirectXMath.h>
#include <DirectXPackedVector.h>

using namespace std;
using namespace DirectX;

ostream& XM_CALLCONV operator<<(ostream& os, FXMVECTOR v)
{
    XMFLOAT3 dest;
    XMStoreFloat3(&dest, v);

    os << "(" << dest.x << "," << dest.y << "," << dest.z << ")";
    return os;
}

int main()
{
    //允许输出 true 和 false
    cout.setf(ios_base::boolalpha);

    //检查是否支持SSE2指令集（Pentium4,AMD K8及其后续版本的处理器）
    if (!XMVerifyCPUSupport())
    {
        cout << "directx math not supported" << endl;
        return 0;
    }

    XMVECTOR p = XMVectorZero();  //返回向量(0,0,0)
    XMVECTOR q = XMVectorSplatOne();  //返回向量(1,1,1)
    XMVECTOR u = XMVectorSet(1.0f,2.0f,3.0f,0.0f); //返回向量(1,2,3)
    XMVECTOR v = XMVectorReplicate(-2.0f);  //返回向量(-2,-2,-2)
    XMVECTOR w = XMVectorSplatZ(u);  //返回向量(u.z,u.z,u.z)

    cout << "p = " << p << endl;
    cout << "q = " << q << endl;
    cout << "u = " << u << endl;
    cout << "v = " << v << endl;
    cout << "w = " << w << endl;

    return 0;
}

2、XMVECTOR向量函数：
示例工程说明：

#include <Windows.h>
#include <iostream>
#include <DirectXMath.h>
#include <DirectXPackedVector.h>

using namespace std;
using namespace DirectX;
using namespace DirectX::PackedVector;

ostream& XM_CALLCONV operator<<(ostream& os, FXMVECTOR v)
{
    
    
    XMFLOAT3 dest;
    XMStoreFloat3(&dest, v);

    os << "(" << dest.x << "," << dest.y << "," << dest.z << ")";
    return os;
}

int main()
{
    
    
    //允许输出 true 和 false
    cout.setf(ios_base::boolalpha);

    //检查是否支持SSE2指令集（Pentium4,AMD K8及其后续版本的处理器）
    if (!XMVerifyCPUSupport())
    {
    
    
        cout << "directx math not supported" << endl;
        return 0;
    }

    XMVECTOR n = XMVectorSet(1.0f, 0.0f, 0.0f, 0.0f);
    XMVECTOR u = XMVectorSet(1.0f, 2.0f, 3.0f, 0.0f);
    XMVECTOR v = XMVectorSet(-2.0f, 1.0f, -3.0f, 0.0f);
    XMVECTOR w = XMVectorSet(0.707f, 0.707f, 0.0f, 0.0f);

    //向量加
    XMVECTOR a = u + v;  // (-1,3,0)

    //向量减
    XMVECTOR b = u - v;  // (3,1,6)

    //标量乘
    XMVECTOR c = 10.0f * u;  // (10,20,30)

    //||u||
    XMVECTOR L = XMVector3Length(u);  // (3.74166,3.74166,3.74166)

    //d = u / ||u||
    XMVECTOR d = XMVector3Normalize(u);  // (0.267261,0.534522,0.801784)

    //s = u dot v
    XMVECTOR s = XMVector3Dot(u, v);  // (-9,-9,-9)

    //e = u × v
    XMVECTOR e = XMVector3Cross(u, v);  // (-9,-3,5)

    //求出proj_n(w)和perp_n(w)
    XMVECTOR projW;  // (0.707,0,0)
    XMVECTOR perpW;  // (0,0.707,0)
    XMVector3ComponentsFromNormal(&projW, &perpW, w, n);

    //projW + perpW == w?
    bool equal = XMVector3Equal(projW + perpW, w) != 0;  // true
    bool notEqual = XMVector3NotEqual(projW + perpW, w) != 0;  // false

    //projW与perpW之间的夹角应为90度
    XMVECTOR angleVec = XMVector3AngleBetweenVectors(projW, perpW);  //获得弧度制  (1.5708,1.5708,1.5708)
    float angleRadians = XMVectorGetX(angleVec);
    float angleDegrees = XMConvertToDegrees(angleRadians);  //转成角度90
    
    cout << "n =                " << n << endl;
    cout << "u =                " << u << endl;
    cout << "v =                " << v << endl;
    cout << "w =                " << w << endl;
    cout << "a = u + v          " << a << endl;
    cout << "b = u - v          " << b << endl;
    cout << "c = 10.0f * u      " << c << endl;
    cout << "L = ||u||          " << L << endl;
    cout << "d = u / ||u||      " << d << endl;
    cout << "s = u dot v        " << s << endl;
    cout << "e = u × v         " << e << endl;
    cout << "proj_n(w) =        " << projW << endl;
    cout << "perp_n(w) =        " << perpW << endl;
    cout << "projW + perpW == w " << equal << endl;
    cout << "projW + perpW != w " << notEqual << endl;
    cout << "angleVec =         " << angleVec << endl;
    cout << "angleRadians =     " << angleRadians << endl;
    cout << "angleDegrees =     " << angleDegrees << endl;
}