顯示一個(gè)物體的顏色需要考慮三個(gè)使物體產(chǎn)生顏色的緣由。第一是環(huán)境光，環(huán)境光是物體展示的顏色可以看作物體材料本身的顏色，一般其亮度比較弱。第二是光源發(fā)出的光在物體表面進(jìn)行漫反射使其發(fā)光，一般發(fā)光面積比較大，產(chǎn)生的視覺顏色是物體材質(zhì)的顏色加強(qiáng)版。第三是鏡面反射光，鏡面反射光面積比較小，聚焦在一小塊有非常強(qiáng)的亮度，幾乎等同于光源本身的光強(qiáng)。一個(gè)物體最終讓人看見的顏色就是上面三種顏色的疊加。



編程實(shí)現(xiàn)的思路：

首先要給物體添加一個(gè)材質(zhì)屬性使其能夠具有環(huán)境光下，漫反射光，鏡面反射光的反射系數(shù)。其次光源本省有坐標(biāo)位置，光強(qiáng)等屬性，所以光源要獨(dú)立作為一個(gè)對(duì)象。最后使一個(gè)將光源與物體材質(zhì)本省聯(lián)系起來(lái)的函數(shù)來(lái)實(shí)現(xiàn)上面的光照模型理論公式，也就是公式10-12.

材質(zhì)屬性類：

#pragma once #ifndef __CMATERIAL__ #define __CMATERIAL__ #include "RGB.h"class CMaterial { public:CMaterial();virtual ~CMaterial();void SetAmbient(const CRGB &Ambient);//設(shè)置材質(zhì)對(duì)環(huán)境光的反射率void SetDiffuse(const CRGB &Diffuse);//設(shè)置材質(zhì)對(duì)漫反射光的反射率void SetSpecular(const CRGB& Specular);//設(shè)置材質(zhì)對(duì)鏡面反射的顏色void SetEmit(const CRGB& Emit);//設(shè)置自身輻射的顏色void SetExp(double Exp);//設(shè)置材質(zhì)的高光指數(shù)CRGB M_Ambient;//材質(zhì)對(duì)環(huán)境光的反射率CRGB M_Diffuse;//材質(zhì)對(duì)漫反射光的反射率CRGB M_Specular;// 材質(zhì)對(duì)鏡面光的反射率CRGB M_Emit;// 材質(zhì)自身的顏色double M_n;//材質(zhì)的高光指數(shù) };#endif // ! __CMATERIAL__#include "pch.h" #include "CMaterial.h"CMaterial::CMaterial() {M_Ambient = CRGB(0.2, 0.2, 0.2);//默認(rèn)材質(zhì)對(duì)環(huán)境光的反射率M_Diffuse = CRGB(0.8, 0.8, 0.8);//材質(zhì)對(duì)漫反射光的反射率M_Specular = CRGB(0.0, 0.0, 0.0);//材質(zhì)對(duì)鏡面反射光的反射率M_Emit = CRGB(0.0, 0.0, 0.0);//材質(zhì)自身發(fā)散的顏色M_n = 1.0;//高光指數(shù) }CMaterial::~CMaterial() {};void CMaterial::SetAmbient(const CRGB& Ambient) {M_Ambient = Ambient; }void CMaterial::SetDiffuse(const CRGB& Diffuse) {M_Diffuse = Diffuse; }void CMaterial::SetSpecular(const CRGB& Specular) {M_Specular = Specular; }void CMaterial::SetEmit(const CRGB& Emit) {M_Emit = Emit; }void CMaterial::SetExp(const double Exp) {M_n = Exp; }

光源對(duì)象實(shí)現(xiàn)：

#pragma once #ifndef __CLIGHT__ #define __CLIGHT__ #include"RGB.h" #include "CPoint3D.h"class CLight { public:CLight();virtual ~CLight() {};void SetDiffuse(const CRGB& Diffuse);//設(shè)置光源的漫反射光void SetSpecular(const CRGB& Specular);//設(shè)置光源的鏡面反射光void SetPosition(double x, double y, double z);//設(shè)置光源位置void SetCoef(double c0, double c1, double c2);//設(shè)置光強(qiáng)的衰減系數(shù)void SetOnOff(bool BL);//設(shè)置光源狀態(tài)CRGB L_Diffuse;//光的漫反射顏色CRGB L_Specular;//光的鏡面高光顏色CPoint3D L_Position;//光源的位置double L_C0;//常數(shù)衰減系數(shù)double L_C1;//線性衰減系數(shù)double L_C2;//二次衰減系數(shù)bool L_OnOff;//光源開關(guān) };#endif // ! __CLIGHT__#include "pch.h" #include "CLight.h"CLight::CLight() {L_Diffuse = CRGB(0.0, 0.0, 0.0);//光源的漫反射顏色 L_Specular = CRGB(1.0, 1.0, 1.0);//光源鏡面高光顏色L_Position.x = 0.0, L_Position.y = 0.0, L_Position.z = 1000;//光源位置直角坐標(biāo)L_C0 = 1.0;//常數(shù)衰減系數(shù)L_C1 = 0.0;//線性衰減系數(shù)L_C2 = 0.0;//二次衰減系數(shù)L_OnOff = TRUE;//光源開啟 }void CLight::SetDiffuse(const CRGB& Diffuse) {L_Diffuse = Diffuse; }void CLight::SetSpecular(const CRGB& Specular) {L_Specular = Specular; }void CLight::SetPosition(double x, double y, double z) {L_Position.x = x;L_Position.y = y;L_Position.z = z; }void CLight::SetOnOff(bool BL) {L_OnOff = BL; }void CLight::SetCoef(double c0, double c1, double c2) {L_C0 = c0;L_C1 = c1;L_C2 = c2; }

將光源與物體材質(zhì)屬性結(jié)合，計(jì)算對(duì)應(yīng)像素的光強(qiáng)顏色：

#pragma once #ifndef __CLIGHTCONTAINER__ #define __CLIGHTCONTAINER__ #include"CMaterial.h" #include "CLight.h" #include "CPoint3D.h" #include <armadillo> //矩陣運(yùn)算庫(kù)class CLightContainer { public:CLightContainer();CLightContainer(int lightNum);~CLightContainer();void SetLightNumber(int lightNum);//設(shè)置光源數(shù)量//計(jì)算頂點(diǎn)光照下的顏色CRGB lighting(const CPoint3D &cameraPosition,const CPoint3D & VetexPosition, CPoint3D faceNormal, CMaterial* Pmaterial) const;int LightNum;//光源數(shù)量CLight* Light;//光源數(shù)組CRGB Ambient;//環(huán)境光 };#endif // ! __CLIGHTCONTAINER__ #include "pch.h" #include "CLightContainer.h" CLightContainer::CLightContainer() {LightNum = 1;Light = new CLight[LightNum];Ambient = CRGB(0.3, 0.3, 0.3);//環(huán)境光恒定不變 }CLightContainer::CLightContainer(int lightNum) {this->LightNum = lightNum;Light = new CLight[LightNum];Ambient = CRGB(0.3, 0.3, 0.3);//環(huán)境光恒定不變 }CLightContainer::~CLightContainer() {if (Light){delete[]Light;Light = NULL;} }void CLightContainer::SetLightNumber(int lightNum) {if (Light){delete[]Light;}LightNum = lightNum;Light = new CLight[lightNum]; }CRGB CLightContainer::lighting(const CPoint3D &cameraPosition, const CPoint3D &VetexPosition, CPoint3D faceNormal, CMaterial* Pmaterial) const {CRGB lastC = Pmaterial->M_Emit;//材質(zhì)自身發(fā)散色為初始值for (int i = 0; i < LightNum; i++){if (Light[i].L_OnOff){CRGB InitC(0, 0, 0);arma::vec VL({ Light[i].L_Position.x - VetexPosition.x,Light[i].L_Position.y - VetexPosition.y,Light[i].L_Position.z - VetexPosition.z });double d = sqrt(VL[0] * VL[0] + VL[1] * VL[1] + VL[2] * VL[2]);//光傳播的距離arma::vec VLNormal({ VL[0] / d,VL[1] / d,VL[2] / d });//單位化光矢量double n = sqrt(faceNormal.x * faceNormal.x+ faceNormal.y * faceNormal.y+ faceNormal.z * faceNormal.z);arma::vec VNNormal({ faceNormal.x / n,faceNormal.y / n,faceNormal.z / n });//單位化法矢量//第一步加入漫反射光double cosTheta = arma::dot(VLNormal, VNNormal);(cosTheta > 0) ? cosTheta : cosTheta = 0;//只有夾角為正才可以漫反射InitC.red += Light[i].L_Diffuse.red * Pmaterial->M_Diffuse.red * cosTheta;InitC.green += Light[i].L_Diffuse.green * Pmaterial->M_Diffuse.green * cosTheta;InitC.blue += Light[i].L_Diffuse.blue * Pmaterial->M_Diffuse.blue * cosTheta;//第2步，加入鏡面反射光arma::vec VV({ cameraPosition.x - VetexPosition.x,cameraPosition.y - VetexPosition.y ,cameraPosition.z - VetexPosition.z });double v = sqrt(VV[0] * VV[0] + VV[1] * VV[1] + VV[2] * VV[2]);arma::vec VVNormal({ VV[0] / v, VV[1] / v,VV[2] / v });//單位化視矢量arma::vec VH = (VVNormal + VLNormal);double h = sqrt(VH[0] * VH[0] + VH[1] * VH[1] + VH[2] * VH[2]);arma::vec VHNormal({ VH[0] / h, VH[1] / h, VH[2] / h });//平分矢量double cosBeta = dot(VHNormal, VNNormal);(cosBeta > 0) ? cosBeta : cosBeta = 0;double nHN = pow(cosBeta, Pmaterial->M_n);InitC.red += Light[i].L_Specular.red * Pmaterial->M_Specular.red * nHN;InitC.green += Light[i].L_Specular.green * Pmaterial->M_Specular.green * nHN;InitC.blue += Light[i].L_Specular.blue * Pmaterial->M_Specular.blue * nHN;//第3步，光強(qiáng)衰減double c0 = Light[i].L_C0;//c0為常數(shù)衰減因子double c1 = Light[i].L_C1;//c1線性衰減因子double c2 = Light[i].L_C2;//c2二次衰減因子 double f = (1.0 / (c0 + c1 * d + c2 * d * d));//光強(qiáng)衰減函數(shù)(f < 1.0) ? f : f = 1.0;lastC += InitC * f;}//else//lastC += VetexPosition.rgb;}//第4步，加入環(huán)境光CRGB amb(Ambient.red * Pmaterial->M_Ambient.red,Ambient.green * Pmaterial->M_Ambient.green,Ambient.blue * Pmaterial->M_Ambient.blue);lastC += amb;//顏色回到0 - 255之間return lastC * 255; }

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