opengl平行光光源，点光源，聚光灯光源同台出现

效果图：左起分别为 平行光光源，点光源，聚光灯光源

片元shader

uniform vec4 U_LightPos;//光源位置
uniform vec3 U_EyePos;//眼睛位置
uniform vec4 U_LightDirection;//聚光灯中心线向量
uniform float U_Cutoff;//聚光灯中心线向量和入射光线最大夹角
uniform float U_DiffuseIntensity; //漫反射光强度
uniform vec4 U_AmbientLightColor;//环境光颜色
uniform vec4 U_AmbientMaterial;//环境光材质
uniform vec4 U_DiffuseLightColor;//漫反射光颜色
uniform vec4 U_DiffuseMaterial;//漫反射光材质
uniform vec4 U_SpecularLightColor;//镜面光颜色
uniform vec4 U_SpecularMaterial;//镜面光材质

varying vec3 V_Normal; //转换到世界空间的法向量
varying vec3 V_WorldPos;

void main()
{
	//角度转弧度
	float radianCutoff=U_Cutoff*3.14/180.0;
	float cosThta=cos(radianCutoff);
	//聚光灯中心线向量归一化
	vec3 spotLightDirection=normalize(U_LightDirection.xyz);

	//--计算环境光
	vec4 ambientColor=U_AmbientLightColor*U_AmbientMaterial;

	//--计算漫反射光
	//入射光向量
	vec3 L=vec3(0.0);
	float distance=0.0;
	float attenuation=1.0;
	
	float constantFactor=0.5;
	float linearFactor=0.3;
	float expFactor=0.1;

	if(U_LightPos.w==0.0)//如果是方向光光源
	{
	//方向光光源  入射光线是平行的
		L=U_LightPos.xyz;
	}
	else  //如果是点光源  
	{
		//入射光线的方向是从被照射点指向光源的位置
		L=U_LightPos.xyz-V_WorldPos;
		//计算入射光线的长度 
		distance=length(L);
		//计算光线的衰减因子
		attenuation=1.0/(constantFactor+linearFactor*distance+expFactor*distance*distance);
	}

	//入射光线归一化
	L=normalize(L);

	//法向量归一化
	vec3 n=normalize(V_Normal);
	float diffuseIntensity=0.0;

	if(U_LightPos.w!=0.0f&&U_Cutoff>0.0)//如果是聚光灯
	{
		//计算聚光灯中心线和入射光线的夹角
		float currentCosThta=max(0.0,dot(-L,spotLightDirection));
		if(currentCosThta>cosThta)
		{
			if(dot(L,n)>0.0)//为了减少计算量，过滤掉照射到背面的光
			{
				//为了让聚光灯边缘变的光滑
				diffuseIntensity=pow(currentCosThta,U_LightDirection.w);
			}
		}
	}
	else
	{
		//点光源或者方向光
		diffuseIntensity=max(0.0,dot(L,n));
	}
	
	vec4 diffuseColor=U_DiffuseLightColor*U_DiffuseMaterial*diffuseIntensity*attenuation*U_DiffuseIntensity;
	
	//--镜面光的计算
	//计算眼睛到被观察点的向量
	vec3 viewDir=U_EyePos-V_WorldPos;
	viewDir=normalize(viewDir);

	//根据Blin-phone计算反射光  
	vec3 halfVector=L+viewDir;
	halfVector=normalize(halfVector);

	float specularIntensity=0.0;
	if(diffuseIntensity==0.0)
	{
		specularIntensity=0.0;
	}
	else
	{
		
		specularIntensity=pow(max(0.0,dot(n,halfVector)),128.0);
	}

	vec4 specularColor=U_SpecularLightColor*U_SpecularMaterial*specularIntensity*attenuation;

	gl_FragColor=ambientColor+diffuseColor+specularColor;
}

顶点shader

attribute vec3 pos;
attribute vec2 texcoord;
attribute vec3 normal;

uniform mat4 M;
uniform mat4 P;
uniform mat4 V;
uniform mat4 NM;

varying vec3 V_Normal;
varying vec3 V_WorldPos;

void main()
{
	V_Normal=mat3(NM)*normal;
	vec4 worldPos=M*vec4(pos,1.0);
	V_WorldPos=worldPos.xyz;

	gl_Position=P*V*worldPos;
}

渲染函数

#include 
#include "glew.h"
#include 
#include 
#include "utils.h"
#include "GPUProgram.h"
#include "ObjModel.h"
#include "FBO.h"
#include "FullScreenQuad.h"
#include "Glm/glm.hpp"
#include "Glm/ext.hpp"
#pragma comment(lib,"opengl32.lib")
#pragma comment(lib,"glew32.lib")

LRESULT CALLBACK GLWindowProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam)
{
	switch (msg)
	{
	case WM_CLOSE:
		PostQuitMessage(0);
		break;
	}
	return DefWindowProc(hwnd,msg,wParam,lParam);
}


INT WINAPI WinMain(_In_ HINSTANCE hInstance, _In_opt_ HINSTANCE hPrevInstance, _In_ LPSTR lpCmdLine, _In_ int nShowCmd)
{
	WNDCLASSEX wndClass;
	wndClass.cbClsExtra = 0;
	wndClass.cbSize = sizeof(WNDCLASSEX);
	wndClass.cbWndExtra = 0;
	wndClass.hbrBackground = NULL;
	wndClass.hCursor = LoadCursor(NULL,IDC_ARROW);
	wndClass.hIcon = NULL;
	wndClass.hIconSm = NULL;
	wndClass.hInstance = hInstance;
	wndClass.lpfnWndProc=GLWindowProc;
	wndClass.lpszClassName = L"OpenGL";
	wndClass.lpszMenuName = NULL;
	wndClass.style = CS_VREDRAW | CS_HREDRAW;
	ATOM atom = RegisterClassEx(&wndClass);

	RECT rect;
	rect.left = 0;
	rect.top = 0;
	rect.right = 800;
	rect.bottom = 600;
	AdjustWindowRect(&rect, WS_OVERLAPPEDWINDOW, FALSE);
	HWND hwnd = CreateWindowEx(NULL, L"OpenGL", L"RenderWindow", WS_OVERLAPPEDWINDOW, 100, 100, rect.right-rect.left, rect.bottom-rect.top, NULL, NULL, hInstance, NULL);
	HDC dc = GetDC(hwnd);
	PIXELFORMATDESCRIPTOR pfd;
	memset(&pfd, 0, sizeof(PIXELFORMATDESCRIPTOR));
	pfd.nVersion = 1;
	pfd.dwFlags = PFD_DRAW_TO_WINDOW | PFD_SUPPORT_OPENGL | PFD_TYPE_RGBA | PFD_DOUBLEBUFFER;
	pfd.iLayerType = PFD_MAIN_PLANE;
	pfd.iPixelType = PFD_TYPE_RGBA;
	pfd.cColorBits = 32;
	pfd.cDepthBits = 24;
	pfd.cStencilBits = 8;

	int pixelFormatID = ChoosePixelFormat(dc, &pfd);

	SetPixelFormat(dc,pixelFormatID,&pfd);

	HGLRC rc = wglCreateContext(dc);
	wglMakeCurrent(dc, rc);
	GetClientRect(hwnd, &rect);
	int viewportWidth = rect.right - rect.left, viewportHeight = rect.bottom - rect.top;
	glewInit();
	//init gpu program
	GPUProgram gpuProgram;
	gpuProgram.AttachShader(GL_VERTEX_SHADER, "Debug/res/shader/Light.vs");
	gpuProgram.AttachShader(GL_FRAGMENT_SHADER, "Debug/res/shader/Light.fs");
	gpuProgram.Link();

	gpuProgram.DetectAttribute("pos");
	gpuProgram.DetectAttribute("texcoord");
	gpuProgram.DetectAttribute("normal");
	gpuProgram.DetectUniform("M");
	gpuProgram.DetectUniform("V");
	gpuProgram.DetectUniform("P");
	gpuProgram.DetectUniform("NM");
	gpuProgram.DetectUniform("U_AmbientLightColor");
	gpuProgram.DetectUniform("U_AmbientMaterial");
	gpuProgram.DetectUniform("U_DiffuseLightColor");
	gpuProgram.DetectUniform("U_DiffuseMaterial");
	gpuProgram.DetectUniform("U_SpecularLightColor");
	gpuProgram.DetectUniform("U_SpecularMaterial");
	gpuProgram.DetectUniform("U_LightPos");
	gpuProgram.DetectUniform("U_EyePos");
	gpuProgram.DetectUniform("U_LightDirection");
	gpuProgram.DetectUniform("U_Cutoff");
	gpuProgram.DetectUniform("U_DiffuseIntensity");
	//init 3d model
	ObjModel cube;
	cube.Init("Debug/res/model/Cube.obj");

	float identity[] = {
		1.0f,0,0,0,
		0,1.0f,0,0,
		0,0,1.0f,0,
		0,0,0,1.0f
	};
	float ambientLightColor[] = { 0.4f,0.4f,0.4f,1.0f };//环境光颜色
	float ambientMaterial[] = { 0.2f,0.2f,0.2f,1.0f };//环境光材质
	float diffuseLightColor[] = { 1.0f,1.0f,1.0f,1.0f };//漫反射光颜色
	float diffuseMaterial[] = { 0.6f,0.6f,0.6f,1.0f };//漫反射光材质
	float diffuseIntensity = 2.0f;//漫反射光强度
	float specularLightColor[] = { 1.0f,1.0f,1.0f,1.0f };//镜面光颜色
	float specularMaterial[] = { 1.0f,1.0f,1.0f,1.0f };//镜面光材质
	float lightPos[] = { 0.0f,1.5f,0.0f,0.0f };//光源位置
	float spotLightDirection[] = { 0.0f,-1.0f,0.0f,128.0f };//聚光灯中心线向量
	float spotLightCutoff = 0.0f;// 15.0f 聚光灯中心线向量和入射光线最大夹角
	float eyePos[] = { 0.0f,0.0f,0.0f };//眼睛的位置

	glm::mat4 model1 = glm::translate(-2.0f, 0.0f, -6.0f)*glm::rotate(-30.0f, 1.0f, 1.0f, 1.0f);
	glm::mat4 model2 = glm::translate(0.0f, 0.0f, -6.0f)*glm::rotate(-30.0f, 1.0f, 1.0f, 1.0f);
	glm::mat4 model3 = glm::translate(2.0f, 0.0f, -6.0f)*glm::rotate(-30.0f, 1.0f, 1.0f, 1.0f);
	glm::mat4 projectionMatrix = glm::perspective(50.0f, (float)viewportWidth / (float)viewportHeight, 0.1f, 1000.0f);

	glm::mat4 normalMatrix1 = glm::inverseTranspose(model1);
	glm::mat4 normalMatrix2 = glm::inverseTranspose(model2);
	glm::mat4 normalMatrix3 = glm::inverseTranspose(model3);

	glClearColor(41.0f/255.0f,  71.0f/255.0f, 121.0f / 255.0f, 1.0f);
	ShowWindow(hwnd, SW_SHOW);
	UpdateWindow(hwnd);

	MSG msg;
	while (true)
	{
		if (PeekMessage(&msg,NULL,NULL,NULL,PM_REMOVE))
		{
			if (msg.message==WM_QUIT)
			{
				break;
			}
			TranslateMessage(&msg);
			DispatchMessage(&msg);
		}
		glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
		glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);
		glEnable(GL_DEPTH_TEST);
		glUseProgram(gpuProgram.mProgram);
		glUniformMatrix4fv(gpuProgram.GetLocation("V"), 1, GL_FALSE, identity);
		glUniformMatrix4fv(gpuProgram.GetLocation("P"), 1, GL_FALSE, glm::value_ptr(projectionMatrix));
		glUniform4fv(gpuProgram.GetLocation("U_AmbientLightColor"), 1, ambientLightColor);
		glUniform4fv(gpuProgram.GetLocation("U_AmbientMaterial"), 1, ambientMaterial);
		glUniform4fv(gpuProgram.GetLocation("U_DiffuseLightColor"), 1, diffuseLightColor);
		glUniform4fv(gpuProgram.GetLocation("U_DiffuseMaterial"), 1, diffuseMaterial);
		glUniform4fv(gpuProgram.GetLocation("U_SpecularLightColor"), 1, specularLightColor);
		glUniform4fv(gpuProgram.GetLocation("U_SpecularMaterial"), 1, specularMaterial);
		glUniform3fv(gpuProgram.GetLocation("U_EyePos"), 1, eyePos);
		glUniform4fv(gpuProgram.GetLocation("U_LightDirection"), 1, spotLightDirection);
		glUniform1f(gpuProgram.GetLocation("U_DiffuseIntensity"), diffuseIntensity);
		//平行光光源
		lightPos[0] = 0.0f;
		lightPos[1] = 1.5f;
		lightPos[2] = 0.0f;
		lightPos[3] = 0.0f;
		diffuseIntensity = 3.0f;
		spotLightCutoff = 0.0f;// 15.0f;//degree
		glUniform4fv(gpuProgram.GetLocation("U_LightPos"), 1, lightPos);
		glUniform1f(gpuProgram.GetLocation("U_DiffuseIntensity"), diffuseIntensity);
		glUniform1f(gpuProgram.GetLocation("U_Cutoff"), spotLightCutoff);
		glUniformMatrix4fv(gpuProgram.GetLocation("M"), 1, GL_FALSE, glm::value_ptr(model1));
		glUniformMatrix4fv(gpuProgram.GetLocation("NM"), 1, GL_FALSE, glm::value_ptr(normalMatrix1));
		cube.Bind(gpuProgram.GetLocation("pos"), gpuProgram.GetLocation("texcoord"), gpuProgram.GetLocation("normal"));
		cube.Draw();
		//点光源
		lightPos[0] = 0.0f;
		lightPos[1] = 3.0f;
		lightPos[2] =-6.0f;
		lightPos[3] = 1.0f;
		diffuseIntensity = 8.5f; //3.0f
		glUniform4fv(gpuProgram.GetLocation("U_LightPos"), 1, lightPos);
		glUniform1f(gpuProgram.GetLocation("U_DiffuseIntensity"), diffuseIntensity);
		glUniformMatrix4fv(gpuProgram.GetLocation("M"), 1, GL_FALSE, glm::value_ptr(model2));
		glUniformMatrix4fv(gpuProgram.GetLocation("NM"), 1, GL_FALSE, glm::value_ptr(normalMatrix2));
		cube.Bind(gpuProgram.GetLocation("pos"), gpuProgram.GetLocation("texcoord"), gpuProgram.GetLocation("normal"));
		cube.Draw();
		//聚光灯
		lightPos[0] = 2.0f;
		lightPos[1] = 3.0f;
		lightPos[2] = -6.0f;
		lightPos[3] = 1.0f;
		diffuseIntensity = 5.8f;
		spotLightCutoff = 15.0f;//degree
		glUniform4fv(gpuProgram.GetLocation("U_LightPos"), 1, lightPos);
		glUniform1f(gpuProgram.GetLocation("U_DiffuseIntensity"), diffuseIntensity);
		glUniform1f(gpuProgram.GetLocation("U_Cutoff"), spotLightCutoff);
		glUniformMatrix4fv(gpuProgram.GetLocation("M"), 1, GL_FALSE, glm::value_ptr(model3));
		glUniformMatrix4fv(gpuProgram.GetLocation("NM"), 1, GL_FALSE, glm::value_ptr(normalMatrix3));
		cube.Bind(gpuProgram.GetLocation("pos"), gpuProgram.GetLocation("texcoord"), gpuProgram.GetLocation("normal"));
		cube.Draw();
		glUseProgram(0);
		glFinish();
		SwapBuffers(dc);
	}
	return 0;
}