Blinn-Phong光照

1|0颜色

颜色是由光的颜色乘物品的颜色得到的
光的颜色值不是比例，如果值大就亮，值小就暗。比如（1.0f, 1.0f, 1.0f)就比（0.2f, 0.2f, 0.2f)亮

fragmentshader

#version 330 core
out vec4 fragColor;
uniform vec3 lightcolor, objectcolor;
void main()
{
	fragColor = vec4(lightcolor * objectcolor, 1.0f);
}

在main函数里，先定位location，再use那个program，然后再改uniform的值

	unsigned int lightLoc = glGetUniformLocation(Cubeshader.ID, "lightcolor");
	unsigned int objectLoc = glGetUniformLocation(Cubeshader.ID, "objectcolor");
	Cubeshader.use();
	glUniform3f(lightLoc, 1.0f, 1.0f, 1.0f);
	glUniform3f(objectLoc, 0.5f, 1.0f, 0.4f);

或者在Shader函数里定义修改Uniform的方法：

	void setMat4(const std::string &name, const glm::mat4 &mat)
	{
		glUniformMatrix4fv(glGetUniformLocation(ID, name.c_str()), 1, GL_FALSE, glm::value_ptr(mat));
	}
	void setvec3(const std::string &name, const glm::vec3 &vec)
	{
		glUniform3fv(glGetUniformLocation(ID, name.c_str()), 1, glm::value_ptr(vec));
	}
	void setvec3(const std::string &name, float x, float y, float z) const
	{
		glUniform3f(glGetUniformLocation(ID, name.c_str()), x, y, z);
	}

main.cpp

                Cubeshader.use();
		Cubeshader.setvec3("lightcolor", 1.0f, 1.0f, 1.0f);
		Cubeshader.setvec3("objectcolor", 0.5f, 1.0f, 0.4f);

然后VAO只记录了glBindBuffer绑定了的VBO的glVertexAttribPointer和glEnableVertexAttribArray的值，在使用这个着色器前需要先shader.use()，然后再改这个shader的uniform值

                lightshader.use();
		glm::mat4 model(1.0f);
		model = glm::translate(model, lightPos);
		view = glm::lookAt(cameraPos, cameraPos + cameraFront, cameraUp);
		projection = glm::perspective(glm::radians(45.0f), (float)800 / (float)600, 0.1f, 100.0f);
		lightshader.setMat4("model", model);
		lightshader.setMat4("view", view);
		lightshader.setMat4("projection", projection);
		glBindVertexArray(lightVAO);
		glDrawArrays(GL_TRIANGLES, 0, 36);

2|0光照

2|1漫反射diffuse

获得每个点的法向量，写在vertices属性里，光照不用法向量属性，物体用

	glBindVertexArray(VAO);
	glBindBuffer(GL_ARRAY_BUFFER, VBO);
	glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);	//第一个是类型，第二个是大小，第三个是数据
	glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 6 * sizeof(float), (void*)0);
	glEnableVertexAttribArray(0);
	glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 6 * sizeof(float), (void*)0);
	glEnableVertexAttribArray(1);

	glBindVertexArray(lightVAO);
	glBindBuffer(GL_ARRAY_BUFFER, VBO);
	glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 6 * sizeof(float), (void*)0);
	glEnableVertexAttribArray(0);

在顶点着色器里把顶点坐标转化到世界坐标系以备与法向量点积
FragPos = vec3(model * vec4(aPos, 1.0));
然后把法向量进行操作使之与view无关
Normal = mat3(transpose(inverse(model))) * aNormal;
并传到fragment shader里。
标准化的法向量与标准化了的（光源-顶点）做点积，得到cos
然后乘光照，就是这个点获得的光照强度

	vec3 norm = normalize(Normal);
	vec3 lightDir = normalize(lightPos - FragPos);
	float diff = max(dot(norm, lightDir), 0.0);
	vec3 diffuse = diff * lightcolor;

2|2镜面反射specular

视线向量（摄像机-物体）点积反射向量（vec3 reflectDir = reflect(-lightDir, norm);）函数，这个0-1之间的值再乘《高光度》次幂，就是高光分量
reflect函数第一个参数必须是光照的方向，需要上面的lightDir取反，第二个是标准化了的法线方向

fragmentshader

uniform viewPos;
	float specularStrength = 0.5;
	vec3 ViewDir = normalize(viewPos-FragPos);
	vec3 reflectDir = reflect(-lightDir, norm);
	float spec = pow(max(dot(ViewDir, reflectDir),0.0), 32);
	vec3 specular = specularStrength * spec * lightcolor;

3|0所有程序

#include<glad/glad.h>
#include<GLFW/glfw3.h>
#include<iostream>
#include<Shader.cpp>
#define STB_IMAGE_IMPLEMENTATION
#include<stb_image.h>
#include<glm/glm.hpp>
#include<glm/gtc/matrix_transform.hpp>
#include<glm/gtc/type_ptr.hpp>
glm::vec3 cameraPos = glm::vec3(0.0f, 0.0f, 3.0f);
glm::vec3 cameraFront = glm::vec3(0.0f, 0.0f, -1.0f);
glm::vec3 cameraUp = glm::vec3(0.0f, 1.0f, 0.0f);
void framebuffer_size_callback(GLFWwindow* window, int width, int height) 
{
	glViewport(0, 0, width, height);
}
void processInput(GLFWwindow* window)
{
	if (glfwGetKey(window, GLFW_KEY_KP_ENTER) == GLFW_PRESS or glfwGetKey(window, GLFW_KEY_ENTER) == GLFW_PRESS or glfwGetKey(window, GLFW_KEY_ESCAPE) == GLFW_PRESS)
		glfwSetWindowShouldClose(window, true);
	float cameraSpeed = 0.05f;
	if (glfwGetKey(window, GLFW_KEY_W) == GLFW_PRESS)
		cameraPos += cameraSpeed * cameraFront;
	if (glfwGetKey(window, GLFW_KEY_S) == GLFW_PRESS)
		cameraPos -= cameraSpeed * cameraFront;
	if (glfwGetKey(window, GLFW_KEY_A) == GLFW_PRESS)
		cameraPos += cameraSpeed * glm::normalize(glm::cross(cameraUp, cameraFront));
	if (glfwGetKey(window, GLFW_KEY_D) == GLFW_PRESS)
		cameraPos -= cameraSpeed * glm::normalize(glm::cross(cameraUp, cameraFront));
}
int main()
{
	glfwInit();
	glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
	glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
	glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
	//创建窗口对象
	GLFWwindow* window = glfwCreateWindow(800, 600, "LJHyyds", NULL, NULL);
	if (window == NULL)
	{
		std::cout << "Failed to create" << std::endl;
		glfwTerminate();
		return -1;
	}
	glfwMakeContextCurrent(window);
	//初始化GLAD管理指针，加载系统OpenGL函数指针
	if (!gladLoadGLLoader((GLADloadproc)glfwGetProcAddress))
	{
		std::cout << "Failed to init GLAD" << std::endl;
		return -1;
	}
	glfwSetFramebufferSizeCallback(window, framebuffer_size_callback);
	Shader Cubeshader("shader.vs", "shader.fs");
	Shader lightshader("shader.vs", "lightshader.fs");
	float vertices[] = {
		-0.5f, -0.5f, -0.5f,  0.0f,  0.0f, -1.0f,
		 0.5f, -0.5f, -0.5f,  0.0f,  0.0f, -1.0f,
		 0.5f,  0.5f, -0.5f,  0.0f,  0.0f, -1.0f,
		 0.5f,  0.5f, -0.5f,  0.0f,  0.0f, -1.0f,
		-0.5f,  0.5f, -0.5f,  0.0f,  0.0f, -1.0f,
		-0.5f, -0.5f, -0.5f,  0.0f,  0.0f, -1.0f,

		-0.5f, -0.5f,  0.5f,  0.0f,  0.0f, 1.0f,
		 0.5f, -0.5f,  0.5f,  0.0f,  0.0f, 1.0f,
		 0.5f,  0.5f,  0.5f,  0.0f,  0.0f, 1.0f,
		 0.5f,  0.5f,  0.5f,  0.0f,  0.0f, 1.0f,
		-0.5f,  0.5f,  0.5f,  0.0f,  0.0f, 1.0f,
		-0.5f, -0.5f,  0.5f,  0.0f,  0.0f, 1.0f,

		-0.5f,  0.5f,  0.5f, -1.0f,  0.0f,  0.0f,
		-0.5f,  0.5f, -0.5f, -1.0f,  0.0f,  0.0f,
		-0.5f, -0.5f, -0.5f, -1.0f,  0.0f,  0.0f,
		-0.5f, -0.5f, -0.5f, -1.0f,  0.0f,  0.0f,
		-0.5f, -0.5f,  0.5f, -1.0f,  0.0f,  0.0f,
		-0.5f,  0.5f,  0.5f, -1.0f,  0.0f,  0.0f,

		 0.5f,  0.5f,  0.5f,  1.0f,  0.0f,  0.0f,
		 0.5f,  0.5f, -0.5f,  1.0f,  0.0f,  0.0f,
		 0.5f, -0.5f, -0.5f,  1.0f,  0.0f,  0.0f,
		 0.5f, -0.5f, -0.5f,  1.0f,  0.0f,  0.0f,
		 0.5f, -0.5f,  0.5f,  1.0f,  0.0f,  0.0f,
		 0.5f,  0.5f,  0.5f,  1.0f,  0.0f,  0.0f,

		-0.5f, -0.5f, -0.5f,  0.0f, -1.0f,  0.0f,
		 0.5f, -0.5f, -0.5f,  0.0f, -1.0f,  0.0f,
		 0.5f, -0.5f,  0.5f,  0.0f, -1.0f,  0.0f,
		 0.5f, -0.5f,  0.5f,  0.0f, -1.0f,  0.0f,
		-0.5f, -0.5f,  0.5f,  0.0f, -1.0f,  0.0f,
		-0.5f, -0.5f, -0.5f,  0.0f, -1.0f,  0.0f,

		-0.5f,  0.5f, -0.5f,  0.0f,  1.0f,  0.0f,
		 0.5f,  0.5f, -0.5f,  0.0f,  1.0f,  0.0f,
		 0.5f,  0.5f,  0.5f,  0.0f,  1.0f,  0.0f,
		 0.5f,  0.5f,  0.5f,  0.0f,  1.0f,  0.0f,
		-0.5f,  0.5f,  0.5f,  0.0f,  1.0f,  0.0f,
		-0.5f,  0.5f, -0.5f,  0.0f,  1.0f,  0.0f
	};
	glm::vec3 cubePositions[] = {
	  glm::vec3(0.0f,  0.0f,  0.0f),
	  glm::vec3(2.0f,  5.0f, -15.0f),
	  glm::vec3(-1.5f, -2.2f, -2.5f),
	  glm::vec3(-3.8f, -2.0f, -12.3f),
	  glm::vec3(2.4f, -0.4f, -3.5f),
	  glm::vec3(-1.7f,  3.0f, -7.5f),
	  glm::vec3(1.3f, -2.0f, -2.5f),
	  glm::vec3(1.5f,  2.0f, -2.5f),
	  glm::vec3(1.5f,  0.2f, -1.5f),
	  glm::vec3(-1.3f,  1.0f, -1.5f)
	};
	unsigned int VBO, VAO, lightVAO;
	glGenBuffers(1, &VBO);
	glGenVertexArrays(1, &VAO);
	glBindVertexArray(VAO);
	glBindBuffer(GL_ARRAY_BUFFER, VBO);
	glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);	//第一个是类型，第二个是大小，第三个是数据
	glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 6 * sizeof(float), (void*)0);
	glEnableVertexAttribArray(0);
	glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 6 * sizeof(float), (void*)0);
	glEnableVertexAttribArray(1);
	glEnable(GL_DEPTH_TEST);

	glGenVertexArrays(1, &lightVAO);
	glBindVertexArray(lightVAO);
	glBindBuffer(GL_ARRAY_BUFFER, VBO);
	glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 6 * sizeof(float), (void*)0);
	glEnableVertexAttribArray(0);

	glm::vec3 lightPos(0.2f, 0.5f, 0.0f);
	glm::mat4 view = glm::mat4(1.0f), projection = glm::mat4(1.0f);

	while (!glfwWindowShouldClose(window))
	{
		processInput(window);
		glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
		glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
		
		Cubeshader.use();
		Cubeshader.setvec3("lightcolor", 1.0f, 1.0f, 1.0f);
		Cubeshader.setvec3("objectcolor", 0.5f, 1.0f, 0.4f);
		Cubeshader.setvec3("lightPos", 0.2f, 0.5f, 0.0f);
		Cubeshader.setvec3("viewPos", cameraPos);

		for (unsigned int i = 0; i < 10; i++)
		{
			glm::mat4 model = glm::mat4(1.0f);
			model = glm::translate(model, cubePositions[i]);
			model = glm::rotate(model, glm::radians(20.0f*i), glm::vec3(1.0f, 0.2f, 0.3f));
			view = glm::lookAt(cameraPos, cameraPos + cameraFront, cameraUp);
			projection = glm::perspective(glm::radians(45.0f), (float)800 / (float)600, 0.1f, 100.0f);
			Cubeshader.setMat4("model", model);
			Cubeshader.setMat4("view", view);
			Cubeshader.setMat4("projection", projection);
			glBindVertexArray(VAO);
			glDrawArrays(GL_TRIANGLES, 0, 36);
		}
		lightshader.use();
		glm::mat4 model(1.0f);
		model = glm::translate(model, lightPos);
		view = glm::lookAt(cameraPos, cameraPos + cameraFront, cameraUp);
		projection = glm::perspective(glm::radians(45.0f), (float)800 / (float)600, 0.1f, 100.0f);
		lightshader.setMat4("model", model);
		lightshader.setMat4("view", view);
		lightshader.setMat4("projection", projection);
		glBindVertexArray(lightVAO);
		glDrawArrays(GL_TRIANGLES, 0, 36);
		glfwSwapBuffers(window);
		glfwPollEvents();
	}
	glDeleteVertexArrays(1, &VAO);
	glDeleteBuffers(1, &VBO);
	//关闭窗口
	glfwTerminate();
	return 0;
}

vertexshader

#version 330 core
layout (location=0) in vec3 aPos;
layout (location=1) in vec3 aNormal;

uniform mat4 transform, model, view, projection;
out vec3 Normal, FragPos;

void main()
{
	gl_Position = projection * view * model * vec4(aPos, 1.0);
	FragPos = vec3(model * vec4(aPos, 1.0));
	Normal = mat3(transpose(inverse(model))) * aNormal;
}

fragment shader

#version 330 core
out vec4 fragColor;
in vec3 Normal, FragPos;
uniform vec3 lightcolor, objectcolor, lightPos, viewPos;
void main()
{
	float ambientstrength = 0.1;
	vec3 ambient = ambientstrength * lightcolor;

	vec3 norm = normalize(Normal);
	vec3 lightDir = normalize(lightPos - FragPos);
	float diff = max(dot(norm, lightDir), 0.0);
	vec3 diffuse = diff * lightcolor;

	float specularStrength = 0.5;
	vec3 ViewDir = normalize(viewPos-FragPos);
	vec3 reflectDir = reflect(-lightDir, norm);
	float spec = pow(max(dot(ViewDir, reflectDir),0.0), 32);
	vec3 specular = specularStrength * spec * lightcolor;


	vec3 result = (ambient + diffuse + specular) * objectcolor;
	fragColor = vec4(result, 1.0f);
}

shader类

#ifndef SHADER_H
#endif SHADER_H

#include<glad/glad.h>
#include<string>
#include<fstream>
#include<sstream>
#include<iostream>
#include<glm/glm.hpp>
#include<glm/gtc/matrix_transform.hpp>
#include<glm/gtc/type_ptr.hpp>

class Shader
{
public:
	unsigned int ID;
	Shader(const char* vertexPath, const char* fragmentPath)
	{
		using namespace std;
		string vertexCode;
		string fragmentCode;
		ifstream vShaderFile;
		ifstream fShaderFile;
		vShaderFile.exceptions(ifstream::failbit | ifstream::badbit);
		fShaderFile.exceptions(ifstream::failbit | ifstream::badbit);
		try
		{
			vShaderFile.open(vertexPath);
			fShaderFile.open(fragmentPath);
			stringstream vShaderStream, fShaderStream;
			vShaderStream << vShaderFile.rdbuf();
			fShaderStream << fShaderFile.rdbuf();
			vShaderFile.close();
			fShaderFile.close();
			vertexCode = vShaderStream.str();
			fragmentCode = fShaderStream.str();
		}
		catch (ifstream::failure e)
		{
			cout << "ERROR::SHADER::FILE_NOT_SUCCESSFULLY_READ" << endl;
		}
		const char* vShaderCode = vertexCode.c_str();
		const char* fShaderCode = fragmentCode.c_str();
		unsigned int vertexShader, fragmentShader;
		vertexShader = glCreateShader(GL_VERTEX_SHADER);
		glShaderSource(vertexShader, 1, &vShaderCode, NULL);
		glCompileShader(vertexShader);
		int success;
		char infolog[512];
		glGetShaderiv(vertexShader, GL_COMPILE_STATUS, &success);
		if (!success)
		{
			glGetShaderInfoLog(vertexShader, 512, NULL, infolog);
			cout << "ERROR::SHADER::VERTEX::COMPILATION_FAILED\n" << infolog << endl;
		}
		fragmentShader = glCreateShader(GL_FRAGMENT_SHADER);
		glShaderSource(fragmentShader, 1, &fShaderCode, NULL);
		glCompileShader(fragmentShader);
		glGetShaderiv(fragmentShader, GL_COMPILE_STATUS, &success);
		if (!success)
		{
			glGetShaderInfoLog(fragmentShader, 512, NULL, infolog);
			cout << "ERROR::SHADER::FRAGMENT::COMPILATION_FAILED\n" << infolog << endl;
		}
		ID = glCreateProgram();
		glAttachShader(ID, vertexShader);
		glAttachShader(ID, fragmentShader);
		glLinkProgram(ID);
		glGetProgramiv(ID, GL_LINK_STATUS, &success);
		if (!success)
		{
			glGetProgramInfoLog(ID, 512, NULL, infolog);
			cout << "ERROR::SHADER::PROGRAM::LINKING_FAILED\n" << infolog << endl;
		}
		glDeleteShader(vertexShader);
		glDeleteShader(fragmentShader);
	}
	void use()
	{
		glUseProgram(ID);
	}
	void setMat4(const std::string &name, const glm::mat4 &mat)
	{
		glUniformMatrix4fv(glGetUniformLocation(ID, name.c_str()), 1, GL_FALSE, glm::value_ptr(mat));
	}
	void setvec3(const std::string &name, const glm::vec3 &vec)
	{
		glUniform3fv(glGetUniformLocation(ID, name.c_str()), 1, glm::value_ptr(vec));
	}
	void setvec3(const std::string &name, float x, float y, float z) const
	{
		glUniform3f(glGetUniformLocation(ID, name.c_str()), x, y, z);
	}
};

4|0材质

物体材质：

struct Material {
    vec3 ambient;
    vec3 diffuse;
    vec3 specular;
    float shininess;
}; 

uniform Material material;

光照参数：

struct Light {
	vec3 position;
	vec3 ambient;
	vec3 diffuse;
	vec3 specular;
};

uniform Light light;

最后的计算就要直接用material的颜色乘光的颜色

void main()
{
	vec3 ambient = light.ambient * material.ambient;

	vec3 norm = normalize(Normal);
	vec3 lightDir = normalize(light.position - FragPos);
	float diff = max(dot(norm, lightDir), 0.0);
	vec3 diffuse = diff * light.diffuse * material.diffuse;

	vec3 ViewDir = normalize(viewPos-FragPos);
	vec3 reflectDir = reflect(-light.position, norm);
	float spec = pow(max(dot(ViewDir, reflectDir),0.0), material.shininess);
	vec3 specular = spec * light.specular * material.specular;


	vec3 result = ambient + diffuse + specular;
	fragColor = vec4(result, 1.0f);
}

fragmentshader

#version 330 core
struct Material{
	vec3 ambient;
	vec3 diffuse;
	vec3 specular;
	float shininess;
};
struct Light {
	vec3 position;
	vec3 ambient;
	vec3 diffuse;
	vec3 specular;
};
uniform Light light;
uniform Material material;
out vec4 fragColor;
in vec3 Normal, FragPos;
in vec2 TexCoords;
uniform vec3 viewPos;
void main()
{
	vec3 ambient = light.ambient * material.ambient;

	vec3 norm = normalize(Normal);
	vec3 lightDir = normalize(light.position - FragPos);
	float diff = max(dot(norm, lightDir), 0.0);
	vec3 diffuse = diff * light.diffuse * material.diffuse;

	vec3 ViewDir = normalize(viewPos-FragPos);
	vec3 reflectDir = reflect(-lightDir, norm);  //哭死，之前写成reflect(-light.position, norm)调了一天的bug
	float spec = pow(max(dot(ViewDir, reflectDir),0.0), material.shininess);
	vec3 specular = spec * light.specular * material.specular;


	vec3 result = ambient + diffuse + specular;
	fragColor = vec4(result, 1.0f);
}

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__EOF__

本文作者：Liujiahang
本文链接：https://www.cnblogs.com/IamIron-Man/p/16616743.html
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posted @ 2022-08-23 16:20 IamIron-Man 阅读(65) 评论(0) 编辑收藏举报

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