定向光:无线远的光源每条光线接近平行
需要定义从光源出发的方向direction。但计算时使用的是从片段指向光源的方向
点光源:从一个位置向所有方向发散光。
需要根据距离计算光的衰减。要定义constant,linear,quadratic设置三个参数作为衰减公式的参数。以及光源的位置position
聚光:位于环境中某处的光源,只朝一个方向照射。如手电筒,路灯
需要定义光源位置position,光的方向direction,光照角度cutOff。以此计算LightDir:片段指向光源的方向,SpotDir聚光所指方向,Phiϕ聚光半径的切光角,Thetaθ聚光方向SpotDir与片段和光源方向LightDir的夹角。θ小于ϕ时才会被聚光照亮。
切光角会分为内部切光角cutOff,外部切光角outerCutOff。通过公式计算亮度,来使聚光的边缘更平滑。
main.cpp
#define GLEW_STATIC
#include <GL/glew.h>
#include <GLFW/glfw3.h>
#include <iostream>
#include "shader.h"
#include "stb_image.h"
#include <glm.hpp>
#include <gtc/matrix_transform.hpp>
#include <gtc/type_ptr.hpp>
#include "Camera.h"
GLfloat vertices[] = {
// positions // normals // texture coords
-0.5f, -0.5f, -0.5f, 0.0f, 0.0f, -1.0f, 0.0f, 0.0f,
0.5f, -0.5f, -0.5f, 0.0f, 0.0f, -1.0f, 1.0f, 0.0f,
0.5f, 0.5f, -0.5f, 0.0f, 0.0f, -1.0f, 1.0f, 1.0f,
0.5f, 0.5f, -0.5f, 0.0f, 0.0f, -1.0f, 1.0f, 1.0f,
-0.5f, 0.5f, -0.5f, 0.0f, 0.0f, -1.0f, 0.0f, 1.0f,
-0.5f, -0.5f, -0.5f, 0.0f, 0.0f, -1.0f, 0.0f, 0.0f,
-0.5f, -0.5f, 0.5f, 0.0f, 0.0f, 1.0f, 0.0f, 0.0f,
0.5f, -0.5f, 0.5f, 0.0f, 0.0f, 1.0f, 1.0f, 0.0f,
0.5f, 0.5f, 0.5f, 0.0f, 0.0f, 1.0f, 1.0f, 1.0f,
0.5f, 0.5f, 0.5f, 0.0f, 0.0f, 1.0f, 1.0f, 1.0f,
-0.5f, 0.5f, 0.5f, 0.0f, 0.0f, 1.0f, 0.0f, 1.0f,
-0.5f, -0.5f, 0.5f, 0.0f, 0.0f, 1.0f, 0.0f, 0.0f,
-0.5f, 0.5f, 0.5f, -1.0f, 0.0f, 0.0f, 1.0f, 0.0f,
-0.5f, 0.5f, -0.5f, -1.0f, 0.0f, 0.0f, 1.0f, 1.0f,
-0.5f, -0.5f, -0.5f, -1.0f, 0.0f, 0.0f, 0.0f, 1.0f,
-0.5f, -0.5f, -0.5f, -1.0f, 0.0f, 0.0f, 0.0f, 1.0f,
-0.5f, -0.5f, 0.5f, -1.0f, 0.0f, 0.0f, 0.0f, 0.0f,
-0.5f, 0.5f, 0.5f, -1.0f, 0.0f, 0.0f, 1.0f, 0.0f,
0.5f, 0.5f, 0.5f, 1.0f, 0.0f, 0.0f, 1.0f, 0.0f,
0.5f, 0.5f, -0.5f, 1.0f, 0.0f, 0.0f, 1.0f, 1.0f,
0.5f, -0.5f, -0.5f, 1.0f, 0.0f, 0.0f, 0.0f, 1.0f,
0.5f, -0.5f, -0.5f, 1.0f, 0.0f, 0.0f, 0.0f, 1.0f,
0.5f, -0.5f, 0.5f, 1.0f, 0.0f, 0.0f, 0.0f, 0.0f,
0.5f, 0.5f, 0.5f, 1.0f, 0.0f, 0.0f, 1.0f, 0.0f,
-0.5f, -0.5f, -0.5f, 0.0f, -1.0f, 0.0f, 0.0f, 1.0f,
0.5f, -0.5f, -0.5f, 0.0f, -1.0f, 0.0f, 1.0f, 1.0f,
0.5f, -0.5f, 0.5f, 0.0f, -1.0f, 0.0f, 1.0f, 0.0f,
0.5f, -0.5f, 0.5f, 0.0f, -1.0f, 0.0f, 1.0f, 0.0f,
-0.5f, -0.5f, 0.5f, 0.0f, -1.0f, 0.0f, 0.0f, 0.0f,
-0.5f, -0.5f, -0.5f, 0.0f, -1.0f, 0.0f, 0.0f, 1.0f,
-0.5f, 0.5f, -0.5f, 0.0f, 1.0f, 0.0f, 0.0f, 1.0f,
0.5f, 0.5f, -0.5f, 0.0f, 1.0f, 0.0f, 1.0f, 1.0f,
0.5f, 0.5f, 0.5f, 0.0f, 1.0f, 0.0f, 1.0f, 0.0f,
0.5f, 0.5f, 0.5f, 0.0f, 1.0f, 0.0f, 1.0f, 0.0f,
-0.5f, 0.5f, 0.5f, 0.0f, 1.0f, 0.0f, 0.0f, 0.0f,
-0.5f, 0.5f, -0.5f, 0.0f, 1.0f, 0.0f, 0.0f, 1.0f
};
Camera* myCamera = new Camera(glm::vec3(0.0f, 0.0f, 3.0f), glm::vec3(0.0f, 0.0f, -1.0f), glm::vec3(0.0f, 1.0f, 0.0f));
void mouse_callback(GLFWwindow* window, double xpos, double ypos) {
myCamera->mouseCb(xpos, ypos);
};
void scroll_callback(GLFWwindow* window, double xoffset, double yoffset)
{
myCamera->scrollCb(xoffset, yoffset);
}
GLfloat deltaTime = 0.0f;
GLfloat lastFrame = 0.0f;
void processInput(GLFWwindow* window) {
GLfloat currentFrame = glfwGetTime();
deltaTime = currentFrame - lastFrame;
lastFrame = currentFrame;
if (glfwGetKey(window, GLFW_KEY_ESCAPE) == GLFW_PRESS)
glfwSetWindowShouldClose(window, true);
if (glfwGetKey(window, GLFW_KEY_W) == GLFW_PRESS) {
myCamera->pressKeyW(deltaTime);
}
if (glfwGetKey(window, GLFW_KEY_S) == GLFW_PRESS) {
myCamera->pressKeyS(deltaTime);
}
if (glfwGetKey(window, GLFW_KEY_A) == GLFW_PRESS) {
myCamera->pressKeyA(deltaTime);
}
if (glfwGetKey(window, GLFW_KEY_D) == GLFW_PRESS) {
myCamera->pressKeyD(deltaTime);
}
}
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)
};
glm::vec3 lightPos(1.2f, 1.0f, 2.0f);//声明全局变量表示光源在场景的坐标
int main()
{
glfwInit();
glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
GLFWwindow* window = glfwCreateWindow(800, 600, "test", nullptr, nullptr);
if (window == nullptr)
{
std::cout << "Failed to create GLFW window" << std::endl;
glfwTerminate();
return -1;
}
glfwMakeContextCurrent(window);
//glfwSetInputMode(window, GLFW_CURSOR, GLFW_CURSOR_DISABLED);
glfwSetCursorPosCallback(window, mouse_callback);
glfwSetScrollCallback(window, scroll_callback);
glewExperimental = GL_TRUE;
if (glewInit() != GLEW_OK)
{
std::cout << "Failed to initialize GLEW" << std::endl;
glfwTerminate();
return -1;
}
glViewport(0, 0, 800, 600);
GLuint VAO;
glGenVertexArrays(1, &VAO);
glBindVertexArray(VAO);
GLuint VBO;
glGenBuffers(1, &VBO);
glBindBuffer(GL_ARRAY_BUFFER, VBO);
glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(GLfloat), (GLvoid*)0);
glEnableVertexAttribArray(0);
glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(GLfloat), (GLvoid*)(3* sizeof(GLfloat)));
glEnableVertexAttribArray(1);
glVertexAttribPointer(2, 2, GL_FLOAT, GL_FALSE, 8 * sizeof(GLfloat), (GLvoid*)(6 * sizeof(GLfloat)));
glEnableVertexAttribArray(2);
GLuint lightVAO;
glGenVertexArrays(1, &lightVAO);
glBindVertexArray(lightVAO);
// 只需要绑定VBO不用再次设置VBO的数据,因为容器(物体)的VBO数据中已经包含了正确的立方体顶点数据
glBindBuffer(GL_ARRAY_BUFFER, VBO);
glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(GLfloat), (GLvoid*)0);
glEnableVertexAttribArray(0);
glBindVertexArray(0);
int width, height;
unsigned char* image = stbi_load("container2.png", &width, &height, 0, 0);
GLuint tex;
glGenTextures(1, &tex);
glBindTexture(GL_TEXTURE_2D, tex);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, image);
glGenerateMipmap(GL_TEXTURE_2D);
unsigned char* image1 = stbi_load("container2_specular.png", &width, &height, 0, 0);
GLuint tex1;
glGenTextures(1, &tex1);
glActiveTexture(GL_TEXTURE1);
glBindTexture(GL_TEXTURE_2D, tex1);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, image1);
glGenerateMipmap(GL_TEXTURE_2D);
glm::mat4 model;
glm::mat4 view;
glm::mat4 projection;
glEnable(GL_DEPTH_TEST);
Shader* testShader = new Shader("test.vert", "test.frag");
glm::vec3 lightColor(0.33f, 0.42f, 0.18f);
glm::vec3 toyColor(1.0f, 0.5f, 0.31f);
glm::vec3 result = lightColor * toyColor; // = (0.33f, 0.21f, 0.06f);
//保持灯不受其他光照影响一直明亮,创建另外一套着色器。
Shader* lightShader = new Shader("test.vert", "light.frag");
while (!glfwWindowShouldClose(window))
{
processInput(window);
glfwPollEvents();
glClearColor(0.1f, 0.1f, 0.1f, 1.0f);
glClear(GL_COLOR_BUFFER_BIT| GL_DEPTH_BUFFER_BIT);
testShader->Use();
glActiveTexture(GL_TEXTURE0);
glBindTexture(GL_TEXTURE_2D, tex);
glUniform1i(glGetUniformLocation(testShader->getProgram(), "material.diffuse"), 0);
glActiveTexture(GL_TEXTURE1);
glBindTexture(GL_TEXTURE_2D, tex1);
glUniform1i(glGetUniformLocation(testShader->getProgram(), "material.specular"), 1);
glUniform1f(glGetUniformLocation(testShader->getProgram(), "material.shininess"), 32.0f);
glUniform3f(glGetUniformLocation(testShader->getProgram(), "objectColor"), 1.0f, 0.5f, 0.31f);// 设置物体颜色珊瑚红
glUniform3f(glGetUniformLocation(testShader->getProgram(), "lightColor"), 1.0f, 1.0f, 1.0f); // 把光源设置为白色
view = myCamera->getViewMat4();
glUniformMatrix4fv(glGetUniformLocation(testShader->getProgram(), "view"), 1, GL_FALSE, glm::value_ptr(view));
projection = glm::perspective(glm::radians(myCamera->getFov()), 800.0f / 600.0f, 0.1f, 100.0f);
glUniformMatrix4fv(glGetUniformLocation(testShader->getProgram(), "projection"), 1, GL_FALSE, glm::value_ptr(projection));
//定向光
//glUniform3f(glGetUniformLocation(testShader->getProgram(), "light.direction"), -0.2f, -1.0f, -0.3f);
//点光源
/*glUniform1f(glGetUniformLocation(testShader->getProgram(), "light.constant"), 1.0f);
glUniform1f(glGetUniformLocation(testShader->getProgram(), "light.linear"), 0.09);
glUniform1f(glGetUniformLocation(testShader->getProgram(), "light.quadratic"), 0.032);*/
//聚光
glm::vec3 cameraFront = myCamera->getCameraPos();
glUniform3f(glGetUniformLocation(testShader->getProgram(), "light.direction"), cameraFront.x, cameraFront.y, cameraFront.z);
glUniform1f(glGetUniformLocation(testShader->getProgram(), "light.cutOff"), glm::cos(glm::radians(12.5f)));
glUniform1f(glGetUniformLocation(testShader->getProgram(), "light.outerCutOff"), glm::cos(glm::radians(17.5f)));
glUniform3f(glGetUniformLocation(testShader->getProgram(), "light.position"), lightPos.x, lightPos.y, lightPos.z);
glUniform3f(glGetUniformLocation(testShader->getProgram(), "light.ambient"), 0.1f, 0.1f, 0.1f);
glUniform3f(glGetUniformLocation(testShader->getProgram(), "light.diffuse"), 0.8f, 0.8f, 0.8f);
glUniform3f(glGetUniformLocation(testShader->getProgram(), "light.specular"), 1.0f, 1.0f, 1.0f);
glUniform1f(glGetUniformLocation(testShader->getProgram(), "light.constant"), 1.0f);
glUniform1f(glGetUniformLocation(testShader->getProgram(), "light.linear"), 0.09);
glUniform1f(glGetUniformLocation(testShader->getProgram(), "light.quadratic"), 0.032);
glm::vec3 viewPos = myCamera->getCameraPos();
glUniform3f(glGetUniformLocation(testShader->getProgram(), "viewPos"), viewPos.x, viewPos.y, viewPos.z);
glBindVertexArray(VAO);
for (GLuint i = 0; i < 10; i++)
{
model = glm::mat4();
model = glm::translate(model, cubePositions[i]);
GLfloat angle = 20.0f * i;
model = glm::rotate(model, angle, glm::vec3(1.0f, 0.3f, 0.5f));
glUniformMatrix4fv(glGetUniformLocation(testShader->getProgram(), "model"), 1, GL_FALSE, glm::value_ptr(model));
glDrawArrays(GL_TRIANGLES, 0, 36);
}
glBindVertexArray(lightVAO);
//平移灯源位置到lightPos
model = glm::mat4();
model = glm::translate(model, lightPos);
model = glm::scale(model, glm::vec3(0.2f));
lightShader->Use();
glUniformMatrix4fv(glGetUniformLocation(lightShader->getProgram(), "model"), 1, GL_FALSE, glm::value_ptr(model));
glUniformMatrix4fv(glGetUniformLocation(lightShader->getProgram(), "view"), 1, GL_FALSE, glm::value_ptr(view));
glUniformMatrix4fv(glGetUniformLocation(lightShader->getProgram(), "projection"), 1, GL_FALSE, glm::value_ptr(projection));
// 绘制灯立方体对象
glDrawArrays(GL_TRIANGLES, 0, 36);
glBindVertexArray(0);
glfwSwapBuffers(window);
}
glfwTerminate();
return 0;
}
顶点着色器
#version 330 core
layout (location = 0) in vec3 position;
layout (location = 1) in vec3 normal; //面的法向量
layout (location = 2) in vec2 texCoords;
uniform mat4 model;
uniform mat4 view;
uniform mat4 projection;
out vec3 Normal;
out vec3 FragPos; //片段位置
out vec2 TexCoords;
void main()
{
gl_Position = projection * view * model * vec4(position, 1.0);
FragPos = vec3(model * vec4(position, 1.0f));
Normal = mat3(transpose(inverse(model))) * normal;
TexCoords = texCoords;
}
片段着色器
#version 330 core
out vec4 color;
in vec3 Normal;
in vec3 FragPos;
uniform vec3 objectColor;
uniform vec3 lightColor;
//物体的材质属性
struct Material
{
sampler2D diffuse;
sampler2D specular;
float shininess;
};
uniform Material material;
uniform vec3 viewPos;
in vec2 TexCoords;
/* 定向光
//光的属性
struct Light
{
//vec3 position; //投光不需要光的位置,因为光的位置无线远,所有光线当作平行线处理
vec3 direction; //定向光,以光源为起点的向量
vec3 ambient;
vec3 diffuse;
vec3 specular;
};*/
/*
//点光源,定向衰减
struct Light
{
vec3 position;
vec3 ambient;
vec3 diffuse;
vec3 specular;
float constant;
float linear;
float quadratic;
}; */
//聚光,位于环境某处的光源,不向所有方向照射,只朝某个方向,只有一定照射方向的确定半径内的物品才被照亮。(路灯/手电筒)
struct Light
{
vec3 position;
vec3 direction;
float cutOff; //切光角
float outerCutOff; //外切角
vec3 ambient;
vec3 diffuse;
vec3 specular;
float constant;
float linear;
float quadratic;
};
uniform Light light;
void main()
{
//vec3 lightDir = normalize(-light.direction); 定向光
vec3 lightDir = normalize(light.position - FragPos);
float theta = dot(lightDir, normalize(light.direction));
float epsilon = light.cutOff - light.outerCutOff;
float intensity = clamp((theta - light.outerCutOff) / epsilon,0.0, 1.0);
/*if(theta > light.cutOff) //90°以内,cos余弦值越大,夹角越小
{
// 执行光照计算
vec3 ambient = light.ambient * vec3(texture(material.diffuse, TexCoords));
vec3 norm = normalize(Normal);
float diff = max(dot(norm, lightDir), 0.0);
vec3 diffuse = light.diffuse * diff * vec3(texture(material.diffuse, TexCoords));
vec3 viewDir = normalize(viewPos - FragPos);
vec3 reflectDir = reflect(-lightDir, norm);
float spec = pow(max(dot(viewDir, reflectDir), 0.0), material.shininess);
vec3 specular = light.specular * spec * vec3(texture(material.specular, TexCoords));
float distance = length(light.position - FragPos);//光源的距离
float attenuation = 1.0f / (light.constant + light.linear*distance +light.quadratic*(distance*distance));
//多个光源的时候,ambient会开始叠加,这时一般也要衰减,看具体效果
//vec3 result = ambient + diffuse + specular;
//result = result * attenuation;
diffuse *= attenuation;
specular *= attenuation;
color = vec4(ambient + diffuse + specular, 1.0f);
}
else // 否则使用环境光,使得场景不至于完全黑暗
color = vec4(light.ambient*vec3(texture(material.diffuse,TexCoords)), 1.0f);*/
vec3 ambient = light.ambient * vec3(texture(material.diffuse, TexCoords));
vec3 norm = normalize(Normal);
float diff = max(dot(norm, lightDir), 0.0);
vec3 diffuse = light.diffuse * diff * vec3(texture(material.diffuse, TexCoords));
vec3 viewDir = normalize(viewPos - FragPos);
vec3 reflectDir = reflect(-lightDir, norm);
float spec = pow(max(dot(viewDir, reflectDir), 0.0), material.shininess);
vec3 specular = light.specular * spec * vec3(texture(material.specular, TexCoords));
float distance = length(light.position - FragPos);//光源的距离
float attenuation = 1.0f / (light.constant + light.linear*distance +light.quadratic*(distance*distance));
//多个光源的时候,ambient会开始叠加,这时一般也要衰减,看具体效果
//vec3 result = ambient + diffuse + specular;
//result = result * attenuation;
diffuse *= attenuation;
specular *= attenuation;
diffuse *= intensity;
specular *= intensity;
color = vec4(ambient + diffuse + specular, 1.0f);
}