OpenGL学习笔记八——使用结构体创建材质
前言
光照基础链接：
OpenGL结构体的创建
OpenGL可支持自定义结构体，其形式与C/C++类似，示例代码如下：
#version 330 core
//创建结构体
struct Material {
vec3 ambient;
vec3 diffuse;
vec3 specular;
float shininess;
};
uniform Material material;//定义一个Material变量
在冯氏光照模型的基础上，我们将冯氏光照模型的三个组成成分封装成为一个结构体，便于对光照参数进行统一管理，这个结构体便是所谓的材质
材质可以简单理解为一个参数集合体，来控制物体的基本属性。
这样，我们就能提高代码的复用性，通过一套shader实现多种效果。
示例程序：
示例程序在冯氏光照模型的基础上进行改动：
顶点着色器
#version 330 core
layout (location = 0) in vec3 aPos;
layout (location = 1) in vec3 aNormal;
out vec3 FragPos;
out vec3 Normal;
uniform mat4 model;
uniform mat4 view;
uniform mat4 projection;
void main()
{
FragPos = vec3(model * vec4(aPos, 1.0));
Normal = mat3(transpose(inverse(model))) * aNormal;
gl_Position = projection * view * vec4(FragPos, 1.0);
}
片元着色器
#version 330 core
out vec4 FragColor;
in vec3 Normal;
in vec3 FragPos;
uniform vec3 viewPos;
uniform vec3 objectColor;
struct Light{
vec3 lightPos;
vec3 lightColor;
float shininess;
};
uniform Light material;
void main()
{
// ambient
float ambientStrength = 0.1;
vec3 ambient = ambientStrength * material.lightColor;
// diffuse
vec3 norm = normalize(Normal);
vec3 lightDir = normalize(material.lightPos - FragPos);
float diff = max(dot(norm, lightDir), 0.0);
vec3 diffuse = diff * material.lightColor;
// specular
float specularStrength = 0.5;
vec3 viewDir = normalize(viewPos - FragPos);
vec3 reflectDir = reflect(-lightDir, norm);
float spec = pow(max(dot(viewDir, reflectDir), 0.0), material.shininess);
vec3 specular = specularStrength * spec * material.lightColor;
vec3 result = (ambient + diffuse + specular) * objectColor;
FragColor = vec4(result, 1.0);
}
#include <glad/glad.h>
#include <GLFW/glfw3.h>
#include <glm/glm.hpp>
#include <glm/gtc/matrix_transform.hpp>
#include <glm/gtc/type_ptr.hpp>
//#include"camera.h"
#include <iostream>
using namespace std;
void framebuffer_size_callback(GLFWwindow* window, int width, int height);
void processInput(GLFWwindow *window);
// settings
const unsigned int SCR_WIDTH = 800;
const unsigned int SCR_HEIGHT = 600;
// camera
//Camera camera(glm::vec3(0.0f, 0.0f, 3.0f));
float lastX = SCR_WIDTH / 2.0f;
float lastY = SCR_HEIGHT / 2.0f;
bool firstMouse = true;
// timing
float deltaTime = 0.0f;
float lastFrame = 0.0f;
// lighting
glm::vec3 lightPos(1.2f, 1.0f, 2.0f);
const char *vertexShaderSource =
"#version 330 core\n"
"layout(location = 0) in vec3 aPos;\n"
"layout(location = 1) in vec3 aNormal;\n"
"out vec3 FragPos;\n"
"out vec3 Normal;\n"
"uniform mat4 model;\n"
"uniform mat4 view;\n"
"uniform mat4 projection;\n"
"void main()\n"
"{\n"
"FragPos = vec3(model * vec4(aPos, 1.0));\n"
"Normal = aNormal;\n"
"gl_Position = projection * view * vec4(FragPos, 1.0);\n"
"}\n";
const char *fragmentShaderSource =
"#version 330 core\n"
"out vec4 FragColor;\n"
"in vec3 Normal;\n"
"in vec3 FragPos;\n"
"uniform vec3 viewPos;\n"
"uniform vec3 objectColor;\n"
"struct Light {\n"
"float shininess;\n"
"vec3 lightPos;\n"
"vec3 lightColor;\n"
"};\n"
"uniform Light material;\n"
"void main()\n"
"{\n"
// ambient
"float ambientStrength = 0.1;\n"
"vec3 ambient = ambientStrength * material.lightColor;\n"
// diffuse
"vec3 norm = normalize(Normal);\n"
"vec3 lightDir = normalize(material.lightPos - FragPos);\n"
"float diff = max(dot(norm, lightDir), 0.0);\n"
"vec3 diffuse = diff * material.lightColor;\n"
// specular
"float specularStrength = 0.5;\n"
"vec3 viewDir = normalize(viewPos - FragPos);\n"
"vec3 reflectDir = reflect(-lightDir, norm);\n"
"float spec = pow(max(dot(viewDir, reflectDir), 0.0), material.shininess);\n"
"vec3 specular = specularStrength * spec * material.lightColor;\n"
"vec3 result = (ambient + diffuse + specular) * objectColor;\n"
"FragColor = vec4(result, 1.0);\n"
"}";
int main()
{
//初始化
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
GLFWwindow* window = glfwCreateWindow(SCR_WIDTH, SCR_HEIGHT, "LearnOpenGL", NULL, NULL);
if (window == NULL)
{
std::cout << "Failed to create GLFW window" << std::endl;
glfwTerminate();
return -1;
}
glfwMakeContextCurrent(window);
glfwSetFramebufferSizeCallback(window, framebuffer_size_callback);
// 错误提示信息
if (!gladLoadGLLoader((GLADloadproc)glfwGetProcAddress))
{
std::cout << "Failed to initialize GLAD" << std::endl;
return -1;
}
// 开启深度测试（深度值粗略可视为与相机近平面的距离）
glEnable(GL_DEPTH_TEST);
//VertexShader创建顶点着色器
int vertexShader = glCreateShader(GL_VERTEX_SHADER);
glShaderSource(vertexShader, 1, &vertexShaderSource, NULL);
glCompileShader(vertexShader);
//Info获取编译出错信息
int success;
char info[512];
glGetShaderiv(vertexShader, GL_COMPILE_STATUS, &success);
if (!success)
{
glGetShaderInfoLog(vertexShader, 512, NULL, info);
std::cout << "ERROR::SHADER::VERTEX::COMPILATION_FAILED\n" << info << std::endl;
}
//片元着色器
int fragmentShader = glCreateShader(GL_FRAGMENT_SHADER);
glShaderSource(fragmentShader, 1, &fragmentShaderSource, NULL);
glCompileShader(fragmentShader);
//编译信息
glGetShaderiv(fragmentShader, GL_COMPILE_STATUS, &success);
if (!success)
{
glGetShaderInfoLog(fragmentShader, 512, NULL, info);
std::cout << "ERROR::SHADER::FRAGMENT::COMPILATION_FAILED\n" << info << std::endl;
}
//shaderProgramshader程序
int shaderProgram = glCreateProgram();
glAttachShader(shaderProgram, vertexShader);
glAttachShader(shaderProgram, fragmentShader);
glLinkProgram(shaderProgram);
glGetProgramiv(shaderProgram, GL_LINK_STATUS, &success);
if (!success)
{
glGetProgramInfoLog(shaderProgram, 512, NULL, info);
std::cout << "ERROR::SHADER::PROGRAM::LINKING_FAILED\n" << info << std::endl;
}
glDeleteShader(vertexShader);
glDeleteShader(fragmentShader);
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
};
// first, configure the cube's VAO (and VBO)
unsigned int VBO, cubeVAO;
glGenVertexArrays(1, &cubeVAO);
glGenBuffers(1, &VBO);
glBindBuffer(GL_ARRAY_BUFFER, VBO);
glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
glBindVertexArray(cubeVAO);
// position attribute
glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 6 * sizeof(float), (void*)0);
glEnableVertexAttribArray(0);
// normal attribute
glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 6 * sizeof(float), (void*)(3 * sizeof(float)));
glEnableVertexAttribArray(1);
glUseProgram(shaderProgram);
// render loop
// -----------
while (!glfwWindowShouldClose(window))
{
// input
// -----
processInput(window);
// render
// ------
glClearColor(0.2f, 0.3f, 0.3f, 1.0f);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); // also clear the depth buffer now!
glUseProgram(shaderProgram);
glm::vec3 objectColor(1.0f, 1.0f, 0.0f);
objectColor = glm::vec3(sin((float)glfwGetTime()), 1.0f, 0.0f);
glUniform3fv(glGetUniformLocation(shaderProgram, "objectColor"), 1, &objectColor[0]);
glm::vec3 viewPos(1.0f, 1.0f, 0.0f);
glUniform3fv(glGetUniformLocation(shaderProgram, "viewPos"), 1, &viewPos[0]);
const glm::vec3 lightColor(1.0f, 1.0f, 1.0f);
glUniform3fv(glGetUniformLocation(shaderProgram, "material.lightColor"), 1, &lightColor[0]);
int a = glGetUniformLocation(shaderProgram, "material.lightColor");
const float shininess = 32.0f;
glUniform1f(glGetUniformLocation(shaderProgram, "material.shininess"), 32.0f);
const glm::vec3 lightPos(1.0f, 0.5f, 0.31f);
glUniform3fv(glGetUniformLocation(shaderProgram, "material.lightPos"), 1, &lightPos[0]);
// create transformations
glm::mat4 model = glm::mat4(1.0f); // make sure to initialize matrix to identity matrix first
glm::mat4 view = glm::mat4(1.0f);
glm::mat4 projection = glm::mat4(1.0f);
model = glm::rotate(model, (float)glfwGetTime() * 100, glm::vec3(1.0f, 1.0f, 0.0f));
view = glm::translate(view, glm::vec3(0.0f, 0.0f, -200.0f));
projection = glm::perspective(glm::radians(80.0f), (float)SCR_WIDTH / (float)SCR_HEIGHT, 0.1f, 300.0f);
// retrieve the matrix uniform locations
unsigned int modelLoc = glGetUniformLocation(shaderProgram, "model");
unsigned int viewLoc = glGetUniformLocation(shaderProgram, "view");
glUniformMatrix4fv(modelLoc, 1, GL_FALSE, glm::value_ptr(model));
glUniformMatrix4fv(viewLoc, 1, GL_FALSE, &view[0][0]);
glUniformMatrix4fv(glGetUniformLocation(shaderProgram, "projection"), 1, GL_FALSE, &projection[0][0]);
// render box
glBindVertexArray(cubeVAO);
glDrawArrays(GL_TRIANGLES, 0, 36);
//glPolygonMode(GL_FRONT, GL_LINE);
glfwSwapBuffers(window);
glfwPollEvents();
}
glDeleteVertexArrays(1, &cubeVAO);
glDeleteBuffers(1, &VBO);
glfwTerminate();
return 0;
}
void processInput(GLFWwindow *window)
{
if (glfwGetKey(window, GLFW_KEY_ESCAPE) == GLFW_PRESS)
glfwSetWindowShouldClose(window, true);
}
void framebuffer_size_callback(GLFWwindow* window, int width, int height)
{
glViewport(0, 0, width, height);
}
运行结果：
