优化
首先将着色器的编译链接进行优化
//Shader.h
#pragma once
#include <glad/glad.h>
class Shader{
public:
//程序ID
unsigned int ID;
//构造器读取并构建着色器
Shader(const GLchar*, const GLchar*);
//使用、激活程序
void use();
//uniform工具函数
void setBool(const std::string& name, bool value) const;
void setInt(const std::string& name, int value) const;
void setFloat(const std::string& name, float value) const;
// void setVec2(const std::string& name, const glm::vec2& value) const;
void setVec2(const std::string& name, float x, float y) const;
// void setVec3(const std::string& name, const glm::vec3& value) const;
void setVec3(const std::string& name, float x, float y, float z) const;
// void setVec4(const std::string& name, const glm::vec4& value) const;
void setVec4(const std::string& name, float x, float y, float z, float w);
// void setMat2(const std::string& name, const glm::mat2& mat) const;
// void setMat3(const std::string& name, const glm::mat3& mat) const;
// void setMat4(const std::string& name, const glm::mat4& mat) const;
};
//Shader.cpp
#include <glad/glad.h>
#include <string>
#include <fstream>
#include <sstream>
#include <iostream>
#include "Shader.h"
GLuint CreateFragmentShaders(GLchar* ShaderSource);
GLuint CreateVertexShaders(GLchar* ShaderSource);
GLuint LinkShaderPrograms(const GLuint& vertexShader, const GLuint& fragmentShader);
Shader::Shader(const GLchar* vertexPath, const GLchar* fragmentPath) {
std::string vertexCode;
std::string fragmentCode;
std::ifstream vShaderFile;//输入文件流 in from file stream
std::ifstream fShaderFile;
vShaderFile.exceptions(std::ifstream::failbit | std::ifstream::badbit);
fShaderFile.exceptions(std::ifstream::failbit | std::ifstream::badbit);
try {
//打开文件
vShaderFile.open(vertexPath);
fShaderFile.open(fragmentPath);
std::stringstream vShaderStream, fShaderStream;
//读取文件的缓冲内容到数据流中
vShaderStream << vShaderFile.rdbuf();
fShaderStream << fShaderFile.rdbuf();
//关闭文件处理器
vShaderFile.close();
fShaderFile.close();
//转换数据到string
vertexCode = vShaderStream.str();
fragmentCode = fShaderStream.str();
}
catch (std::ifstream::failure e) {
std::cout << "ERROR::SHADER::FILE_NOT_SUCCESSFULLY_READ" << std::endl;
}
const char* vshaderCode = vertexCode.c_str();//返回一个正规的指向c字符串的指针，主要为了c兼容
const char* fshaderCode = fragmentCode.c_str();
/*使用顶点着色器*/
GLuint vertexShader = CreateVertexShaders((GLchar*)vshaderCode);
/*使用片段着色器*/
GLuint fragmentShader = CreateFragmentShaders((GLchar*)fshaderCode);
/*链接为着色器程序对象*/
ID = LinkShaderPrograms(vertexShader, fragmentShader);
//把着色器对象链接到程序对象以后，我们就不再需要它们了
glDeleteShader(vertexShader);
glDeleteShader(fragmentShader);
}
void Shader::use() {
glUseProgram(ID);
}
void Shader::setBool(const std::string& name, bool value) const {
glUniform1i(glGetUniformLocation(ID, name.c_str()), (int)(value));
}
void Shader::setInt(const std::string& name, int value) const {
glUniform1i(glGetUniformLocation(ID, name.c_str()), value);
}
void Shader::setFloat(const std::string& name, float value) const {
glUniform1f(glGetUniformLocation(ID, name.c_str()), value);
}
//void Shader::setVec2(const std::string& name, const glm::vec2& value) const{
// glUniform2fv(glGetUniformLocation(ID, name.c_str()), 1, &value[0]);
//}
void Shader::setVec2(const std::string& name, float x, float y) const{
glUniform2f(glGetUniformLocation(ID, name.c_str()), x, y);
}
// ------------------------------------------------------------------------
//void Shader::setVec3(const std::string& name, const glm::vec3& value) const{
// glUniform3fv(glGetUniformLocation(ID, name.c_str()), 1, &value[0]);
//}
void Shader::setVec3(const std::string& name, float x, float y, float z) const{
glUniform3f(glGetUniformLocation(ID, name.c_str()), x, y, z);
}
// ------------------------------------------------------------------------
//void Shader::setVec4(const std::string& name, const glm::vec4& value) const{
// glUniform4fv(glGetUniformLocation(ID, name.c_str()), 1, &value[0]);
//}
void Shader::setVec4(const std::string& name, float x, float y, float z, float w){
glUniform4f(glGetUniformLocation(ID, name.c_str()), x, y, z, w);
}
// ------------------------------------------------------------------------
//void Shader::setMat2(const std::string& name, const glm::mat2& mat) const{
// glUniformMatrix2fv(glGetUniformLocation(ID, name.c_str()), 1, GL_FALSE, &mat[0][0]);
//}
------------------------------------------------------------------------
//void Shader::setMat3(const std::string& name, const glm::mat3& mat) const{
// glUniformMatrix3fv(glGetUniformLocation(ID, name.c_str()), 1, GL_FALSE, &mat[0][0]);
//}
------------------------------------------------------------------------
//void Shader::setMat4(const std::string& name, const glm::mat4& mat) const{
// glUniformMatrix4fv(glGetUniformLocation(ID, name.c_str()), 1, GL_FALSE, &mat[0][0]);
//}
GLuint LinkShaderPrograms(const GLuint& vertexShader, const GLuint& fragmentShader) {
GLuint shaderProgram;
shaderProgram = glCreateProgram();
glAttachShader(shaderProgram, vertexShader);
glAttachShader(shaderProgram, fragmentShader);
glLinkProgram(shaderProgram);
//检查链接状态
GLint success;
GLchar infoLog[512];
glGetProgramiv(shaderProgram, GL_LINK_STATUS, &success);
if (!success) {
glGetProgramInfoLog(shaderProgram, 512, NULL, infoLog);
std::cout << "ERROR::PROGRAM::SHADER::LINK_FAILED\\n" << infoLog << std::endl;
}
return shaderProgram;
}
GLuint CreateFragmentShaders(GLchar* ShaderSource) {
GLuint fragmentShader;
GLint success;
GLchar infoLog[512];//存储错误信息
fragmentShader = glCreateShader(GL_FRAGMENT_SHADER);
glShaderSource(fragmentShader, 1, &ShaderSource, NULL);
glCompileShader(fragmentShader);
glGetShaderiv(fragmentShader, GL_COMPILE_STATUS, &success);
if (!success) {
glGetShaderInfoLog(fragmentShader, 512, NULL, infoLog);
std::cout << "ERROR::SHADER::FRAGMENT::COMPILATION_FAILED\\n" << infoLog << std::endl;
}
return fragmentShader;
}
GLuint CreateVertexShaders(GLchar* ShaderSource) {
GLuint vertexShader;
vertexShader = glCreateShader(GL_VERTEX_SHADER);
glShaderSource(vertexShader, 1, &ShaderSource, NULL);
glCompileShader(vertexShader);
//判断编译是否成功
GLint success;
GLchar infoLog[512];//存储错误信息
glGetShaderiv(vertexShader, GL_COMPILE_STATUS, &success);
//检查是否编译成功
if (!success) {
glGetShaderInfoLog(vertexShader, 512, NULL, infoLog);
//获取错误消息
std::cout << "ERROR::SHADER::VERTEX::COMPILATION_FAILED\\n" << infoLog << std::endl;
}
return vertexShader;
}
其中：
1.Shader的构造器（Shader::Shader）传入参数（顶点着色器文件地址，片段着色器文件地址），构建链接为着色器程序对象，保存该着色器程序对象—-命名为ID。
2.uniform工具函数中，首先需要使用
glGetUniformLocation(着色器程序对象, 全局变量名称)
获取该名称全局变量的地址。
然后使用
glUniform**(全局变量的地址, 改变的值*);
改变该变量的值。
将上方两式联合使用：
glUniform1i( glGetUniformLocation( ID , name ), value1, value2, ~ );
在OpenGL主函数中用
Shader ShaderProgram1("./vertex1.vs","./fragment1.fs");
Shader ShaderProgram2("./vertex2.vs","./fragment2.fs");
来设置图形管线。
着色器内部参数传递
在顶点着色器中传入的参数由out传入后续的着色器中。
每个输入变量也叫顶点属性(Vertex Attribute)。我们能声明的顶点属性是有上限的，它一般由硬件来决定。OpenGL确保至少有16个包含4分量的顶点属性可用。
例如：
//vertexShader
layout (location = 0) in vec3 position;
layout (location = 1) in vec3 color;
out vec3 outColor;
void main(){
gl_Position = vec4(position, 1.0);
outColor = color;
}
该顶点着色器将1号位的数据传入color,再将color传入输出参数outColor.
在另一边有
//fragmentShader
in vec3 outColor;
out vec4 FragColor;
void main(){
FragColor = vec4(outColor,1.0f);
}
接收outcolor。
在主函数中，有：
GLfloat vertices[] = {
//location color
-1.0f, 0.0f, 0.0f, 1.0f, 0.0f, 0.0f,
0.0f, -1.0f, 0.0f, 0.0f, 1.0f, 0.0f,
-1.0f, -1.0f, 0.0f, 0.0f, 0.0f, 1.0f,
0.0f, 0.0f, 0.0f, 0.3f, 0.3f, 0.3f,
-1.0f, 0.0f, 0.0f, 1.0f, 0.0f, 0.0f,
0.0f, -1.0f, 0.0f, 0.0f, 1.0f, 0.0f,
};
glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 6 * sizeof(float), (void*)0);
glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 6 * sizeof(float), (void*)(3*sizeof(float)));
glEnableVertexAttribArray(0);//启用顶点属性
glEnableVertexAttribArray(1);
对不同顶点属性传不同类型的值。
uniform全局变量
若在着色器中有uniform vec3 Color;
现需要对着色器内参数Color传值。
有：
ShaderProgram.use();//设置uniform值前必须先使用程序。
ShaderProgram.set*参数类型(全局变量名称, value1,value2,~);
value由主函数内计算给定。
全部代码
#include <iostream>
//包含命名空间std
#include <glad/glad.h>
#include <GLFW/glfw3.h>
#include "Shader.h"
//glad需要在glfw之前,因为GLAD的头文件包含了正确的OpenGL头文件，glfw依赖于OpenGL
void key_callback(GLFWwindow* window, int key, int scancode, int action, int mode);
void framebuffer_size_callback(GLFWwindow* window, int width, int height);
void key_callback(GLFWwindow* window, int key, int scancode, int action, int mode){
// 当用户按下ESC键,我们设置window窗口的WindowShouldClose属性为true
// 关闭应用程序
if (key == GLFW_KEY_ESCAPE && action == GLFW_PRESS)
glfwSetWindowShouldClose(window, GL_TRUE);
}
void framebuffer_size_callback(GLFWwindow* window, int width, int height){
glViewport(0, 0, width, height);
}
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, "LearnOpenGL", nullptr, nullptr);
if (window == nullptr) {
std::cout << "Failed to create GLFW window" << std::endl;
glfwTerminate();
return -1;
}
glfwMakeContextCurrent(window);
glfwSetKeyCallback(window, key_callback);
glfwSetFramebufferSizeCallback(window, framebuffer_size_callback);
//glad初始化（GLAD是用来管理OpenGL的函数指针的）
if (!gladLoadGLLoader((GLADloadproc)glfwGetProcAddress)){
std::cout << "Failed to initialize GLAD" << std::endl;
return -1;
}
int width, height;
glfwGetFramebufferSize(window, &width, &height);
glViewport(0, 0, width, height);
//生成着色器
Shader PVPCShader("./Normal.vs","./setcolor.fs");
Shader ChangingColorShader("./Normal.vs", "./Changing.fs");
/*使用顶点缓冲将顶点储存在显卡的内存中，用VBO顶点缓冲对象管理*/
GLfloat vertices[] = {
//location color
-1.0f, 0.0f, 0.0f, 1.0f, 0.0f, 0.0f,
0.0f, -1.0f, 0.0f, 0.0f, 1.0f, 0.0f,
-1.0f, -1.0f, 0.0f, 0.0f, 0.0f, 1.0f,
0.0f, 0.0f, 0.0f, 0.3f, 0.3f, 0.3f,
-1.0f, 0.0f, 0.0f, 1.0f, 0.0f, 0.0f,
0.0f, -1.0f, 0.0f, 0.0f, 1.0f, 0.0f,
};
GLuint VBO, VAO;
glGenBuffers(1, &VBO);
glGenVertexArrays(1, &VAO);
glBindVertexArray(VAO);
glBindBuffer(GL_ARRAY_BUFFER, VBO);
glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 6 * sizeof(float), (void*)0);
glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 6 * sizeof(float), (void*)(3*sizeof(float)));
glEnableVertexAttribArray(0);//启用顶点属性
glEnableVertexAttribArray(1);
/*使用索引数据存储点的顺序，用IBO索引缓冲对象管理*/
GLfloat vertices1[] = {
0.5f, 0.5f, 0.0f, // 右上角
0.5f, -0.5f, 0.0f, // 右下角
-0.5f, -0.5f, 0.0f, // 左下角
-0.5f, 0.5f, 0.0f // 左上角
};
unsigned int indices1[] = { // 注意索引从0开始!
0, 1, 3, // 第一个三角形
1, 2, 3 // 第二个三角形
};
GLuint VBO1,EBO1,VAO1;
//生成三类对象，不分先后顺序
glGenBuffers(1, &EBO1);
glGenBuffers(1, &VBO1);
glGenVertexArrays(1, &VAO1);
//绑定三类对象
glBindVertexArray(VAO1);//VAO必须为第一
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, EBO1);
glBindBuffer(GL_ARRAY_BUFFER, VBO1);
//绑定缓冲数据
glBufferData(GL_ARRAY_BUFFER, sizeof(vertices1), vertices1, GL_STATIC_DRAW);
glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(indices1), indices1, GL_STATIC_DRAW);
glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 3 * sizeof(float), (void*)0);
glEnableVertexAttribArray(0);
glBindBuffer(GL_ARRAY_BUFFER, 0);
glBindVertexArray(0);
//glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);//设置为线框模式
//glPolygonMode(GL_FRONT_AND_BACK, GL_FILL);//设置为填充模式（默认）
//设置为一类，在后续将一直为该类，直到再次修改
while (!glfwWindowShouldClose(window)){//检查glfw是否被要求退出
glfwPollEvents();
//检查有没有触发什么事件,然后调用对应的回调函数.
glClearColor(0.2f, 0.3f, 0.3f, 1.0f);
glClear(GL_COLOR_BUFFER_BIT);
PVPCShader.use();
glPolygonMode(GL_FRONT_AND_BACK, GL_FILL);//设置为填充模式（默认）
glBindVertexArray(VAO);
glDrawArrays(GL_TRIANGLES, 0, 2*3);//数量必须为3的倍数
float timeValue = glfwGetTime();
float greenValue = (sin(timeValue) / 2.0f) + 0.5f;
ChangingColorShader.use();//设置uniform值前必须先使用程序。
ChangingColorShader.setVec3("Color", 0.0f, greenValue, 0.0f);
glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);//设置为线框模式
glBindVertexArray(VAO1);
glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, 0);
glfwSwapBuffers(window);
//交换颜色缓冲
}
//Game Loop
glDeleteVertexArrays(1, &VAO);
glDeleteBuffers(1, &VBO);
glDeleteVertexArrays(1, &VAO1);
glDeleteBuffers(1, &VBO1);
glDeleteBuffers(1, &EBO1);
glDeleteProgram(PVPCShader.ID);
glfwTerminate();
//释放GLFW分配的内存。
return 0;
}
//vertexShader
#version 330 core
layout (location = 0) in vec3 position;
layout (location = 1) in vec3 color;
out vec3 outColor;
void main(){
gl_Position = vec4(position, 1.0);
outColor = color;
}
//fragmentShader
//1
#version 330 core
out vec4 FragColor;
uniform vec3 Color;
void main(){
FragColor = vec4(Color,1.0f);
}
//2
#version 330 core
in vec3 outColor;
out vec4 FragColor;
void main(){
FragColor = vec4(outColor,1.0f);
}
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