1立方体，需要将空间坐标转换为人眼坐标，所以需要一系列的矩阵运算；需要用到glm;请自行安装
2 本次直接使用RGB贴图
3立方体贴图中的每一个纹理图（正方体贴图），RGB图片也要是正方形的
4 介绍一个中文OpenGL学习网站 http://learnopengl.com
5 立方体贴相当于在不同的坐标位置（这里用到了Z轴），分别做一个正方形贴图；正方形的顶点顺序一定要按照坐标轴的逆时针方向画三角形的顶点(图有点乱，但是是为了展示每个面的坐标轴，以及每个三角形的顶点方向；)
6 顶点着色器中，顶点位置，要转换成你的人眼坐标系的位置；涉及到MVP矩阵，用于旋转，平移，投影映射的矩阵
7 立方体六个面，六张图，每张图有自己的纹理采样器；这里并没有使用cubemap;而是直接用的六张2D纹理，你熟悉了这个立方体贴图，cubemap也就同理；
8本例中建立顶点数组的时候，顶点坐标的的中心是（0,0,0）；也就是这个正方体本质是以坐标中心为中心的一个立方体；
9 注意，绑定一个纹理ID，就给他设置好平滑过滤方式，并且将数据加载到显存，不要生成完全部的2D纹理ID，再去glTexImage2D加载6张图片，都不知道要把图片给哪个纹理ID了；
10 采样器的序号要与激活的纹理序号对应
glActiveTexture(GL_TEXTURE0);
glBindTexture(GL_TEXTURE_2D, tesarr[0]);
glUniform1i(glGetUniformLocation(shaderProgram, "texture1"), 0);11 MVP
模型，视图，投影
glm::mat4 model = glm::mat4(1.0f); 定义一个4*4 的单位矩阵
glm::mat4 view = glm::mat4(1.0f);
glm::mat4 projection = glm::mat4(1.0f);
model = glm::rotate(model, glm::radians(70.0f), glm::vec3(.0f, 1.0f, 1.0f));//沿着某个向量方向旋转，以这个向量为中心轴线
view = glm::translate(view, glm::vec3(0.0f, 0.0f, -3.0f));//沿着某个方向平移
projection = glm::perspective((float)30.0f, (float)SCR_WIDTH / (float)SCR_HEIGHT, 0.1f, 10.0f);//设置视角等
glm::radians()
角度制转弧度制，可应用于glm::rotate()中。
glm::translate()
返回一个平移矩阵，第一个参数是目标矩阵，第二个参数是平移的方向向量。
glm::rotate()
返回一个将点绕某个轴逆时针旋转一定弧度的旋转矩阵，第一个参数是目标矩阵，第二个参数是弧度，第三个参数是旋转轴。
glm::scale()
返回一个缩放矩阵，第一个参数是目标矩阵，第二个参数是在各坐标轴上的缩放系数。
glm::ortho(float left, float right, float bottom, float top, float zNear, float zFar);
正交投影矩阵。前四个参数分别是视口的左、右、上、下坐标。第五和第六个参数则定义了近平面和远平面的距离。
glm::perspective(float fovy, float aspect, float zNear, float zFar);
透视投影矩阵。第一个参数为视锥上下面之间的夹角，第二个参数为视口宽高比，第三、四个参数分别为近平面和远平面的深度。
glm::value_ptr()
传入一个矩阵，返回一个数组，从左到右按列优先。
glm::normalize(vector)
向量的单位化（保持其方向不变，将其长度化为1）.
---------------------------------------------------------------------
链接：https://www.jianshu.com/p/7bbe387109ea
来源：简书12 代码：参考 OpenGL立方体纹理贴图_LV小猪精的博客-CSDN博客
// Win32GL1.cpp : 定义应用程序的入口点。
#include "stdafx.h"
#include <glad/glad.h>
#include <GLFW/glfw3.h>
#include<string>
#include<fstream>
#include<sstream>
#include<iostream>
#include<stdio.h>
#define STB_IMAGE_IMPLEMENTATION
#include "stb_image.h"
#include <glm/glm.hpp>
#include <glm/gtc/matrix_transform.hpp>
#include <glm/gtc/type_ptr.hpp>
#include <learnopengl/shader_m.h>
const unsigned int SCR_WIDTH = 700;
const unsigned int SCR_HEIGHT = 900;
unsigned int VBO[6] ;
unsigned int VAO[6] ;
unsigned int texturePIC = 0;
int shaderProgram = 0;
unsigned int tesarr[6] = {99};
void LoadPicture()
{
glGenTextures(6, tesarr);
//------------------------------每一块的纹理ID绑定与数据加载，要写在一起--------------------------------
glBindTexture(GL_TEXTURE_2D, tesarr[0]);
//为bind的纹理设置环绕，过滤方式
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
//stbi是一个图片载入的开源组件,文件名，宽高，通道数，你期望的通道数
int W, H, desired_channels ;
unsigned char* data = stbi_load("./front.jpg", &W, &H, &desired_channels, 0);
if (data)
{
//数据生成纹理；根据指定的参数，把输入数据生成一张2D纹理
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, W, H, 0, GL_RGB, GL_UNSIGNED_BYTE, data);
//生成mipmap数组
glGenerateMipmap(GL_TEXTURE_2D);
}
stbi_image_free(data);
//-------------------------------------------------------------
//图2
glBindTexture(GL_TEXTURE_2D, tesarr[1]);
//为bind的纹理设置环绕，过滤方式
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
data = stbi_load("./front.jpg", &W, &H, &desired_channels, 0);
if (data)
{
//数据生成纹理；根据指定的参数，把输入数据生成一张2D纹理
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, W, H, 0, GL_RGB, GL_UNSIGNED_BYTE, data);
//生成mipmap数组
glGenerateMipmap(GL_TEXTURE_2D);
}
stbi_image_free(data);
//3
glBindTexture(GL_TEXTURE_2D, tesarr[2]);
//为bind的纹理设置环绕，过滤方式
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
data = stbi_load("./front.jpg", &W, &H, &desired_channels, 0);
if (data)
{
//数据生成纹理；根据指定的参数，把输入数据生成一张2D纹理
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, W, H, 0, GL_RGB, GL_UNSIGNED_BYTE, data);
//生成mipmap数组
glGenerateMipmap(GL_TEXTURE_2D);
}
stbi_image_free(data);
//4
glBindTexture(GL_TEXTURE_2D, tesarr[3]);
//为bind的纹理设置环绕，过滤方式
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
data = stbi_load("./front.jpg", &W, &H, &desired_channels, 0);
if (data)
{
//数据生成纹理；根据指定的参数，把输入数据生成一张2D纹理
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, W, H, 0, GL_RGB, GL_UNSIGNED_BYTE, data);
//生成mipmap数组
glGenerateMipmap(GL_TEXTURE_2D);
}
stbi_image_free(data);
//5
glBindTexture(GL_TEXTURE_2D, tesarr[4]);
//为bind的纹理设置环绕，过滤方式
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
data = stbi_load("./front.jpg", &W, &H, &desired_channels, 0);
if (data)
{
//数据生成纹理；根据指定的参数，把输入数据生成一张2D纹理
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, W, H, 0, GL_RGB, GL_UNSIGNED_BYTE, data);
//生成mipmap数组
glGenerateMipmap(GL_TEXTURE_2D);
}
stbi_image_free(data);
//6
glBindTexture(GL_TEXTURE_2D, tesarr[5]);
//为bind的纹理设置环绕，过滤方式
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
data = stbi_load("./front.jpg", &W, &H, &desired_channels, 0);
if (data)
{
//数据生成纹理；根据指定的参数，把输入数据生成一张2D纹理
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, W, H, 0, GL_RGB, GL_UNSIGNED_BYTE, data);
//生成mipmap数组
glGenerateMipmap(GL_TEXTURE_2D);
}
stbi_image_free(data);
glUseProgram(shaderProgram);
glActiveTexture(GL_TEXTURE0);
glBindTexture(GL_TEXTURE_2D, tesarr[0]);
glUniform1i(glGetUniformLocation(shaderProgram, "texture1"), 0);
glActiveTexture(GL_TEXTURE1);
glBindTexture(GL_TEXTURE_2D, tesarr[1]);
glUniform1i(glGetUniformLocation(shaderProgram, "texture2"), 1);
glActiveTexture(GL_TEXTURE2);
glBindTexture(GL_TEXTURE_2D, tesarr[2]);
glUniform1i(glGetUniformLocation(shaderProgram, "texture3"), 2);
glActiveTexture(GL_TEXTURE3);
glBindTexture(GL_TEXTURE_2D, tesarr[3]);
glUniform1i(glGetUniformLocation(shaderProgram, "texture4"), 3);
glActiveTexture(GL_TEXTURE4);
glBindTexture(GL_TEXTURE_2D, tesarr[4]);
glUniform1i(glGetUniformLocation(shaderProgram, "texture5"), 4);
glActiveTexture(GL_TEXTURE5);
glBindTexture(GL_TEXTURE_2D, tesarr[5]);
glUniform1i(glGetUniformLocation(shaderProgram, "texture6"), 5);
glUseProgram(shaderProgram);
}
void render()
{
//
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);
//沿着某轴旋转
model = glm::rotate(model, glm::radians(70.0f), glm::vec3(.0f, 1.0f, 1.0f));
//沿着Z轴平移
view = glm::translate(view, glm::vec3(0.0f, 0.0f, -3.0f));
//设置视角
projection = glm::perspective((float)30.0f, (float)SCR_WIDTH / (float)SCR_HEIGHT, 0.1f, 10.0f);
// retrieve the matrix uniform locations
unsigned int modelLoc = glGetUniformLocation(shaderProgram, "model");
unsigned int viewLoc = glGetUniformLocation(shaderProgram, "view");
// pass them to the shaders (3 different ways)
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]);
glUniform1i(glGetUniformLocation(shaderProgram, "mixValue"), 1);
glBindVertexArray(VAO[0]);
glDrawArrays(GL_TRIANGLES,0,6);//6个面，每个面画两个三角形（6个点）；6*6
glGetError();
glUniform1i(glGetUniformLocation(shaderProgram, "mixValue"), 2);
glBindVertexArray(VAO[1]);
glDrawArrays(GL_TRIANGLES, 0, 6);//6个面，每个面画两个三角形（6个点）；6*6
glGetError();
glUniform1i(glGetUniformLocation(shaderProgram, "mixValue"), 3);
glBindVertexArray(VAO[2]);
glDrawArrays(GL_TRIANGLES, 0, 6);//6个面，每个面画两个三角形（6个点）；6*6
glGetError();
glUniform1i(glGetUniformLocation(shaderProgram, "mixValue"), 4);
glBindVertexArray(VAO[3]);
glDrawArrays(GL_TRIANGLES, 0, 6);//6个面，每个面画两个三角形（6个点）；6*6
glGetError();
glUniform1i(glGetUniformLocation(shaderProgram, "mixValue"),5);
glBindVertexArray(VAO[4]);
glDrawArrays(GL_TRIANGLES, 0, 6);//6个面，每个面画两个三角形（6个点）；6*6
glGetError();
glUniform1i(glGetUniformLocation(shaderProgram, "mixValue"), 6);
glBindVertexArray(VAO[5]);
glDrawArrays(GL_TRIANGLES, 0, 6);//6个面，每个面画两个三角形（6个点）；6*6
glGetError();
}
void initmodule()
{
//注意：画正面逆时针012-230；三角形顺序一定不能乱
// //第一个面的 顶点和纹理 后面
float vertices0[] = {
-0.5f, -0.5f, -0.5f, 0.0f, 0.0f,
0.5f, -0.5f, -0.5f, 1.0f, 0.0f,
0.5f, 0.5f, -0.5f, 1.0f, 1.0f,
0.5f, 0.5f, -0.5f, 1.0f, 1.0f,
-0.5f, 0.5f, -0.5f, 0.0f, 1.0f,
-0.5f, -0.5f, -0.5f, 0.0f, 0.0f
};
//前面
float vertices1[] = {
-0.5f, -0.5f, 0.5f, 0.0f, 0.0f,
0.5f, -0.5f, 0.5f, 1.0f, 0.0f,
0.5f, 0.5f, 0.5f, 1.0f, 1.0f,
0.5f, 0.5f, 0.5f, 1.0f, 1.0f,
-0.5f, 0.5f, 0.5f, 0.0f, 1.0f,
-0.5f, -0.5f, 0.5f, 0.0f, 0.0f
};
//左面
float vertices2[] = {
-0.5f, 0.5f, 0.5f, 1.0f, 0.0f,
-0.5f, 0.5f, -0.5f, 1.0f, 1.0f,
-0.5f, -0.5f, -0.5f, 0.0f, 1.0f,
-0.5f, -0.5f, -0.5f, 0.0f, 1.0f,
-0.5f, -0.5f, 0.5f, 0.0f, 0.0f,
-0.5f, 0.5f, 0.5f, 1.0f, 0.0f
};
//右面
float vertices3[] = {
0.5f, 0.5f, 0.5f, 1.0f, 0.0f,
0.5f, 0.5f, -0.5f, 1.0f, 1.0f,
0.5f, -0.5f, -0.5f, 0.0f, 1.0f,
0.5f, -0.5f, -0.5f, 0.0f, 1.0f,
0.5f, -0.5f, 0.5f, 0.0f, 0.0f,
0.5f, 0.5f, 0.5f, 1.0f, 0.0f
};
//下面
float vertices4[] = {
-0.5f, -0.5f, -0.5f, 0.0f, 1.0f,
0.5f, -0.5f, -0.5f, 1.0f, 1.0f,
0.5f, -0.5f, 0.5f, 1.0f, 0.0f,
0.5f, -0.5f, 0.5f, 1.0f, 0.0f,
-0.5f, -0.5f, 0.5f, 0.0f, 0.0f,
-0.5f, -0.5f, -0.5f, 0.0f, 1.0f
};
//上面
float vertices5[] = {
-0.5f, 0.5f, -0.5f, 0.0f, 1.0f,
0.5f, 0.5f, -0.5f, 1.0f, 1.0f,
0.5f, 0.5f, 0.5f, 1.0f, 0.0f,
0.5f, 0.5f, 0.5f, 1.0f, 0.0f,
-0.5f, 0.5f, 0.5f, 0.0f, 0.0f,
-0.5f, 0.5f, -0.5f, 0.0f, 1.0f
};
//做VAO VBo
glGenVertexArrays(6,VAO);
glGenBuffers(6, VBO);
glBindVertexArray(VAO[0]);
glBindBuffer(GL_ARRAY_BUFFER, VBO[0]);
//创建显存空间
glBufferData(GL_ARRAY_BUFFER, sizeof(vertices0), vertices0, GL_STATIC_DRAW);
//设置第0个锚点,3个点，不需要归一化，跨度5个float可以读下一个点
glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 5 * sizeof(float), (void*)0);
glEnableVertexAttribArray(0);
glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE, 5 * sizeof(float), (void*)(3 * sizeof(float)));
glEnableVertexAttribArray(1);
glBindVertexArray(VAO[1]);
glBindBuffer(GL_ARRAY_BUFFER, VBO[1]);
//创建显存空间
glBufferData(GL_ARRAY_BUFFER, sizeof(vertices1), vertices1, GL_STATIC_DRAW);
glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 5 * sizeof(float), (void*)0);
glEnableVertexAttribArray(0);
glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE, 5 * sizeof(float), (void*)(3 * sizeof(float)));
glEnableVertexAttribArray(1);
glBindVertexArray(VAO[2]);
glBindBuffer(GL_ARRAY_BUFFER, VBO[2]);
//创建显存空间
glBufferData(GL_ARRAY_BUFFER, sizeof(vertices2), vertices2, GL_STATIC_DRAW);
glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 5 * sizeof(float), (void*)0);
glEnableVertexAttribArray(0);
glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE, 5 * sizeof(float), (void*)(3 * sizeof(float)));
glEnableVertexAttribArray(1);
glBindVertexArray(VAO[3]);
glBindBuffer(GL_ARRAY_BUFFER, VBO[3]);
//创建显存空间
glBufferData(GL_ARRAY_BUFFER, sizeof(vertices3), vertices3, GL_STATIC_DRAW);
glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 5 * sizeof(float), (void*)0);
glEnableVertexAttribArray(0);
glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE, 5 * sizeof(float), (void*)(3 * sizeof(float)));
glEnableVertexAttribArray(1);
glBindVertexArray(VAO[4]);
glBindBuffer(GL_ARRAY_BUFFER, VBO[4]);
//创建显存空间
glBufferData(GL_ARRAY_BUFFER, sizeof(vertices4), vertices4, GL_STATIC_DRAW);
glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 5 * sizeof(float), (void*)0);
glEnableVertexAttribArray(0);
glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE, 5 * sizeof(float), (void*)(3 * sizeof(float)));
glEnableVertexAttribArray(1);
glBindVertexArray(VAO[5]);
glBindBuffer(GL_ARRAY_BUFFER, VBO[5]);
//创建显存空间
glBufferData(GL_ARRAY_BUFFER, sizeof(vertices5), vertices5, GL_STATIC_DRAW);
glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 5 * sizeof(float), (void*)0);
glEnableVertexAttribArray(0);
glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE, 5 * sizeof(float), (void*)(3 * sizeof(float)));
glEnableVertexAttribArray(1);
//设置纹理图片
//加载纹理图片,生成纹理
LoadPicture();
}
void initshader(const char* verpath,const char* fragpath)
{
//编译shader，并记录shaderID
std::string VerCode("");
std::string fregCode("");
//读文件
std::ifstream vShaderFile;
std::ifstream fShaderFile;
vShaderFile.exceptions(std::ifstream::failbit | std::ifstream::badbit);
fShaderFile.exceptions(std::ifstream::failbit | std::ifstream::badbit);
try
{
vShaderFile.open(verpath);
fShaderFile.open(fragpath);
std::stringstream vsstream, fsstream;
vsstream << vShaderFile.rdbuf();
fsstream << fShaderFile.rdbuf();
VerCode = vsstream.str();
fregCode = fsstream.str();
}
catch (const std::exception&)
{
std::cout << "read file error" << std::endl;
}
const char* vshader = VerCode.c_str();
const char* fshader = fregCode.c_str();
//shader 编译连接
unsigned int vertexID = 0, fragID = 0;
char infoLog[512];//存储错误信息
int successflag = 0;
vertexID = glCreateShader(GL_VERTEX_SHADER);
glShaderSource(vertexID,1,&vshader,NULL );
glCompileShader(vertexID);
//获取编译是否成功
glGetShaderiv(vertexID,GL_COMPILE_STATUS,&successflag);
if (!successflag)
{
glGetShaderInfoLog(vertexID,512,NULL,infoLog);
std::string errstr(infoLog);
std::cout << "v shader err"<<infoLog;
}
//frag
fragID = glCreateShader(GL_FRAGMENT_SHADER);
glShaderSource(fragID, 1, &fshader, NULL);
glCompileShader(fragID);
//获取编译是否成功
glGetShaderiv(fragID, GL_COMPILE_STATUS, &successflag);
if (!successflag)
{
glGetShaderInfoLog(fragID, 512, NULL, infoLog);
std::string errstr(infoLog);
std::cout << "f shader err"<<infoLog;
}
//链接
shaderProgram = glCreateProgram();
glAttachShader(shaderProgram,vertexID);
glAttachShader(shaderProgram,fragID);
//glBindAttribLocation(shaderProgram, 0, "aPos");
//glBindAttribLocation(shaderProgram, 1, "aTexCoord");
glLinkProgram(shaderProgram);
glGetProgramiv(shaderProgram,GL_LINK_STATUS,&successflag);
if (!successflag)
{
glGetShaderInfoLog(shaderProgram, 512, NULL, infoLog);
std::string errstr(infoLog);
std::cout << "link error";
}
//编译完成后，可以把中间的步骤程序删除
glDeleteShader(vertexID);
glDeleteShader(fragID);
}
void processInput(GLFWwindow *window)
{
if (glfwGetKey(window, GLFW_KEY_ESCAPE) == GLFW_PRESS)
{
//将窗口设置为关闭，跳出循环
glfwSetWindowShouldClose(window, true);
}
}
void framebuffer_size_callback(GLFWwindow* window, int width, int height)
{
glViewport(0, 0, width, height);
}
int main()
{
//glfw初始化
glfwInit();
glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
//glfw创建窗口
GLFWwindow* window = glfwCreateWindow(SCR_WIDTH, SCR_HEIGHT, "LearnOpenGL", NULL, NULL);
if (window == NULL)
{
printf("创建窗口失败");
//终止
glfwTerminate();
return -1;
}
//显示窗口
glfwMakeContextCurrent(window);
//设置回调，当窗口大小调整后将调用该回调函数
glfwSetFramebufferSizeCallback(window, framebuffer_size_callback);
// glad初始化
if (!gladLoadGLLoader((GLADloadproc)glfwGetProcAddress))
{
printf("加载失败");
return -1;
}
glEnable(GL_DEPTH_TEST);
initshader("./vertexShader.glsl", "./fragmentShader.glsl");//先编译着色器
initmodule();
// 使用循环达到循环渲染效果
while (!glfwWindowShouldClose(window))
{
//自定义输入事件
processInput(window);
glClearColor(0.0f,0.3f,0.0f,1.0f);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
render();
//交互缓冲区，否则显示空白
glfwSwapBuffers(window);
//输入输出事件,否则无法对窗口进行交互
glfwPollEvents();
}
glDeleteVertexArrays(6, VAO);
glDeleteBuffers(6, VBO);
//终止渲染 关闭并清理glfw本地资源
glfwTerminate();
return 0;
}#version 330 core
out vec4 FragColor;
in vec2 TexCoord;
uniform int mixValue;
// texture samplers
uniform sampler2D texture1;
uniform sampler2D texture2;
uniform sampler2D texture3;
uniform sampler2D texture4;
uniform sampler2D texture5;
uniform sampler2D texture6;
void main()
{
if(mixValue==1)
FragColor = texture(texture1, TexCoord);
else if(mixValue==2)
FragColor = texture(texture2, TexCoord);
else if(mixValue==3)
FragColor = texture(texture3, TexCoord);
else if(mixValue==4)
FragColor = texture(texture4, TexCoord);
else if(mixValue==5)
FragColor = texture(texture5, TexCoord);
else
FragColor = texture(texture6, TexCoord);
}#version 330 core
layout (location = 0) in vec3 aPos;
layout (location = 1) in vec2 aTexCoord;
out vec2 TexCoord;
uniform mat4 model;
uniform mat4 view;
uniform mat4 projection;
void main()
{
//将物体的空间坐标，转换到人眼坐标，位置数据*MVP
gl_Position = projection * view * model * vec4(aPos, 1.0);
TexCoord = vec2(aTexCoord.x, aTexCoord.y);
}13结果：
14 如果你不想自己编译着色器代码，可以去learnOpenGL下载shader_m.h 这里边会给你集成好编译的相关事宜；GitHub上有learnOpenGL的源代码，内部有一些可以节省你工作量的高度集成的接口；相机，shader之类的；本例子中严格来说并没有用到#include<learnopengl/shader_m.h>；
15 如果你的顶点，或者三角形的顺序是错的会怎么样？
16 不开深度测试会怎么样？
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