There is a problem:
1. The texture output in the shader is texture type
2. At present, the order of my code is somewhat different from the official one. It may be that there are still some problems with the execution process I understand.
#include <glad/glad.h>
#include <GLFW/glfw3.h>
#include <iostream>
#define STB_IMAGE_IMPLEMENTATION
#include "stb_image.h"
void framebuffer_size_callback(GLFWwindow *window, int width,int height);
void processInput(GLFWwindow *window);
const unsigned int HEIGHT = 600;
const unsigned int WIDTH = 800;
// shader
const char* vertexShaderSource = "#version 330 core\n"
"layout (location = 0) in vec3 aPos;\n"
"layout (location = 1) in vec3 aColor;\n"
"layout (location = 2) in vec2 aTexCoord;\n"
"out vec3 ourColor;\n"
"out vec2 TexCoord;\n"
"void main()\n"
"{\n"
" gl_Position = vec4(aPos, 1.0);\n"
" ourColor = aColor;\n"
" TexCoord = aTexCoord;\n"
"}\0";
const char *fragmentShaderSource = "#version 330 core\n"
"out vec4 FragColor;\n"
"in vec3 ourColor;\n"
"in vec2 TexCoord;\n"
"uniform sampler2D ourTexture;\n"
"void main()\n"
"{\n"
" FragColor = texture(ourTexture, TexCoord);\n"
"}\n\0";
int main() {
// 配置
glfwInit();
glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
// MacOSX
//glfwWindowHint(GLFW_OPENGL_FORWARD_COMPAT, GL_TRUE);
GLFWwindow* window = glfwCreateWindow(WIDTH, HEIGHT, "LearnOpenGL", NULL, NULL);
if (window == NULL) {
std::cout << "Failed to create GLFW window" << std::endl;
return -1;
}
// 设置当前线程的主上下文
glfwMakeContextCurrent(window);
glfwSetFramebufferSizeCallback(window, framebuffer_size_callback);
// glad管理函数指针
if (!gladLoadGLLoader((GLADloadproc)glfwGetProcAddress)) {
std::cout << "Failed to initialize GLAD" << std::endl;
return -1;
}
// 坐标转换
//glViewport(0, 0, HEIGHT, HEIGHT);
unsigned int vertexShader;
vertexShader = glCreateShader(GL_VERTEX_SHADER);
glShaderSource(vertexShader, 1, &vertexShaderSource, NULL);
// 动态编译
glCompileShader(vertexShader);
unsigned int fragmentShader;
fragmentShader = glCreateShader(GL_FRAGMENT_SHADER);
glShaderSource(fragmentShader, 1, &fragmentShaderSource, NULL);
glCompileShader(fragmentShader);
// link
unsigned int shaderProgram;
shaderProgram = glCreateProgram();
glAttachShader(shaderProgram, vertexShader);
glAttachShader(shaderProgram, fragmentShader);
glLinkProgram(shaderProgram);
glDeleteShader(vertexShader);
glDeleteShader(fragmentShader);
//float vertices[] = {
//-0.5f,-0.5f,0.0f,
//0.5f,-0.5f,0.0f,
//0.0f,0.5f,0.0f,
//0.5f,-0.5f,0.0f,
//1.0f,0.5f,0.0f,
//0.0f,0.5f,0.0f,
//};
// 使用索引缓冲区
float vertices[] = {
// 位置 // 颜色 // 纹理坐标
0.5f, 0.5f, 0.0f, 1.0f, 0.0f, 0.0f, 0.0f, 0.0f,// 右上角
0.5f, -0.5f, 0.0f, 0.0f, 1.0f, 0.0f, 1.0f, 0.0f,// 右下角
-0.5f, -0.5f, 0.0f, 0.0f, 0.0f, 1.0f, 1.0f, 1.0f,// 左下角
-0.5f, 0.5f, 0.0f, 1.0f, 0.0f, 0.0f, 0.0f, 1.0f// 左上角
};
unsigned int indices[] =
{
0, 1, 3,
1, 2, 3
};
unsigned int VBO, VAO;
// create obj
glGenVertexArrays(1, &VAO);
glGenBuffers(1, &VBO);
glBindVertexArray(VAO);
// bind to target
glBindBuffer(GL_ARRAY_BUFFER, VBO);
// copy vertices to gpu
glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
unsigned int EBO;
glGenBuffers(1, &EBO);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, EBO);
glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(indices), indices, GL_STATIC_DRAW);
// 纹理
int width, height, nrChannels;
unsigned int texture;
glGenTextures(1, &texture);
glBindTexture(GL_TEXTURE_2D, texture);
// 设置纹理环绕方式
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT); // set texture wrapping to GL_REPEAT (default wrapping method)
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
// 设置纹理过滤方式
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
// 生成纹理
unsigned char* data = stbi_load("D:/OpenGL/Resource/wall.jpg", &width, &height, &nrChannels, 0);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, width, height, 0, GL_RGB, GL_UNSIGNED_BYTE,
data);
glGenerateMipmap(GL_TEXTURE_2D);
stbi_image_free(data);
// 告知opengl如何解析
// 位置属性 0为layout=0
glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(float), (void*)0);
// 启用顶点属性
glEnableVertexAttribArray(0);
// 颜色属性 最后一个参数为offset
glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(float), (void*)(3*sizeof(float)));
glEnableVertexAttribArray(1);
// 纹理
glVertexAttribPointer(2, 2, GL_FLOAT, GL_FALSE, 8 * sizeof(float), (void*)(6 * sizeof(float)));
glEnableVertexAttribArray(2);
// note that this is allowed, the call to glVertexAttribPointer registered VBO as the vertex attribute's bound vertex buffer object so afterwards we can safely unbind
//glBindBuffer(GL_ARRAY_BUFFER, 0);
// You can unbind the VAO afterwards so other VAO calls won't accidentally modify this VAO, but this rarely happens. Modifying other
// VAOs requires a call to glBindVertexArray anyways so we generally don't unbind VAOs (nor VBOs) when it's not directly necessary.
//glBindVertexArray(0);
// uncomment this call to draw in wireframe polygons.
//glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);
// shader很少变化，所以不是动态改变的也行
//glUseProgram(shaderProgram);
//
// render
while (!glfwWindowShouldClose(window)) {
processInput(window);
glClearColor(0.2f, 0.3f, 0.3f, 1.0f);
glClear(GL_COLOR_BUFFER_BIT);
// ourColor随着时间变化
//float timeValue = glfwGetTime();
0-1 不知道为啥这么写
//float newColorValue = (sin(timeValue) / 2.0f) + 0.5f;
查询位置值
//int vertextColorLocation = glGetUniformLocation(shaderProgram, "ourColor");
设置
//glUniform4f(vertextColorLocation, 1.0f, newColorValue, 0.0f, 1.0f);
// 自动把纹理赋值给片段着色器的采样器
glBindTexture(GL_TEXTURE_2D, texture);
glUseProgram(shaderProgram);
glBindVertexArray(VAO);
glDrawArrays(GL_TRIANGLES, 0, 6);
//glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, EBO);
// 代替glDrawArrays 0：指定EBO中的偏移量
glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, 0);
glfwSwapBuffers(window);
// 检查事件，调用对应的回调函数
glfwPollEvents();
}
glDeleteVertexArrays(1, &VAO);
glDeleteBuffers(1, &VBO);
glDeleteBuffers(1, &EBO);
glDeleteProgram(shaderProgram);
// 释放/删除资源
glfwTerminate();
return 0;
}
void framebuffer_size_callback(GLFWwindow* window, int width, int height) {
glViewport(0, 0, HEIGHT, HEIGHT);
}
void processInput(GLFWwindow* window) {
if (glfwGetKey(window, GLFW_KEY_ESCAPE) == GLFW_PRESS)
glfwSetWindowShouldClose(window, true);
}Running result 
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