环境
- 系统：ubuntu20.04
- opengl版本：4.6
- glfw版本：3.3
- glad版本：4.6
- cmake版本：3.16.3
- gcc版本：10.3.0
直接上代码
CMakeLists.txt
cmake_minimum_required(VERSION 3.5)
set(CMAKE_C_STANDARD 11)
set(CMAKE_CXX_STANDARD 11)
project(textureTest)
find_package(glfw3 REQUIRED)
file(GLOB project_file main.cpp glad.c stb_image.h stbimage.h)
message("PROJECT_NAME:${PROJECT_NAME}")
add_executable(${PROJECT_NAME} ${project_file})
target_link_libraries(${PROJECT_NAME}
-lglfw
-lGL
-lm
-lXrandr
-lX11
-lpthread
-ldl
)main.cpp
#include <glad/glad.h>
#include <GLFW/glfw3.h>
#include "stbimage.h"
#include <iostream>
const unsigned int SCR_WIDTH = 800;
const unsigned int SCR_HEIGHT = 600;
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"
"}\0";
int main()
{
glfwInit();
glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
std::cout << "start..." << std::endl;
//创建一个窗口
GLFWwindow *window = glfwCreateWindow(SCR_WIDTH, SCR_HEIGHT, "hello Triangle", NULL, NULL);
if (window == NULL)
{
std::cout << "Failed to create GLFW window" << std::endl;
glfwTerminate();
return -1;
}
glfwMakeContextCurrent(window);
if (!gladLoadGLLoader((GLADloadproc)glfwGetProcAddress))
{
std::cout << "Failed to initialize GLAD" << std::endl;
return -1;
}
//顶点着色器代码
unsigned int vertexShader;
vertexShader = glCreateShader(GL_VERTEX_SHADER);
glShaderSource(vertexShader, 1, &vertexShaderSource, NULL);
glCompileShader(vertexShader);
// check for shader compile errors
int success;
char infoLog[512];
glGetShaderiv(vertexShader, GL_COMPILE_STATUS, &success);
if (!success)
{
glGetShaderInfoLog(vertexShader, 512, NULL, infoLog);
std::cout << "ERROR::SHADER::VERTEX::COMPILATION_FAILED\n"
<< infoLog << std::endl;
}
//片段着色器
unsigned int fragmentShader;
fragmentShader = glCreateShader(GL_FRAGMENT_SHADER);
glShaderSource(fragmentShader, 1, &fragmentShaderSource, NULL);
glCompileShader(fragmentShader);
// check for shader compile errors
glGetShaderiv(fragmentShader, GL_COMPILE_STATUS, &success);
if (!success)
{
glGetShaderInfoLog(fragmentShader, 512, NULL, infoLog);
std::cout << "ERROR::SHADER::FRAGMENT::COMPILATION_FAILED\n"
<< infoLog << std::endl;
}
//着色器程序
unsigned int shaderProgram;
shaderProgram = glCreateProgram();
glAttachShader(shaderProgram, vertexShader);
glAttachShader(shaderProgram, fragmentShader);
glLinkProgram(shaderProgram);
// check for linking errors
glGetProgramiv(shaderProgram, GL_LINK_STATUS, &success);
if (!success)
{
glGetProgramInfoLog(shaderProgram, 512, NULL, infoLog);
std::cout << "ERROR::SHADER::PROGRAM::LINKING_FAILED\n"
<< infoLog << std::endl;
}
glDeleteShader(vertexShader);
glDeleteShader(fragmentShader);
//加载纹理图片
int width, height, nrChannels;
//生成纹理
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_CLAMP_TO_BORDER);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_BORDER);
//设置边缘的颜色值
float borderColor[] = {1.0f, 1.0f, 0.0f, 1.0f};
glTexParameterfv(GL_TEXTURE_2D, GL_TEXTURE_BORDER_COLOR, borderColor);
// //纹理过滤设置
// glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
// glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
//多级渐远纹理设置,这里第二句设置是什么意思呢？
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
unsigned char *data = stbi_load("wall.jpg", &width, &height, &nrChannels, 0);
if (data) {
//绑定和纹理图片数据结合
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, width, height, 0, GL_RGB, GL_UNSIGNED_BYTE, data);
glGenerateMipmap(GL_TEXTURE_2D);
} else {
std::cout << "读取图片数据错误" << std::endl;
}
//释放图像内存
stbi_image_free(data);
//设置三角形纹理坐标
float vertices[] = {
// ---- 位置 ---- ---- 颜色 ---- - 纹理坐标 -
0.5f, 0.5f, 0.0f, 1.0f, 0.0f, 0.0f, 1.0f, 1.0f, // 右上
0.5f, -0.5f, 0.0f, 0.0f, 1.0f, 0.0f, 1.0f, 0.0f, // 右下
-0.5f, -0.5f, 0.0f, 0.0f, 0.0f, 1.0f, 0.0f, 0.0f // 左下
// -0.5f, 0.5f, 0.0f, 1.0f, 1.0f, 0.0f, 0.0f, 1.0f // top left
};
unsigned int indices[] = {
0, 1, 3, // first triangle
1, 2, 3 // second triangle
};
//绑定VAO等
unsigned int VAO,VBO,EBO;
glGenVertexArrays(1,&VAO);
glGenBuffers(1,&VBO);
glGenBuffers(1,&EBO);
glBindVertexArray(VAO);
glBindBuffer(GL_ARRAY_BUFFER,VBO);
glBufferData(GL_ARRAY_BUFFER,sizeof(vertices),vertices,GL_STATIC_DRAW);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, EBO);
glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(indices), indices, GL_STATIC_DRAW);
//定位各个点的关系
// position attribute
glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(float), (void *)0);
glEnableVertexAttribArray(0);
// color attribute
glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(float), (void *)(3 * sizeof(float)));
glEnableVertexAttribArray(1);
// texture coord attribute
glVertexAttribPointer(2, 2, GL_FLOAT, GL_FALSE, 8 * sizeof(float), (void *)(6 * sizeof(float)));
glEnableVertexAttribArray(2);
// render loop
// -----------
while (!glfwWindowShouldClose(window))
{
// render
// ------
glClearColor(0.2f, 0.3f, 0.3f, 1.0f);
glClear(GL_COLOR_BUFFER_BIT);
// bind Texture
glBindTexture(GL_TEXTURE_2D, texture);
// render container
// ourShader.use();
glUseProgram(shaderProgram);
glBindVertexArray(VAO);
glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, (const GLvoid *)0);
// glfw: swap buffers and poll IO events (keys pressed/released, mouse moved etc.)
// -------------------------------------------------------------------------------
glfwSwapBuffers(window);
glfwPollEvents();
}
glDeleteVertexArrays(1, &VAO);
glDeleteBuffers(1, &VBO);
glDeleteBuffers(1, &EBO);
glDeleteProgram(shaderProgram);
glfwTerminate();
return 0;
}stbimage.h
#define STB_IMAGE_IMPLEMENTATION
#include "stb_image.h"总结
- 在这个例程中，使用了索引缓存对象EBO，使用了这个对象，就需要使用
glDrawElements函数来绘制图像，如果不使用EBO，而用glDrawElements进行绘制，则会报段错误 - 如果不使用EBO，则绘制图像则需要使用
glDrawArrays函数来绘制图像 - 使用了EBO，则需要做如下操作来支持
//定义绘制顶点的顺序
unsigned int indices[] = {
0, 1, 3, // first triangle
1, 2, 3 // second triangle
};
//内存拷贝
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, EBO);
glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(indices), indices, GL_STATIC_DRAW);
//定位各个点偏移位置的关系
// position attribute
glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(float), (void *)0);
glEnableVertexAttribArray(0);
// color attribute
glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(float), (void *)(3 * sizeof(float)));
glEnableVertexAttribArray(1);
// texture coord attribute
glVertexAttribPointer(2, 2, GL_FLOAT, GL_FALSE, 8 * sizeof(float), (void *)(6 * sizeof(float)));
glEnableVertexAttribArray(2);
//根据索引对象进行绘制
glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, (const GLvoid *)0);- 如果在你的绘制区域出现全黑的框，可能是纹理图片没有正确的加载，在这里正确的顺序是：纹理的定义–读取纹理图片
- 如果出现显示的箱体是个三角形，并且另外一部分是边缘拉伸状，则可以看一下1.点定位关系是否正确
参考
中国软件行业倡议书
精简软件开发，电脑性能越来越好，打出的程序安装包越来越大，磁盘，内存越吃越多，这不是好现象，手机同理，大家觉得呢，欢迎发表看法，各抒己见。
手机app随意读取用户通讯录，就是流氓行为，即使有时候弹窗提示是否授权，选择了否，但是他其实还是悄悄读取你的通讯录，并且随便给你的通讯录好友发推广信息，这一点是非常反感的，并且也触犯了用户的权益，这不仅是流氓行为，更是违法行为，某软件就不说了。
作者有话说
个人简介：多年工作工程经验，擅长linux下软件开发，qt，ffmpeg音视频二次开发。
欢迎各位叨扰作者，如果有什么项目合作，创业合伙需要研发，网站推广，猎头服务，内推等等，尽管来联系，对于能挣钱的事，作者可是很感兴趣的哦。
关于内卷
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