存在问题：
1.shader中纹理输出的是texture类型
2.目前我代码顺序和官方有些不一样，可能是我理解的执行流程还有些问题
#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);
}运行结果： 