c++ - 在 OpenGL 中加载 JPG 时出现白屏

Question

我正在尝试使用“stb_image.h”库渲染 JPG 图像。我使用 GLEW 和 GLFW，代码如下：

#include "glew.h"
#include "glfw3.h"
#include <iostream>

#define STB_IMAGE_IMPLEMENTATION
#include "stb_image.h"


#define WIDTH 800
#define HEIGHT 600

void framebuffer_size_callback(GLFWwindow* window, int width, int height);

int main(){

    GLFWwindow *window;
    

    if (!glfwInit())
    {
        std::cout << "Failed to Init GLFW" << std::endl;
        return -1;
    }

    glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
    glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
    glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);

    window = glfwCreateWindow(WIDTH, HEIGHT, "OpenGL CPP", NULL, NULL);
    if (!window)
    {
        std::cout << "Failed to create GLFW Window" << std::endl;
        glfwTerminate();
        return -1;
    }

    glfwMakeContextCurrent(window);
    glfwSetFramebufferSizeCallback(window, framebuffer_size_callback);

    GLenum err = glewInit();
    if (GLEW_OK != err)
    {
        std::cout << "Failed to Init GLEW" << std::endl;
        glfwTerminate();
        return -1;
    }

    float vertices[] = {
    // positions          // colors           // texture coords
     0.5f,  0.5f, 0.0f,   1.0f, 0.0f, 0.0f,   1.0f, 1.0f,   // top right
     0.5f, -0.5f, 0.0f,   0.0f, 1.0f, 0.0f,   1.0f, 0.0f,   // bottom right
    -0.5f, -0.5f, 0.0f,   0.0f, 0.0f, 1.0f,   0.0f, 0.0f,   // bottom left
    -0.5f,  0.5f, 0.0f,   1.0f, 1.0f, 0.0f,   0.0f, 1.0f    // top left 
    };
    float indices[] = {
        0, 1, 3, // first triangle
        1, 2, 3  // second triangle
    };

    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 = vec2(aTexCoord.x, aTexCoord.y);\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";

    unsigned int vertexShader;
    vertexShader = glCreateShader(GL_VERTEX_SHADER);
    glShaderSource(vertexShader, 1, &vertexShaderSource, NULL);
    glCompileShader(vertexShader);
    
    int success;
    char infoLog[512];
    glGetShaderiv(vertexShader, GL_COMPILE_STATUS, &success);
    if (!success)
    {
        glGetShaderInfoLog(vertexShader, 512, NULL, infoLog);
        std::cout << "ERROR COMPILING VERTEX SHADER" << infoLog << std::endl;
    }

    unsigned int fragmentShader;
    fragmentShader = glCreateShader(GL_FRAGMENT_SHADER);
    glShaderSource(fragmentShader, 1, &fragmentShaderSource, NULL);
    glCompileShader(fragmentShader);
    
    glGetShaderiv(fragmentShader, GL_COMPILE_STATUS, &success);
    if (!success)
    {
        glGetShaderInfoLog(fragmentShader, 512, NULL, infoLog);
        std::cout << "ERROR COMPILING FRAGMENT SHADER" << infoLog << std::endl;
    }
    
    unsigned int shaderProgram;
    shaderProgram = glCreateProgram();
    glAttachShader(shaderProgram, vertexShader);
    glAttachShader(shaderProgram, fragmentShader);
    glLinkProgram(shaderProgram);

    glDeleteShader(vertexShader);
    glDeleteShader(fragmentShader);

    unsigned int VBO, VAO, 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);

    // 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);

    unsigned int texture;
    glGenTextures(1, &texture);
    glBindTexture(GL_TEXTURE_2D, texture);

    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);
    // set texture filtering parameters
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);

    int width, height, nrChannels;
    unsigned char *data = stbi_load("C:/Users/user3/Documents/cppopengl/res/container.jpg", &width, &height, &nrChannels, 0);

    if (data)
    {
        glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, width, height, 0, GL_RGB, GL_UNSIGNED_BYTE, data);
        glGenerateMipmap(GL_TEXTURE_2D);
        std::cout << "data loaded successfully"<< std::endl;
    }
    else
    {
        std::cout << "Failed to load texture" << std::endl;
    }
    
    stbi_image_free(data);


    glUseProgram(shaderProgram);
    //std::cout << glGetUniformLocation(shaderProgram, "ourTexture") << std::endl;
    glUniform1i(glGetUniformLocation(shaderProgram, "ourTexture"), 0);

    while (!glfwWindowShouldClose(window))
    {
        err = glGetError();
        glClearColor(0.5, 0.5, 0.5, 1);
        glClear(GL_COLOR_BUFFER_BIT);

        glActiveTexture(GL_TEXTURE0);
        glBindTexture(GL_TEXTURE_2D, texture);

        glUseProgram(shaderProgram);
        
        glBindVertexArray(VAO);
        glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, 0);

        glfwPollEvents();

        if (((err = glGetError()) != GL_NO_ERROR))
        {
            std::cout << err << std::endl;
        }
        
    }
    glDeleteShader(vertexShader);
    glDeleteShader(fragmentShader);
    glDeleteProgram(shaderProgram);
    return 0;   
}

void framebuffer_size_callback(GLFWwindow* window, int width, int height)
{
    glViewport(0, 0, width, height);
}

代码编译得很好，没有错误和警告。当我启动可执行文件时，它显示白屏。顶点着色器和片段着色器都编译和链接没有错误。stbi_load()不返回错误glGetError()也不返回错误，glGetUniformLocation()返回统一位置就好了。你能帮帮我吗？提前致谢。

编辑：索引必须unsigned int代替float，谢谢@Rabbid76

unsigned int indices[] = {
        0, 1, 3, // first triangle
        1, 2, 3  // second triangle
    };

标签： c++opengltextures