c++ - 我已经转换了 The Red Book 9ed ex。3.7 从旧功能到 4.5 功能，但它没有显示任何内容

Question

出于练习目的，我已经转换了 OpenGL Red Book 9ed ex。3.7 从“旧”功能到 4.5 功能。我以前做过，它已经在我的系统上运行了，但是这一次，它没有显示任何东西，只是显示glClearBufferfv()颜色。我试着按照这个例子做一个发球台，我没有遗漏任何东西。我刚刚转换glBufferData()为glNamedBufferStorage(). 还有一些其他的事情。这是书中出现的原始代码。但是让我复制粘贴我自己的代码和着色器：

主文件

#include <iostream>

#include <glad/glad.h>
#include <KHR/khrplatform.h>

#include <GLFW/glfw3.h>

#define GLM_FORCE_RADIANS
#include <glm/glm.hpp>
#include <glm/gtc/matrix_transform.hpp>
#include <glm/gtc/type_ptr.hpp>

#include <SOIL2/SOIL2.h>

#include <Shader.h>
#include <Camera.h>


enum VAO_IDs { Triangles, NumVAOs, ID3 };
enum Buffer_IDs { ArrayBuffer1, ArrayBuffer2, EBOBuffer, NumBuffers
};
enum Attrib_IDs { vPosition = 0, cPosition = 1 };

GLuint  VAOs[NumVAOs];
GLuint  Buffers[NumBuffers];

const GLuint NumVertices = 6;

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

// settings
const unsigned int SCR_WIDTH = 800;
const unsigned int SCR_HEIGHT = 600;



void init()
{
    GLfloat cube_positions[] = {

    -1.0f, -1.0f, -1.0f, 1.0f,
    -1.0f, -1.0f,  1.0f, 1.0f,
    -1.0f,  1.0f, -1.0f, 1.0f,
    -1.0f,  1.0f,  1.0f, 1.0f,
     1.0f, -1.0f, -1.0f, 1.0f,
     1.0f, -1.0f,  1.0f, 1.0f,
     1.0f,  1.0f, -1.0f, 1.0f,
     1.0f,  1.0f,  1.0f, 1.0f

    };

    GLfloat cube_colors[] = {
    1.0f, 1.0f, 1.0f, 1.0f,
    1.0f, 1.0f, 0.0f, 1.0f,
    1.0f, 0.0f, 1.0f, 1.0f,
    1.0f, 0.0f, 0.0f, 1.0f,
    0.0f, 1.0f, 1.0f, 1.0f,
    0.0f, 1.0f, 0.0f, 1.0f,
    0.0f, 0.0f, 1.0f, 1.0f,
    0.5f, 0.5f, 0.5f, 1.0f

    };

    GLushort cube_indices[] = {
        0, 1, 2, 3, 6, 7, 4, 5,        
    0xFFFF,                         
    2, 6, 0, 4, 1, 5, 3, 7
    };

    glCreateVertexArrays(NumVAOs, VAOs);
    glCreateBuffers(NumBuffers, Buffers);
    glNamedBufferStorage(Buffers[ArrayBuffer1], sizeof(cube_positions), cube_positions, GL_ARRAY_BUFFER);
    glNamedBufferStorage(Buffers[ArrayBuffer2], sizeof(cube_colors), cube_colors, GL_ARRAY_BUFFER);
    glNamedBufferStorage(Buffers[EBOBuffer], sizeof(cube_indices), cube_indices, GL_ELEMENT_ARRAY_BUFFER);
    Shader myShader("TirangleVert.glsl", "TriangleFrag.glsl");

    myShader.Use();

    glBindVertexArray(VAOs[Triangles]);

    glBindBuffer(GL_ARRAY_BUFFER, Buffers[ArrayBuffer1]);
    glBindBuffer(GL_ARRAY_BUFFER, Buffers[ArrayBuffer2]);
    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, Buffers[EBOBuffer]);
    glVertexAttribPointer(vPosition, 4, GL_FLOAT, GL_FALSE, 0, 0);
    glVertexAttribPointer(cPosition, 4, GL_FLOAT, GL_FALSE, 0, (const GLvoid *) sizeof(cube_positions));

    glEnableVertexAttribArray(vPosition);
    glEnableVertexAttribArray(cPosition);





}

void display()
{
    GLfloat black[] = { 0.2f, 0.5f, 0.6f };

    glClearBufferfv(GL_COLOR, 0, black);

    glBindVertexArray(VAOs[Triangles]);
    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, Buffers[EBOBuffer]);
    glLineWidth(20);
    glPointSize(20);
    glEnable(GL_PRIMITIVE_RESTART);
    glPrimitiveRestartIndex(0xFFFF);
    glDrawElements(GL_TRIANGLE_STRIP, 17, GL_UNSIGNED_SHORT, NULL);
    //glDrawElements(GL_TRIANGLE_STRIP, 8, GL_UNSIGNED_SHORT, NULL);
    //glDrawElements(GL_TRIANGLE_STRIP, 8, GL_UNSIGNED_SHORT,
    //  (const GLvoid *)(9 * sizeof(GLushort)));


}

void dealloc()
{
    glDeleteVertexArrays(NumVAOs, VAOs);
    glDeleteBuffers(NumBuffers, Buffers);
}

int main()
{
    // glfw: initialize and configure
    // ------------------------------
    glfwInit();
    glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 4);
    glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 5);
    glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);



    // glfw window creation
    // --------------------
    GLFWwindow* window = glfwCreateWindow(SCR_WIDTH, SCR_HEIGHT, "LearnOpenGL", NULL, NULL);
    if (window == NULL)
    {
        std::cout << "Failed to create GLFW window" << std::endl;
        glfwTerminate();
        return -1;
    }
    glfwMakeContextCurrent(window);
    glfwSetFramebufferSizeCallback(window, framebuffer_size_callback);

    // glad: load all OpenGL function pointers
    // ---------------------------------------
    if (!gladLoadGLLoader((GLADloadproc)glfwGetProcAddress))
    {
        std::cout << "Failed to initialize GLAD" << std::endl;
        return -1;
    }


    init();

    // render loop
    // -----------
    while (!glfwWindowShouldClose(window))
    {
        // input
        // -----
        processInput(window);

        // render
        // ------       
        display();

        // glfw: swap buffers and poll IO events (keys pressed/released, mouse moved etc.)
        // -------------------------------------------------------------------------------
        glfwSwapBuffers(window);
        glfwPollEvents();
    }

    dealloc();

    // glfw: terminate, clearing all previously allocated GLFW resources.
    // ------------------------------------------------------------------
    glfwTerminate();
    return 0;
}

// process all input: query GLFW whether relevant keys are pressed/released this frame and react accordingly
// ---------------------------------------------------------------------------------------------------------
void processInput(GLFWwindow *window)
{
    if (glfwGetKey(window, GLFW_KEY_ESCAPE) == GLFW_PRESS)
        glfwSetWindowShouldClose(window, true);
}

// glfw: whenever the window size changed (by OS or user resize) this callback function executes
// ---------------------------------------------------------------------------------------------
void framebuffer_size_callback(GLFWwindow* window, int width, int height)
{
    // make sure the viewport matches the new window dimensions; note that width and 
    // height will be significantly larger than specified on retina displays.
    glViewport(0, 0, width, height);
}

TirangleVert.glsl：

#version 450 core


layout (location = 0) in vec4 cube_pos;
layout (location = 1) in vec4 colors; 

out vec4 myColor;

void main()
{
    gl_Position = cube_pos;

    myColor = colors;



}

TriangleFrag.glsl：

#version 450 core


layout (location = 0) in vec4 myColor;

out vec4 color;


void main()
{
    color = myColor;
}

PS：我意识到顶点着色器的名称有错别字，但都已解决。此外，Shader.h 没有问题，因为我之前使用过它没有任何问题。

非常感谢。

标签： c++openglglslshaderopengl-4

Answer 1

的最后一个参数glNamedBufferStorage是位域，它指定缓冲区数据存储的预期用途，而不是GL_ARRAY_BUFFERor GL_ELEMENT_ARRAY_BUFFER。这将导致GL_INVALID_VALUE错误：

GLbitfield flags = GL_DYNAMIC_STORAGE_BIT | GL_MAP_WRITE_BIT | GL_MAP_PERSISTENT_BIT;
glNamedBufferStorage(Buffers[ArrayBuffer1], sizeof(cube_positions), cube_positions, flags);
glNamedBufferStorage(Buffers[ArrayBuffer2], sizeof(cube_colors), cube_colors, flags);
glNamedBufferStorage(Buffers[EBOBuffer], sizeof(cube_indices), cube_indices, flags);

glVertexAttribPointer指定一个顶点数组，它是指当前绑定的数组缓冲区。
正确的缓冲区必须在调用glBindBuffer之前绑定。glVertexAttribPointer请注意，当前只能绑定 1 个缓冲区。
如果绑定了缓冲区，则最后一个参数（指针）被视为缓冲区对象数据存储中的字节偏移量。在您的情况下，此参数必须为 0。请注意，在核心配置文件上下文中，您必须使用数组缓冲区，直接寻址的内存无效。

glBindVertexArray(VAOs[Triangles]);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, Buffers[EBOBuffer]);

glBindBuffer(GL_ARRAY_BUFFER, Buffers[ArrayBuffer1]);
glVertexAttribPointer(vPosition, 4, GL_FLOAT, GL_FALSE, 0, 0);

glBindBuffer(GL_ARRAY_BUFFER, Buffers[ArrayBuffer2]);
glVertexAttribPointer(cPosition, 4, GL_FLOAT, GL_FALSE, 0, 0);

glEnableVertexAttribArray(vPosition);
glEnableVertexAttribArray(cPosition);