c ++ opengl无法使用glBufferSubData移动对象[关闭]

Question

我尝试仅在 y 轴上移动我的对象。我创建了一个具有 4 个顶点的数组，并将数据放入我的 vertexBuffer 并绑定它。我还创建了一个 vertexArray 和一个 indexBuffer 来绑定它们并绘制我的四边形。

现在我只更改了四边形的 y 坐标，并想用 glBufferSubData(GL_ARRAY_BUFFER, 0, sizeof(moveObject), moveObject); 覆盖我的 vertexBuffer 中的数据，但没有任何反应。只有在绑定索引缓冲区之前填充数据时，它才会起作用。之后我无法更改 VertexBuffer。

这是我的主要代码

#include <iostream>
#include "headerData/VertexBuffer.h"
#include "headerData/IndexBuffer.h"
#include "headerData/Shader.h"
#include "headerData/VertexLayout.h"
#include "headerData/VertexArray.h"
#include "headerData/Road.h"
#include "glm.hpp"
#include <gtc/matrix_transform.hpp>
#include <gtc/type_ptr.hpp>


static struct VertexShader {
    std::string defaultShader = "#version 330 core\n"
        "layout (location = 0) in vec4 aPos;\n"
        "uniform mat4 scale;"
        "void main()\n"
        "{\n"
        "gl_Position =  vec4(aPos.x, aPos.y, aPos.z, 1.0f)*scale;\n"
        "}\0";

    std::string yMoveShader = "#version 330 core\n"
        "layout (location = 0) in vec4 aPos;\n"
        "uniform mat4 scale;"
        "uniform vec4 transform;\n"
        "void main()\n"
        "{\n"
        "gl_Position =  vec4(aPos.x, aPos.y+transform.y, aPos.z, 1.0f)*scale;\n"
        "}\0";
};

static struct FragmentShader {

    std::string defaultShader = "#version 330 core\n"
        "out vec4 FragColor;\n"
        "void main()\n"
        "{\n"
        "   FragColor = vec4(0.5f, 0.5f, 0.5f, 1.0);\n"
        "}\n\0";

    std::string greenShader = "#version 330 core\n"
        "out vec4 FragColor;\n"
        "void main()\n"
        "{\n"
        "   FragColor = vec4(0.5f, 1.0f, 0.5f, 1.0);\n"
        "}\n\0";

};

void framebuffer_size_callback(GLFWwindow* window, int width, int height);
void processInput(GLFWwindow* window)
{
    if (glfwGetKey(window, GLFW_KEY_ESCAPE) == GLFW_PRESS)
        glfwSetWindowShouldClose(window, true);
}

int main()
{
    // glfw: initialize and configure
    // ------------------------------
    glfwInit();
    glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
    glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
    glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);


#ifdef __APPLE__
    glfwWindowHint(GLFW_OPENGL_FORWARD_COMPAT, GL_TRUE);
#endif

    // glfw window creation
    // --------------------
    GLFWwindow* window = glfwCreateWindow(800, 800, "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;
    }

    // set up vertex data (and buffer(s)) and configure vertex attributes
    // ------------------------------------------------------------------

    VertexShader vertexShader;
    FragmentShader fragmentShader;
    Shader shaderCol(vertexShader.defaultShader, fragmentShader.defaultShader);
    Shader shaderMove(vertexShader.yMoveShader, fragmentShader.greenShader);
    shaderCol.bind();
    //shaderMove.bind();
    glm::mat4 scale = glm::ortho(-100.0f, 100.0f, -100.0f, 100.0f, -1.0f, 1.0f);
    //glUniformMatrix4fv(glGetUniformLocation(shaderMove.getShaderID(), "scale"), 1, GL_FALSE, glm::value_ptr(scale));
    glUniformMatrix4fv(glGetUniformLocation(shaderCol.getShaderID(), "scale"), 1, GL_FALSE, glm::value_ptr(scale));
    glm::vec3 transform(0.0f, 0.0f, 0.0f);


    float moveObject[] = {
         20.0f,  -50.0f,  // top right
         20.0f, -90.0f,  // bottom right
        -20.0f, -90.0f,  // bottom left
        -20.0f,  -50.0f   // top left


    };

    float colObject[] = {
        2.0f, 2.0f,         //top right
        2.0f, -2.0f,        //bottom right
        -2.0f, 2.0f,        //top left
        -2.0, -2.0f         //bot left
    };

    unsigned int indices[] = {  // note that we start from 0!
        0, 1, 3,   // first triangle
        1, 2, 3    // second triangle
    };

    unsigned int VA, VB, IB;
    glGenVertexArrays(1, &VA);


    // bind the Vertex Array Object first, then bind and set vertex buffer(s), and then configure vertex attributes(s).

    //glBindBuffer(GL_ARRAY_BUFFER, VBO);
    //glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);

    //VertexBuffer vb;
    //vb.bind(moveObject, 4 * 2 * sizeof(float));

    //VertexBuffer
    glGenBuffers(1, &VB);
    glBindBuffer(GL_ARRAY_BUFFER, VB);
    glBufferData(GL_ARRAY_BUFFER, 8 * 2 * sizeof(float), nullptr, GL_DYNAMIC_DRAW);

    glBindVertexArray(VA);


    //LAyout vom Buffer
    glVertexAttribPointer(0, 2, GL_FLOAT, GL_FALSE, 2 * sizeof(float), (void*)(0));
    glEnableVertexAttribArray(0);


    //VertexLayout layout;
    //layout.layoutPush(3);
    //VertexArray va;
    //va.addBuffer(vb, layout);
    //IndexBuffer ib;
    //ib.bind(indices, 6 * sizeof(unsigned int));

    glGenBuffers(1, &IB);
    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, IB);
    glBufferData(GL_ELEMENT_ARRAY_BUFFER, 6 * sizeof(unsigned int), indices, GL_STATIC_DRAW);
    glBindBuffer(GL_ARRAY_BUFFER, IB);


    //Parameter
    //glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 3 * sizeof(float), (void*)(0));
    //glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 3 * sizeof(float), (void*)(3 * sizeof(float)));
    //glEnableVertexAttribArray(0);
    //glEnableVertexAttribArray(1);


    // uncomment this call to draw in wireframe polygons.
    //glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);
    //Road road;

    // render loop
    // -----------
    float time = 0;
    while (!glfwWindowShouldClose(window))
    {
        // input
        // -----
        processInput(window);

        // render
        // ------
        glClearColor(0.2f, 0.3f, 0.3f, 1.0f);
        glClear(GL_COLOR_BUFFER_BIT);

        //shader.bind();
        //glDrawElements(GL_TRIANGLES, 3, GL_UNSIGNED_INT, (void*)(sizeof(unsigned int) * 3));
        //glDrawArrays(GL_TRIANGLES, 0, 3);
        //glDrawElements(GL_TRIANGLES, 3, GL_UNSIGNED_INT, (void*)(sizeof(unsigned int) * 3));
        //glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, 0);
        //road.render();

        
        //That not work
        moveObject[1] += abs(90 * sin(glfwGetTime()));
        moveObject[3] += abs(90 * sin(glfwGetTime()));
        moveObject[5] += abs(90 * sin(glfwGetTime()));
        moveObject[7] += abs(90 * sin(glfwGetTime()));
        glBufferSubData(GL_ARRAY_BUFFER, 0, sizeof(moveObject), moveObject);
        


        //transform.y = 90 * abs(sin(glfwGetTime()));
        //glUniform4f(glGetUniformLocation(shaderMove.getShaderID(), "transform"), transform.x, transform.y, 0.0f, 1.0f);
        glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, 0);
        //glDeleteBuffers(1, &IB);

        //glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, 0);
        // glBindVertexArray(0); // no need to unbind it every time 

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

    // optional: de-allocate all resources once they've outlived their purpose:
    // ------------------------------------------------------------------------
    //glDeleteVertexArrays(1, &test);


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


void framebuffer_size_callback(GLFWwindow* window, int width, int height)
{
    std::cout << "callback" << std::endl;
    glViewport(0, 0, width, height);

}

Answer 1

当你执行这一行时

glBufferSubData(GL_ARRAY_BUFFER, 0, sizeof(moveObject), moveObject);

GPU 上绑定到GL_ARRAY_BUFFER 的数据已更新。但它绑定了哪些数据？往上看

glBindBuffer(GL_ARRAY_BUFFER, IB);

您似乎绑定了您的索引数组，而您的意思可能是

glBindBuffer(GL_ARRAY_BUFFER, VB);