C++ OpenGL 线框立方体渲染空白

coder 2024-02-11 原文

我只是想画一堆线组成一个“立方体”。我一辈子都弄不明白为什么会出现黑屏。调试器在任何时候都不会中断。

我确定这是我的指针的问题，因为我只在常规 C++ 中表现不错，而在 OpenGL 中它变得更糟。

const char* vertexSource = 
    "#version 150\n"
    "in vec3 position;"
    "void main() {"
    "   gl_Position = vec4(position, 1.0);"
    "}";

const char* fragmentSource = 
    "#version 150\n"
    "out vec4 outColor;"
    "void main() {"
    "   outColor = vec4(1.0, 1.0, 1.0, 1.0);"
    "}";

int main() {

    initializeGLFW();

    // Initialize GLEW
    glewExperimental = GL_TRUE;
    glewInit();

    // Create Vertex Array Object
    GLuint vao;
    glGenVertexArrays(1, &vao);
    glBindVertexArray(vao);

    // Create a Vertex Buffer Object and copy the vertex data to it
    GLuint vbo;
    glGenBuffers( 1, &vbo );

    float vertices[] = {
         1.0f,  1.0f,  1.0f, // Vertex 0 (X, Y, Z)
        -1.0f,  1.0f,  1.0f, // Vertex 1 (X, Y, Z)
        -1.0f, -1.0f,  1.0f, // Vertex 2 (X, Y, Z)
         1.0f, -1.0f,  1.0f, // Vertex 3 (X, Y, Z)
         1.0f,  1.0f, -1.0f, // Vertex 4 (X, Y, Z)
        -1.0f,  1.0f, -1.0f, // Vertex 5 (X, Y, Z)
        -1.0f, -1.0f, -1.0f, // Vertex 6 (X, Y, Z)
         1.0f, -1.0f, -1.0f  // Vertex 7 (X, Y, Z)
    };

    GLuint indices[] = {
        0, 1,
        1, 2,
        2, 3,
        3, 0,
        4, 5,
        5, 6,
        6, 7,
        7, 4,
        0, 4,
        1, 5,
        2, 6,
        3, 7
    };

    glBindBuffer( GL_ARRAY_BUFFER, vbo );
    glBufferData( GL_ARRAY_BUFFER, sizeof( vertices ), vertices, GL_STATIC_DRAW );
    //glBindBuffer( GL_ELEMENT_ARRAY_BUFFER, vbo);
    //glBufferData( GL_ELEMENT_ARRAY_BUFFER, sizeof( indices ), indices, GL_STATIC_DRAW );

    // Create and compile the vertex shader
    GLuint vertexShader = glCreateShader( GL_VERTEX_SHADER );
    glShaderSource( vertexShader, 1, &vertexSource, NULL );
    glCompileShader( vertexShader );

    // Create and compile the fragment shader
    GLuint fragmentShader = glCreateShader( GL_FRAGMENT_SHADER );
    glShaderSource( fragmentShader, 1, &fragmentSource, NULL );
    glCompileShader( fragmentShader );

    // Link the vertex and fragment shader into a shader program
    GLuint shaderProgram = glCreateProgram();
    glAttachShader( shaderProgram, vertexShader );
    glAttachShader( shaderProgram, fragmentShader );
    glBindFragDataLocation( shaderProgram, 0, "outColor" );
    glLinkProgram (shaderProgram);
    glUseProgram( shaderProgram);

    // Specify the layout of the vertex data
    GLint posAttrib = glGetAttribLocation( shaderProgram, "position" );
    glEnableVertexAttribArray( posAttrib );
    glVertexAttribPointer( posAttrib, 3, GL_FLOAT, GL_FALSE, 0, 0 );

    // Main loop
    while(glfwGetWindowParam(GLFW_OPENED)) {

        // Clear the screen to black
        glClearColor( 0.0f, 0.0f, 0.0f, 1.0f );
        glClear( GL_COLOR_BUFFER_BIT );

        // Draw lines from 2 vertices
        glDrawElements(GL_LINES, sizeof(indices), GL_UNSIGNED_INT, indices );

        // Swap buffers
        glfwSwapBuffers();
    }

    // Clean up
    glDeleteProgram( shaderProgram );
    glDeleteShader( fragmentShader );
    glDeleteShader( vertexShader );

    //glDeleteBuffers( 1, &ebo );
    glDeleteBuffers( 1, &vbo );

    glDeleteVertexArrays( 1, &vao );

    glfwTerminate();
    exit( EXIT_SUCCESS );
}

编辑:尝试第一个答案推荐的完整代码。还是空白。

#define GLEW_STATIC

#include <GL/glew.h>
#include <GL/glfw.h>
#include <iostream>

#pragma comment( lib, "glfw.lib")
#pragma comment( lib, "opengl32.lib")
#pragma comment( lib, "glew32s.lib")

const char* vertexSource = 
    "#version 150\n"
    "in vec3 position;"
    "void main() {"
    "   gl_Position = vec4(position.x, position.y, position.z - 0.9, 1.0);"
    "}";

const char* fragmentSource = 
    "#version 150\n"
    "out vec4 outColor;"
    "void main() {"
    "   outColor = vec4(1.0, 1.0, 1.0, 1.0);"
    "}";

void initializeGLFW();

int main() {

    initializeGLFW();

    // Initialize GLEW
    glewExperimental = GL_TRUE;
    glewInit();

    // Create Vertex Array Object
    GLuint vao;
    glGenVertexArrays(1, &vao);
    glBindVertexArray(vao);

    // Create a Vertex Buffer Object and copy the vertex data to it
    GLuint vbo;
    glGenBuffers( 1, &vbo );

    float vertices[] = {
         1.0f,  1.0f,  1.0f, // Vertex 0 (X, Y, Z)
        -1.0f,  1.0f,  1.0f, // Vertex 1 (X, Y, Z)
        -1.0f, -1.0f,  1.0f, // Vertex 2 (X, Y, Z)
         1.0f, -1.0f,  1.0f, // Vertex 3 (X, Y, Z)
         1.0f,  1.0f, -1.0f, // Vertex 4 (X, Y, Z)
        -1.0f,  1.0f, -1.0f, // Vertex 5 (X, Y, Z)
        -1.0f, -1.0f, -1.0f, // Vertex 6 (X, Y, Z)
         1.0f, -1.0f, -1.0f  // Vertex 7 (X, Y, Z)
    };

    size_t vertCount = sizeof( vertices ) / sizeof( float );
    for( size_t i = 0; i < vertCount; ++i ) {
        vertices[i] /= 2.0f;
    }

    GLubyte indices[] = {
        0, 1,
        1, 2,
        2, 3,
        3, 0,
        4, 5,
        5, 6,
        6, 7,
        7, 4,
        0, 4,
        1, 5,
        2, 6,
        3, 7
    };

    glBindBuffer( GL_ARRAY_BUFFER, vbo );
    //glBindBuffer( GL_ELEMENT_ARRAY_BUFFER, vbo);
    glBufferData( GL_ARRAY_BUFFER, sizeof( vertices ), vertices, GL_STATIC_DRAW );

    // Create and compile the vertex shader
    GLuint vertexShader = glCreateShader( GL_VERTEX_SHADER );
    glShaderSource( vertexShader, 1, &vertexSource, NULL );
    glCompileShader( vertexShader );

    // Create and compile the fragment shader
    GLuint fragmentShader = glCreateShader( GL_FRAGMENT_SHADER );
    glShaderSource( fragmentShader, 1, &fragmentSource, NULL );
    glCompileShader( fragmentShader );

    // Link the vertex and fragment shader into a shader program
    GLuint shaderProgram = glCreateProgram();
    glAttachShader( shaderProgram, vertexShader );
    glAttachShader( shaderProgram, fragmentShader );
    glBindFragDataLocation( shaderProgram, 0, "outColor" );
    glLinkProgram (shaderProgram);
    glUseProgram( shaderProgram);

    // Specify the layout of the vertex data
    GLint posAttrib = glGetAttribLocation( shaderProgram, "position" );
    glEnableVertexAttribArray( posAttrib );
    glVertexAttribPointer( posAttrib, 3, GL_FLOAT, GL_FALSE, 0, vertices );

    // Main loop
    while(glfwGetWindowParam(GLFW_OPENED)) {

        // Clear the screen to black
        glClearColor( 0.0f, 0.0f, 0.0f, 1.0f );
        glClear( GL_COLOR_BUFFER_BIT );

        // Draw lines from 2 vertices
        glDrawElements(GL_LINES, 24, GL_UNSIGNED_BYTE, indices);

        // Swap buffers
        glfwSwapBuffers();
    }

    // Clean up
    glDeleteProgram( shaderProgram );
    glDeleteShader( fragmentShader );
    glDeleteShader( vertexShader );

    //glDeleteBuffers( 1, &ebo );
    glDeleteBuffers( 1, &vbo );

    glDeleteVertexArrays( 1, &vao );

    glfwTerminate();
    exit( EXIT_SUCCESS );
}

void initializeGLFW() {
    glfwInit();
    glfwOpenWindowHint( GLFW_OPENGL_VERSION_MAJOR, 3 );
    glfwOpenWindowHint( GLFW_OPENGL_VERSION_MINOR, 2 );
    glfwOpenWindowHint( GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE );

    glfwOpenWindowHint( GLFW_WINDOW_NO_RESIZE, GL_TRUE );
    glfwOpenWindow( 800, 600, 0, 0, 0, 0, 0, 0, GLFW_WINDOW );
    glfwSetWindowTitle( "OpenGL" );
}

最佳答案

“默认”投影本质上是 glOrtho(-1, 1, -1, 1, -1, 1)，相机位于 (0,0,0) 向下看 -Z 轴。

向后移动相机:

const char* vertexSource = 
    "#version 150\n"
    "in vec3 position;"
    "void main() {"
    "   gl_Position = vec4(position.x, position.y, position.z - 0.9, 1.0);"
    "}";

让你的对象变小:

float vertices[] = {
     1.0f,  1.0f,  1.0f, // Vertex 0 (X, Y, Z)
    -1.0f,  1.0f,  1.0f, // Vertex 1 (X, Y, Z)
    -1.0f, -1.0f,  1.0f, // Vertex 2 (X, Y, Z)
     1.0f, -1.0f,  1.0f, // Vertex 3 (X, Y, Z)
     1.0f,  1.0f, -1.0f, // Vertex 4 (X, Y, Z)
    -1.0f,  1.0f, -1.0f, // Vertex 5 (X, Y, Z)
    -1.0f, -1.0f, -1.0f, // Vertex 6 (X, Y, Z)
     1.0f, -1.0f, -1.0f  // Vertex 7 (X, Y, Z)
};

size_t vertCount = sizeof( vertices ) / sizeof( float );
for( size_t i = 0; i < vertCount; ++i )
{
    vertices[i] /= 2.0f;
}

完成:

#include <GL/glew.h>
#include <GL/glfw.h>
#include <cstdlib>

const char* vertexSource = 
    "#version 150\n"
    "in vec3 position;"
    "void main() {"
    "   gl_Position = vec4(position.x, position.y, position.z - 0.9, 1.0);"
    "}";

const char* fragmentSource = 
    "#version 150\n"
    "out vec4 outColor;"
    "void main() {"
    "   outColor = vec4(1.0, 1.0, 1.0, 1.0);"
    "}";

void initializeGLFW() 
{
    glfwInit();
    glfwOpenWindowHint( GLFW_OPENGL_VERSION_MAJOR, 3 );
    glfwOpenWindowHint( GLFW_OPENGL_VERSION_MINOR, 2 );
    glfwOpenWindowHint( GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE );

    glfwOpenWindowHint( GLFW_WINDOW_NO_RESIZE, GL_TRUE );
    glfwOpenWindow( 800, 600, 0, 0, 0, 0, 0, 0, GLFW_WINDOW );
    glfwSetWindowTitle( "OpenGL" );
}

int main()
{
    initializeGLFW();

    // Initialize GLEW
    glewExperimental = GL_TRUE;
    glewInit();

    // Create Vertex Array Object
    GLuint vao;
    glGenVertexArrays(1, &vao);
    glBindVertexArray(vao);

    // Create a Vertex Buffer Object and copy the vertex data to it
    GLuint vbo;
    glGenBuffers( 1, &vbo );

    float vertices[] = 
    {
         1.0f,  1.0f,  1.0f, // Vertex 0 (X, Y, Z)
        -1.0f,  1.0f,  1.0f, // Vertex 1 (X, Y, Z)
        -1.0f, -1.0f,  1.0f, // Vertex 2 (X, Y, Z)
         1.0f, -1.0f,  1.0f, // Vertex 3 (X, Y, Z)
         1.0f,  1.0f, -1.0f, // Vertex 4 (X, Y, Z)
        -1.0f,  1.0f, -1.0f, // Vertex 5 (X, Y, Z)
        -1.0f, -1.0f, -1.0f, // Vertex 6 (X, Y, Z)
         1.0f, -1.0f, -1.0f  // Vertex 7 (X, Y, Z)
    };

    size_t vertCount = sizeof( vertices ) / sizeof( float );
    for( size_t i = 0; i < vertCount; ++i )
    {
        vertices[i] /= 2.0f;
    }

    GLuint indices[] = 
    {
        0, 1,
        1, 2,
        2, 3,
        3, 0,
        4, 5,
        5, 6,
        6, 7,
        7, 4,
        0, 4,
        1, 5,
        2, 6,
        3, 7
    };

    glBindBuffer( GL_ARRAY_BUFFER, vbo );
    glBufferData( GL_ARRAY_BUFFER, sizeof( vertices ), vertices, GL_STATIC_DRAW );

    // Create and compile the vertex shader
    GLuint vertexShader = glCreateShader( GL_VERTEX_SHADER );
    glShaderSource( vertexShader, 1, &vertexSource, NULL );
    glCompileShader( vertexShader );

    // Create and compile the fragment shader
    GLuint fragmentShader = glCreateShader( GL_FRAGMENT_SHADER );
    glShaderSource( fragmentShader, 1, &fragmentSource, NULL );
    glCompileShader( fragmentShader );

    // Link the vertex and fragment shader into a shader program
    GLuint shaderProgram = glCreateProgram();
    glAttachShader( shaderProgram, vertexShader );
    glAttachShader( shaderProgram, fragmentShader );
    glBindFragDataLocation( shaderProgram, 0, "outColor" );
    glLinkProgram (shaderProgram);
    glUseProgram( shaderProgram);

    // Specify the layout of the vertex data
    GLint posAttrib = glGetAttribLocation( shaderProgram, "position" );
    glEnableVertexAttribArray( posAttrib );
    glVertexAttribPointer( posAttrib, 3, GL_FLOAT, GL_FALSE, 0, 0 );

    // Main loop
    while(glfwGetWindowParam(GLFW_OPENED)) 
    {
        // Clear the screen to black
        glClearColor( 0.0f, 0.0f, 0.0f, 1.0f );
        glClear( GL_COLOR_BUFFER_BIT );

        // Draw lines from 2 vertices
        glDrawElements(GL_LINES, sizeof(indices), GL_UNSIGNED_INT, indices );

        // Swap buffers
        glfwSwapBuffers();
    }

    // Clean up
    glDeleteProgram( shaderProgram );
    glDeleteShader( fragmentShader );
    glDeleteShader( vertexShader );

    //glDeleteBuffers( 1, &ebo );
    glDeleteBuffers( 1, &vbo );

    glDeleteVertexArrays( 1, &vao );

    glfwTerminate();
    exit( EXIT_SUCCESS );
}

关于C++ OpenGL 线框立方体渲染空白，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/13420407/

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C++ OpenGL 线框立方体渲染空白

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