c++ - OpenGL不渲染任何东西

Question

我正在关注一个在线教程（大致），虽然我没有错误，但没有任何渲染。

这是我的代码的重要部分。

初始化：

    void init()
{
    GLfloat firstTriangle[] = {
        -0.9f, -0.5f, 0.0f,  // left 
        -0.0f, -0.5f, 0.0f,  // right
        -0.45f, 0.5f, 0.0f,  // top 
    };
    GLfloat secondTriangle[] = {
        0.0f, -0.5f, 0.0f,  // left
        0.9f, -0.5f, 0.0f,  // right
        0.45f, 0.5f, 0.0f   // top 
    };
    // Set up the shaders
    buildandcomp();
    //generate VAOs/VBOs
    generateVertexArrayObjects(firstTriangle, secondTriangle);
}

这里 buildandcomp()：

void buildandcomp() {
    vertexShader = glCreateShader(GL_VERTEX_SHADER);
    fragmentShaderOrange = glCreateShader(GL_FRAGMENT_SHADER); // the first fragment shader that outputs the color orange
    fragmentShaderYellow = glCreateShader(GL_FRAGMENT_SHADER); // the second fragment shader that outputs the color yellow
    shaderProgramOrange = glCreateProgram();
    shaderProgramYellow = glCreateProgram(); // the second shader program
    glShaderSource(vertexShader, 1, &vertexShaderSource, NULL);
    glCompileShader(vertexShader);
    glShaderSource(fragmentShaderOrange, 1, &fragmentShader1Source, NULL);
    glCompileShader(fragmentShaderOrange);
    glShaderSource(fragmentShaderYellow, 1, &fragmentShader2Source, NULL);
    glCompileShader(fragmentShaderYellow);
    // link the first program object
    glAttachShader(shaderProgramOrange, vertexShader);
    glAttachShader(shaderProgramOrange, fragmentShaderOrange);
    glLinkProgram(shaderProgramOrange);
    // then link the second program object using a different fragment shader (but same vertex shader)
    // this is perfectly allowed since the inputs and outputs of both the vertex and fragment shaders are equally matched.
    glAttachShader(shaderProgramYellow, vertexShader);
    glAttachShader(shaderProgramYellow, fragmentShaderYellow);
    glLinkProgram(shaderProgramYellow);
}

请注意，变量是全局定义的。

这是 generateVertexArrayObjects()：

void generateVertexArrayObjects(GLfloat t1[], GLfloat t2[]) {
    glGenVertexArrays(2, VAOs);
    glGenBuffers(2, VBOs);
    //triangle 1
    glBindVertexArray(VAOs[0]);
    glBindBuffer(GL_ARRAY_BUFFER, VBOs[0]);
    glBufferData(GL_ARRAY_BUFFER, sizeof(t1), t1, GL_STATIC_DRAW);
    glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 3* sizeof(GLfloat), (void*)0);
    glEnableVertexAttribArray(0);
    //triangle 2
    glBindVertexArray(VAOs[1]);
    glBindBuffer(GL_ARRAY_BUFFER, VBOs[1]);
    glBufferData(GL_ARRAY_BUFFER, sizeof(t2), t2, GL_STATIC_DRAW);
    glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 3 * sizeof(GLfloat), (void*)0);
    glEnableVertexAttribArray(0);

    glBindVertexArray(0);
}

以下是着色器：

const char* vertexShaderSource = "#version 330 core\n"
"layout (location = 0) in vec3 aPos;\n"
"void main()\n"
"{\n"
"   gl_Position = vec4(aPos.x, aPos.y, aPos.z, 1.0);\n"
"}\0";
const char* fragmentShader1Source = "#version 330 core\n"
"out vec4 FragColor;\n"
"void main()\n"
"{\n"
"   FragColor = vec4(1.0f, 0.5f, 0.2f, 1.0f);\n"
"}\n\0";
const char* fragmentShader2Source = "#version 330 core\n"
"out vec4 FragColor;\n"
"void main()\n"
"{\n"
"   FragColor = vec4(1.0f, 1.0f, 0.0f, 1.0f);\n"
"}\n\0";

这是我的显示功能：

void display() {
    keyOperations();
    glClear(GL_COLOR_BUFFER_BIT);
    glClearColor(0.2f, 0.3f, 0.3f, 1.0f);

    glUseProgram(shaderProgramOrange);
    glBindVertexArray(VAOs[0]);
    glDrawArrays(GL_TRIANGLES, 0, 3);

    glUseProgram(shaderProgramYellow);
    glBindVertexArray(VAOs[1]);
    glDrawArrays(GL_TRIANGLES, 0, 3);
    glutSwapBuffers();
}

我怀疑这与我的着色器有关，但我看不出它可能是什么。我还是 OpenGL 的新手，所以我不确定我哪里出错了。我已经加载了我的数据，我已经构建并编译了我的着色器，并且我已经使用这些着色器显示了我的三角形。任何见解将不胜感激，谢谢。

标签： c++openglgraphics