我想知道 pixel/fragment. 的原始模板值，零还是一？如果可能得到什么具体的行动修改模板值？

Question

我对 OpenGL 中模板缓冲区的许多事情感到困惑。我在这里阅读了 opengl 教程，https://learnopengl.com/Advanced-OpenGL/Stencil-testing。我只是加了一行代码

glStencilFunc(GL_EQUAL, 1, 0xFF);

然后什么都不会呈现。如果我将线路代码设置为

glStencilFunc(GL_NOTEQUAL, 1, 0xFF);

我的 objs 将被正确渲染。

我想知道为什么？原来的模板值是零而不是一吗？下面的一些代码：

glEnable(GL_DEPTH_TEST);
glDepthFunc(GL_LESS);
glEnable(GL_STENCIL_TEST);
glStencilFunc(GL_EQUAL, 1, 0xFF);
//glStencilFunc(GL_NOTEQUAL, 1, 0xFF);
//glStencilOp(GL_KEEP, GL_KEEP, GL_REPLACE);
while (!glfwWindowShouldClose(window))
{
    glfwPollEvents();
    glClearColor(0.1f, 0.1f, 0.1f, 1.0f);
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT | GL_STENCIL_BUFFER_BIT);
    shader.use();
    glm::mat4 model = glm::mat4(1.0f);
    glm::mat4 view = g_camera.GetViewMatrix();
    glm::mat4 projection = glm::perspective(g_camera.Zoom, (float)AppGlobal::getInstance()->windowWidth / (float)AppGlobal::getInstance()->windowHeight, 0.1f, 100.0f);
    glUniformMatrix4fv(glGetUniformLocation(shader.m_program, "view"), 1, GL_FALSE, glm::value_ptr(view));
    glUniformMatrix4fv(glGetUniformLocation(shader.m_program, "projection"), 1, GL_FALSE, glm::value_ptr(projection));

    // Floor
    glBindVertexArray(planeVAO);
    glBindTexture(GL_TEXTURE_2D, floorTexture);
    model = glm::mat4(1.0f);
    glUniformMatrix4fv(glGetUniformLocation(shader.m_program, "model"), 1, GL_FALSE, glm::value_ptr(model));
    glDrawArrays(GL_TRIANGLES, 0, 6);
    // some other objects
    glBindVertexArray(0);
    glfwSwapBuffers(window);
}

Answer 1

[...] Is it that the original stencil value is zero not one?

默认情况下，模板缓冲区的清除值为 0。

模板缓冲区在调用glClear(GL_STENCIL_BUFFER_BIT)时被清除。模板缓冲区的清除值可以由 glClearStencil 指定。初始值为 0.

我想知道 pixel/fragment. 的原始模板值，零还是一？如果可能得到什么具体的行动修改模板值？

I want to know the original stencil value of a pixel/fragment., zero or one? If possible to get what specific action modify the stencil value?

c++

opengl

glfw

glm-math

stencil-buffer