模板测试似乎没有做任何事情

Question

似乎无论我做什么，模板缓冲区都不会影响我正在绘制的内容。我正在绘制两个矩形，一个绘制在另一个上方并略微偏离它。它们相交的部分是我唯一想要显示的部分。这将为我的 UI.

的可滚动区域实现我想要的效果

这是我的绘制调用：

void drawGL(sf::Window& i_Window)
{
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT | GL_STENCIL_BUFFER_BIT);

    glStencilOp(GL_KEEP, GL_KEEP, GL_REPLACE);
    glStencilFunc(GL_ALWAYS, 1, 0xFF);
    glStencilMask(0xFF);
    glUtil::DrawQuad(0.0f, 0.0f, 300, 300, 1.0f, 1.0f, 1.0f);

    glStencilOp(GL_KEEP, GL_KEEP, GL_KEEP);
    glStencilFunc(GL_EQUAL, 1, 0xFF);
    glStencilMask(0x00);
    glUtil::DrawQuad(200.0f, 200.0f, 200.0f, 200.0f, 0.0f, 1.0f, 0.0f);
}

下面是我如何初始化 OpenGL

void initGL(sf::Window& i_Window)
{
    glHint(GL_PERSPECTIVE_CORRECTION_HINT, GL_FASTEST);
    glShadeModel(GL_SMOOTH);
    glEnable(GL_CULL_FACE);
    glEnable(GL_TEXTURE_2D);
    glEnable(GL_BLEND);
    glEnable(GL_STENCIL_TEST);
    glDisable(GL_DEPTH_TEST);
    glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
    glEnableClientState(GL_VERTEX_ARRAY);
    //glEnableClientState(GL_TEXTURE_COORD_ARRAY);
    glLoadIdentity();
    glOrtho(0, i_Window.getSize().x, i_Window.getSize().y, 0, 0, 10);
    glClearColor(0.0245f, 0.1294f, 0.27255f, 1.0f);
}

我的DrawQuad()实现

    void DrawQuad(GLfloat i_fX, GLfloat i_fY, GLfloat i_fWidth, GLfloat i_fHeight, GLfloat i_fR, GLfloat i_fG, GLfloat i_fB, GLfloat i_fA = 1.0f)
    {
        GLfloat Vertices[18] = {};
        Vertices[0] = 0;            Vertices[1] = 0;            Vertices[2] = 0.0f;
        Vertices[3] = 0;            Vertices[4] = i_fHeight;    Vertices[5] = 0.0f;
        Vertices[6] = i_fWidth;     Vertices[7] = i_fHeight;    Vertices[8] = 0.0f;

        Vertices[9] = 0;            Vertices[10] = 0;           Vertices[11] = 0.0f;
        Vertices[12] = i_fWidth;    Vertices[13] = i_fHeight;   Vertices[14] = 0.0f;
        Vertices[15] = i_fWidth;    Vertices[16] = 0;           Vertices[17] = 0.0f;

        glPushMatrix();
        glTranslatef(i_fX, i_fY, 0.0f);
        glColor4f(i_fR, i_fG, i_fB, i_fA);
        glVertexPointer(3, GL_FLOAT, 0, Vertices);
        glDrawArrays(GL_TRIANGLES, 0, 6);
        glPopMatrix();
    }

还有我的 main() 函数，以防它对诊断有用...

int main()
{
    sf::Window window(sf::VideoMode(1200, 720), "My window");
    initGL(window);

    sf::Event event;
    int nNumFrames = 0;
    while (window.isOpen())
    {
        while (window.pollEvent(event))
        {
            switch (event.type)
            {
            case sf::Event::Closed:
            case sf::Event::KeyPressed:
                window.close();
                break;
            case sf::Event::Resized:
                glViewport(0, 0, window.getSize().x, window.getSize().y);
                glLoadIdentity();
                glOrtho(0, window.getSize().x, window.getSize().y, 0, 0, 10);
                break;
            }
        }

        drawGL(window);
        window.display();

        ++nNumFrames;
    }

    return 0;
}

这是我得到的屏幕截图，无论我如何设置模板缓冲区函数。我想看到的只是白色和绿色框相交处的一个小绿色框。

Answer 1

您的 window（默认帧缓冲区）根本没有模板缓冲区。您必须使用 sf::ContextSettings class.

设置带有模板缓冲区的 OpenGL window

见Using OpenGL in a SFML window:

sf::ContextSettings settings;
settings.depthBits = 24;
settings.stencilBits = 8;
settings.antialiasingLevel = 4;
settings.majorVersion = 4;
settings.minorVersion = 6;

sf::Window window(sf::VideoMode(1200, 720), "My window", sf::Style::Default, settings);

模板测试似乎没有做任何事情

Stencil Test doesn't seem to do anything

c++

opengl

sfml

masking

stencil-buffer