LWJGL：在opengl中不能呈现多个形状

Question

只是对lwjgl做一些修修补补，制作一些2D形状。我不确定我做错了什么，但我不能在屏幕上显示比第一个绿色方块更多的东西。下面是我的窗口循环函数的代码：

private void loop() {
// This line is critical for LWJGL's interoperation with GLFW's
// OpenGL context, or any context that is managed externally.
// LWJGL detects the context that is current in the current thread,
// creates the GLCapabilities instance and makes the OpenGL
// bindings available for use.
GL.createCapabilities();
GLFWVidMode vidmode = glfwGetVideoMode(glfwGetPrimaryMonitor());
glOrtho(0, vidmode.width(),0, vidmode.height(),-1,1);

// Set the clear color
glClearColor(.0f, 0.6f, 0.6f, 0.0f);


// Run the rendering loop until the user has attempted to close
// the window or has pressed the ESCAPE key.
while (!glfwWindowShouldClose(window) && !dataH.isGameOver()) {


    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); // clear the framebuffer

    glBegin(GL_QUADS);
    {
        glColor3f(0.1f, 1.0f, 0.1f);  // Green
        glVertex2d(xMapCentre - 100,yMapCentre - 100);
        glVertex2d(xMapCentre - 100,yMapCentre + 100);
        glVertex2d(xMapCentre + 100,yMapCentre + 100);
        glVertex2d(xMapCentre + 100,yMapCentre - 100);

        glColor3f(0.2f, 0.2f, 0.2f); // Dark Gray
        glVertex2f(-0.9f, -0.7f);
        glColor3f(1.0f, 1.0f, 1.0f); // White
        glVertex2f(-0.5f, -0.7f);
        glColor3f(0.2f, 0.2f, 0.2f); // Dark Gray
        glVertex2f(-0.5f, -0.3f);
        glColor3f(1.0f, 1.0f, 1.0f); // White
        glVertex2f(-0.9f, -0.3f);
    }
    glEnd();



    glBegin(GL_TRIANGLES);          // Each set of 3 vertices form a triangle
    {
    glColor3f(0.0f, 0.0f, 1.0f); // Blue
    glVertex2f(0.1f, -0.6f);
    glVertex2f(0.7f, -0.6f);
    glVertex2f(0.4f, -0.1f);

    glColor3f(1.0f, 0.0f, 0.0f); // Red
    glVertex2f(0.3f, -0.4f);
    glColor3f(0.0f, 1.0f, 0.0f); // Green
    glVertex2f(0.9f, -0.4f);
    glColor3f(0.0f, 0.0f, 1.0f); // Blue
    glVertex2f(0.6f, -0.9f);
    }
    glEnd();


    glfwSwapBuffers(window); // swap the color buffers
    // Poll for window events. The key callback above will only be
    // invoked during this call.
    glfwPollEvents();
}
}

任何帮助都将不胜感激，如果我太含糊，请告诉我。谢了。

Answer 1

通常，当在三维空间中呈现2D结构时，应该禁用背面剔除gldisable(GL_CULL_FACE)。否则你只能从一个侧面看到他们。在你的着色器中，你必须意识到正常的方向。

在仅2D的情况下，如果要进行背面或正面剔除，请检查三角形的缠绕顺序，将glfontface(GL_CCW)或glfrontface(GL_CW)分别设置为逆时针和顺时针缠绕顺序。（当使用glvertex2f时，我无法确认缠绕顺序是否会在2D中产生差异）

还要尝试diable深度测试和深度写入gldisable(GL_DEPTH_TEST)和gldepthmask(GL_FALSE)。