c++ - 在glPushMatrix内外执行glulookat？

我知道在opengl中使用gluLookAt(...)，glPushMatrix和其他基本转换对象的目的是什么。我陷入了这些代码中。在为opengl设置适当的要求后，在glPushMatrix()中实现glulookat(.....)时。代码可以正常工作，并且在按键时可以通过适当的旋转渲染多维数据集，但是当我在glPushMatrix()和glPopMatrix()外部实现gluLookAt(....)时，事情就变得很疯狂。多维数据集显示异常行为，最后得到
从屏幕上消失了。

gluLookAt(0.0f, 0.0f, 400.0f, 0.0f, 0.0f, 0.0f, 0.0f, 1.0f, 0.0f);
glPushMatrix();

//gluLookAt(0.0f, 0.0f, 400.0f, 0.0f, 0.0f, 0.0f, 0.0f, 1.0f, 0.0f);
glRotatef(xRot, 1.0f, 0.0f, 0.0f);
glRotatef(yRot, 0.0f, 1.0f, 0.0f);


glBegin(GL_QUADS);

    // Front Face
    // White
    glColor3ub((GLubyte) 255, (GLubyte)255, (GLubyte)255);
    glVertex3f(50.0f,50.0f,50.0f);

    // Yellow
    glColor3ub((GLubyte) 255, (GLubyte)255, (GLubyte)0);
    glVertex3f(50.0f,-50.0f,50.0f);

    // Red
    glColor3ub((GLubyte) 255, (GLubyte)0, (GLubyte)0);
    glVertex3f(-50.0f,-50.0f,50.0f);

    // Magenta
    glColor3ub((GLubyte) 255, (GLubyte)0, (GLubyte)255);
    glVertex3f(-50.0f,50.0f,50.0f);


// Back Face
    // Cyan
    glColor3f(0.0f, 1.0f, 1.0f);
    glVertex3f(50.0f,50.0f,-50.0f);

    // Green
    glColor3f(0.0f, 1.0f, 0.0f);
    glVertex3f(50.0f,-50.0f,-50.0f);

    // Black
    glColor3f(0.0f, 0.0f, 0.0f);
    glVertex3f(-50.0f,-50.0f,-50.0f);

    // Blue
    glColor3f(0.0f, 0.0f, 1.0f);
    glVertex3f(-50.0f,50.0f,-50.0f);

// Top Face
    // Cyan
    glColor3f(0.0f, 1.0f, 1.0f);
    glVertex3f(50.0f,50.0f,-50.0f);

    // White
    glColor3f(1.0f, 1.0f, 1.0f);
    glVertex3f(50.0f,50.0f,50.0f);

    // Magenta
    glColor3f(1.0f, 0.0f, 1.0f);
    glVertex3f(-50.0f,50.0f,50.0f);

    // Blue
    glColor3f(0.0f, 0.0f, 1.0f);
    glVertex3f(-50.0f,50.0f,-50.0f);

// Bottom Face
    // Green
    glColor3f(0.0f, 1.0f, 0.0f);
    glVertex3f(50.0f,-50.0f,-50.0f);

    // Yellow
    glColor3f(1.0f, 1.0f, 0.0f);
    glVertex3f(50.0f,-50.0f,50.0f);

    // Red
    glColor3f(1.0f, 0.0f, 0.0f);
    glVertex3f(-50.0f,-50.0f,50.0f);

    // Black
    glColor3f(0.0f, 0.0f, 0.0f);
    glVertex3f(-50.0f,-50.0f,-50.0f);

// Left face
    // White
    glColor3f(1.0f, 1.0f, 1.0f);
    glVertex3f(50.0f,50.0f,50.0f);

    // Cyan
    glColor3f(0.0f, 1.0f, 1.0f);
    glVertex3f(50.0f,50.0f,-50.0f);

    // Green
    glColor3f(0.0f, 1.0f, 0.0f);
    glVertex3f(50.0f,-50.0f,-50.0f);

    // Yellow
    glColor3f(1.0f, 1.0f, 0.0f);
    glVertex3f(50.0f,-50.0f,50.0f);

// Right face
    // Magenta
    glColor3f(1.0f, 0.0f, 1.0f);
    glVertex3f(-50.0f,50.0f,50.0f);

    // Blue
    glColor3f(0.0f, 0.0f, 1.0f);
    glVertex3f(-50.0f,50.0f,-50.0f);

    // Black
    glColor3f(0.0f, 0.0f, 0.0f);
    glVertex3f(-50.0f,-50.0f,-50.0f);

    // Red
    glColor3f(1.0f, 0.0f, 0.0f);
    glVertex3f(-50.0f,-50.0f,50.0f);
glEnd();

glPopMatrix();

最佳答案

gluLookAt将 Activity 矩阵堆栈中当前最顶层的元素与查找矩阵进行多行复制，并将其替换为最顶层的元素。

推入和弹出是标准的堆栈操作。推入创建最顶层元素的副本，并将其推入堆栈的顶部，弹出将其删除。

因此，您在push-pop块中所做的任何更改都将通过pop操作恢复。但是在堆栈框架(推入式弹出)之外，更改将累积。如果将glLoadIdentity放在push-pop之外的gluLookAt之前，它也可以工作，但是那是因为您将矩阵重置为合理的值，而不是在先前渲染的基础上进行处理。

关于c++ - 在glPushMatrix内外执行glulookat？，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/21730632/