Question

这是代码，没有任何错误，有什么问题吗？

我编译它，命令提示符打开，窗口打开，窗口全是白色，我把它重新变成灰色..，它也没有画出我的形状，所以有什么问题？

    #ifdef __APPLE__
    #include <GLUT/glut.h>
    #else
    #include <GL/glut.h>
    #endif

    #include <stdlib.h>



    void ProcessSpecialKeys(int key, int x, int y){

        switch(key){

           case GLUT_KEY_RIGHT:


    exit(0);



           case GLUT_KEY_LEFT:

    exit(0);

           case GLUT_KEY_UP:
    exit(0);

           case GLUT_KEY_DOWN:

    exit(0);
           default:

    exit(0);

        }




        }



    void renderScene(void) {
    glClearColor(0.3f, 0.3f, 0.3f, 0.3f);
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);


        glutSwapBuffers();
}

    void renderPrimitive(void){
    glBegin(GL_QUADS);
    glVertex3f(-1.0f,-1.0f,0.0f);
    glVertex3f(-1.0f,1.0f,0.0f);
    glVertex3f(1.0f,1.0f,0.0f);
    glVertex3f(1.0f,-1.0f,0.0f);
    glEnd();
}

    void display(void){
    glTranslatef(0.0f,0.0f,-0.5f);
    renderPrimitive();
    glFlush();
    glClearColor(0.3f,0.3f,0.3f,0.3f);
    glClear(GL_COLOR_BUFFER_BIT);
}

int main(int argc, char **argv) {

    glutInit(&argc, argv);
    glutInitDisplayMode(GLUT_DEPTH | GLUT_DOUBLE | GLUT_RGBA);
    glutInitWindowPosition(100,100);
    glutInitWindowSize(320,320);
    glutCreateWindow("Dimension");
    glutDisplayFunc(display);

    glLoadIdentity();

glutSpecialFunc(ProcessSpecialKeys);


    glutMainLoop();

    return 1;
}

Answer 1

问题是在显示功能中绘制场景后清除显示。此外，还有一个无用的glFlush()电话。删除这些行：

glFlush();
glClearColor(0.3f,0.3f,0.3f,0.3f);
glClear(GL_COLOR_BUFFER_BIT);

添加glutSwapBuffers()代替它们。

glFlush()用于单缓冲模式。

请记住，您使用的是双缓冲模式，因此有两个缓冲区。您的场景被绘制到后台缓冲区，要显示它，您必须通过调用显示功能结束时的glutSwapBuffers()将其复制到前台缓冲区。

Answer 2

试试这个：

#include <GL/glut.h>
#include <stdlib.h>

void ProcessSpecialKeys(int key, int x, int y)
{
    switch(key)
    {
    case GLUT_KEY_RIGHT:
    case GLUT_KEY_LEFT:
    case GLUT_KEY_UP:
    case GLUT_KEY_DOWN:
        exit(0);
        break;
    default:
        exit(0);
        break;
    }
}

void renderPrimitive()
{
    glBegin(GL_QUADS);
    glVertex3f(-1.0f,-1.0f,0.0f);
    glVertex3f(-1.0f,1.0f,0.0f);
    glVertex3f(1.0f,1.0f,0.0f);
    glVertex3f(1.0f,-1.0f,0.0f);
    glEnd();
}

void display()
{
    glClearColor(0.3f,0.3f,0.3f,0.3f);
    glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT );

    glMatrixMode( GL_PROJECTION );
    glLoadIdentity();
    glOrtho( -2, 2, -2, 2, -1, 1 );

    glMatrixMode( GL_MODELVIEW );
    glLoadIdentity();

    glPushMatrix();
    glTranslatef(0.0f,0.0f,-0.5f);
    renderPrimitive();
    glPopMatrix();

    glutSwapBuffers();
}

int main(int argc, char **argv)
{
    glutInit(&argc, argv);
    glutInitDisplayMode(GLUT_DEPTH | GLUT_DOUBLE | GLUT_RGBA);
    glutInitWindowPosition(100,100);
    glutInitWindowSize(320,320);
    glutCreateWindow("Dimension");
    glutDisplayFunc(display);
    glutSpecialFunc(ProcessSpecialKeys);
    glutMainLoop();
    return 1;
}

GLUT只是渲染一个空白的白色屏幕？

2 个答案: