c++ - 这只是显示一个空白的黑屏，如果我不在两个地方都放置 glutSwapBuffers() 它会显示一个空白的白屏？

Question

当我编译它时，它会出现一个空白的黑屏，如果我从任何一个位置取出 glut 交换缓冲区，或者同时我得到一个空白的白屏，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 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();
    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);

    glLoadIdentity();

    glutSpecialFunc(ProcessSpecialKeys);

glutMainLoop();

return 0;
}

Answer 1

Try glColor3f(0.5f, 0.5f, 0.5f); And remove glClearColor(0.5, 0.5, 0.5, 1);

Answer 2

在开始新的绘图之前，您需要清除缓冲区。换句话说，在您的显示功能中执行此操作：

void display(void){
    glClear(GL_COLOR_BUFFER_BIT); // <-----
    glTranslatef(0.0f,0.0f,-0.5f);
    renderPrimitive();
    glutSwapBuffers();
}

并阅读函数glClearColor

编辑：

那不是正确的地方，但要更改背景颜色，请执行以下操作：

void display(void){
    glClearColor(0.5, 0.5, 0.5, 1);
    glClear(GL_COLOR_BUFFER_BIT); // <-----
    glScalef(0.5f,0.5f,0.5f);  // Your Quad is taking all the framebuffer
    renderPrimitive();
    glutSwapBuffers();
}