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POOpengl+c++ Need to render a multicolored square but my code is showing blank screen
 

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  1. POOpengl+c++ Need to render a multicolored square but my code is showing blank screen
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    <p>I am learning Opengl in c++ I am trying to render a multi color square but first I want to show up a simple square. But all in vain it is showing a blank screen. I am trying it on xcode my code is </p> <pre><code>#include &lt;iostream&gt; #include &lt;GLUT/GLUT.h&gt; #include&lt;OpenGL/OpenGL.h&gt; void init(void) { glShadeModel( GL_SMOOTH ); glClearColor( 1.0, 1.0, 1.0, 1.0 ); glEnable( GL_COLOR_MATERIAL ); glEnable( GL_BLEND ); glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA); } void coloredSquare(void) { glClear(GL_COLOR_BUFFER_BIT); glBegin ( GL_LINES ); glColor3f ( 0.9,0.9,0.9 ); // very light gray for(int i=10;i&lt;180;i+=10) // vertical lines { glVertex2f( i,0 ); glVertex2f( i,180 ); } for(int j=10;j&lt;180;j+=10) // horizontal lines { glVertex2f( 0,j ); glVertex2f( 180,j ); } glEnd(); // b. points glPointSize(3.0); // 3 pixel point. why it only works outside of glBegin-glEnd. glBegin ( GL_POINTS ); glColor3f ( 0.3,0.3,0.3 ); // dark gray for(int i=10;i&lt;180;i+=10) // draw point at every grid intersection { for(int j=10;j&lt;180;j+=10) { glVertex2f( i,j ); } } glEnd(); glFlush(); // Render now } int main(int argc, char** argv) { //GLUT &amp; OpenGL glutInit(&amp;argc, argv); glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB); glutInitWindowSize(200, 200); //glutInitWindowPosition(0, 0); glutCreateWindow("GLUT Program"); //glutCreateWindow("Colored Square"); init(); glutDisplayFunc(coloredSquare); glutMainLoop(); return 0; /* ISO C requires main to return int. */ } </code></pre> <p>If some body has some idea please do throw some light on this thanks</p>
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    1. PTQuestion
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    1. USSajan
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      1. VTUpMod
    1. COTry calling `glutSwapBuffers()` after `glFlush()` see if that works.
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      1. POOpengl+c++ Need to render a multicolored square but my code is showing blank screen
      1. USDair
    2. CO@anon: He specified `GLUT_SINGLE`, so there should not be a backbuffer to swap with.
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      1. USBen Voigt
    3. CO@BenVoigt: Oops. Didn't see that at first.
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      1. USDair
 

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