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sumit_kang

OpenGL BEVEL THE SIDES OF A STAR SHAPE

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HI I HAVE WRITTEN THE CODE FOR A STAR SHAPE OBJECT IN OPENGL , COULD SOMEONE KINDLY TELL ME HOW CAN I BEVEL THE EDGES OF THE STAR SHAPE. THANKS #include <windows.h> #include <math.h> #include <GL/gl.h> #include <GL/glu.h> #include <freeglut.h> #include <stdlib.h> #include <stdio.h> #define M_PI 3.14 //////////////////////////////////////////////////////////////////// void init(void) { glClearColor(0.0,0.0,0.0,0.0); glOrtho(-15,15,-15,15,-5,5); glEnable(GL_DEPTH_TEST); } //////////////////////////////////////////////////////////////////////////// void CreateStar() { int i,j; glBegin(GL_TRIANGLE_FAN); glVertex3f(0.0,0.0,0.0); for(i = 0; i<=13;i++) { if(i % 2 == 0) { float angle = 2.0 * M_PI *i/12; glTexCoord2f(cos(angle)+0.5,sin(angle)+0.5); glVertex3f(cos(angle)*1.0,sin(angle)*1.0,0.0); } else { float angle = 2.0 * M_PI *i/12; glTexCoord2f(cos(angle)+0.5,sin(angle)+0.5); glVertex3f(cos(angle)*0.5,sin(angle)*0.5,0.0); } } glEnd(); glFlush(); } ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// void display(void) { glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT); CreateStar(); } ////////////////////////////////////////////////////////////////////////////////////////////////// int _tmain(int argc, CHAR* argv[]) { glutInit (&argc, argv); glutInitDisplayMode (GLUT_SINGLE||GLUT_RGB); glutInitWindowSize (500,500); glutCreateWindow ("Star Project"); glutDisplayFunc (display); glutMainLoop (); return 0; }

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Hey sumit_kang, Welcome to the forums!

Yes, you should draw a slightly upscaled version of the star, with depth writing disabled.
-Then draw your original star shape on the top of it.
The first star will act as the bevel. Remember to put all vertices into the same
vertex buffer if possible, and remember to turn caps lock off while writing on the forums.
People might as well just ignore a message written in capital letters.
(And there's a cool source code feature here too; check out the FAQ)

Happy coding,

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Phew, that's a toughie.
You should either create the smooth geometry yourself,
or you could use a post process filter like HQ and such.

Really, OpenGL is, unlike photoshop, very strict when
it comes to geometry. You give it what you want to see,
even though telling it what you want to see might sound better.

Perhaps, what you're looking for for smooth edges is really a trianglestrip.
The mentioned simple bevel effect can be acheived with nearly everything, though.
But it will be the same shape as the original geometry, just larger.

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