cocos2d for iPhone

A fast, easy to use, free, and community supported 2D game engine

1. 

   hemmi
   Member

   Hey guys,

   I can't find anything on google about this. Has anyone been able to draw a disk shape in opengl? usually you'd use gluDisk but opengl es doesn't support glu. Any ideas? Thanks!

   Posted 2 years ago #
2. 

   Thomvis
   Member

   I ran into the same problem some time ago when I was working on a game. This is wat should do the job. NR_OF_SEGMENTS determines the quality of the render, the higher, the smoother, the slower. INNER_RADIUS is the distance from the center to the inner disc border and OUTER_RADIUS is the outer border (thus: OUTER_RADIUS-INNER_RADIUS is the width of the disc)

   - (GLfloat *) calculateSegmentPoints {
   
       float step = (2*M_PI) / NR_OF_SEGMENTS;
   
   	float *vertices = malloc( sizeof(float)*4*(NR_OF_SEGMENTS+1));
   	if( ! vertices )
   		return 0;
   
   	memset( vertices,0, sizeof(float)*4*(NR_OF_SEGMENTS+1));
   
   	int count = 0;
   	for( int i = 0; i <= NR_OF_SEGMENTS; i++ ) {
   		// calculating the current vertice on the outer side of the segment
   		float outerRads = i*step;
   		float outerX = OUTER_RADIUS * cos( outerRads );
   		float outerY = OUTER_RADIUS * sin( outerRads );
   		vertices[count++]	= outerX;
   		vertices[count++]	= outerY;
   
   		// calculating the current vertice on the inner side of the segment
   		float innerRads = i*step;
   		float innerX = INNER_RADIUS * cos( innerRads );
   		float innerY = INNER_RADIUS * sin( innerRads );
   		vertices[count++]		= innerX;
   		vertices[count++]		= innerY;
   	}
       return vertices;
   }

   I hope it is of any use.

   Posted 2 years ago #

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