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copied!<p>I edited your code and put a comment here and there:</p> <pre><code>void init() { /* One time OpenGL initialization would be textures and * other static stuff. Nothing like that here */ } /* CALLED TO DRAW THE HELICES */ void RenderHelix() { GLfloat x,y,z; float aspectratio; GLfloat c = 2.5f; //helical pitch GLfloat theta; //constant angle between tangent and x-axis GLfloat r = 4.5f; //radius //GLint i = 1; //loop through code to render 7 helices /* assuming w and h are globals or somehow else accessible */ aspectratio = (float)w/(float)h; glViewport(0,0,w,h); glClearColor(0.0f, 0.0f, 0.0f, 1.0f); // Black background glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); glMatrixMode(GL_PROJECTION); glLoadIdentity(); GLfloat aspectratio = (GLfloat)w/(GLfloat)h; if(w<=h) glFrustum(-10.f,10.f, -10.f/aspectratio, 10.f/aspectratio, 1.0f, 10.f); else glFrustum(-10.f*aspectratio,10.f*aspectratio,-10.f,10.f, 1.0f,10.f); /* enable depth testing, also make sure the right depth func is used */ glEnable(GL_DEPTH_TEST); glDepthFunc(GL_LESS); /* GREEN HELIX */ glLineWidth(8.0); glMatrixMode(GL_MODELVIEW); glLoadIdentity(); glTranslatef(0.f, 0.f, -4.5f); glPushMatrix(); /* this helix will be drawn in the center, as it's not moved anywhere. */ glBegin(GL_LINE_STRIP); glColor3f(0.0, 1.0, 0.0); /* trigonometric functions take radians, not degrees */ for(theta = 0; theta <= M_PI2; theta += M_PI2*0.01;) { /* instead of calculating the helices a new each rendering * pass you should store them to a vertex array. */ x = r*cosf(theta); y = r*sinf(theta); z = c*theta; glVertex3f(x,y,z); } glEnd(); glPopMatrix(); /* Other 6 helices .... */ glScalef(1.0,1.0,12.0); glTranslatef(50.0, 100.0, 0.0); //Move Position of next helix, you may want to use glPushMatrix/glPopMatrix glRotatef(90.0, 0.0, 0.0, 0.0); // a null rotation, what's that's supposed to do? glFlush(); // redundant, glFlush is implied by SwapBuffers glutSwapBuffers(); } void Reshape(GLint w, GLint h) { /* Pleast don't set OpenGL stuff in the window reshape handler. * This just causes confusion, as soon one uses multiple projections * in a single rendering */ } </code></pre>

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