用opengl生成螺旋线算法

// test01.cpp : Defines the entry point for the console application.
//

#include "stdafx.h"
#include <gl/glut.h>
#include <math.h>
#define GL_PI 3.1415f

// Rotation amounts
static GLfloat xRot = 0.0f;
static GLfloat yRot = 0.0f;

// Called to draw scene
void RenderScene(void)
{
GLfloat x,y,z,angle; // Storeage for coordinates and angles

// Clear the window with current clearing color
glClear(GL_COLOR_BUFFER_BIT);

// Save matrix state and do the rotation
glPushMatrix();
glRotatef(xRot, 1.0f, 0.0f, 0.0f);
glRotatef(yRot, 0.0f, 1.0f, 0.0f);

// Call only once for all remaining points
/*glBegin(GL_POINTS);*/
glBegin(GL_LINE_STRIP);
z = -50.0f;
for(angle = 0.0f; angle <= (2.0f*GL_PI)*3.0f; angle += 0.1f)
{
x = 50.0f*sin(angle);
y = 50.0f*cos(angle);

// Specify the point and move the Z value up a little
glVertex3f(x, y, z);
z += 0.5f;
}

// Done drawing points
glEnd();

// Restore transformations
glPopMatrix();

// Flush drawing commands
glutSwapBuffers();
}

// This function does any needed initialization on the rendering
// context.
void SetupRC()
{
// Black background
glClearColor(0.0f, 0.0f, 0.0f, 1.0f );

// Set drawing color to green
glColor3f(0.0f, 1.0f, 0.0f);
}

void SpecialKeys(int key, int x, int y)
{
if(key == GLUT_KEY_UP)
xRot-= 5.0f;

if(key == GLUT_KEY_DOWN)
xRot += 5.0f;

if(key == GLUT_KEY_LEFT)
yRot -= 5.0f;

if(key == GLUT_KEY_RIGHT)
yRot += 5.0f;

if(key > 356.0f)
xRot = 0.0f;

if(key < -1.0f)
xRot = 355.0f;

if(key > 356.0f)
yRot = 0.0f;

if(key < -1.0f)
yRot = 355.0f;

// Refresh the Window
glutPostRedisplay();
}

void ChangeSize(int w, int h)
{
GLfloat nRange = 100.0f;

// Prevent a divide by zero
if(h == 0)
h = 1;

// Set Viewport to window dimensions
glViewport(0, 0, w, h);

// Reset projection matrix stack
glMatrixMode(GL_PROJECTION);
glLoadIdentity();

// Establish clipping volume (left, right, bottom, top, near, far)
if (w <= h)
glOrtho (-nRange, nRange, -nRange*h/w, nRange*h/w, -nRange, nRange);
else
glOrtho (-nRange*w/h, nRange*w/h, -nRange, nRange, -nRange, nRange);

// Reset Model view matrix stack
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
}

int main(int argc, char* argv[])
{
glutInit(&argc, argv);
glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB | GLUT_DEPTH);
glutCreateWindow("Points Example");
glutReshapeFunc(ChangeSize);
glutSpecialFunc(SpecialKeys);
glutDisplayFunc(RenderScene);
SetupRC();
glutMainLoop();

return 0;
}