opengl绘制弹簧模型

#include <windows.h> #include <math.h> #include <GL/glut.h> #include <GL/glaux.h> #include <GL/glu.h> #include <GL/gl.h> // Define a constant for the value of PI #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 GLfloat sizes[2]; // Store supported point size range GLfloat step; // Store supported point size increments GLfloat curSize; // Store current size // 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); // Get supported point size range and step size glGetFloatv(GL_POINT_SIZE_RANGE,sizes); //范围 glGetFloatv(GL_POINT_SIZE_GRANULARITY,&step); //间隔尺度 不同大小的点point // Set the initial point size curSize = sizes[0]; // Set beginning z coordinate z = -50.0f; // Loop around in a circle three times for(angle = 0.0f; angle <= (2.0f*3.1415f)*3.0f; angle += 0.1f) { // Calculate x and y values on the circle x = 50.0f*sin(angle); y = 50.0f*cos(angle); // Specify the point size before the primative is specified glPointSize(curSize); // Draw the point glBegin(GL_POINTS); glVertex3f(x, y, z); glEnd(); // Bump up the z value and the point size z += 0.5f; curSize += step; } // Restore matrix state 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 Size Example"); glutReshapeFunc(ChangeSize); glutSpecialFunc(SpecialKeys); glutDisplayFunc(RenderScene); SetupRC(); glutMainLoop(); return 0; }