338 lines
8.6 KiB
C
338 lines
8.6 KiB
C
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/******************************Module*Header*******************************\
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* Module Name: genlem.c
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*
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* The Twist style of the 3D Flying Objects screen saver.
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*
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* Solid model of a 3D lemniscate.
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*
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* Copyright (c) 1994 Microsoft Corporation
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*
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\**************************************************************************/
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#include <stdlib.h>
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#include <windows.h>
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#include <GL\gl.h>
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#include <string.h>
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#include <math.h>
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#include "ss3dfo.h"
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#include "mesh.h"
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#define ROT_PREC 10
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#define NORMS(x, y) lemMesh.norms[((x) * iPrec) + y]
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#define GRID(x, y) lemMesh.pts[((x) * iPrec) + y]
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static MESH lemMesh;
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static POINT3D basis[ROT_PREC];
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static double zrot = 0.2;
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static int iPrec = 32;
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static double *lemX;
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static double *lemY;
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static double *lemXT;
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static double *lemYT;
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static void getLem(double index, double max, double *angle, double *r)
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{
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double a, sina;
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a = (index * PI) / (max - 1.0);
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if (a >= PI)
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a -= PI;
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if (a > PI / 2.0) {
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*angle = (2.0 * PI) - a;
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sina = sin( 2.0 * *angle );
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if( sina < 0.0 )
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sina = 0.0; // protect against sqrt fpe
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*r = 0.5 * sqrt(sina);
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} else {
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*angle = a;
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sina = sin( 2.0 * *angle );
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if( sina < 0.0 )
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sina = 0.0;
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*r = 0.5 * sqrt(sina);
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}
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}
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static void initLemCoords(int iMax)
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{
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int i;
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double max = (double)iMax;
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double angle;
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double r;
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for (i = 0; i < iMax; i++) {
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getLem((double)i, (double)iPrec, &angle, &r);
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lemX[i] = r * cos(angle);
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lemY[i] = r * sin(angle);
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getLem((double)i + 0.00001, (double)iPrec, &angle, &r);
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lemXT[i] = r * cos(angle);
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lemYT[i] = r * sin(angle);
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}
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}
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void genLemniscate(void)
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{
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int i;
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int j;
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double posInc = 2.0 / (float)iPrec;
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int facecount = 0;
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int ptcount = 0;
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POINT3D norm;
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static float twistFact = 0.0f;
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static float twistFactAdd = 0.05f;
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POINT3D a[ROT_PREC];
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POINT3D b[ROT_PREC];
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MATRIX matrix;
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MESH *mesh = &lemMesh;
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mesh->numPoints = 0;
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mesh->numFaces = 0;
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for (i = 0; i < (iPrec - 1) * (ROT_PREC - 1); i++)
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mesh->norms[i] = ss_ptZero;
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for (i = 0; i < (iPrec - 1); i++) {
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double x1, y1, x2, y2;
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double len;
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double sinAngle;
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double rotZ;
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int id[4];
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x1 = lemX[i];
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y1 = lemY[i];
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x2 = lemXT[i];
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y2 = lemYT[i];
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x2 -= x1;
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y2 -= y1;
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len = sqrt(x2 * x2 + y2 * y2);
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if (len > 0.0)
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sinAngle = y2 / len;
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else
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sinAngle = 0.0;
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if (y2 < 0.0)
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sinAngle = -sinAngle;
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rotZ = asin(sinAngle);
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if (x2 < 0.0)
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rotZ = PI - rotZ;
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if (y2 < 0.0)
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rotZ = -rotZ;
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if (rotZ < 0.0)
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rotZ = 2.0 * PI + rotZ;
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ss_matrixIdent(&matrix);
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ss_matrixRotate(&matrix, 0.0, 0.0, -rotZ);
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ss_matrixTranslate(&matrix, x1, y1,
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twistFact * cos((2.0 * PI * (float)i) / ((float)iPrec - 1)));
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for (j = 0; j < ROT_PREC; j++)
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ss_xformPoint(&a[j], &basis[j], &matrix);
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x1 = lemX[i+1];
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y1 = lemY[i+1];
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x2 = lemXT[i+1];
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y2 = lemYT[i+1];
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x2 -= x1;
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y2 -= y1;
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len = sqrt(x2 * x2 + y2 * y2);
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if (len > 0.0)
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sinAngle = y2 / len;
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else
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sinAngle = 0.0;
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if (y2 < 0.0)
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sinAngle = -sinAngle;
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rotZ = asin(sinAngle);
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if (x2 < 0.0)
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rotZ = PI - rotZ;
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if (y2 < 0.0)
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rotZ = -rotZ;
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if (rotZ < 0.0)
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rotZ = 2.0 * PI + rotZ;
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ss_matrixIdent(&matrix);
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ss_matrixRotate(&matrix, 0.0, 0.0, -rotZ);
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ss_matrixTranslate(&matrix, x1, y1,
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twistFact * cos((2.0 * PI * ((float)i + 1.0)) / ((float)iPrec - 1)));
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for (j = 0; j < ROT_PREC; j++)
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ss_xformPoint(&b[j], &basis[j], &matrix);
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memcpy(&mesh->pts[ptcount], &a, sizeof(POINT3D) * (ROT_PREC - 1));
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ptcount += (ROT_PREC - 1);
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mesh->numPoints += (ROT_PREC - 1);
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for (j = 0; j < (ROT_PREC - 1); j++) {
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int k;
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int jj;
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if (j == (ROT_PREC - 2))
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jj = 0;
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else
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jj = j + 1;
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ss_calcNorm(&norm, &b[j + 1], &b[j], &a[j]);
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mesh->faces[facecount].material = 3;
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mesh->faces[facecount].norm = norm;
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if (i == iPrec - 2) {
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id[0] = mesh->faces[facecount].p[0] = j;
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id[1] = mesh->faces[facecount].p[1] = jj;
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} else {
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id[0] = mesh->faces[facecount].p[0] = ptcount + j;
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id[1] = mesh->faces[facecount].p[1] = ptcount + jj;
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}
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id[2] = mesh->faces[facecount].p[2] = ptcount - (ROT_PREC - 1) + j;
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id[3] = mesh->faces[facecount].p[3] = ptcount - (ROT_PREC - 1) + jj;
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for (k = 0; k < 4; k++) {
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POINT3D *pn = &mesh->norms[id[k]];
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pn->x += norm.x;
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pn->y += norm.y;
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pn->z += norm.z;
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}
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mesh->numFaces++;
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facecount++;
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}
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}
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ss_normalizeNorms(lemMesh.norms, lemMesh.numPoints);
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if (twistFact >= 1.0f)
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twistFactAdd = -0.01f;
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else if (twistFact <= -1.0f)
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twistFactAdd = 0.01f;
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twistFact += twistFactAdd;
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}
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void initLemScene()
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{
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int i;
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RGBA lightAmbient = {0.0f, 0.0f, 0.0f, 1.0f};
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iPrec = (int)(fTesselFact * 32.5);
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if (iPrec < 5)
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iPrec = 5;
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lemX = SaverAlloc(sizeof(double) * iPrec);
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lemY = SaverAlloc(sizeof(double) * iPrec);
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lemXT = SaverAlloc(sizeof(double) * iPrec);
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lemYT = SaverAlloc(sizeof(double) * iPrec);
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glMatrixMode(GL_PROJECTION);
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glLoadIdentity();
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glOrtho(-1.5, 1.5, -1.5, 1.5, 0.0, 3.0);
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glTranslatef(0.0f, 0.0f, -1.5f);
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newMesh(&lemMesh, (ROT_PREC - 1) * (iPrec - 1) ,
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(ROT_PREC - 1) * (iPrec - 1));
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for (i = 0; i < ROT_PREC; i++) {
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basis[i].x = 0.0f;
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basis[i].y = (float) (0.15 * cos((i * 2.0 * PI) / (ROT_PREC - 1.0)));
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basis[i].z = (float) (0.15 * sin((i * 2.0 * PI) / (ROT_PREC - 1.0)));
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}
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initLemCoords(iPrec);
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glFrontFace(GL_CW);
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glEnable(GL_CULL_FACE);
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glLightModelfv(GL_LIGHT_MODEL_AMBIENT, (GLfloat *) &lightAmbient);
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glMaterialfv(GL_FRONT_AND_BACK, GL_AMBIENT_AND_DIFFUSE,
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(GLfloat *) &Material[3].kd);
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}
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void delLemScene()
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{
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delMesh(&lemMesh);
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SaverFree(lemX);
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SaverFree(lemY);
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SaverFree(lemXT);
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SaverFree(lemYT);
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}
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void updateLemScene(int flags)
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{
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static double mxrot = 0.0;
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static double myrot = 0.0;
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static double mzrot = 0.0;
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static double mxrotInc = 0.0;
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static double myrotInc = 0.1;
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static double zrotInc = 0.1;
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static double mzrotInc = 0.0;
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static int h = 0;
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RGBA color;
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MATRIX model;
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mxrot += mxrotInc;
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myrot += myrotInc;
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mzrot += mzrotInc;
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if( gbBounce ) {
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// floating window bounced off an edge
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if (mxrotInc) {
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mxrotInc = 0.0;
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myrotInc = 0.1;
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} else if (myrotInc) {
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myrotInc = 0.0;
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mzrotInc = 0.1;
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} else if (mzrotInc) {
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mzrotInc = 0.0;
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mxrotInc = 0.1;
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}
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gbBounce = FALSE;
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}
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zrot += zrotInc;
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if (zrot >= PI / 4.0) {
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zrot = PI / 4.0;
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zrotInc = -0.03;
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} else if (zrot <= -PI / 4.0) {
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zrot = -PI / 4.0;
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zrotInc = 0.03;
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}
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genLemniscate();
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if (bColorCycle) {
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ss_HsvToRgb((float)h, 1.0f, 1.0f, &color );
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glMaterialfv(GL_FRONT_AND_BACK, GL_AMBIENT_AND_DIFFUSE, (GLfloat *) &color);
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h++;
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h %= 360;
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}
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glMatrixMode(GL_PROJECTION);
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glLoadIdentity();
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glOrtho(-1.5, 1.5, -1.5, 1.5, 0.0, 3.0);
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glTranslatef(0.0f, 0.0f, -1.5f);
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glRotatef((GLfloat) (zrot * (180.0 / PI)), 0.0f, 1.0f, 0.0f);
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glRotatef(50.0f, 1.0f, 0.0f, 0.0f);
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glRotatef(50.0f, 0.0f, 0.0f, 1.0f);
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glMatrixMode(GL_MODELVIEW);
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glLoadIdentity();
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glTranslatef(0.0f, -0.5f, 0.0f);
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glRotatef((GLfloat) (mxrot * (180.0 / PI)), 1.0f, 0.0f, 0.0f);
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glRotatef((GLfloat) (myrot * (180.0 / PI)), 0.0f, 1.0f, 0.0f);
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glRotatef((GLfloat) (mzrot * (180.0 / PI)), 0.0f, 0.0f, 1.0f);
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ss_matrixIdent(&model);
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ss_matrixRotate(&model, mxrot, myrot, mzrot);
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ss_matrixTranslate(&model, 0.0, -0.5, 0.0);
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updateObject(&lemMesh, bSmoothShading);
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}
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