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openGL学习

原创 IT综合 作者：liiinuuux 时间：2016-09-26 16:01:56 0 删除 编辑
由小到大绘制多个点，排成螺旋

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  1. void RenderScene(void)
  2. {
  3.     GLfloat x, y, z, angle;
  4.     z = -50.0f;
  5.     GLfloat zStep = 0.5f;
  6.     GLfloat sizes[2];
  7.     GLfloat sizeStep;
  8.     GLfloat curSize;
  9.    
  10.     glGetFloatv(GL_POINT_SIZE_RANGE, sizes);
  11.     glGetFloatv(GL_POINT_SIZE_GRANULARITY, &sizeStep);

  13.     curSize = sizes[0] + sizeStep;
  14.    
  15.     glClear(GL_COLOR_BUFFER_BIT);
  16.     glPushMatrix();
  17.     glRotatef(40.0f, 10.0f, -10.0f, 0.0f);
  18.    
  19.    

  21.     for (angle = 0.0f; angle <= (2.0f * GL_PI) * 3.0f; angle += 0.1f)
  22.     {
  23.         x = 50.0f * sin(angle);
  24.         y = 50.0f * cos(angle);
  25.         z += zStep;
  26.         glPointSize(curSize);
  27.         glBegin(GL_POINTS);
  28.         glVertex3f(x, y, z);
  29.         glEnd();
  30.         if (curSize < 10.0f) curSize += sizeStep;
  31.        
  32.     }
  33.    
  34.    
  35.     glPopMatrix();
  36.     glutSwapBuffers();
  37. }

  39. void ChangeSize(GLsizei w, GLsizei h)
  40. {
  41.     GLfloat nRange = 100.0f;
  42.     if (h == 0) h = 1;
  43.     glViewport(0, 0, w, h);
  44.     glMatrixMode(GL_PROJECTION);
  45.     glLoadIdentity();
  46.    
  47.    
  48.     if (w <= h)
  49.     {
  50.         glOrtho(-nRange, nRange, -nRange * h / w, nRange * h / w, -nRange, nRange);
  51.     }
  52.     else
  53.     {
  54.         glOrtho(-nRange * w / h, nRange * w / h, -nRange, nRange, -nRange, nRange);
  55.     }
  56.    
  57.     glMatrixMode(GL_MODELVIEW);
  58.     glLoadIdentity();
  59. }



绘制直线、折线

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  1. void RenderScene(void)
  2. {
  3.     glClear(GL_COLOR_BUFFER_BIT);
  4.     glPushMatrix();
  5.     glRotatef(40.0f, 10.0f, -10.0f, 0.0f);
  6.    
  7.     GLfloat x, y, z, angle;

  9.     glBegin(GL_LINE_STRIP); //如果用GL_LINE_LOOP,会自动加一条线，形成环，如果用GL_LINES，则只是画一条线
  10.     glVertex3f(x, y, z);
  11.     glVertex3f(x + 30, y + 30, z + 30);
  12.     glVertex3f(x + 30, y + 60, z + 30);
  13.     glVertex3f(x + 20, y + 40, z + 80);
  14.     glEnd();

  16.     glPopMatrix();
  17.     glutSwapBuffers();
  18. }

用折线画螺旋，并且用上下左右控制旋转

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  1. /*
  2. * File: main.c
  3. * Author: root
  4. *
  5. * Created on August 30, 2013, 12:57 PM
  6. */

  8. #include <stdio.h>
  9. #include <stdlib.h>
  10. #include <time.h>
  11. #include <GL/glut.h>
  12. #include <GL/gl.h>
  13. #include <math.h>


  16. #define GL_PI 3.1415f
  17. #define KEY_UP 101
  18. #define KEY_DOWN 103
  19. #define KEY_LEFT 102
  20. #define KEY_RIGHT 100

  22. GLfloat rotateX = 0.0f;
  23. GLfloat rotateY = 0.0f;

  25. void RenderScene(void)
  26. {
  27.     glClear(GL_COLOR_BUFFER_BIT);
  28.     glPushMatrix();
  29.     glRotatef(rotateX, 1.0f, 0.0f, 0.0f);
  30.     glRotatef(rotateY, 0.0f, 1.0f, 0.0f);
  31.    
  32.    
  33.     GLfloat x, y, z, angle;
  34.     z = -50.0f;
  35.     glBegin(GL_LINE_STRIP);
  36.     for(angle = 0.0f; angle < (2.0f * GL_PI) * 4; angle += 0.1f)
  37.     {
  38.         x = 50.0f * sin(angle);
  39.         y = 50.0f * cos(angle);
  40.         z += 0.5f;
  41.        
  42.         glVertex3f(x, y, z);
  43.         
  44.     }
  45.     glEnd();
  46.    
  47.    
  48.    
  49.     glPopMatrix();
  50.     glutSwapBuffers();
  51. }

  53. void ChangeSize(GLsizei w, GLsizei h)
  54. {
  55.     GLfloat nRange = 100.0f;
  56.     if (h == 0) h = 1;
  57.     glViewport(0, 0, w, h);
  58.     glMatrixMode(GL_PROJECTION);
  59.     glLoadIdentity();
  60.    
  61.    
  62.     if (w <= h)
  63.     {
  64.         glOrtho(-nRange, nRange, -nRange * h / w, nRange * h / w, -nRange, nRange);
  65.     }
  66.     else
  67.     {
  68.         glOrtho(-nRange * w / h, nRange * w / h, -nRange, nRange, -nRange, nRange);
  69.     }
  70.    
  71.     glMatrixMode(GL_MODELVIEW);
  72.     glLoadIdentity();
  73. }

  75. void SetupRC(void)
  76. {
  77.     glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
  78.     glColor3f(0.0f, 1.0f, 0.0f);
  79. }

  81. void myTimer(int i)
  82. {

  84. }

  86. void keyAction (int key, int x, int y)
  87. {
  88.     switch (key)
  89.     {
  90.         case KEY_UP:
  91.             rotateX += 1.5f;
  92.             break;
  93.         case KEY_DOWN:
  94.             rotateX -= 1.5f;
  95.             break;
  96.         case KEY_LEFT:
  97.             rotateY -= 1.5f;
  98.             break;
  99.         case KEY_RIGHT:
  100.             rotateY += 1.5f;
  101.             break;
  102.         default:
  103.             break;
  104.     }
  105.     RenderScene();
  106. }


  109. /*
  110. *
  111. */
  112. int main(int argc, char** argv) {
  113.     glutInit(&argc, argv);
  114.     glutInitWindowPosition(100, 100);
  115.     glutInitWindowSize(399, 400);
  116.     glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB);
  117.     glutCreateWindow("asd");
  118.     SetupRC();
  119.     glutDisplayFunc(RenderScene);
  120.     glutReshapeFunc(ChangeSize);
  121.     glutSpecialFunc(keyAction);
  122.     glutMainLoop();
  123.     return (EXIT_SUCCESS);
  124. }


用三角形画圆锥
两个扇面组成封口的锥形

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  1. void RenderScene(void)
  2. {
  3.     glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
  4.     glPushMatrix();
  5.    
  6.     glRotatef(rotateX, 10.0f, 0.0f, 0.0f);
  7.     glRotatef(rotateY, 0.0f, 10.0f, 0.0f);

  9.     char p0[3] = {0.0f, 50.0f, 0.0f};
  10.     char p1[3] = {20.0f, 0.0, 20.0f};
  11.     GLfloat angle;
  12.     glShadeModel(GL_SMOOTH);
  13.     glEnable(GL_CULL_FACE); //开启多边形剔除，不渲染多边形的背面，这样如果要显示一个正面朝外的封闭多边形，则背面超前的地方根本就不渲染。如果是创建不发呢关闭的集合形体，如纸，就不能打开这个选项。
  14.     glEnable(GL_DEPTH_TEST); // 开启深度测试，可以避免晚描绘的像素错误遮挡之前描绘的Z坐标靠前的像素
  15.    
  16.     glPolygonMode(GL_BACK, GL_FILL); // 显示填充好的多边形，如果选GL_LINE，则只显示每个多边形的轮廓。
  17.    
  18.     glBegin(GL_TRIANGLE_FAN);
  19.     glVertex3f(p0[0], p0[1], p0[2]);
  20.     for (angle = 0; angle <= 2*GL_PI + 0.1f; angle += 0.1f)
  21.     {
  22.         glColor3f(sin(angle), 0.0f, 0.5f);
  23.         glVertex3f(p1[0] * sin(angle), p1[1], p1[2] * cos(angle));
  24.     }
  25.     glEnd();

  27.     glBegin(GL_TRIANGLE_FAN);
  28.     glColor3f(1.0f, 1.0f, 1.0f);
  29.     glVertex3f(p0[0], p1[1], p0[2]);
  30.     for (angle = 0; angle <= 2*GL_PI + 0.1f; angle += 0.1f)
  31.     {
  32.         glVertex3f(p1[0] * cos(angle), p1[1], p1[2] * sin(angle));
  33.     }
  34.     glEnd();
  35.    
  36.     glPopMatrix();
  37.     glutSwapBuffers();
  38. }


用GL_QUAD_STRIP绘制连续的四边形。提供顶点的方向是折线形的
提供顶点的顺序逆时针，则为正面。

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  1. void RenderScene(void)
  2. {
  3.     glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
  4.     glRotatef(rotateX, 1.0f, 0.0f, 0.0f);
  5.     glRotatef(rotateY, 0.0f, 1.0f, 0.0f);
  6.     glEnable(GL_CULL_FACE);
  7.     glEnable(GL_DEPTH_TEST);
  8.     glPolygonMode(GL_BACK, GL_FILL);

  10.     GLfloat r = 2.0f;
  11.    
  12.     glPushMatrix();
  13.    
  14.     glBegin(GL_QUAD_STRIP);
  15.     glColor3f(1.0, 0.0f, 0.0f);
  16.    
  17.     glVertex3f(r, -r, -r);
  18.     glVertex3f(r, -r, r);
  19.     glVertex3f(-r, -r, -r);
  20.     glVertex3f(-r, -r, r);
  21.    
  22.     glColor3f(0.0, 1.0f, 0.0f);
  23.     glVertex3f(-r, r, -r);
  24.     glVertex3f(-r, r, r);

  26.     glColor3f(0.0, 0.0f, 1.0f);
  27.     glVertex3f(r, r, -r);
  28.     glVertex3f(r, r, r);

  30.     glColor3f(0.0, 1.0f, 1.0f);
  31.     glVertex3f(r, -r, -r);
  32.     glVertex3f(r, -r, r);
  33.     glEnd();
  34.    
  35.     glBegin(GL_QUADS);
  36.     glColor3f(1.0, 1.0f, 1.0f);
  37.     glVertex3f(-r, -r, r);
  38.     glVertex3f(r, -r, r);
  39.     glVertex3f(r, r, r);
  40.     glVertex3f(-r, r, r);
  41.    
  42.     glEnd();
  43.    
  44.     glBegin(GL_QUADS);
  45.     glColor3f(1.0, 0.0f, 1.0f);
  46.     glVertex3f(r, -r, -r);
  47.     glVertex3f(-r, -r, -r);
  48.     glVertex3f(-r, r, -r);
  49.     glVertex3f(r, r, -r);
  50.    
  51.    
  52.     glEnd();
  53.    
  54.     glPopMatrix();
  55.     glutSwapBuffers();
  56. }


透视效果

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  1. void ChangeSize(GLsizei w, GLsizei h)
  2. {
  3.     if (h == 0) h = 1;
  4.     glViewport(0, 0, w, h);
  5.     glMatrixMode(GL_PROJECTION);
  6.     glLoadIdentity();
  7.    
  8.     gluPerspective(80.0f, (GLfloat)w/(GLfloat)h, 11.0, 30.0);
  9.    
  10.     glMatrixMode(GL_MODELVIEW);
  11.     glLoadIdentity();
  12.     glTranslatef(0.0f, 0.0f, -15.0f); 把坐标向x轴负方向推，使得图像装到gluPerspective的后两个参数范围里
  13. }


方块回弹

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  1. /*
  2. * File: main.c
  3. * Author: root
  4. *
  5. * Created on August 30, 2013, 12:57 PM
  6. */

  8. #include <stdio.h>
  9. #include <stdlib.h>
  10. #include <time.h>
  11. #include <GL/glut.h>
  12. #include <GL/gl.h>


  15. GLfloat rsize = 25.0f;
  16. GLfloat x = 200.0f;
  17. GLfloat y = 25.0f;

  19. GLfloat xStep = 5.0f;
  20. GLfloat yStep = 5.0f;

  22. GLfloat windowWidth;
  23. GLfloat windowHight;

  25. void RenderScene(void)
  26. {
  27.    
  28.     glClear(GL_COLOR_BUFFER_BIT);
  29.     glColor3f(1.0f, 0.0f, 0.0f);
  30.     glRectf(x , y , x + rsize, y - rsize);
  31.    
  32.    
  33.     glutSwapBuffers();
  34. }

  36. void ChangeSize(GLsizei w, GLsizei h)
  37. {
  38.     windowWidth = w;
  39.     windowHight = h;
  40.     glViewport(0, 0, windowWidth, windowHight);
  41.     glMatrixMode(GL_PROJECTION);
  42.     glLoadIdentity();
  43.     glOrtho(0, windowWidth, 0, windowHight, 20.0, -20.0);
  44.     glMatrixMode(GL_MODELVIEW);
  45.     glLoadIdentity();
  46. }

  48. void SetupRC(void)
  49. {
  50.     glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
  51. // glColor3f(0.0f, 1.0f, 0.0f);
  52. }

  54. void myTimer(int i)
  55. {
  56.     if (x > windowWidth - rsize || x < 0) xStep *= -1;
  57.     if (y > windowHight || y < rsize) yStep *= -1;
  58.     x += xStep;
  59.     y += yStep;
  60.    
  61.     glutPostRedisplay();
  62.    
  63.     glutTimerFunc(30, myTimer, i);
  64. }

  66. /*
  67. *
  68. */
  69. int main(int argc, char** argv) {
  70.     glutInit(&argc, argv);
  71.     glutInitWindowPosition(100, 100);
  72.     glutInitWindowSize(399, 400);
  73.     glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB);
  74.     glutCreateWindow("asd");
  75. // glEnable(GL_LIGHTING);
  76.     glutDisplayFunc(RenderScene);
  77.     glutReshapeFunc(ChangeSize);
  78.     glutTimerFunc(30, myTimer, 1);
  79.     SetupRC();
  80.     glutMainLoop();
  81.     return (EXIT_SUCCESS);
  82. }








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