電腦圖形學第一次實驗

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步驟一：尋找相關函數，瞭解其功能和調用

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77534803

50216979中點畫線法

簡單圖元代碼：

#include<GL/glut.h>#include<math.h>void MidPointLine(int x0, int y0, int x1, int y1){float dx, dy,m,x,y,d,a,b;a = y0 - y1;b = x1 - x0;dx = x1 - x0;dy = y1 - y0;x = x0;y = y0;m = 1.0*dy / dx;glBegin(GL_POINTS);glVertex2f(x, y);glEnd();if (m >= 0 && m <= 1){d = 2 * a + b;while (x <=x1){if (d > 0)//取下面的點{x++;d += 2 * a;glBegin(GL_POINTS);glVertex2f(x, y);glEnd();}else{x++;y++;d = d + 2 * a + 2 * b;glBegin(GL_POINTS);glVertex2f(x, y);glEnd();}}}else if (m > 1){d =a + 2*b;while (y<=y1){if (d > 0){d = d + 2 * a + 2 * b;y++;glBegin(GL_POINTS);glVertex2f(x, y);glEnd();}else{d += 2 * b;x++;y++;glBegin(GL_POINTS);glVertex2f(x, y);glEnd();}}}else if (m<= 0&&m>= -1){d = 2 * a - b;while (x <=x1){if (d > 0){d = d + 2 * a - 2 * b;x++;glBegin(GL_POINTS);glVertex2f(x, y);glEnd();}else{d = d + 2 * a;x++;y--; glBegin(GL_POINTS);glVertex2f(x, y);glEnd();}}}else{d = a - 2 * b;while (y >=y1){if (d > 0){d = d - 2 * a;x++;y--;glBegin(GL_POINTS);glVertex2f(x, y);glEnd();}else{d = d + 2 * a - 2 * b;y--;glBegin(GL_POINTS);glVertex2f(x, y);glEnd();}}}}void changeSize(GLsizei w, GLsizei h){if (h == 0)h = 1;glViewport(0, 0, w, h);glMatrixMode(GL_PROJECTION);glLoadIdentity();if (w <= h){glOrtho(0.0f, 500.0f, 0.0f, 500.0f * h / w, 1.0f, -1.0f);}else{glOrtho(0.0f, 500.0f * w / h, 0.0f, 500.0f, 1.0f, -1.0f);}glMatrixMode(GL_MODELVIEW);glLoadIdentity();}void init(){glClearColor(0.0f, 1.0f, 1.0f, 1.0f);}void RenderScene(){glClear(GL_COLOR_BUFFER_BIT);glColor3f(1.0, 0.0, 0.0);MidPointLine(100,250,250,50);glFlush();}int main(int argc, char *argv[]){glutInit(&argc, argv);glutInitDisplayMode(GLUT_RGB | GLUT_SINGLE);glutCreateWindow("Line");init();glutInitWindowPosition(100, 100);glutInitWindowSize(500, 500);glutDisplayFunc(RenderScene);glutReshapeFunc(changeSize);glutMainLoop();return 0;}

　　中點線演算法代碼：

#include<GL/glut.h>#include<math.h>void MidPointLine(int x0, int y0, int x1, int y1){float dx, dy,m,x,y,d,a,b;a = y0 - y1;b = x1 - x0;dx = x1 - x0;dy = y1 - y0;x = x0;y = y0;m = 1.0*dy / dx;glBegin(GL_POINTS);glVertex2f(x, y);glEnd();if (m >= 0 && m <= 1){d = 2 * a + b;while (x <=x1){if (d > 0)//取下面的點{x++;d += 2 * a;glBegin(GL_POINTS);glVertex2f(x, y);glEnd();}else{x++;y++;d = d + 2 * a + 2 * b;glBegin(GL_POINTS);glVertex2f(x, y);glEnd();}}}else if (m > 1){d =a + 2*b;while (y<=y1){if (d > 0){d = d + 2 * a + 2 * b;y++;glBegin(GL_POINTS);glVertex2f(x, y);glEnd();}else{d += 2 * b;x++;y++;glBegin(GL_POINTS);glVertex2f(x, y);glEnd();}}}else if (m<= 0&&m>= -1){d = 2 * a - b;while (x <=x1){if (d > 0){d = d + 2 * a - 2 * b;x++;glBegin(GL_POINTS);glVertex2f(x, y);glEnd();}else{d = d + 2 * a;x++;y--; glBegin(GL_POINTS);glVertex2f(x, y);glEnd();}}}else{d = a - 2 * b;while (y >=y1){if (d > 0){d = d - 2 * a;x++;y--;glBegin(GL_POINTS);glVertex2f(x, y);glEnd();}else{d = d + 2 * a - 2 * b;y--;glBegin(GL_POINTS);glVertex2f(x, y);glEnd();}}}}void changeSize(GLsizei w, GLsizei h){if (h == 0)h = 1;glViewport(0, 0, w, h);glMatrixMode(GL_PROJECTION);glLoadIdentity();if (w <= h){glOrtho(0.0f, 500.0f, 0.0f, 500.0f * h / w, 1.0f, -1.0f);}else{glOrtho(0.0f, 500.0f * w / h, 0.0f, 500.0f, 1.0f, -1.0f);}glMatrixMode(GL_MODELVIEW);glLoadIdentity();}void init(){glClearColor(0.0f, 1.0f, 1.0f, 1.0f);}void RenderScene(){glClear(GL_COLOR_BUFFER_BIT);glColor3f(1.0, 0.0, 0.0);MidPointLine(100,250,250,50);glFlush();}int main(int argc, char *argv[]){glutInit(&argc, argv);glutInitDisplayMode(GLUT_RGB | GLUT_SINGLE);glutCreateWindow("Line");init();glutInitWindowPosition(100, 100);glutInitWindowSize(500, 500);glutDisplayFunc(RenderScene);glutReshapeFunc(changeSize);glutMainLoop();return 0;}

　　

電腦圖形學第一次實驗