计算机图形学实验五：图形变换

1、贵州大学实验报告学院：计算机科学与技术 专业： 计算机科学与技术 班级：计科131姓名学号实验组实验时间指导教师黄初华成绩实验项目名称图形变换实验目的实验目的通过本实验，使学生了解并掌握在光栅显示系统中直线的生成和显示算法，熟悉相关开发平台。为后继实验打下基础。实验要求对于设计性实验，应根据“由学生自行设计实验方案并加以实现的实验”内涵要求，注意省略由学生自主设计的“实验方案”。根据本实验的特点、要求和具体条件，采用“以学生自主训练为主的开放模式组织教学，还是采用集中授课形式”，须加以明确。实验原理标准齐次坐标(x,y,1) 二维变换的矩阵表示平移变换旋转变换放缩变换l 平移变换只改变图形的位

2、置，不改变图形的大小。l 旋转变换不改变图形的形状l 放缩变换引起图形形状的变化。复合变换结果与变换的顺序有关（矩阵乘法不可交换实验环境硬件平台：PC软件(推荐)：Windows平台，Visual stdio2013,openGL实验步骤实验步骤1. 掌握算法原理；2. 依据算法，编写源程序并进行调试；3. 对运行结果进行保存与分析；4. 把源程序以文件的形式提交；5. 按格式书写实验报告。实验内容#include"stdafx.h"#include <glut.h>#include <stdlib.h>#include <math.h>

3、GLsizei winWidth = 600, winHeight = 600;GLfloat xwcMin = 0.0, xwcMax = 225.0;GLfloat ywcMin = 0.0, ywcMax = 225.0;class wcPt2Dpublic:GLfloat x, y;typedef GLfloat Matrix3x333;Matrix3x3 matComposite;const GLdouble pi = 3.14159;void init(void)glClearColor(1.0, 1.0, 1.0, 0.0);void matrix3x3SetIdentity(M

4、atrix3x3 matIdent3x3)GLint row, col;for (row = 0; row<3; row+)for (col = 0; col<3; col+)matIdent3x3rowcol = (row = col);/生成1,0,00,1,00,0,1void matrix3x3PreMultiply(Matrix3x3 m1, Matrix3x3 m2)GLint row, col;Matrix3x3 matTemp;for (row = 0; row<3; row+)for (col = 0; col<3; col+)matTemprowco

5、l = m1row0 * m20col + m1row1 * m21col + m1row2 * m22col;for (row = 0; row<3; row+)for (col = 0; col<3; col+)m2rowcol = matTemprowcol;void translate2D(GLfloat tx, GLfloat ty)/平移Matrix3x3 matTransl;matrix3x3SetIdentity(matTransl);matTransl02 = tx;matTransl12 = ty;matrix3x3PreMultiply(matTransl,

6、matComposite);void rotate2D(wcPt2D pivotPt, GLfloat theta)/旋转Matrix3x3 matRot;matrix3x3SetIdentity(matRot);matRot00 = cos(theta);matRot01 = -sin(theta);matRot02 = pivotPt.x*(1 - cos(theta) + pivotPt.y*sin(theta);matRot10 = sin(theta);matRot11 = cos(theta);matRot312 = pivotPt.x*(1 - cos(theta) - pivo

7、tPt.y*sin(theta);matrix3x3PreMultiply(matRot, matComposite);void scale2D(GLfloat sx, GLfloat sy, wcPt2D fixedPt)/缩放Matrix3x3 matScale;matrix3x3SetIdentity(matScale);matScale00 = sx;matScale02 = (1 - sx)*fixedPt.x;matScale11 = sy;matScale12 = (1 - sy)*fixedPt.y;matrix3x3PreMultiply(matScale, matCompo

8、site);void transformVerts2D(GLint nVerts, wcPt2D * verts)/组合变化后的矩阵GLint k;GLfloat temp;for (k = 0; k<nVerts; k+)temp = matComposite00 * vertsk.x + matComposite01 * vertsk.y + matComposite02;vertsk.y = matComposite10 * vertsk.x + matComposite11 * vertsk.y + matComposite12;vertsk.x = temp;void tria

9、ngle(wcPt2D*verts)GLint k;glBegin(GL_TRIANGLES);for (k = 0; k<3; k+)glVertex2f(vertsk.x, vertsk.y);glEnd();void displayFcn(void)GLint nVerts = 3;wcPt2D verts3 = 50.0, 25.0 , 150.0, 25.0 , 100.0, 100.0 ;wcPt2D centroidPt;GLint k, xSum = 0, ySum = 0;for (k = 0; k<nVerts; k+)xSum += vertsk.x;ySum

10、 += vertsk.y;centroidPt.x = GLfloat(xSum) / GLfloat(nVerts);centroidPt.y = GLfloat(ySum) / GLfloat(nVerts);wcPt2D pivPt, fixedPt;pivPt = centroidPt;fixedPt = centroidPt;GLfloat tx = 0.0, ty = 100.0;GLfloat sx = 0.5, sy = 0.5;GLdouble theta = pi / 2.0;glClear(GL_COLOR_BUFFER_BIT);glColor3f(0.0, 0.0,

11、1.0);triangle(verts);/三角形matrix3x3SetIdentity(matComposite);scale2D(sx, sy, fixedPt);/缩小transformVerts2D(nVerts, verts);glColor3f(1.0, 0.0, 0.0);triangle(verts);matrix3x3SetIdentity(matComposite);rotate2D(pivPt, theta);/旋转90transformVerts2D(nVerts, verts); glColor3f(1.0, 0.0, 0.0);triangle(verts);ma

12、trix3x3SetIdentity(matComposite);translate2D(tx, ty);/平移transformVerts2D(nVerts, verts); glColor3f(1.0, 0.0, 0.0);triangle(verts);matrix3x3SetIdentity(matComposite);transformVerts2D(nVerts, verts);glColor3f(1.0, 0.0, 0.0);triangle(verts);glFlush();void winReshapeFcn(GLint newWidth, GLint newHeight)g

13、lMatrixMode(GL_PROJECTION);gluOrtho2D(xwcMin, xwcMax, ywcMin, ywcMax);glClear(GL_COLOR_BUFFER_BIT);void main(int argc, char* argv)glutInit(&argc, argv);glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB);glutInitWindowPosition(50, 50);glutInitWindowSize(winWidth, winHeight);glutCreateWindow("Geometr