計算機圖形學實驗五：圖形變換

1、貴州大學實驗報告學院：計算機科學與技術(shù) 專業(yè)： 計算機科學與技術(shù) 班級：計科131姓名學號實驗組實驗時間指導教師黃初華成績實驗項目名稱圖形變換實驗目的實驗目的通過本實驗，使學生了解并掌握在光柵顯示系統(tǒng)中直線的生成和顯示算法，熟悉相關(guān)開發(fā)平臺。為后繼實驗打下基礎(chǔ)。實驗要求對于設計性實驗，應根據(jù)“由學生自行設計實驗方案并加以實現(xiàn)的實驗”內(nèi)涵要求，注意省略由學生自主設計的“實驗方案”。根據(jù)本實驗的特點、要求和具體條件，采用“以學生自主訓練為主的開放模式組織教學，還是采用集中授課形式”，須加以明確。實驗原理標準齊次坐標(x,y,1) 二維變換的矩陣表示平移變換旋轉(zhuǎn)變換放縮變換l 平移變換只改變圖形的位

2、置，不改變圖形的大小。l 旋轉(zhuǎn)變換不改變圖形的形狀l 放縮變換引起圖形形狀的變化。復合變換結(jié)果與變換的順序有關(guān)（矩陣乘法不可交換實驗環(huán)境硬件平臺：PC軟件(推薦)：Windows平臺，Visual stdio2013,openGL實驗步驟實驗步驟1. 掌握算法原理；2. 依據(jù)算法，編寫源程序并進行調(diào)試；3. 對運行結(jié)果進行保存與分析；4. 把源程序以文件的形式提交；5. 按格式書寫實驗報告。實驗內(nèi)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)/旋轉(zhuǎn)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)/縮放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)/組合變化后的矩陣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);/縮小transformVerts2D(nVerts, verts);glColor3f(1.0, 0.0, 0.0);triangle(verts);matrix3x3SetIdentity(matComposite);rotate2D(pivPt, theta);/旋轉(zhuǎn)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