Projection of a Barn
Projecting a 3D barn in 2D view plan.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 | #include <windows.h> #include <gl/Gl.h> #include <gl/glut.h> #include <cmath> int WinWidth = 500, WinHeight = 500; typedef struct{float x;float y;}Point2D; typedef struct{float x;float y;float z;}Point3D; Point3D COP = {0,0,-200}; // Centre Of Projection is at (0,0,-200) Point3D A,B,C,D,E,F,G,H; // Vertices of the cube Point2D Projected_A,Projected_B,Projected_C,Projected_D,Projected_E,Projected_F,Projected_G,Projected_H; void InitCube(){ A.x = 0; A.y = 0; A.z = 0; // A(0,0,0) B.x = 200; B.y = 0; B.z = 0; // B(200,0,0) C.x = 200; C.y = 200; C.z = 0; // C(200,200,0) D.x = 0; D.y = 200; D.z = 0; // D(0,200,0) E.x = 0; E.y = 200; E.z = 200; // E(0,200,200) F.x = 0; F.y = 0; F.z = 200; // F(0,0,200) G.x = 200; G.y = 0; G.z = 200; // G(200,0,200) H.x = 200; H.y = 200; H.z = 200; // H(200,200,200) } void DrawCube(Point2D A, Point2D B, Point2D C, Point2D D, Point2D E, Point2D F, Point2D G, Point2D H){ glPointSize(1.0); glBegin(GL_LINE_LOOP); //DRAWING FRONT FACE glVertex2i(A.x, A.y); glVertex2i(B.x, B.y); glVertex2i(C.x, C.y); glVertex2i(D.x, D.y); glEnd(); glBegin(GL_LINE_LOOP); //DRAWING BACK FACE glVertex2i(E.x, E.y); glVertex2i(F.x, F.y); glVertex2i(G.x, G.y); glVertex2i(H.x, H.y); glEnd(); glBegin(GL_LINES); //DRAWING OTHER LINES glVertex2i(A.x, A.y); glVertex2i(F.x, F.y); glVertex2i(B.x, B.y); glVertex2i(G.x, G.y); glVertex2i(C.x, C.y); glVertex2i(H.x, H.y); glVertex2i(D.x, D.y); glVertex2i(E.x, E.y); glEnd(); glFlush(); } Point2D Project_Perspective(Point3D p, Point3D CoP){ Point2D p2; float d = abs(CoP.z); // The distance between the COP and orign p2.x = d*(p.x)/(p.z+d); p2.y = d*(p.y)/(p.z+d); //.....wite necessary equations here for perspective transformation return p2; } Point2D translate2D(Point2D p, float tx, float ty){ Point2D tp2; tp2.x = p.x + tx; tp2.y = p.y + ty; return tp2; } Point3D translate3D(Point3D p, float tx, float ty, float tz){ Point3D tp3; //.....wite the equations for 3D translation tp3.x = p.x + tx; tp3.y = p.y + ty; tp3.z = p.z + tz; return tp3; } void Draw3DTranslation(){ glClearColor(1.0f, 1.0f, 1.0f, 0.0f); glClear(GL_COLOR_BUFFER_BIT); glColor3f(0.0f, 0.0f, 0.0f); Point3D COP ={100,100,-200}; A = translate3D(A,-100,-100,200); B = translate3D(B,-100,-100,200); C = translate3D(C,-100,-100,200); D = translate3D(D,-100,-100,200); E = translate3D(E,-100,-100,200); F = translate3D(F,-100,-100,200); G = translate3D(G,-100,-100,200); H = translate3D(H,-100,-100,200); Projected_A = Project_Perspective(A,COP); Projected_B = Project_Perspective(B,COP); Projected_C = Project_Perspective(C,COP); Projected_D = Project_Perspective(D,COP); Projected_E = Project_Perspective(E,COP); Projected_F = Project_Perspective(F,COP); Projected_G = Project_Perspective(G,COP); Projected_H = Project_Perspective(H,COP); //2D Translation to Move Projected to Center Screen Projected_A = translate2D(Projected_A,WinWidth/2,WinHeight/2); Projected_B = translate2D(Projected_B,WinWidth/2,WinHeight/2); Projected_C = translate2D(Projected_C,WinWidth/2,WinHeight/2); Projected_D = translate2D(Projected_D,WinWidth/2,WinHeight/2); Projected_E = translate2D(Projected_E,WinWidth/2,WinHeight/2); Projected_F = translate2D(Projected_F,WinWidth/2,WinHeight/2); Projected_G = translate2D(Projected_G,WinWidth/2,WinHeight/2); Projected_H = translate2D(Projected_H,WinWidth/2,WinHeight/2); DrawCube(Projected_A,Projected_B,Projected_C,Projected_D,Projected_E,Projected_F,Projected_G,Projected_H); } void keyboard(unsigned char key, int x, int y) { if (key == 'q' || key == 'Q') exit(EXIT_SUCCESS); } void myMouse(int button, int state, int x, int y) { if(state == GLUT_DOWN) { if(button == GLUT_LEFT_BUTTON) { } else if (button == GLUT_RIGHT_BUTTON) { Draw3DTranslation(); } } } void myDisplay() { glClearColor(1.0f, 1.0f, 1.0f, 0.0f); glClear(GL_COLOR_BUFFER_BIT); glColor3f(0.0f, 0.0f, 0.0f); Projected_A = Project_Perspective(A,COP); Projected_B = Project_Perspective(B,COP); Projected_C = Project_Perspective(C,COP); Projected_D = Project_Perspective(D,COP); Projected_E = Project_Perspective(E,COP); Projected_F = Project_Perspective(F,COP); Projected_G = Project_Perspective(G,COP); Projected_H = Project_Perspective(H,COP); //TRANSLATE TO MID POINT OF THE SCREEN Projected_A = translate2D(Projected_A,WinWidth/2,WinHeight/2); Projected_B = translate2D(Projected_B,WinWidth/2,WinHeight/2); Projected_C = translate2D(Projected_C,WinWidth/2,WinHeight/2); Projected_D = translate2D(Projected_D,WinWidth/2,WinHeight/2); Projected_E = translate2D(Projected_E,WinWidth/2,WinHeight/2); Projected_F = translate2D(Projected_F,WinWidth/2,WinHeight/2); Projected_G = translate2D(Projected_G,WinWidth/2,WinHeight/2); Projected_H = translate2D(Projected_H,WinWidth/2,WinHeight/2); DrawCube( // Calculate the following values Projected_A, Projected_B, Projected_C, Projected_D, Projected_E, Projected_F, Projected_G, Projected_H ); } int main( int argc, char ** argv ) { glutInit( &argc, argv ); glutInitWindowPosition( 0, 0 ); glutInitWindowSize( WinWidth, WinHeight ); glutCreateWindow( "Projection of a Cube" ); glMatrixMode( GL_PROJECTION ); glLoadIdentity(); gluOrtho2D( 0, WinWidth, 0, WinHeight ); glViewport(0, 0, WinWidth, WinHeight); InitCube(); glutKeyboardFunc(keyboard); glutMouseFunc( myMouse ); glutDisplayFunc( myDisplay ); glutMainLoop(); return( 0 ); } |
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