Lect1_Giới thiệu OpenGL

8/4/2019 Lect1_Gii thiu OpenGL

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Gii thiu OpenGL


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Cc cng c HMT

Cng c

Phncng

Thit b raThit b

vo

Phnmm

Hm vc bn

Hm viql ca s

Hm vmy quay


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ha c lp thit b

Th vin ha c lp thit b: cho php sdng tp hm ha chung chy trn nhiuh thng khc nhau.

OpenGL


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ha c lp thit b: OpenGL

Cho php cng chng trnh ha chy trnnhiu my khc nhau v cho ra kt qu hunh hon ton ging nhau.

Dng cc tp .dll OpenGL nh l mt API: n iu khin phn

cng bn ang s dujg v bn ch cn dngcc hm ca OpenGL thay v iu khin thitb phn cng trc tip.

OpenGL l open source (free).


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Chng trnh hng s kin

p ng cc s kit nh click, di chuynchut, bm phm, thay i kch c ca s. Hthng qun l s kin theo hng i.

Ngi lp trnh cung cp cc hm call-back iu khin mi s kin.

Hm call-back phi c ng k vi OpenGL

OpenGL bit hm no iu khin s kinno.

Hm ng k khng gi n!


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Ci t v cu hnh

Files: .h, .lib, .dll

Ton b th mc glc t trong th mcInclude ca Visual C++

Ton b cc tp libc t trong th mc libca Visual C++

Ton b cc tp dllc t trong

C:\Windows\System32


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S dng OpenGL

Includes:

(nu s dng)


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Th vin thm vo th mc include

GL, cu lnh bt u vi GL; GLUT, GL Utility Toolkit, m ca s, pht trin thc

n v qun l s kin. GLU, GL Utility Library, cung cp cc hm mc cao

iu khin cc thao tc v phc tp. GLUI, User Interface Library, c tch hp vo GLUT

library. Hm GLUT phi c sn cho GLUI thao tc c chnh

xc. GLUI cung cp cc iu khin v thc n phc tp cho

cc ng dng OpenGL


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S dng OpenGL

Thay i project settings: Visual C++ 6.0

Project /Settings

Trong Object/library modules: thm glui32.lib

glut32.lib glu32.lib opengl32.lib(dng du cchphn cch)

Trong Project Options: thm cng tp cc tp .lib

ngthc n Project v lu workspace


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S dng OpenGL (2)

Thay i project settings: Visual C++ .NET2003

Project/Properties/Linker/Command Line

Thm glui32.lib glut32.lib glu32.lib opengl32.lib

ng thc nProject v lu s thay i


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Lnh v c bn

setPixel(x, y, color)

Pixel ti (x, y) c mu color

Tn khc: putPixel(), SetPixel(),hoc drawPoint()

line(x1, y1, x2, y2)

ng thng gia (x1, y1) v (x2, y2)

Tn khc: drawLine() or Line().


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Lnh v c bn (2)

current position (cp), v tr hin ti.

moveTo(x,y)chuyn v tr hin ti n (x, y).

lineTo(x,y)v ng thng t v tr hin tin (x, y) v thay i cp thnh (x, y).


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V d: v hnh vung

moveTo(4, 4); //move

to starting corner

lineTo(-2, 4);

lineTo(-2, -2);

lineTo(4, -2);

lineTo(4, 4); //close

the square


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Khung mt chng trnh// include OpenGL libraries

void main()

{

glutDisplayFunc(myDisplay); // register the redraw function

glutReshapeFunc(myReshape); // register the reshape function

glutMouseFunc(myMouse); // register the mouse action functionglutMotionFunc(myMotionFunc); // register the mouse motionfunction

glutKeyboardFunc(myKeyboard); // register the keyboard actionfunction

perhaps initialize other thingsglutMainLoop(); // enter the unending main loop

}

all of the callback functions are defined here


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Hm Callback

glutDisplayFunc(myDisplay);

V li ca mn hnh khi ca s c m.

glutReshapeFunc(myReshape);

Khi thay i kch c ca s

glutIdleFunc(myIdle);

Khi khng c s kin g xy ra vic v li ch cn s dngvoid myIdle() {glutPostRedisplay();}


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Hm Callback (2)

glutMouseFunc(myMouse);

Handles mouse button presses. Knows mouse

location and nature of button (up or down and

which button).

glutMotionFunc(myMotionFunc);

Handles case when the mouse is moved with one

or more mouse buttons pressed.


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Hm Callback (3)

glutPassiveMotionFunc(myPassiveMotionFunc)

iu khin khi chut i vo ca s nhng khng cnt no c bm.

glutKeyboardFunc(myKeyboardFunc); iu khin n v nh phm.

glutMainLoop()

Chy lin tc v ch cc s kin xy ra. Khi c s kin xyra, th tham chiu n hm callback tng ng.


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Mt ct GL m mt ca s (2)// appropriate #includes go here see Appendix 1void main(int argc, char** argv){

glutInit(&argc, argv); // initialize the toolkitglutInitDisplayMode(GLUT_SINGLE |

GLUT_RGB); // set the display modeglutInitWindowSize(640,480); // set window sizeglutInitWindowPosition(100, 150);

// set window upper left corner position on screen

glutCreateWindow("my first attempt");// open the screen window (Title: my first attempt)


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Mt ct GL m mt ca s (3)

// register the callback functions

glutDisplayFunc(myDisplay);

glutReshapeFunc(myReshape);

glutMouseFunc(myMouse);glutKeyboardFunc(myKeyboard);

myInit(); // additional initializations as necessary

glutMainLoop(); // go into a perpetual loop

} Terminate program by closing window(s) it is using.


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Gii thch

glutInit (&argc, argv) khi to Open-GL Toolkit

glutInitDisplayMode (GLUT_SINGLE |

GLUT_RGB) nh v buffer hin th n v ch mu RGB v.

glutInitWindowSize (640, 480) To ca s640x480.


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Gii thch (2)

glutInitWindowPosition (100, 150) v tr cagc trn bn tri ca ca s.

glutCreateWindow (my first attempt) Mca s c tn my first attempt


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Kt qu ca chng trnh


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V cc im trong OpenGL

H trc ta 0 n 679 cho trc x v 0 n479 cho trc y.

OpenGL v da trn cc nh (vertices hoc

corners). v mt i tng trong OpenGL,t mt danh sch cc nh trong glBegin vglEnd Danh sch bt u vi glBegin(arg);v kt thc vi

glEnd();

Argxc nh i tng v. glEnd()Gi d liu v vo lung OpenGL .


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V d

glBegin (GL_POINTS);

glVertex2i (100, 50);



glEnd();

GL_POINTS hng Open-GL (GL_LINES,

GL_POLYGON, )


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Hin th cc im


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Hm OpenGL


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V d v hm OpenGL

glVertex2i () ly mt gi tr nguyn

glVertex2d () ly mt gi tr thc

OpenGL s dng kiu d liu ca OpenGL


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Kiu d liu OpenGL

suffix data type C/C++ type OpenGL type name

b 8-bit integer signed char GLbyte

s 16-bit integer Short GLshort

i32-bit integer int or long GLint, GLsizei

f 32-bit float Float GLfloat, GLclampf

d 64-bit float Double GLdouble,GLclampd

ub

8-bit unsignednumber unsigned char GLubyte,GLboolean

us 16-bit unsignednumber

unsigned short GLushort

ui 32-bit unsigned

number

unsigned int or

unsigned long

GLuint,Glenum,GLbitfield


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Mu trong OpenGL

glColor3f(red, green, blue);

// set drawing color glColor3f(1.0, 0.0, 0.0); // red

glColor3f(0.0, 1.0, 0.0); // green

glColor3f(0.0, 0.0, 1.0); // blue

glColor3f(0.0, 0.0, 0.0); // black

glColor3f(1.0, 1.0, 1.0); // bright white

glColor3f(1.0, 1.0, 0.0); // bright yellow

glColor3f(1.0, 0.0, 1.0); // magenta


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Mu nn trong OpenGL

glClearColor (red, green, blue, alpha);

Thit lp mu nn.

Alpha trong sut; ban u s dng 0.0 .

glClear(GL_COLOR_BUFFER_BIT);

Thit lp ca s thnh mu nn.


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Cu hnh h trc ta

void myInit(void)

{

glMatrixMode(GL_PROJECTION);

glLoadIdentity();

gluOrtho2D(0, 640.0, 0, 480.0);

}

// sets up coordinate system for window from(0,0) to (679, 479)


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V ng thng

glBegin (GL_LINES); //draws one line

glVertex2i (40, 100); // between 2 vertices


glEnd (); glFlush();

Nu c hn 2 nh trong cp

glBegin(GL_LINES) v glEnd() chng cghp thnh cp v tng on thng tch ri sc v ni gia cc cp ny.


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Mi lin h gia cc thit b


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Mi lin h gia cc thit b (2)

frame buffer

pixel at address [x,y]

0 639

479

0 x

ydisplay surface

scancontroller

x

y

x

y

spot at (x,y)

geometricposition

logicaladdress

at (639, 0)

at (639, 479)

convert pixelvalue to color


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Mi lin h gia cc thit b (3)

Based on cathode ray tube (CRT).

framebuffer(6 planes)

DAC's

scan controller

x

y

y

x

deflectioncoils

electronbeamguns

red

green

bluespot

pixelvalue

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Lect1_Giới thiệu OpenGL