OpenGL Programminggraphics.hallym.ac.kr/teach/2009/cga/src/01prac.pdf · 2010-03-02 · OpenGL API Easy to learn, compared with other APIs Device Nevertheless powerful Graphics functions:

OpenGL Programming

1 t W k 20091st Week, 2009

Visual Studio 2008Visual Studio 2008

새 프로젝트새 프로젝트

■ Visual C++ Win32 프로젝트■ Visual C++ Win32 프로젝트

응용 프로그램 설정응용 프로그램 설정

■ 빈 프로젝트■ 빈 프로젝트

솔루션 ‘Prac01’솔루션 Prac01

새 항목 추가새 항목 추가

‘main cpp’ 추가main.cpp 추가

‘main cpp’main.cpp

Downloading Sample ProgramDownloading Sample Program

‘main cpp’ 소스 코드main.cpp 소스 코드

프로젝트 속성프로젝트 속성

멀티바이트 문자 집합 사용멀티바이트 문자 집합 사용

Unicode vs Multi ByteUnicode vs. Multi-Byte

■ SBCS (Single Byte Character Set)■ SBCS (Single Byte Character Set)■■ ASCIIASCII code: 1 byte character set

■ DBCS (Double Byte Character Set)■ Korean■ Korean

■ MBCS (Multi Byte Character Set)■ MBCS (Multi Byte Character Set)■ SBCS + DBCS: ~ Windows 9x

■ WBCS (Wide Byte Character Set)■■ UnicodeUnicode: Windows 2000 ~■■ UnicodeUnicode: Windows 2000

OpenGL 라이브러리 링크OpenGL 라이브러리 링크

OpenGL API (1)OpenGL API (1)

■ API (application programming interface)■ API (application programming interface)■ Interface between an application program and a

graphics system Inputg p yApplication Program

Application Program

Graphics Library (API)

Graphics Library (API)

HardwareHardware

InputDevice

Output

■ OpenGL API■ Easy to learn, compared with other APIs

Device

■ Nevertheless powerful

■ Graphics functions: black boxblack boxp■ Described by only its inputs and outputs■ Nothing known about its internal working

F ti C ll O t tUserProgram

UserProgram

GraphicsSystemGraphicsSystem

Input/OutputDevices

Input/OutputDevices

Function Calls Output

Data Input


■ OpenGL interface■ OpenGL interface

OpenGLOpenGL

GLUGLU

GLGLOpenGLApplicationProgram

OpenGLApplicationProgram

GLGL

GLUTGLUT Xlib, XtkXlib, XtkFrameBufferFrameBuffer

■ OpenGL core library (names : gl~) : GLGLGLXGLX

■ OpenGL utility library : GLUGLU■ Using only GL functions

C ti bj t■ Creating common objects■ Other tasks that users prefer not to write repeatedly

■ OpenGL utility toolkit : GLUTGLUT■ OpenGL utility toolkit : GLUTGLUT■ Interface with the window system


■ OpenGL function format■ OpenGL function format

Function name Dimensions

lV t 3f( )glVertex3f( x, y, z );

Belongs to GL library x, y, z are floats

p is a pointer to an arrayp p y

glVertex3fv( p );

실행 결과실행 결과

GLUT LibraryGLUT Library

■■ glut hglut h ( /Microsoft SDKs/Windows/v6 0A/Include/gl)■■ glut.hglut.h ( /Microsoft SDKs/Windows/v6.0A/Include/gl)■■ glut32.libglut32.lib ( /Microsoft SDKs/Windows/v6.0A/Lib)■■ glut32.dllglut32.dll ( Windows/system32)void glutWireSphere(GLdouble radius, GLint slices, Glint stacks);void glutSoildSphere(GLdouble radius, GLint slices, Glint stacks);void glutWireSphere(GLdouble radius, GLint slices, Glint stacks);void glutSoildSphere(GLdouble radius, GLint slices, Glint stacks);g p ( , , );g p ( , , );

void glutWireCone(GLdouble base, GLdouble height, GLint slices, Glint stacks);void glutSoildCone(GLdouble base, GLdouble height, GLint slices, Glint stacks);void glutWireCone(GLdouble base, GLdouble height, GLint slices, Glint stacks);void glutSoildCone(GLdouble base, GLdouble height, GLint slices, Glint stacks);

void glutWireCube(GLdouble size);void glutWireCube(GLdouble size);

void glutWireTorus(GLdouble inner, GLdouble outer, GLint sides, Glint slices);void glutSoildTorus(GLdouble inner, GLdouble outer, GLint sides, Glint slices);void glutWireTorus(GLdouble inner, GLdouble outer, GLint sides, Glint slices);void glutSoildTorus(GLdouble inner, GLdouble outer, GLint sides, Glint slices);

void glutWireTetrahedron();void glutWireTetrahedron();void glutWireCube(GLdouble size);void glutSoildCube(GLdouble size);void glutWireCube(GLdouble size);void glutSoildCube(GLdouble size);

void glutWireTeapot(GLdouble size);void glutSoildTeapot(GLdouble size);void glutWireTeapot(GLdouble size);void glutSoildTeapot(GLdouble size);

void glutWireTetrahedron();void glutSoildTetrahedron();void glutWireOctahedron();void glutWireOctahedron();void glutWireDodecahedron();

void glutWireTetrahedron();void glutSoildTetrahedron();void glutWireOctahedron();void glutWireOctahedron();void glutWireDodecahedron();void glutSoildTeapot(GLdouble size);void glutSoildTeapot(GLdouble size); void glutWireDodecahedron();void glutSoildDodecahedron();void glutWireIcosahedron();void glutWireIcosahedron();

void glutWireDodecahedron();void glutSoildDodecahedron();void glutWireIcosahedron();void glutWireIcosahedron();

연습문제 (1)연습문제 (1)

■ GLUT 함수를 이용하여 다른 오브젝트로 변경하■ GLUT 함수를 이용하여 다른 오브젝트로 변경하시오.

Rendering PipelineRendering Pipeline

3D Primitives Local coordinates3D Primitives

World Transformation

Local coordinates

World coordinates

Viewing Transformation

LightingWorld coordinates

Viewing Transformation

Projection Transformation

Viewing coordinates

P j ti di tClipping

Vi t T f ti

Projection coordinates

Viewport Transformation

Rasterization

Device coordinates

2D Image

World TransformationWorld Transformation

■ Changing coordinates relative local coordinate■ Changing coordinates relative local coordinate system into world coordinate system

World

Localdi

WorldTransformation

CoordinateSystem W3

WorldC di t

W2

W1Coordinate

System

Viewing TransformationsViewing Transformations

■ Transforming all of the objects in world space■ Transforming all of the objects in world space to viewing space

Letting camera be centered about

Up Vector

■ Letting camera be centered about camera coordinate system

Right Vector

Front VectorViewing

CoordinateSystemSystem

Viewing

WorldCoordinate V

gTransformation

CoordinateSystem

Projection TransformationProjection Transformation

■ Mapping a view volume into a box■ Mapping a view volume into a box■ x and y coordinates: [-1, 1] 2D projection coord.

coordinates: [0 1] depth testing■ z coordinates: [0, 1] depth testing(1, 1, 1)

ViewingCoordinate

System

ViewVolume Normalized

ProjectionTransformation

VolumeView

Volume

(-1, -1, 0)

Viewport TransformationViewport Transformation

■ Transforming projection coordinates to a■ Transforming projection coordinates to a rectangle (viewport)

Aspect ratio = width / height■ Aspect ratio = width / height

LightingLighting

■ Realistic scene■ Realistic scene■ Specifying lights in world space

transforming lights into viewing spacetransforming lights into viewing space carrying out the light calculation

A U it S h A Lit S h A Lit SphereAn Unit Sphere A Lit Sphere A Lit Sphereand its Shadow

ClippingClipping

■ Culling the geometry that is outside the■ Culling the geometry that is outside the viewing volume

Three possible locations

+z

■ Three possible locations(1) completely inside

keeping it Insidekeeping it(2) completely outside

lli itculling it(3) partially inside

( ti ll t id )(partially outside)splitting it

OutsidePartially Inside

+x+x

RasterizationRasterization

■ Computing the color of the individual pixels■ Computing the color of the individual pixels that make up the interiors and boundaries of trianglestriangles

RasterizationRasterization

Primitives in OpenGLPrimitives in OpenGL

■ Points■ Points■ Lines

Li■ Line segments■ Polylines

■ Polygons■ Polygons■ Triangles and quadrilaterals■ Strips and fans

■ Text■ Curved objects■ Curved objects

Points in OpenGLPoints in OpenGL

glBegin(GL_POINTS);glVertex2fv(p0);

glBegin(GL_POINTS);glVertex2fv(p0); p0

7glVertex2fv(p0);glVertex2fv(p1);glVertex2fv(p2);glVertex2fv(p3);

glVertex2fv(p0);glVertex2fv(p1);glVertex2fv(p2);glVertex2fv(p3);

p0p1

26

p7



p2

p3p5

p6

g (p );glVertex2fv(p7);

glEnd();


glEnd();

p3

p4

p

Lines in OpenGL (1)Lines in OpenGL (1)

■ Line segments■ Line segments

glBegin(GL_LINES);glVertex2fv(p0);

glBegin(GL_LINES);glVertex2fv(p0); p0glVertex2fv(p0);glVertex2fv(p1);glVertex2fv(p2);glVertex2fv(p3);


p0p1

p7



p2p6


glEnd();


glEnd();p3

p4

p5


■ Polylines – line strip■ Polylines – line strip

glBegin(GL_LINE_STRIP);glVertex2fv(p0);

glBegin(GL_LINE_STRIP);glVertex2fv(p0); p0glVertex2fv(p0);glVertex2fv(p1);glVertex2fv(p2);glVertex2fv(p3);


p0p1

p7



p2p6


glEnd();


glEnd(); p3p4

p5


■ Polylines – line loop■ Polylines – line loop

glBegin(GL_LINE_LOOP);glVertex2fv(p0);

glBegin(GL_LINE_LOOP);glVertex2fv(p0); p0glVertex2fv(p0);glVertex2fv(p1);glVertex2fv(p2);glVertex2fv(p3);


p0p1

p7



p2p6


glEnd();


glEnd(); p3p4

p5


■ 오브젝트 앞에 X모양의 선을 추가하시오■ 오브젝트 앞에 X모양의 선을 추가하시오.

Polygons in OpenGL (1)Polygons in OpenGL (1)

■ Polygon■ Polygon

glBegin(GL_POLYGON);glVertex2fv(p0);

glBegin(GL_POLYGON);glVertex2fv(p0); p0glVertex2fv(p0);glVertex2fv(p1);glVertex2fv(p2);glVertex2fv(p3);


p0p1

p7



p2p6


glEnd();


glEnd(); p3p4

p5


■ Quadrilaterals■ Quadrilaterals

glBegin(GL_QUADS);glVertex2fv(p0);

glBegin(GL_QUADS);glVertex2fv(p0); p0glVertex2fv(p0);glVertex2fv(p1);glVertex2fv(p2);glVertex2fv(p3);


p0p1

p7



p2p6


glEnd();


glEnd(); p3p4

p5


■ Quadstrip■ Quadstrip

glBegin(GL_QUAD_STRIP);glVertex2fv(p0);

glBegin(GL_QUAD_STRIP);glVertex2fv(p0); p1glVertex2fv(p0);glVertex2fv(p1);glVertex2fv(p2);glVertex2fv(p3);


pp3

p0



p5p2


glEnd();


glEnd(); p7p6

p4


■ Triangles■ Triangles

glBegin(GL_TRIANGLES);glVertex2fv(p0);

glBegin(GL_TRIANGLES);glVertex2fv(p0); p0glVertex2fv(p0);glVertex2fv(p1);glVertex2fv(p2);glVertex2fv(p3);


p0p1

p7



p2p6


glEnd();


glEnd(); p3p4

p5


■ Triangle strip■ Triangle strip

glBegin(GL_TRIANGLE_STRIP);glVertex2fv(p0);

glBegin(GL_TRIANGLE_STRIP);glVertex2fv(p0); p0glVertex2fv(p0);glVertex2fv(p1);glVertex2fv(p2);glVertex2fv(p3);


p0p2

p1



p4p3


glEnd();


glEnd(); p6p7

p5


■ Triangle fan■ Triangle fan

glBegin(GL_TRIANGLE_FAN);glVertex2fv(p0);

glBegin(GL_TRIANGLE_FAN);glVertex2fv(p0); p0glVertex2fv(p0);glVertex2fv(p1);glVertex2fv(p2);glVertex2fv(p3);


p0p1

p7



p2p6


glEnd();


glEnd(); p3p4

p5


■ 오브젝트 뒤에 사각형을 추가하시오■ 오브젝트 뒤에 사각형을 추가하시오.

AttributesAttributes

■ Properties that determines how to render a■ Properties that determines how to render a geometric primitive (appearance of objects)

Color (points lines polygons)■ Color (points, lines, polygons)■ Size and width (points, lines)

Stipple pattern (lines polygons)■ Stipple pattern (lines, polygons)■ Polygon mode

Display as filled: solid color or stipple pattern■ Display as filled: solid color or stipple pattern■ Display edges■ Display verticesp y

Setting of Color Attributes (1)Setting of Color Attributes (1)

■ Setting of the clear color■ Setting of the clear color

■ Opaque: opacity is 1.0

glClearColorglClearColor(1.0, 1.0, 1.0, 1.0);

■ Opaque: opacity is 1.0■ Window is cleared by white color

■ Setting of the color state variable■ Setting of the color state variable

■ RGB color – red colorglColor3fglColor3f(1.0, 0.0, 0.0);

■ Setting of the size of points■ 2 pixels wide: glPointSizeglPointSize(2.0);

■ Setting of the width of lines■ 2 pixels width: glLineWidthglLineWidth(2.0);

Setting of Color Attributes (2)Setting of Color Attributes (2)

■ Creating conceptual vertex colors■ Creating conceptual vertex colorsglColor3fglColor3f(1.0, 0.0, 0.0);glVertex2fglVertex2f(0.5, 0.5);glVertex2fglVertex2f(0.5, 0.5);glColor3fglColor3f(0.0, 0.0, 1.0);glVertex2fglVertex2f(-0.5, -0.5);

■ Default – smooth shading■ Alternative – flat shading

■ Color of first vertex determines fill color

glShadeModelglShadeModel(GL_SMOOTH);glShadeModelglShadeModel(GL_FLAT);


■ 사각형의 꼭지점마다 색을 다르게 지정하고 사■ 사각형의 꼭지점마다 색을 다르게 지정하고, 사각형의 테두리를 두께 10.0f로 그리시오.

Documents

OpenGL Programminggraphics.hallym.ac.kr/teach/2009/cga/src/01prac.pdf · 2010-03-02 · OpenGL API Easy to learn, compared with other APIs Device Nevertheless powerful Graphics functions: