Å tegne:>Bordlampe
En bordlampe
Struktur | oneLamp | Rendering | Navngivning | Lyssetting
Struktur
Ei lampe består av sylindere (fot, 2 armer og lampeskjermen). Leddene er lage med kuler.
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oneLamp
Lampene er plasserte på et rundt bord som ligger i xy-planet. En lampe er implementert i klassen oneLamp:
package tablelamp;
import javax.media.opengl.GL;
import javax.media.opengl.glu.GLU;
import javax.media.opengl.glu.GLUquadric;
/**
*
* @author borres
*/
public class oneLamp
{
// nice to have
private final float G2R=0.01745277777778f;
private final float R2G=57.29577951308f;
//id for lamp
int m_LampID;
// the geometry of the lamp
// length of the three arms
int[] m_Arm={40,50,10};
// angles for armposition:
// thickness of arm
int m_ArmW=3;
// radius for spheres in elbows
int m_ElbowRadius=6;
// base board
int m_BaseRadius=40;
int m_BaseHeight=2;
// lamps head
float m_TopR=10;
float m_OpenR=30;
float m_HeadCyl=30;
float m_HeadSpread=30;;
// angles for each rotation
float m_v1=0.0f;
float m_v2=0.0f;
float m_v3=10.0f;
float m_v4=30.0f;
// spot smoothness
float m_SpotExp=0.0f;
// quadric drawing precision
int nLong=10;
int nRound=20;
// which lightsource
int m_MyLight;
boolean m_LampIsOn=false;
public oneLamp(int LampID)
{
m_MyLight=GL.GL_LIGHT0+LampID+1;
m_LampID=LampID;
}
public void draw(GL gl)
{
GLU glu=new GLU();
// preserve modelview
gl.glPushMatrix();
if(!m_LampIsOn)
gl.glDisable(m_MyLight);
// use a quadric to draw parts of lamp
GLUquadric glpQ=glu.gluNewQuadric();
// material
int baseMaterial=stdMaterials.MAT_GREEN_PLASTIC;
int elbowMaterial=stdMaterials.MAT_GREEN_PLASTIC;
int armMaterial=stdMaterials.MAT_WARM_WHITE;
// scale the integer coordinates down to unit box
gl.glScalef(0.01f,0.01f,0.01f);
// display the lamp
// use lightsource as ID for lamp
gl.glLoadName(m_LampID*10+0);
// base, foot
stdMaterials.setMaterial(gl,baseMaterial,GL.GL_FRONT);
gl.glTranslatef(0.0f,0.0f,(float)-m_BaseHeight);
glu.gluDisk(glpQ,0.0f,(float)m_BaseRadius,20,20);
glu.gluCylinder(glpQ,(float)m_BaseRadius,(float)m_BaseRadius,
(float)m_BaseHeight,nRound,nLong);
gl.glTranslatef(0.0f,0.0f,(float)m_BaseHeight);
glu.gluDisk(glpQ,0,(float)m_BaseRadius,nRound,nRound);
stdMaterials.setMaterial(gl,elbowMaterial,GL.GL_FRONT);
glu.gluSphere(glpQ,(float)m_ElbowRadius,20,20);
// first arm, basic orientation around z-axis
gl.glLoadName(m_LampID*10+1);
gl.glRotatef(m_v1,0.0f,0.0f,1.0f);
// from now on all arms are rotated around y-axis
gl.glRotatef(m_v2,0.0f,1.0f,0.0f);
stdMaterials.setMaterial(gl,armMaterial,GL.GL_FRONT);
glu.gluCylinder(glpQ,m_ArmW,m_ArmW,m_Arm[0],nRound,nLong);
gl.glTranslatef(0.0f,0.0f,(float)m_Arm[0]);
stdMaterials.setMaterial(gl,elbowMaterial,GL.GL_FRONT);
glu.gluSphere(glpQ,m_ElbowRadius,nRound,nRound);
// second arm
gl.glLoadName(m_LampID*10+2);
gl.glRotatef(m_v3,0.0f,1.0f,0.0f);
stdMaterials.setMaterial(gl,armMaterial,GL.GL_FRONT);
glu.gluCylinder(glpQ,m_ArmW,m_ArmW,m_Arm[1],nRound,nLong);
gl.glTranslatef(0.0f,0.0f,(float)m_Arm[1]);
stdMaterials.setMaterial(gl,elbowMaterial,GL.GL_FRONT);
glu.gluSphere(glpQ,m_ElbowRadius,nRound,nRound);
// head
gl.glLoadName(m_LampID*10+3);
gl.glTranslatef(0.0f,0.0f,(float)m_ElbowRadius);
gl.glRotatef(m_v4,0.0f,1.0f,0.0f);
gl.glTranslatef(0.0f,0.0f,(float)-m_HeadCyl/2.0f);
stdMaterials.setMaterial(gl,elbowMaterial,GL.GL_FRONT);
glu.gluDisk(glpQ,0.0,m_TopR,nRound,nRound);
glu.gluCylinder(glpQ,m_TopR,m_TopR,m_HeadCyl,nRound,nLong);
gl.glTranslatef(0.0f,0.0f,(float)m_HeadCyl);
glu.gluCylinder(glpQ,m_TopR,m_OpenR,m_HeadSpread,nRound,nLong);
//lighton
// lightbulb and inner screen
if(m_LampIsOn)
{
// light inside of head
stdMaterials.setMaterial(gl,stdMaterials.MAT_BRIGHT_WHITE,GL.GL_FRONT);
glu.gluCylinder(glpQ,m_TopR-0.1f,m_OpenR-0.1f,m_HeadSpread,nRound,nLong);
// specify and set the spotlight
float spambient[] = {0.2f,0.2f,0.2f,1.0f };
float spdiffuse[] = {0.8f,0.8f,0.8f,1.0f };
float spspecular[] = {0.8f,0.8f,0.8f,1.0f };
float spposition[] = {0.0f,0.0f,0.0f,1.0f};
float spdirection[] = {0.0f,0.0f,1.0f};
float spotangle= R2G*(float)Math.atan((m_OpenR-m_TopR)/m_HeadSpread)+10;
gl.glLightfv(m_MyLight, GL.GL_AMBIENT, spambient,0);
gl.glLightfv(m_MyLight, GL.GL_DIFFUSE, spdiffuse,0);
gl.glLightfv(m_MyLight, GL.GL_SPECULAR, spspecular,0);
gl.glLightfv(m_MyLight, GL.GL_POSITION, spposition,0);
gl.glLightfv(m_MyLight, GL.GL_SPOT_DIRECTION, spdirection,0);
gl.glLightf (m_MyLight, GL.GL_SPOT_CUTOFF, spotangle);
gl.glLightf(m_MyLight, GL.GL_SPOT_EXPONENT, m_SpotExp);
gl.glEnable(GL.GL_LIGHTING);
gl.glEnable(m_MyLight);
// light the bulb
float[] ev={1.0f,1.0f,1.0f};
float[] nev={0.0f,0.0f,0.0f};
gl.glMaterialfv(GL.GL_FRONT,GL.GL_EMISSION,ev,0);
gl.glTranslatef(0.0f,0.0f,m_HeadSpread/5.0f);
glu.gluSphere(glpQ,m_TopR,nRound,nRound);
gl.glMaterialfv(GL.GL_FRONT,GL.GL_EMISSION,nev,0);
}
glu.gluSphere(glpQ,m_TopR,nRound,nRound);
//eoflighton
// finished with quadric, kill it
glu.gluDeleteQuadric(glpQ);
// reset matrix
gl.glPopMatrix();
}
public float GetAngle(int ix)
{
switch(ix)
{
case 0: return m_v1;
case 1:return m_v2;
case 2:return m_v3;
case 3:return m_v4;
default: return 0.0f;
}
}
public void SetAngle(int x,float v)
{
switch(x)
{
case 0:m_v1=v; break;
case 1:m_v2=v; break;
case 2:m_v3=v; break;
case 3:m_v4=v; break;
default: ;
}
}
public void SetLightOn(boolean on){m_LampIsOn=on;}
public boolean GetLightOn() {return m_LampIsOn;}
public void setSpotExponent(int v) {m_SpotExp=v/10.0f;}
}
Rendering
Klassen GLrenderer kontrollerer uttegningen av scenen Lampene holdes i en Vector:
private Vector<oneLamp> pLamp
Methoden display administrerer uttegningen:
public void display(GLAutoDrawable drawable)
{
GL gl = drawable.getGL();
// Clear the color and depth buffers.
gl.glClear(GL.GL_COLOR_BUFFER_BIT | GL.GL_DEPTH_BUFFER_BIT);
if(m_pressed)// we have pressed right mousebutton
{
m_pressed=false;
int n=pickSelected(m_thePanel.getGL(),m_lastX,m_lastY);
if(n!=NO_OBJECT)
{
m_hilitedPart=n%10; // lamp part
m_hilitedLamp=n/10; // lampindex
m_bIsManipulating=true;
}
else
{
m_hilitedLamp=NO_OBJECT; // to make sure
}
}
DrawScene(gl);
}
Methoden DrawScene er slik:
private void DrawScene(GL gl)
{
GLU glu=new GLU();
// Set up for scene
gl.glMatrixMode(GL.GL_MODELVIEW);
gl.glLoadIdentity();
glu.gluLookAt(m_zx,m_zy,m_zz, // eye
0.0f,0.0f,0.0f, // VRF
0.0f,0.0f,1.0f); // VUP
// interactive movement
// rotate around z-axis
gl.glRotatef(m_zv,0.0f,0.0f,1.0f);
// rotate around x-axis
gl.glRotatef(m_xv,1.0f,0.0f,0.0f);
// set a name;NO_OBJECT on anything irrelevant we draw
gl.glLoadName(NO_OBJECT);
GLUquadric glpQ=glu.gluNewQuadric();
//----------------
// draw table
gl.glPushMatrix();
gl.glTranslatef(0.0f, 0.0f, -0.01f);
stdMaterials.setMaterial(gl, stdMaterials.MAT_EMERALD, GL.GL_FRONT_AND_BACK);
glu.gluDisk(glpQ,0.0,2.0,table_res,table_res);
gl.glPopMatrix();
//-----------------
// draw lamps
// lamp 0
gl.glPushMatrix();
gl.glTranslatef(-1.0f,1.0f,0.0f);
gl.glLoadName(0);
pLamp.elementAt(0).draw(gl);
gl.glPopMatrix();
// lamp 1
gl.glPushMatrix();
gl.glTranslatef(1.0f,1.0f,0.0f);
gl.glLoadName(1);
pLamp.elementAt(1).draw(gl);
gl.glPopMatrix();
// lamp 2
gl.glPushMatrix();
gl.glTranslatef(1.0f,-1.0f,0.0f);
gl.glLoadName(2);
pLamp.elementAt(2).draw(gl);
gl.glPopMatrix();
// lamp 3
gl.glPushMatrix();
gl.glTranslatef(-1.0f,-1.0f,0.0f);
gl.glLoadName(2);
pLamp.elementAt(3).draw(gl);
gl.glPopMatrix();
// set a name on anything irrelevant we draw
gl.glLoadName(NO_OBJECT);
// finnish drawing
gl.glFlush();
}
Navngivning
Vi vet at vi må identifisere, sette navn på, alle delene som skal kunne identifiseres ved når vi peker med musa. I dette tilfellet betyr det at vi må kunne identifisere hvar lampe og hver lampes del. Vi bruker en enkel strategi der lampene nummereres fra 0 og delene slik: 10*lamppnumber + partnumber. I DrawScene:
// lamp 1 gl.glPushMatrix(); gl.glTranslatef(1.0f,1.0f,0.0f); gl.glLoadName(1); pLamp.elementAt(1).draw(gl); gl.glPopMatrix();
og i uttegning av hver lampe:
// first arm, basic orientation around z-axis gl.glLoadName(m_LampID*10+1); ...
Mekanismen for å velger er lik den som er brukt i Identifikasjon og er implementert i metodepickSelected in GLRenderer.
Lyssetting
Lyskontroll er en kombinasjon av tre effekter
- Vi vil ha en spotlight som "passer" til lampeskjermen
- Vi vil at lyspæra skal være lysende eller mørk
- Vi vil at innsiden av lampeskjermen skal være lys eller mørk.
// lightbulb and inner screen
if(m_LampIsOn)
{
// light inside of head
stdMaterials.setMaterial(gl,stdMaterials.MAT_BRIGHT_WHITE,GL.GL_FRONT);
glu.gluCylinder(glpQ,m_TopR-0.1f,m_OpenR-0.1f,m_HeadSpread,nRound,nLong);
// specify and set the spotlight
float spambient[] = {0.2f,0.2f,0.2f,1.0f };
float spdiffuse[] = {0.8f,0.8f,0.8f,1.0f };
float spspecular[] = {0.8f,0.8f,0.8f,1.0f };
float spposition[] = {0.0f,0.0f,0.0f,1.0f};
float spdirection[] = {0.0f,0.0f,1.0f};
float spotangle= R2G*(float)Math.atan((m_OpenR-m_TopR)/m_HeadSpread)+10;
gl.glLightfv(m_MyLight, GL.GL_AMBIENT, spambient,0);
gl.glLightfv(m_MyLight, GL.GL_DIFFUSE, spdiffuse,0);
gl.glLightfv(m_MyLight, GL.GL_SPECULAR, spspecular,0);
gl.glLightfv(m_MyLight, GL.GL_POSITION, spposition,0);
gl.glLightfv(m_MyLight, GL.GL_SPOT_DIRECTION, spdirection,0);
gl.glLightf (m_MyLight, GL.GL_SPOT_CUTOFF, spotangle);
gl.glLightf(m_MyLight, GL.GL_SPOT_EXPONENT, m_SpotExp);
gl.glEnable(GL.GL_LIGHTING);
gl.glEnable(m_MyLight);
// light the bulb
float[] ev={1.0f,1.0f,1.0f};
float[] nev={0.0f,0.0f,0.0f};
gl.glMaterialfv(GL.GL_FRONT,GL.GL_EMISSION,ev,0);
gl.glTranslatef(0.0f,0.0f,m_HeadSpread/5.0f);
glu.gluSphere(glpQ,m_TopR,nRound,nRound);
gl.glMaterialfv(GL.GL_FRONT,GL.GL_EMISSION,nev,0);
}
glu.gluSphere(glpQ,m_TopR,nRound,nRound);
Merk at bruken av GL_SPOT_EXPONENT som glatter kantene på spoten. Kombinert med oppløsningen på bordplate (og de andre lampene) gir dette oss bra kontroll over spoten. Begge deler, spoteksponenten og oppløsningen på bordplate, kan manipuleres i programmet. Se ogsp Module Skygge og glatting
