6. GLSL -- HelloWorld

< 간단한 GLSL 예제 >

// Test.java
import javax.media.opengl.*;
import com.sun.opengl.util.*;

import java.awt.*;
import java.awt.event.*;

public class Test extends Frame{
    public Test(){
        this.setSize(400, 300);
        this.setTitle("Test1");

        GLCapabilities    glCaps=    new GLCapabilities();
        glCaps.setRedBits(8);
        glCaps.setBlueBits(8);
        glCaps.setGreenBits(8);
        glCaps.setAlphaBits(8);

        GLCanvas canvas=    new GLCanvas(glCaps);
        
        canvas.addGLEventListener(new Render());
        
        this.add(canvas);
        this.addWindowListener(new WindowAdapter(){
            public void windowClosing(WindowEvent we){
                System.exit(0);
            }
        });

        Animator anim=  new Animator(canvas);   //에니메이션 등록
        anim.start();                           //에니메이션 시작(GLEventListener 의 display(...) 지속적인 호출)
    }

    public static void main(String args[]){
        Test test=    new Test();
        test.setVisible(true);
    }
};

// Render.java
import javax.media.opengl.*;
import javax.media.opengl.glu.*;
import com.sun.opengl.util.*;

public class Render implements GLEventListener{
    private GL          gl;
    private GLU         glu=    new GLU();
    private GLUT        glut=   new GLUT();
    private GLSLUtil    glsl;

    //########################################################################################
    //# GLEventListener 클래스의 추상 메소드
    //########################################################################################
    public void display(GLAutoDrawable drawable){
        gl.glClear(GL.GL_COLOR_BUFFER_BIT | GL.GL_DEPTH_BUFFER_BIT);
        gl.glLoadIdentity();

        gl.glTranslatef(0, 0, -5);

        glut.glutSolidTeapot(1.0f);

        gl.glRasterPos3f(1.0f, 1.0f, 0.0f);                     //현재 perspective 이므로
                                                                //z값에 따라 위치가 달라진다.
        glut.glutBitmapString(GLUT.BITMAP_8_BY_13, "Hello~~ ");
    }

    //########################################################################################
    //# GLEventListener 클래스의 추상 메소드
    //########################################################################################
    public void displayChanged(GLAutoDrawable drawable, boolean modeChanged, boolean deviceChanged){

    }

    //########################################################################################
    //# GLEventListener 클래스의 추상 메소드
    //########################################################################################
    public void init(GLAutoDrawable drawable){
        gl=            drawable.getGL();
        glsl=          new GLSLUtil(gl);                     //#! GLSL 설정을 위한 클래스

         gl.glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
    }

    //########################################################################################
    //# GLEventListener 클래스의 추상 메소드
    //########################################################################################
    public void reshape(GLAutoDrawable drawable, int x, int y, int w, int h){
        gl.glMatrixMode(GL.GL_PROJECTION);
        gl.glLoadIdentity();

        gl.glViewport(0, -10, w, h);                                    //-10은 제목표시줄 두께

        glu.gluPerspective(45.0f, (float)w/(float)h, 1.0f, 60.0f);

        gl.glMatrixMode(GL.GL_MODELVIEW);
        gl.glLoadIdentity();
    }
};

// GLSLUtil.java
import javax.media.opengl.*;
import javax.media.opengl.glu.*;
import com.sun.opengl.util.*;

import java.io.*;

public class GLSLUtil{
    public GLSLUtil(GL gl){
        int vs= gl.glCreateShader(GL.GL_VERTEX_SHADER);             //vs 생성.
        int fs= gl.glCreateShader(GL.GL_FRAGMENT_SHADER);           //fs 생성.

        String  strVS=       readShaderFile("VertexShader.vs");     //파일 읽기.
        String  strFS=       readShaderFile("FragmentShader.fs");   //파일 읽기.

        String  strAryVS[]=  { strVS };                             //vs 배열 생성.
        String  strAryFS[]=  { strFS };                             //fs 배열 생성.

        int     intAryVS[]=  { strVS.length() };                    //vs 파일의 문자수.
        int     intAryFS[]=  { strFS.length() };                    //fx 파일의 문자수.

        gl.glShaderSource(vs, 1, strAryVS, intAryVS, 0);            //vs 컴파일 준비
         gl.glShaderSource(fs, 1, strAryFS, intAryFS, 0);            //fs 컴파일 준비

         gl.glCompileShader(vs);                                     //컴파일
         gl.glCompileShader(fs);                                     //컴파일

         int progID= gl.glCreateProgram();                           //prog 생성.

        gl.glAttachShader(progID, vs);                              //prog에 vs 적용
        gl.glAttachShader(progID, fs);                              //prog에 fs 적용

         gl.glLinkProgram(progID);                                   //링크
         gl.glUseProgram(progID);                                    //사용
    }

    //###############################################################################
    //# GLSL 파일을 읽어 들인다.
    //###############################################################################
    private String readShaderFile(String path){
        try{
            File        f=      new File(path);         //파일 객체 생성.
            FileReader  fr=     new FileReader( f );    //파일 리더 객체 생성.

            int         size=   (int)f.length();        //파일 크기 얻기.
            char        buf[]=  new char[size];         //파일 크기 만큼 버퍼 생성.
            int         len=    fr.read(buf);           //버퍼(buf)에 파일 내용 담음.
            
            fr.close();                                 //파일 닫기

            return new String(buf, 0, len);             //!! 파일 내용을 문자열로 변환하여 리턴.

        }catch(Exception e){
            System.err.println(e);
            System.exit(0);
        }

        return null;
    }


    public int getProgID(){      //프로그램 ID를 리턴.
        return progID;
    }
}

// VertexShader.vs
void main(){
	gl_Position=	ftransform();
}

// FragmentShader.fs
void main(){
	gl_FragColor = vec4(1.0,0.4,0.8,1.0);
}