Slick Forums

import org.newdawn.slick.AppGameContainer;
import org.newdawn.slick.BasicGame;
import org.newdawn.slick.GameContainer;
import org.newdawn.slick.Graphics;
import org.newdawn.slick.Image;
import org.newdawn.slick.SlickException;

public class Program extends BasicGame {

   
   private Image image = null;
   private Shader shader;

   public Program(String title) {
      super(title);
   }

   public void init(GameContainer container) throws SlickException {
      try {
         image = new Image("data/test.png");
      } catch (SlickException e) {
         e.printStackTrace();
      }
      
      shader = new Shader("data/shader/test");
   }

   public void update(GameContainer container, int delta) throws SlickException {
      
   }

   public void render(GameContainer container, Graphics g) throws SlickException {
      
      g.drawString("Fixed pipeline:", 10f, 216f);
      g.drawString("Shader:", 148f, 216f);
      
      g.drawImage(image, 10f, 236.0f);
      //g.drawImage(image, 148f, 236.0f);
      shader.render(image, 148f, 236f);
   }
   
   
   public static void main(String[] args) {
      try {
         AppGameContainer container = new AppGameContainer(new Program("Shader Test"));
         container.setDisplayMode(800, 600, false);
         container.start();
      } catch (SlickException e) {
         e.printStackTrace();
      }
   }
}

import java.io.DataInputStream;
import java.io.FileInputStream;
import java.io.InputStream;
import java.nio.ByteBuffer;

import org.lwjgl.BufferUtils;
import org.lwjgl.opengl.ARBFragmentShader;
import org.lwjgl.opengl.ARBShaderObjects;
import org.lwjgl.opengl.ARBVertexShader;
import org.lwjgl.opengl.GL11;
import org.newdawn.slick.Image;

public class Shader {

   protected int shaderProgramId = -1;
   protected int vertexShaderId = -1;
   protected int fragmentShaderId = -1;
   
   protected int locationBaseTexture = -1;
   
   /** Basic Shader object */
   public Shader (String filename) {
      
      vertexShaderId = ARBShaderObjects.glCreateShaderObjectARB(ARBVertexShader.GL_VERTEX_SHADER_ARB);
      ARBShaderObjects.glShaderSourceARB(vertexShaderId, getProgramCode(filename + ".vert"));
      ARBShaderObjects.glCompileShaderARB(vertexShaderId);
      
      fragmentShaderId = ARBShaderObjects.glCreateShaderObjectARB(ARBFragmentShader.GL_FRAGMENT_SHADER_ARB);
      ARBShaderObjects.glShaderSourceARB(fragmentShaderId, getProgramCode(filename + ".frag"));
      ARBShaderObjects.glCompileShaderARB(fragmentShaderId);
      
      shaderProgramId = ARBShaderObjects.glCreateProgramObjectARB();
      ARBShaderObjects.glAttachObjectARB(shaderProgramId, vertexShaderId);
      ARBShaderObjects.glAttachObjectARB(shaderProgramId, fragmentShaderId);
      
      ARBShaderObjects.glLinkProgramARB(shaderProgramId);
      
      ARBShaderObjects.glUseProgramObjectARB(shaderProgramId);
      locationBaseTexture = ARBShaderObjects.glGetUniformLocationARB(shaderProgramId, toByteString("baseTexture"));
      ARBShaderObjects.glUseProgramObjectARB(0);
   }
   
   public void render(Image image, float x, float y) {
      ARBShaderObjects.glUseProgramObjectARB(shaderProgramId);
      GL11.glBegin(GL11.GL_QUADS);
         image.drawEmbedded(x, y, image.getWidth(), image.getHeight());
      GL11.glEnd();
      ARBShaderObjects.glUseProgramObjectARB(0);
   }
   
   // helper function from: http://lwjgl.org/wiki/doku.php/lwjgl/tutorials/opengl/basicshaders
   private ByteBuffer getProgramCode(String filename) {
      
      InputStream fileInputStream = null;
      byte[] shaderCode = null;

      try
      {
         if (fileInputStream == null)
               fileInputStream = new FileInputStream(filename);
         DataInputStream dataStream = new DataInputStream(fileInputStream);
         dataStream.readFully(shaderCode = new byte[ fileInputStream.available() ]);
         fileInputStream.close();
         dataStream.close();
      }
      catch (Exception e)
      {
         System.out.println(e.getMessage());
      }
      ByteBuffer shaderPro = BufferUtils.createByteBuffer(shaderCode.length);

      shaderPro.put(shaderCode);
      shaderPro.flip();

      return shaderPro;
   }
   
   
   // see above
   private ByteBuffer toByteString(String str, boolean isNullTerminated) {
      int length = str.length();
      if (isNullTerminated)
         length++;
      ByteBuffer buff = BufferUtils.createByteBuffer(length);
      buff.put( str.getBytes() );

      if (isNullTerminated)
         buff.put( (byte)0 );

      buff.flip();
      return buff;
   }
   
   private ByteBuffer toByteString(String str) {
      return toByteString(str, true);
   }
   
}