package demos.dualDepthPeeling;


// Translated from C++ Version see below:
//
// GLSLProgramObject.h - Wrapper for GLSL program objects
//
// Author: Louis Bavoil
// Email: sdkfeedback@nvidia.com
//
// Copyright (c) NVIDIA Corporation. All rights reserved.
////////////////////////////////////////////////////////////////////////////////

import java.io.BufferedReader;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.Vector;

import javax.media.opengl.GL2;

import java.net.URL;

public class GLSLProgramObject
{
	public GLSLProgramObject()
	{
		_progId = 0;
	}

	public void destroy(GL2 gl)
	{
		for (int i = 0; i < _vertexShaders.size(); i++) {
			gl.glDeleteShader(_vertexShaders.elementAt(i));
		}
		for (int i = 0; i < _fragmentShaders.size(); i++) {
			gl.glDeleteShader(_fragmentShaders.elementAt(i));
		}
		if (_progId != 0) {
			gl.glDeleteProgram(_progId);
		}
	}


	public void bind(GL2 gl)
	{
		gl.glUseProgram(_progId);
	}


	public void unbind(GL2 gl)
	{
		gl.glUseProgram(0);
	}


	public void setUniform(GL2 gl, String name, float[] val, int count)
	{
		int id = gl.glGetUniformLocation(_progId, name );
		if (id == -1) {
			System.err.println( "Warning: Invalid uniform parameter " + name ) ;
			return;
		}
		switch (count) {
		case 1:
			gl.glUniform1fv(id, 1, val, 0);
			break;
		case 2:
			gl.glUniform2fv(id, 1, val, 0);
			break;
		case 3:
			gl.glUniform3fv(id, 1, val, 0);
			break;
		case 4:
			gl.glUniform4fv(id, 1, val, 0);
			break;
		}
	}


	public void setTextureUnit(GL2 gl, String texname, int texunit)
	{
		int[] params = new int[]{0};
		gl.glGetProgramiv( _progId, GL2.GL_LINK_STATUS, params, 0);
		if ( params[0] != 1 ) {
			System.err.println( "Error: setTextureUnit needs program to be linked.");
		}
		int id = gl.glGetUniformLocation(_progId, texname );
		if (id == -1) {
			System.err.println( "Warning: Invalid texture " + texname );
			return;
		}
		gl.glUniform1i(id, texunit);
	}


	public void bindTexture(GL2 gl, int target,String texname, int texid, int texunit)
	{
		gl.glActiveTexture(GL2.GL_TEXTURE0 + texunit);
		gl.glBindTexture(target, texid);
		setTextureUnit(gl, texname, texunit);
		gl.glActiveTexture(GL2.GL_TEXTURE0);
	}


	public void bindTexture2D(GL2 gl, String texname, int texid, int texunit) {
		bindTexture(gl, GL2.GL_TEXTURE_2D, texname, texid, texunit);
	}

	public void bindTexture3D(GL2 gl, String texname, int texid, int texunit) {
		bindTexture(gl, GL2.GL_TEXTURE_3D, texname, texid, texunit);
	}

	public void bindTextureRECT(GL2 gl, String texname, int texid, int texunit) {
		bindTexture(gl, GL2.GL_TEXTURE_RECTANGLE_ARB, texname, texid, texunit);
	}

	public void attachVertexShader(GL2 gl, String filename)
	{
		URL fileURL = getClass().getClassLoader().getResource(
				File.separator + "demos" +
				File.separator + "dualDepthPeeling" +
				File.separator + "shaders" + File.separator + filename);
		if ( fileURL != null )
		{
			String content = "";
			BufferedReader input = null;
			try {

				input = new BufferedReader(new InputStreamReader(fileURL.openStream()));
				String line = null;

				while ( (line = input.readLine()) != null) {
					content += line + "\n";
				}
			} catch (FileNotFoundException kFNF) {
				System.err.println("Unable to find the shader file " + filename);
			} catch (IOException kIO) {
				System.err.println("Problem reading the shader file " + filename);
			} finally {
				try {
					if (input != null) {
						input.close();
					}
				} catch (IOException closee) {}
			}


			int iID = gl.glCreateShader( GL2.GL_VERTEX_SHADER );

			String[] akProgramText = new String[1];
			// find and replace program name with "main"
			akProgramText[0] = content;

			int[] params = new int[]{0};

			int[] aiLength = new int[1];
			aiLength[0] = akProgramText[0].length();
			int iCount = 1;
			gl.glShaderSource( iID, iCount, akProgramText, aiLength, 0);
			gl.glCompileShader(iID);            
			gl.glGetShaderiv( iID, GL2.GL_COMPILE_STATUS, params, 0);
			if ( params[0] != 1 )
			{
				System.err.println(filename);
				System.err.println("compile status: " + params[0]);
				gl.glGetShaderiv( iID, GL2.GL_INFO_LOG_LENGTH, params, 0);
				System.err.println("log length: " + params[0]);
				byte[] abInfoLog = new byte[params[0]];
				gl.glGetShaderInfoLog(iID, params[0], params, 0, abInfoLog, 0);
				System.err.println( new String(abInfoLog) );
				System.exit(-1);
			}
			_vertexShaders.add(iID);
		}
		else
		{
			System.err.println("Unable to find the shader file " + filename);
		}        
	}

	public void attachFragmentShader(GL2 gl, String filename)
	{
		URL fileURL = getClass().getClassLoader().getResource(
				File.separator + "demos" +
				File.separator + "dualDepthPeeling" +
				File.separator + "shaders" + File.separator + filename);
		if ( fileURL != null )
		{
			String content = "";
			BufferedReader input = null;
			try {

				input = new BufferedReader(new InputStreamReader(fileURL.openStream()));
				String line = null;

				while ( (line = input.readLine()) != null) {
					content += line + "\n";
				}
			} catch (FileNotFoundException kFNF) {
				System.err.println("Unable to find the shader file " + filename);
			} catch (IOException kIO) {
				System.err.println("Problem reading the shader file " + filename);
			} finally {
				try {
					if (input != null) {
						input.close();
					}
				} catch (IOException closee) {}
			}


			int iID = gl.glCreateShader( GL2.GL_FRAGMENT_SHADER );

			String[] akProgramText = new String[1];
			// find and replace program name with "main"
			akProgramText[0] = content;

			int[] params = new int[]{0};

			int[] aiLength = new int[1];
			aiLength[0] = akProgramText[0].length();
			int iCount = 1;
			gl.glShaderSource( iID, iCount, akProgramText, aiLength, 0);
			gl.glCompileShader(iID);            
			gl.glGetShaderiv( iID, GL2.GL_COMPILE_STATUS, params, 0);
			if ( params[0] != 1 )
			{
				System.err.println(filename);
				System.err.println("compile status: " + params[0]);
				gl.glGetShaderiv( iID, GL2.GL_INFO_LOG_LENGTH, params, 0);
				System.err.println("log length: " + params[0]);
				byte[] abInfoLog = new byte[params[0]];
				gl.glGetShaderInfoLog(iID, params[0], params, 0, abInfoLog, 0);
				System.err.println( new String(abInfoLog) );
				System.exit(-1);
			}
			_fragmentShaders.add(iID);
		}
		else
		{
			System.err.println("Unable to find the shader file " + filename);
		}        
	}


	public void link(GL2 gl)
	{
		_progId = gl.glCreateProgram();

		for (int i = 0; i < _vertexShaders.size(); i++) {
			gl.glAttachShader(_progId, _vertexShaders.elementAt(i));
		}

		for (int i = 0; i < _fragmentShaders.size(); i++) {
			gl.glAttachShader(_progId, _fragmentShaders.elementAt(i));
		}

		gl.glLinkProgram(_progId);

		int[] params = new int[]{0};
		gl.glGetProgramiv( _progId, GL2.GL_LINK_STATUS, params, 0);

		if (params[0] != 1) {

			System.err.println("link status: " + params[0]);
			gl.glGetProgramiv( _progId, GL2.GL_INFO_LOG_LENGTH, params, 0);
			System.err.println("log length: " + params[0]);

			byte[] abInfoLog = new byte[params[0]];
			gl.glGetProgramInfoLog(_progId, params[0], params, 0, abInfoLog, 0);
			System.err.println( new String(abInfoLog) );      
		}
	}


	public Integer getProgId() { return _progId; }

	protected Vector<Integer> _vertexShaders = new Vector<Integer>();
	protected Vector<Integer> _fragmentShaders = new Vector<Integer>();
	protected Integer _progId;
};