eu.over9000.veya.rendering.Program.java Source code

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Here is the source code for eu.over9000.veya.rendering.Program.java

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/*
 * Veya
 * Copyright (C) 2015 s1mpl3x
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License along
 *  with this program; if not, write to the Free Software Foundation, Inc.,
 *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */

package eu.over9000.veya.rendering;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.HashMap;
import java.util.Map;

import org.lwjgl.opengl.GL11;
import org.lwjgl.opengl.GL20;
import org.lwjgl.opengl.OpenGLException;
import org.lwjgl.opengl.Util;

public class Program {
    private final int id;
    private final Map<String, Integer> uniformLocations;

    public Program(final String shaderName, final String[] uniformNames) {
        final int vsID = Program.loadShader(
                Program.class.getResourceAsStream("/shaders/" + shaderName + "/vertex.glsl"),
                GL20.GL_VERTEX_SHADER);
        final int fsID = Program.loadShader(
                Program.class.getResourceAsStream("/shaders/" + shaderName + "/fragment.glsl"),
                GL20.GL_FRAGMENT_SHADER);

        this.id = GL20.glCreateProgram();
        GL20.glAttachShader(this.id, vsID);
        GL20.glAttachShader(this.id, fsID);

        GL20.glLinkProgram(this.id);
        Program.checkLinkage(this.id);

        //GL20.glValidateProgram(this.id);
        //Program.checkValidation(this.id);

        GL20.glDetachShader(this.id, vsID);
        GL20.glDetachShader(this.id, fsID);

        GL20.glDeleteShader(vsID);
        GL20.glDeleteShader(fsID);

        this.uniformLocations = new HashMap<>(uniformNames.length + 1, 1);
        for (final String name : uniformNames) {
            final int loc = GL20.glGetUniformLocation(this.id, name);
            this.uniformLocations.put(name, loc);
            System.out.println("UniformLoc for " + name + "=" + loc);
        }

        Util.checkGLError();
    }

    public void use(final boolean use) {
        if (use) {
            GL20.glUseProgram(this.id);
        } else {
            GL20.glUseProgram(0);
        }
    }

    public void unload() {
        GL20.glDeleteProgram(this.id);
    }

    public int getUniformLocation(final String name) {
        return this.uniformLocations.get(name);
    }

    private static int loadShader(final InputStream inputStream, final int type) {
        final StringBuilder builder = new StringBuilder();

        try (BufferedReader reader = new BufferedReader(new InputStreamReader(inputStream))) {
            String line;
            while ((line = reader.readLine()) != null) {
                builder.append(line).append("\n");
            }
            reader.close();
        } catch (final IOException e) {
            e.printStackTrace();
            System.exit(2);
        }

        final int shaderID = GL20.glCreateShader(type);
        GL20.glShaderSource(shaderID, builder);
        GL20.glCompileShader(shaderID);

        Program.checkCompilation(shaderID);

        return shaderID;
    }

    private static void checkValidation(final int programID) {
        final int error = GL20.glGetProgrami(programID, GL20.GL_VALIDATE_STATUS);
        if (error == GL11.GL_FALSE) {
            throw new OpenGLException(
                    GL20.glGetProgramInfoLog(programID, GL20.glGetProgrami(programID, GL20.GL_INFO_LOG_LENGTH)));
        } else {
            System.out.println("Shader Validation OK");
        }
    }

    private static void checkCompilation(final int shaderID) {
        final int error = GL20.glGetShaderi(shaderID, GL20.GL_COMPILE_STATUS);
        if (error == GL11.GL_FALSE) {
            throw new OpenGLException(
                    GL20.glGetShaderInfoLog(shaderID, GL20.glGetShaderi(shaderID, GL20.GL_INFO_LOG_LENGTH)));
        } else {
            System.out.println("Shader Compilation OK");
        }
    }

    private static void checkLinkage(final int programID) {
        final int error = GL20.glGetProgrami(programID, GL20.GL_LINK_STATUS);
        if (error == GL11.GL_FALSE) {
            throw new OpenGLException(
                    GL20.glGetProgramInfoLog(programID, GL20.glGetProgrami(programID, GL20.GL_INFO_LOG_LENGTH)));
        } else {
            System.out.println("Shader Linkage OK");
        }
    }
}