ShaderProgram.java

/**
 * Copyright (c) Lambda Innovation, 2013-2015
 * 本作品版权由Lambda Innovation所有。
 * http://www.li-dev.cn/
 *
 * This project is open-source, and it is distributed under
 * the terms of GNU General Public License. You can modify
 * and distribute freely as long as you follow the license.
 * 本项目是一个开源项目，且遵循GNU通用公共授权协议。
 * 在遵照该协议的情况下，您可以自由传播和修改。
 * http://www.gnu.org/licenses/gpl.html
 */
package cn.liutils.util.client.shader;

import static org.lwjgl.opengl.GL11.*;
import static org.lwjgl.opengl.GL20.*;
import java.io.IOException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import org.apache.commons.io.IOUtils;

import cn.liutils.core.LIUtils;
import cn.liutils.util.generic.RegistryUtils;
import cpw.mods.fml.relauncher.Side;
import cpw.mods.fml.relauncher.SideOnly;
import net.minecraft.util.ResourceLocation;

/**
 * A simple GL Shader Program wrapper.
 * @author WeAthFolD
 */
@SideOnly(Side.CLIENT)
public class ShaderProgram {
    
    static Map<ResourceLocation, Integer> loadedShaders = new HashMap();
    public static void releaseResources() {
        for(Integer e : loadedShaders.values())
            glDeleteShader(e);
        loadedShaders.clear();
    }
    
    private boolean compiled = false;
    private int programID;
    private List<Integer> attachedShaders = new ArrayList();
    
    public ShaderProgram() {
        programID = glCreateProgram();
    }
    
    public void linkShader(ResourceLocation location, int type) {
        try {
            int shaderID;
            if(loadedShaders.containsKey(location)) {
                shaderID = loadedShaders.get(location);
            } else {
                String str = IOUtils.toString(RegistryUtils.getResourceStream(location));
                shaderID = glCreateShader(type);
                glShaderSource(shaderID, str);
                glCompileShader(shaderID);
                
                int successful = glGetShaderi(shaderID, GL_COMPILE_STATUS);
                if(successful == GL_FALSE) {
                    String log = glGetShaderInfoLog(shaderID, glGetShaderi(shaderID, GL_INFO_LOG_LENGTH));
                    LIUtils.log.error("Error when linking shader '" + location + "'. code: " + successful + ", Error string: \n" + log);
                    throw new RuntimeException();
                }
            }
            
            attachedShaders.add(shaderID);
            glAttachShader(programID, shaderID);
        } catch (IOException e) {
            LIUtils.log.error("Error when linking shader " + location, e);
            throw new RuntimeException();
        }
    }
    
    public int getProgramID() {
        return programID;
    }
    
    public void useProgram() {
        if(compiled) {
            glUseProgram(programID);
        } else {
            LIUtils.log.error("Trying to use a uncompiled program");
            throw new RuntimeException();
        }
    }
    
    public int getUniformLocation(String name) {
        return glGetUniformLocation(getProgramID(), name);
    }
    
    public void compile() {
        if(compiled) {
            LIUtils.log.error("Trying to compile shader " + this + " twice.");
            throw new RuntimeException();
        }
        
        glLinkProgram(programID);
        
        for(Integer i : attachedShaders)
            glDetachShader(programID, i);
        attachedShaders = null;
        
        int status = glGetProgrami(programID, GL_LINK_STATUS);
        if(status == GL_FALSE) {
            String log = glGetProgramInfoLog(programID, glGetProgrami(programID, GL_INFO_LOG_LENGTH));
            LIUtils.log.error("Error when linking program #" + programID + ". Error code: " + status + ", Error string: ");
            LIUtils.log.error(log);
            throw new RuntimeException();
        }
        
        compiled = true;
    }
    
    /**
     * Get the src of a shader in liutils namespace.
     * @param name
     * @return
     */
    public static ResourceLocation getShader(String name) {
        return new ResourceLocation("liutils:shaders/" + name);
    }
    
}