openGL es2.0 创建和管理shader

桃扇骨 2022-08-06 17:27 139阅读 0赞

一、创建shader工具，Java代码如下：

package com.gzdxid.utils;
    
    import java.io.ByteArrayOutputStream;
    import java.io.InputStream;
    
    import android.content.res.Resources;
    import android.opengl.GLES20;
    import android.util.Log;
    
    public class ShaderUtil {
    	public static int loadShader(int shaderType, String source) {
    		int shader = GLES20.glCreateShader(shaderType);
    		if (shader != 0) {
    			GLES20.glShaderSource(shader, source);
    			GLES20.glCompileShader(shader);
    			int[] compiled = new int[1];
    			GLES20.glGetShaderiv(shader, GLES20.GL_COMPILE_STATUS, compiled, 0);
    			if (compiled[0] == 0) {
    				Log.e("ES20_ERROR", "Could not compile shader " + shaderType + ":");
    				Log.e("ES20_ERROR", GLES20.glGetShaderInfoLog(shader));
    				GLES20.glDeleteShader(shader);
    				shader = 0;
    			}
    		}
    		return shader;
    	}
    
    	public static int createProgram(String vertexSource, String fragmentSource) {
    		int vertexShader = loadShader(GLES20.GL_VERTEX_SHADER, vertexSource);
    		if (vertexShader == 0) {
    			return 0;
    		}
    
    		int pixelShader = loadShader(GLES20.GL_FRAGMENT_SHADER, fragmentSource);
    		if (pixelShader == 0) {
    			return 0;
    		}
    
    		int program = GLES20.glCreateProgram();
    		if (program != 0) {
    			GLES20.glAttachShader(program, vertexShader);
    			checkGlError("glAttachShader");
    			GLES20.glAttachShader(program, pixelShader);
    			checkGlError("glAttachShader");
    			GLES20.glLinkProgram(program);
    			int[] linkStatus = new int[1];
    			GLES20.glGetProgramiv(program, GLES20.GL_LINK_STATUS, linkStatus, 0);
    			if (linkStatus[0] != GLES20.GL_TRUE) {
    				Log.e("ES20_ERROR", "Could not link program: ");
    				Log.e("ES20_ERROR", GLES20.glGetProgramInfoLog(program));
    				GLES20.glDeleteProgram(program);
    				program = 0;
    			}
    		}
    		return program;
    	}
    
    	public static void checkGlError(String op) {
    		int error;
    		while ((error = GLES20.glGetError()) != GLES20.GL_NO_ERROR) {
    			Log.e("ES20_ERROR", op + ": glError " + error);
    			throw new RuntimeException(op + ": glError " + error);
    		}
    	}
    
    	public static String loadFromAssetsFile(String fname, Resources r) {
    		String result = null;
    		try {
    			InputStream in = r.getAssets().open(fname);
    			int ch = 0;
    			ByteArrayOutputStream baos = new ByteArrayOutputStream();
    			while ((ch = in.read()) != -1) {
    				baos.write(ch);
    			}
    			byte[] buff = baos.toByteArray();
    			baos.close();
    			in.close();
    			result = new String(buff, "UTF-8");
    			result = result.replaceAll("\\r\\n", "\n");
    		} catch (Exception e) {
    			e.printStackTrace();
    		}
    		return result;
    	}
    }

二、管理shader，Java代码如下：

package com.gzdxid.utils;
    
    import android.content.res.Resources;
    
    public class ShaderManager {
    	final static String[][] shaderName = { 
    		    { "sh_light_texture_v.sh", "sh_light_texture_f.sh" },// hexagon_shader
    			{ "sh_rect_color_v.sh", "sh_rect_color_f.sh" },// rectColor_shader
    			{ "sh_rect_texture_v.sh", "sh_rect_texture_f.sh" },// rectTexture_shader
    			{ "sh_rect_move_v.sh", "sh_rect_move_f.sh" },// rectMove_shader
    			{ "sh_light_color_v.sh", "sh_light_color_f.sh" }, 
    			{ "sh_particle_color_v.sh", "sh_particle_color_f.sh" }, 
    			{ "sh_grain_color_v.sh", "sh_grain_color_f.sh" } };
    	
    	static String[] mVertexShader = new String[shaderName.length];
    	static String[] mFragmentShader = new String[shaderName.length];
    	static int[] program = new int[shaderName.length];
    
    	public static void loadCodeFromFile(Resources r) {
    		for (int i = 0; i < shaderName.length; i++) {
    			mVertexShader[i] = ShaderUtil.loadFromAssetsFile(shaderName[i][0], r);
    			mFragmentShader[i] = ShaderUtil.loadFromAssetsFile(shaderName[i][1], r);
    		}
    	}
    
    	public static void compileShader() {
    		for (int i = 0; i < shaderName.length; i++) {
    			program[i] = ShaderUtil.createProgram(mVertexShader[i], mFragmentShader[i]);
    		}
    	}
    
    	public static int getLightTextureShaderProgram() {
    		return program[0];
    	}
    
    	public static int getOnlyColorShaderProgram() {
    		return program[1];
    	}
    
    	public static int getOnlyTextureShaderProgram() {
    		return program[2];
    	}
    
    	public static int getMoveTextureShaderProgram() {
    		return program[3];
    	}
    
    	public static int getLightColorShaderProgram() {
    		return program[4];
    	}
    
    	public static int getParticleColorShaderProgram() {
    		return program[5];
    	}
    
    	public static int getGrainColorShaderProgram() {
    		return program[6];
    	}
    
    }

三、应用

初始化程序时，首先调用ShaderManager.loadCodeFromFile(r)和ShaderManager.compileShader()。之后通过get等方法得到相应的渲染管线的程序，直接传给需要的object。当然ShaderName的二维数组存放assets文件里面的shader。我为了方便分类，shader都是以sh开头的，为了和其它类型文件分开。