1 /*
2  * Copyright (C) 2019 The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 
17 package com.android.systemui.glwallpaper;
18 
19 import static android.opengl.GLES20.GL_FRAGMENT_SHADER;
20 import static android.opengl.GLES20.GL_VERTEX_SHADER;
21 import static android.opengl.GLES20.glAttachShader;
22 import static android.opengl.GLES20.glCompileShader;
23 import static android.opengl.GLES20.glCreateProgram;
24 import static android.opengl.GLES20.glCreateShader;
25 import static android.opengl.GLES20.glGetAttribLocation;
26 import static android.opengl.GLES20.glGetUniformLocation;
27 import static android.opengl.GLES20.glLinkProgram;
28 import static android.opengl.GLES20.glShaderSource;
29 import static android.opengl.GLES20.glUseProgram;
30 
31 import android.content.Context;
32 import android.content.res.Resources;
33 import android.util.Log;
34 
35 import java.io.BufferedReader;
36 import java.io.IOException;
37 import java.io.InputStreamReader;
38 
39 /**
40  * This class takes charge of linking shader codes and then return a handle for OpenGL ES program.
41  */
42 class ImageGLProgram {
43     private static final String TAG = ImageGLProgram.class.getSimpleName();
44 
45     private Context mContext;
46     private int mProgramHandle;
47 
ImageGLProgram(Context context)48     ImageGLProgram(Context context) {
49         mContext = context.getApplicationContext();
50     }
51 
loadShaderProgram(int vertexId, int fragmentId)52     private int loadShaderProgram(int vertexId, int fragmentId) {
53         final String vertexSrc = getShaderResource(vertexId);
54         final String fragmentSrc = getShaderResource(fragmentId);
55         final int vertexHandle = getShaderHandle(GL_VERTEX_SHADER, vertexSrc);
56         final int fragmentHandle = getShaderHandle(GL_FRAGMENT_SHADER, fragmentSrc);
57         return getProgramHandle(vertexHandle, fragmentHandle);
58     }
59 
getShaderResource(int shaderId)60     private String getShaderResource(int shaderId) {
61         Resources res = mContext.getResources();
62         StringBuilder code = new StringBuilder();
63 
64         try (BufferedReader reader = new BufferedReader(
65                 new InputStreamReader(res.openRawResource(shaderId)))) {
66             String nextLine;
67             while ((nextLine = reader.readLine()) != null) {
68                 code.append(nextLine).append("\n");
69             }
70         } catch (IOException | Resources.NotFoundException ex) {
71             Log.d(TAG, "Can not read the shader source", ex);
72             code = null;
73         }
74 
75         return code == null ? "" : code.toString();
76     }
77 
getShaderHandle(int type, String src)78     private int getShaderHandle(int type, String src) {
79         final int shader = glCreateShader(type);
80         if (shader == 0) {
81             Log.d(TAG, "Create shader failed, type=" + type);
82             return 0;
83         }
84         glShaderSource(shader, src);
85         glCompileShader(shader);
86         return shader;
87     }
88 
getProgramHandle(int vertexHandle, int fragmentHandle)89     private int getProgramHandle(int vertexHandle, int fragmentHandle) {
90         final int program = glCreateProgram();
91         if (program == 0) {
92             Log.d(TAG, "Can not create OpenGL ES program");
93             return 0;
94         }
95 
96         glAttachShader(program, vertexHandle);
97         glAttachShader(program, fragmentHandle);
98         glLinkProgram(program);
99         return program;
100     }
101 
useGLProgram(int vertexResId, int fragmentResId)102     boolean useGLProgram(int vertexResId, int fragmentResId) {
103         mProgramHandle = loadShaderProgram(vertexResId, fragmentResId);
104         glUseProgram(mProgramHandle);
105         return true;
106     }
107 
getAttributeHandle(String name)108     int getAttributeHandle(String name) {
109         return glGetAttribLocation(mProgramHandle, name);
110     }
111 
getUniformHandle(String name)112     int getUniformHandle(String name) {
113         return glGetUniformLocation(mProgramHandle, name);
114     }
115 }
116