| /* |
| * Copyright 2018 Google LLC All Rights Reserved. |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| package com.google.skar.examples.helloskar.rendering; |
| |
| import android.content.Context; |
| import android.opengl.GLES20; |
| import android.util.Log; |
| |
| import java.io.BufferedReader; |
| import java.io.IOException; |
| import java.io.InputStream; |
| import java.io.InputStreamReader; |
| |
| /** |
| * Shader helper functions. |
| */ |
| public class ShaderUtil { |
| /** |
| * Converts a raw text file, saved as a resource, into an OpenGL ES shader. |
| * |
| * @param type The type of shader we will be creating. |
| * @param filename The filename of the asset file about to be turned into a shader. |
| * @return The shader object handler. |
| */ |
| public static int loadGLShader(String tag, Context context, int type, String filename) |
| throws IOException { |
| String code = readRawTextFileFromAssets(context, filename); |
| int shader = GLES20.glCreateShader(type); |
| GLES20.glShaderSource(shader, code); |
| GLES20.glCompileShader(shader); |
| |
| // Get the compilation status. |
| final int[] compileStatus = new int[1]; |
| GLES20.glGetShaderiv(shader, GLES20.GL_COMPILE_STATUS, compileStatus, 0); |
| |
| // If the compilation failed, delete the shader. |
| if (compileStatus[0] == 0) { |
| Log.e(tag, "Error compiling shader: " + GLES20.glGetShaderInfoLog(shader)); |
| GLES20.glDeleteShader(shader); |
| shader = 0; |
| } |
| |
| if (shader == 0) { |
| throw new RuntimeException("Error creating shader."); |
| } |
| |
| return shader; |
| } |
| |
| /** |
| * Checks if we've had an error inside of OpenGL ES, and if so what that error is. |
| * |
| * @param label Label to report in case of error. |
| * @throws RuntimeException If an OpenGL error is detected. |
| */ |
| public static void checkGLError(String tag, String label) { |
| int lastError = GLES20.GL_NO_ERROR; |
| // Drain the queue of all errors. |
| int error; |
| while ((error = GLES20.glGetError()) != GLES20.GL_NO_ERROR) { |
| Log.e(tag, label + ": glError " + error); |
| lastError = error; |
| } |
| if (lastError != GLES20.GL_NO_ERROR) { |
| throw new RuntimeException(label + ": glError " + lastError); |
| } |
| } |
| |
| /** |
| * Converts a raw text file into a string. |
| * |
| * @param filename The filename of the asset file about to be turned into a shader. |
| * @return The context of the text file, or null in case of error. |
| */ |
| private static String readRawTextFileFromAssets(Context context, String filename) |
| throws IOException { |
| try (InputStream inputStream = context.getAssets().open(filename); |
| BufferedReader reader = new BufferedReader(new InputStreamReader(inputStream))) { |
| StringBuilder sb = new StringBuilder(); |
| String line; |
| while ((line = reader.readLine()) != null) { |
| sb.append(line).append("\n"); |
| } |
| return sb.toString(); |
| } |
| } |
| } |