1 /* 2 * Copyright (C) 2015 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.performanceLaunch.helper; 18 19 import java.nio.ByteBuffer; 20 import java.nio.ByteOrder; 21 import java.nio.FloatBuffer; 22 23 import android.opengl.GLES20; 24 25 /** 26 * A two-dimensional triangle for use as a drawn object in OpenGL ES 2.0. 27 * Source : development/samples/OpenGL/HelloOpenGLES20 28 */ 29 public class Triangle { 30 31 private final String vertexShaderCode = 32 // This matrix member variable provides a hook to manipulate 33 // the coordinates of the objects that use this vertex shader 34 "uniform mat4 uMVPMatrix;" + 35 "attribute vec4 vPosition;" + 36 "void main() {" + 37 // the matrix must be included as a modifier of gl_Position 38 // Note that the uMVPMatrix factor *must be first* in order 39 // for the matrix multiplication product to be correct. 40 " gl_Position = uMVPMatrix * vPosition;" + 41 "}"; 42 43 private final String fragmentShaderCode = 44 "precision mediump float;" + 45 "uniform vec4 vColor;" + 46 "void main() {" + 47 " gl_FragColor = vColor;" + 48 "}"; 49 50 private final FloatBuffer vertexBuffer; 51 private final int mProgram; 52 private int mPositionHandle; 53 private int mColorHandle; 54 private int mMVPMatrixHandle; 55 56 // number of coordinates per vertex in this array 57 static final int COORDS_PER_VERTEX = 3; 58 static float triangleCoords[] = { 59 // in counterclockwise order: 60 0.0f, 0.622008459f, 0.0f, // top 61 -0.5f, -0.311004243f, 0.0f, // bottom left 62 0.5f, -0.311004243f, 0.0f 63 // bottom right 64 }; 65 private final int vertexCount = triangleCoords.length / COORDS_PER_VERTEX; 66 private final int vertexStride = COORDS_PER_VERTEX * 4; // 4 bytes per vertex 67 68 float color[] = { 69 0.63671875f, 0.76953125f, 0.22265625f, 0.0f 70 }; 71 72 /** 73 * Sets up the drawing object data for use in an OpenGL ES context. 74 */ 75 public Triangle() { 76 // initialize vertex byte buffer for shape coordinates 77 ByteBuffer bb = ByteBuffer.allocateDirect( 78 // (number of coordinate values * 4 bytes per float) 79 triangleCoords.length * 4); 80 // use the device hardware's native byte order 81 bb.order(ByteOrder.nativeOrder()); 82 83 // create a floating point buffer from the ByteBuffer 84 vertexBuffer = bb.asFloatBuffer(); 85 // add the coordinates to the FloatBuffer 86 vertexBuffer.put(triangleCoords); 87 // set the buffer to read the first coordinate 88 vertexBuffer.position(0); 89 90 // prepare shaders and OpenGL program 91 int vertexShader = SimpleGLRenderer.loadShader( 92 GLES20.GL_VERTEX_SHADER, vertexShaderCode); 93 int fragmentShader = SimpleGLRenderer.loadShader( 94 GLES20.GL_FRAGMENT_SHADER, fragmentShaderCode); 95 96 mProgram = GLES20.glCreateProgram(); // create empty OpenGL Program 97 GLES20.glAttachShader(mProgram, vertexShader); // add the vertex shader to program 98 GLES20.glAttachShader(mProgram, fragmentShader); // add the fragment shader to program 99 GLES20.glLinkProgram(mProgram); // create OpenGL program executables 100 101 } 102 103 /** 104 * Encapsulates the OpenGL ES instructions for drawing this shape. 105 * 106 * @param mvpMatrix - The Model View Project matrix in which to draw this shape. 107 */ 108 public void draw(float[] mvpMatrix) { 109 // Add program to OpenGL environment 110 GLES20.glUseProgram(mProgram); 111 112 // get handle to vertex shader's vPosition member 113 mPositionHandle = GLES20.glGetAttribLocation(mProgram, "vPosition"); 114 115 // Enable a handle to the triangle vertices 116 GLES20.glEnableVertexAttribArray(mPositionHandle); 117 118 // Prepare the triangle coordinate data 119 GLES20.glVertexAttribPointer( 120 mPositionHandle, COORDS_PER_VERTEX, 121 GLES20.GL_FLOAT, false, 122 vertexStride, vertexBuffer); 123 124 // get handle to fragment shader's vColor member 125 mColorHandle = GLES20.glGetUniformLocation(mProgram, "vColor"); 126 127 // Set color for drawing the triangle 128 GLES20.glUniform4fv(mColorHandle, 1, color, 0); 129 130 // get handle to shape's transformation matrix 131 mMVPMatrixHandle = GLES20.glGetUniformLocation(mProgram, "uMVPMatrix"); 132 SimpleGLRenderer.checkGlError("glGetUniformLocation"); 133 134 // Apply the projection and view transformation 135 GLES20.glUniformMatrix4fv(mMVPMatrixHandle, 1, false, mvpMatrix, 0); 136 SimpleGLRenderer.checkGlError("glUniformMatrix4fv"); 137 138 // Draw the triangle 139 GLES20.glDrawArrays(GLES20.GL_TRIANGLES, 0, vertexCount); 140 141 // Disable vertex array 142 GLES20.glDisableVertexAttribArray(mPositionHandle); 143 } 144 145 } 146
