Sample code for OpenGL Android training class

( Original Id: Ib1650025a3c4b018c60d70ede3f25113660f68d8 )

Change-Id: I1d760b75d1f2bfe1ec90c71471867577bd146241

1 files changed, 85 insertions, 0 deletions

diff --git a/samples/OpenGL/HelloOpenGLES10/src/com/example/android/opengl/Triangle.java b/samples/OpenGL/HelloOpenGLES10/src/com/example/android/opengl/Triangle.java
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index 000000000..e207f9281
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+++ b/samples/OpenGL/HelloOpenGLES10/src/com/example/android/opengl/Triangle.java
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+/*
+ * Copyright (C) 2011 The Android Open Source Project
+ *
+ * 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.example.android.opengl;
+
+import java.nio.ByteBuffer;
+import java.nio.ByteOrder;
+import java.nio.FloatBuffer;
+
+import javax.microedition.khronos.opengles.GL10;
+
+/**
+ * A two-dimensional triangle for use as a drawn object in OpenGL ES 1.0/1.1.
+ */
+public class Triangle {
+
+    private final FloatBuffer vertexBuffer;
+
+    // number of coordinates per vertex in this array
+    static final int COORDS_PER_VERTEX = 3;
+    static float triangleCoords[] = {
+            // in counterclockwise order:
+            0.0f,  0.622008459f, 0.0f,// top
+           -0.5f, -0.311004243f, 0.0f,// bottom left
+            0.5f, -0.311004243f, 0.0f // bottom right
+    };
+
+    float color[] = { 0.63671875f, 0.76953125f, 0.22265625f, 0.0f };
+
+    /**
+     * Sets up the drawing object data for use in an OpenGL ES context.
+     */
+    public Triangle() {
+        // initialize vertex byte buffer for shape coordinates
+        ByteBuffer bb = ByteBuffer.allocateDirect(
+                // (number of coordinate values * 4 bytes per float)
+                triangleCoords.length * 4);
+        // use the device hardware's native byte order
+        bb.order(ByteOrder.nativeOrder());
+
+        // create a floating point buffer from the ByteBuffer
+        vertexBuffer = bb.asFloatBuffer();
+        // add the coordinates to the FloatBuffer
+        vertexBuffer.put(triangleCoords);
+        // set the buffer to read the first coordinate
+        vertexBuffer.position(0);
+    }
+
+    /**
+     * Encapsulates the OpenGL ES instructions for drawing this shape.
+     *
+     * @param gl - The OpenGL ES context in which to draw this shape.
+     */
+    public void draw(GL10 gl) {
+        // Since this shape uses vertex arrays, enable them
+        gl.glEnableClientState(GL10.GL_VERTEX_ARRAY);
+
+        // draw the shape
+        gl.glColor4f(       // set color:
+                color[0], color[1],
+                color[2], color[3]);
+        gl.glVertexPointer( // point to vertex data:
+                COORDS_PER_VERTEX,
+                GL10.GL_FLOAT, 0, vertexBuffer);
+        gl.glDrawArrays(    // draw shape:
+                GL10.GL_TRIANGLES, 0,
+                triangleCoords.length / COORDS_PER_VERTEX);
+
+        // Disable vertex array drawing to avoid
+        // conflicts with shapes that don't use it
+        gl.glDisableClientState(GL10.GL_VERTEX_ARRAY);
+    }
+}