Sample code for OpenGL Android training class

( Original Id: Ib1650025a3c4b018c60d70ede3f25113660f68d8 )

Change-Id: I1d760b75d1f2bfe1ec90c71471867577bd146241

1 files changed, 166 insertions, 0 deletions

diff --git a/samples/OpenGL/HelloOpenGLES20/src/com/example/android/opengl/MyGLRenderer.java b/samples/OpenGL/HelloOpenGLES20/src/com/example/android/opengl/MyGLRenderer.java
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index 000000000..71f5b284e
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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 javax.microedition.khronos.egl.EGLConfig;
+import javax.microedition.khronos.opengles.GL10;
+
+import android.opengl.GLES20;
+import android.opengl.GLSurfaceView;
+import android.opengl.Matrix;
+import android.util.Log;
+
+/**
+ * Provides drawing instructions for a GLSurfaceView object. This class
+ * must override the OpenGL ES drawing lifecycle methods:
+ * <ul>
+ *   <li>{@link android.opengl.GLSurfaceView.Renderer#onSurfaceCreated}</li>
+ *   <li>{@link android.opengl.GLSurfaceView.Renderer#onDrawFrame}</li>
+ *   <li>{@link android.opengl.GLSurfaceView.Renderer#onSurfaceChanged}</li>
+ * </ul>
+ */
+public class MyGLRenderer implements GLSurfaceView.Renderer {
+
+    private static final String TAG = "MyGLRenderer";
+    private Triangle mTriangle;
+    private Square   mSquare;
+
+    // mMVPMatrix is an abbreviation for "Model View Projection Matrix"
+    private final float[] mMVPMatrix = new float[16];
+    private final float[] mProjectionMatrix = new float[16];
+    private final float[] mViewMatrix = new float[16];
+    private final float[] mRotationMatrix = new float[16];
+
+    private float mAngle;
+
+    @Override
+    public void onSurfaceCreated(GL10 unused, EGLConfig config) {
+
+        // Set the background frame color
+        GLES20.glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
+
+        mTriangle = new Triangle();
+        mSquare   = new Square();
+    }
+
+    @Override
+    public void onDrawFrame(GL10 unused) {
+        float[] scratch = new float[16];
+
+        // Draw background color
+        GLES20.glClear(GLES20.GL_COLOR_BUFFER_BIT | GLES20.GL_DEPTH_BUFFER_BIT);
+
+        // Set the camera position (View matrix)
+        Matrix.setLookAtM(mViewMatrix, 0, 0, 0, -3, 0f, 0f, 0f, 0f, 1.0f, 0.0f);
+
+        // Calculate the projection and view transformation
+        Matrix.multiplyMM(mMVPMatrix, 0, mProjectionMatrix, 0, mViewMatrix, 0);
+
+        // Draw square
+        mSquare.draw(mMVPMatrix);
+
+        // Create a rotation for the triangle
+
+        // Use the following code to generate constant rotation.
+        // Leave this code out when using TouchEvents.
+        // long time = SystemClock.uptimeMillis() % 4000L;
+        // float angle = 0.090f * ((int) time);
+
+        Matrix.setRotateM(mRotationMatrix, 0, mAngle, 0, 0, 1.0f);
+
+        // Combine the rotation matrix with the projection and camera view
+        // Note that the mMVPMatrix factor *must be first* in order
+        // for the matrix multiplication product to be correct.
+        Matrix.multiplyMM(scratch, 0, mMVPMatrix, 0, mRotationMatrix, 0);
+
+        // Draw triangle
+        mTriangle.draw(scratch);
+    }
+
+    @Override
+    public void onSurfaceChanged(GL10 unused, int width, int height) {
+        // Adjust the viewport based on geometry changes,
+        // such as screen rotation
+        GLES20.glViewport(0, 0, width, height);
+
+        float ratio = (float) width / height;
+
+        // this projection matrix is applied to object coordinates
+        // in the onDrawFrame() method
+        Matrix.frustumM(mProjectionMatrix, 0, -ratio, ratio, -1, 1, 3, 7);
+
+    }
+
+    /**
+     * Utility method for compiling a OpenGL shader.
+     *
+     * <p><strong>Note:</strong> When developing shaders, use the checkGlError()
+     * method to debug shader coding errors.</p>
+     *
+     * @param type - Vertex or fragment shader type.
+     * @param shaderCode - String containing the shader code.
+     * @return - Returns an id for the shader.
+     */
+    public static int loadShader(int type, String shaderCode){
+
+        // create a vertex shader type (GLES20.GL_VERTEX_SHADER)
+        // or a fragment shader type (GLES20.GL_FRAGMENT_SHADER)
+        int shader = GLES20.glCreateShader(type);
+
+        // add the source code to the shader and compile it
+        GLES20.glShaderSource(shader, shaderCode);
+        GLES20.glCompileShader(shader);
+
+        return shader;
+    }
+
+    /**
+    * Utility method for debugging OpenGL calls. Provide the name of the call
+    * just after making it:
+    *
+    * <pre>
+    * mColorHandle = GLES20.glGetUniformLocation(mProgram, "vColor");
+    * MyGLRenderer.checkGlError("glGetUniformLocation");</pre>
+    *
+    * If the operation is not successful, the check throws an error.
+    *
+    * @param glOperation - Name of the OpenGL call to check.
+    */
+    public static void checkGlError(String glOperation) {
+        int error;
+        while ((error = GLES20.glGetError()) != GLES20.GL_NO_ERROR) {
+            Log.e(TAG, glOperation + ": glError " + error);
+            throw new RuntimeException(glOperation + ": glError " + error);
+        }
+    }
+
+    /**
+     * Returns the rotation angle of the triangle shape (mTriangle).
+     *
+     * @return - A float representing the rotation angle.
+     */
+    public float getAngle() {
+        return mAngle;
+    }
+
+    /**
+     * Sets the rotation angle of the triangle shape (mTriangle).
+     */
+    public void setAngle(float angle) {
+        mAngle = angle;
+    }
+
+}
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