move spinning quad to touch point

assets/shaders/vertex.glsl

@@ -7,6 +7,6 @@ varying vec3 color_i;
 
 void main()
 {
-    gl_Position = projection * modelview * vec4(pos * 0.75, 1);
+    gl_Position = projection * modelview * vec4(pos, 1);
     color_i = color;
 }

src/com/homelinux/holtrop/opengltest/MyGLSurfaceView.java

@@ -3,15 +3,25 @@ package com.homelinux.holtrop.opengltest;
 import android.opengl.GLSurfaceView;
 import android.content.Context;
 import android.content.res.AssetManager;
+import android.view.MotionEvent;
 
 public class MyGLSurfaceView extends GLSurfaceView
 {
+    MyRenderer m_renderer;
+
     public MyGLSurfaceView(Context context, AssetManager am)
     {
         super(context);
 
         setEGLContextClientVersion(2);
 
-        setRenderer(new MyRenderer(am));
+        m_renderer = new MyRenderer(am);
+        setRenderer(m_renderer);
+    }
+
+    @Override
+    public boolean onTouchEvent(MotionEvent e)
+    {
+        return m_renderer.onTouchEvent(e);
     }
 }

src/com/homelinux/holtrop/opengltest/MyRenderer.java

@@ -16,6 +16,7 @@ import java.io.BufferedReader;
 import java.io.IOException;
 import android.opengl.Matrix;
 import android.os.SystemClock;
+import android.view.MotionEvent;
 
 public class MyRenderer implements GLSurfaceView.Renderer
 {
@@ -25,6 +26,10 @@ public class MyRenderer implements GLSurfaceView.Renderer
     private AssetManager m_asset_manager;
     private float m_proj_matrix[] = new float[16];
     private float m_modelview[] = new float[16];
+    private int m_width;
+    private int m_height;
+    private float m_x = 0.0f;
+    private float m_y = 0.0f;
 
     public MyRenderer(AssetManager am)
     {
@@ -119,7 +124,10 @@ public class MyRenderer implements GLSurfaceView.Renderer
 
         long time = SystemClock.uptimeMillis() % 4000L;
         float angle = 0.090f * ((int) time);
-        Matrix.setRotateM(m_modelview, 0, angle, 0, 0, 1);
+        Matrix.setIdentityM(m_modelview, 0);
+        Matrix.translateM(m_modelview, 0, m_x, m_y, 0);
+        Matrix.rotateM(m_modelview, 0, angle, 0, 0, 1);
+        Matrix.scaleM(m_modelview, 0, 0.2f, 0.2f, 0.2f);
         GLES20.glUniformMatrix4fv(
                 GLES20.glGetUniformLocation(m_program, "modelview"),
                 1, false, m_modelview, 0);
@@ -144,6 +152,9 @@ public class MyRenderer implements GLSurfaceView.Renderer
 
     public void onSurfaceChanged(GL10 unused, int width, int height)
     {
+        m_width = width;
+        m_height = height;
+
         GLES20.glViewport(0, 0, width, height);
 
         if (width < height)
@@ -164,4 +175,18 @@ public class MyRenderer implements GLSurfaceView.Renderer
                 GLES20.glGetUniformLocation(m_program, "projection"),
                 1, false, m_proj_matrix, 0);
     }
+
+    public boolean onTouchEvent(MotionEvent e)
+    {
+        if (e.getAction() == MotionEvent.ACTION_DOWN)
+        {
+            float x = (e.getX() / (float) m_width) * 2.0f - 1.0f;
+            float y = -((e.getY() / (float) m_height) * 2.0f - 1.0f);
+
+            m_x = x;
+            m_y = y;
+        }
+
+        return false;
+    }
 }