new plotter

android-app-core/res/values/text_strings.xml

@@ -282,5 +282,6 @@
     <string name="cpp_onscreen_remove_icon_message">You can remove second icon in applications\' list from application settings or by pressing next button</string>
     <string name="cpp_onscreen_remove_icon_button_text">Remove icon</string>
     <string name="cpp_this_change_may_require_reboot">This change may require reboot</string>
+    <string name="cpp_plot_3d">3D</string>
 
 </resources>

android-app-core/src/main/java/org/solovyev/android/calculator/CalculatorDisplayMenuItem.java

@@ -85,7 +85,13 @@ public enum CalculatorDisplayMenuItem implements LabeledMenuItem<CalculatorDispl
             assert generic != null;
 
             final List<Constant> variables = new ArrayList<Constant>(CalculatorUtils.getNotSystemConstants(generic));
-            final Constant xVariable = variables.get(0);
+
+            final Constant xVariable;
+            if ( variables.size() > 0 ) {
+                xVariable = variables.get(0);
+            } else {
+                xVariable = null;
+            }
 
             final Constant yVariable;
             if ( variables.size() > 1 ) {

android-app-core/src/main/java/org/solovyev/android/calculator/plot/PlotInput.java

@@ -15,7 +15,7 @@ public class PlotInput {
     @NotNull
     private Generic function;
 
-    @NotNull
+    @Nullable
     private Constant xVariable;
 
     @Nullable
@@ -26,7 +26,7 @@ public class PlotInput {
 
     @NotNull
     public static PlotInput newInstance(@NotNull Generic function,
-                                        @NotNull Constant xVariable,
+                                        @Nullable  Constant xVariable,
                                         @Nullable Constant yVariable) {
         PlotInput result = new PlotInput();
 
@@ -42,7 +42,7 @@ public class PlotInput {
         return function;
     }
 
-    @NotNull
+    @Nullable
     public Constant getXVariable() {
         return xVariable;
     }

android-app/res/menu/plot_menu.xml

@@ -8,8 +8,14 @@
 
 <menu xmlns:a="http://schemas.android.com/apk/res/android">
 
+    <item a:id="@+id/menu_plot_3d"
+        a:title="@string/cpp_plot_3d"
+        a:icon="@drawable/ab_icon"
+        a:showAsAction="always"/>
+
 	<item a:id="@+id/menu_plot_settings"
 		  a:title="@string/c_settings"
           a:icon="@drawable/ab_settings"
           a:showAsAction="always"/>
+
 </menu>

android-app/src/main/java/org/solovyev/android/calculator/AndroidCalculatorNotifier.java

@@ -48,9 +48,9 @@ public class AndroidCalculatorNotifier implements CalculatorNotifier {
 
     @Override
     public void showDebugMessage(@Nullable final String tag, @NotNull final String message) {
-        /*if (AndroidUtils.isDebuggable(application)) {
+        if (AndroidUtils.isDebuggable(application)) {
             showMessageInUiThread(tag == null ? message : tag + ": " + message);
-        }*/
+        }
     }
 
     private void showMessageInUiThread(@NotNull final String message) {

android-app/src/main/java/org/solovyev/android/calculator/CalculatorActivityLauncher.java

@@ -102,11 +102,11 @@ public final class CalculatorActivityLauncher implements CalculatorEventListener
 
 	public static void plotGraph(@NotNull final Context context,
                                  @NotNull Generic generic,
-                                 @NotNull Constant xVariable,
+                                 @Nullable  Constant xVariable,
                                  @Nullable Constant yVariable){
 		final Intent intent = new Intent();
 		intent.putExtra(ChartFactory.TITLE, context.getString(R.string.c_graph));
-        final AbstractCalculatorPlotFragment.Input input = new CalculatorPlotFragment.Input(generic.toString(), xVariable.getName(), yVariable == null ? null : yVariable.getName());
+        final AbstractCalculatorPlotFragment.Input input = new CalculatorPlotFragment.Input(generic.toString(), xVariable == null ? null : xVariable.getName(), yVariable == null ? null : yVariable.getName());
         intent.putExtra(CalculatorPlotFragment.INPUT, input);
 		intent.setClass(context, CalculatorPlotActivity.class);
         AndroidUtils2.addFlags(intent, false, context);

android-app/src/main/java/org/solovyev/android/calculator/plot/AbstractCalculatorPlotFragment.java

@@ -75,7 +75,7 @@ public abstract class AbstractCalculatorPlotFragment extends CalculatorFragment
     private PreparedInput preparedInput;
 
     @NotNull
-    private ActivityMenu<Menu, MenuItem> fragmentMenu = ListActivityMenu.fromResource(R.menu.plot_menu, PlotMenu.class, SherlockMenuHelper.getInstance());
+    private ActivityMenu<Menu, MenuItem> fragmentMenu;
 
     // thread which calculated data for graph view
     @NotNull
@@ -150,8 +150,14 @@ public abstract class AbstractCalculatorPlotFragment extends CalculatorFragment
                 final CalculatorEventHolder.Result result = this.lastEventHolder.apply(calculatorEventData);
                 if (result.isNewAfter()) {
                     preparedInput = prepareInputFromDisplay(((CalculatorDisplayChangeEventData) data).getNewValue(), null);
-                    this.preparedInput = preparedInput;
+                    onNewPreparedInput(preparedInput);
+                }
+            }
+        }
+    }
 
+    private void onNewPreparedInput(@NotNull PreparedInput preparedInput) {
+        this.preparedInput = preparedInput;
 
         final PreparedInput finalPreparedInput = preparedInput;
         getUiHandler().post(new Runnable() {
@@ -172,10 +178,6 @@ public abstract class AbstractCalculatorPlotFragment extends CalculatorFragment
         });
     }
 
-            }
-        }
-    }
-
     protected abstract void onError();
 
     protected abstract void createGraphicalView(@NotNull View view, @NotNull PreparedInput preparedInput);
@@ -230,12 +232,32 @@ public abstract class AbstractCalculatorPlotFragment extends CalculatorFragment
     public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
         super.onCreateOptionsMenu(menu, inflater);
 
+        final List<IdentifiableMenuItem<MenuItem>> menuItems = new ArrayList<IdentifiableMenuItem<MenuItem>>();
+        menuItems.add(PlotMenu.preferences);
+        if ( is3dPlotSupported() ) {
+            menuItems.add(new IdentifiableMenuItem<MenuItem>() {
+                @NotNull
+                @Override
+                public Integer getItemId() {
+                    return R.id.menu_plot_3d;
+                }
+
+                @Override
+                public void onClick(@NotNull MenuItem data, @NotNull Context context) {
+                     onNewPreparedInput(PreparedInput.force3dInstance(preparedInput));
+                }
+            });
+        }
+        fragmentMenu = ListActivityMenu.fromResource(R.menu.plot_menu, menuItems, SherlockMenuHelper.getInstance());
+
         final FragmentActivity activity = this.getActivity();
         if (activity != null) {
             fragmentMenu.onCreateOptionsMenu(activity, menu);
         }
     }
 
+    protected abstract boolean is3dPlotSupported();
+
     @Override
     public void onPrepareOptionsMenu(Menu menu) {
         super.onPrepareOptionsMenu(menu);
@@ -266,7 +288,13 @@ public abstract class AbstractCalculatorPlotFragment extends CalculatorFragment
                 final Generic expression = displayState.getResult();
                 if (CalculatorUtils.isPlotPossible(expression, displayState.getOperation())) {
                     final List<Constant> variables = new ArrayList<Constant>(CalculatorUtils.getNotSystemConstants(expression));
-                    final Constant xVariable = variables.get(0);
+
+                    final Constant xVariable;
+                    if ( variables.size() > 0 ) {
+                        xVariable = variables.get(0);
+                    } else {
+                        xVariable = null;
+                    }
 
                     final Constant yVariable;
                     if ( variables.size() > 1 ) {
@@ -275,7 +303,7 @@ public abstract class AbstractCalculatorPlotFragment extends CalculatorFragment
                         yVariable = null;
                     }
 
-                    final Input input = new Input(expression.toString(), xVariable.getName(), yVariable == null ? null : yVariable.getName());
+                    final Input input = new Input(expression.toString(), xVariable == null ? null : xVariable.getName(), yVariable == null ? null : yVariable.getName());
                     return prepareInput(input, false, savedInstanceState);
                 }
             }
@@ -293,7 +321,13 @@ public abstract class AbstractCalculatorPlotFragment extends CalculatorFragment
         try {
             final PreparedExpression preparedExpression = ToJsclTextProcessor.getInstance().process(input.getExpression());
             final Generic expression = Expression.valueOf(preparedExpression.getExpression());
-            final Constant xVar = new Constant(input.getXVariableName());
+
+            final Constant xVar;
+            if (input.getXVariableName() != null) {
+                xVar = new Constant(input.getXVariableName());
+            } else {
+                xVar = null;
+            }
 
             final Constant yVar;
             if (input.getYVariableName() != null) {
@@ -416,6 +450,8 @@ public abstract class AbstractCalculatorPlotFragment extends CalculatorFragment
 
         private boolean fromInputArgs;
 
+        private boolean force3d = false;
+
         @NotNull
         private PlotBoundaries plotBoundaries = PlotBoundaries.newDefaultInstance();
 
@@ -425,7 +461,7 @@ public abstract class AbstractCalculatorPlotFragment extends CalculatorFragment
         @NotNull
         public static PreparedInput newInstance(@NotNull Input input,
                                                 @NotNull Generic expression,
-                                                @NotNull Constant xVariable,
+                                                @Nullable  Constant xVariable,
                                                 @Nullable Constant yVariable,
                                                 boolean fromInputArgs,
                                                 @NotNull  PlotBoundaries plotBoundaries) {
@@ -454,6 +490,17 @@ public abstract class AbstractCalculatorPlotFragment extends CalculatorFragment
             return result;
         }
 
+        @NotNull
+        public static PreparedInput force3dInstance(final PreparedInput that) {
+            if (!that.isError()) {
+                final PreparedInput result = PreparedInput.newInstance(that.input, that.expression, that.xVariable, that.yVariable, that.fromInputArgs, that.plotBoundaries);
+                result.force3d = true;
+                return result;
+            } else {
+                return that;
+            }
+        }
+
         public boolean isFromInputArgs() {
             return fromInputArgs;
         }
@@ -483,8 +530,12 @@ public abstract class AbstractCalculatorPlotFragment extends CalculatorFragment
             return yVariable;
         }
 
+        public boolean isForce3d() {
+            return force3d;
+        }
+
         public boolean isError() {
-            return input == null || expression == null || xVariable == null;
+            return input == null || expression == null;
         }
     }
 
@@ -493,14 +544,14 @@ public abstract class AbstractCalculatorPlotFragment extends CalculatorFragment
         @NotNull
         private String expression;
 
-        @NotNull
+        @Nullable
         private String xVariableName;
 
         @Nullable
         private String yVariableName;
 
         public Input(@NotNull String expression,
-                     @NotNull String xVariableName,
+                     @Nullable  String xVariableName,
                      @Nullable String yVariableName) {
             this.expression = expression;
             this.xVariableName = xVariableName;
@@ -512,7 +563,7 @@ public abstract class AbstractCalculatorPlotFragment extends CalculatorFragment
             return expression;
         }
 
-        @NotNull
+        @Nullable
         public String getXVariableName() {
             return xVariableName;
         }

android-app/src/main/java/org/solovyev/android/calculator/plot/CalculatorArityPlotFragment.java

@@ -57,19 +57,21 @@ public class CalculatorArityPlotFragment extends AbstractCalculatorPlotFragment
             final Constant xVariable = preparedInput.getXVariable();
             final Constant yVariable = preparedInput.getYVariable();
 
-            final int arity = yVariable == null ? 1 : 2;
+            final int arity = xVariable == null ? 0 : (yVariable == null ? 1 : 2);
 
             final List<FunctionPlotDef> functions = new ArrayList<FunctionPlotDef>();
 
             functions.add(FunctionPlotDef.newInstance(new RealArityFunction(arity, expression, xVariable, yVariable), FunctionLineDef.newInstance(realLineColor.getColor(), FunctionLineStyle.solid, 3f)));
-
-            if (arity == 1) {
             functions.add(FunctionPlotDef.newInstance(new ImaginaryArityFunction(arity, expression, xVariable, yVariable), FunctionLineDef.newInstance(imagLineColor.getColor(), FunctionLineStyle.solid, 3f)));
-            }
 
             switch (arity) {
+                case 0:
                 case 1:
+                    if (preparedInput.isForce3d()) {
+                        graphView = new Graph3dView(getActivity());
+                    } else {
                         graphView = new Graph2dView(getActivity());
+                    }
                     break;
                 case 2:
                     graphView = new Graph3dView(getActivity());
@@ -91,6 +93,11 @@ public class CalculatorArityPlotFragment extends AbstractCalculatorPlotFragment
     protected void createChart(@NotNull PreparedInput preparedInput) {
     }
 
+    @Override
+    protected boolean is3dPlotSupported() {
+        return true;
+    }
+
 
     @Override
     public void onResume() {
@@ -133,19 +140,35 @@ public class CalculatorArityPlotFragment extends AbstractCalculatorPlotFragment
         @NotNull
         protected final Generic expression;
 
-        @NotNull
+        @Nullable
         protected final Constant xVariable;
 
         @Nullable
         protected final Constant yVariable;
 
-        public AbstractArityFunction(int arity, @NotNull Generic expression, @NotNull Constant xVariable, @Nullable Constant yVariable) {
+        @Nullable
+        private Double constant = null;
+
+        public AbstractArityFunction(int arity,
+                                     @NotNull Generic expression,
+                                     @Nullable  Constant xVariable,
+                                     @Nullable Constant yVariable) {
             this.arity = arity;
             this.expression = expression;
             this.xVariable = xVariable;
             this.yVariable = yVariable;
         }
 
+        @Override
+        public final double eval() {
+            if (constant == null) {
+                constant = eval0();
+            }
+            return constant;
+        }
+
+        protected abstract double eval0();
+
         @Override
         public final int arity() {
             return arity;
@@ -157,11 +180,16 @@ public class CalculatorArityPlotFragment extends AbstractCalculatorPlotFragment
 
         private RealArityFunction(int arity,
                                   @NotNull Generic expression,
-                                  @NotNull Constant xVariable,
+                                  @Nullable  Constant xVariable,
                                   @Nullable Constant yVariable) {
             super(arity, expression, xVariable, yVariable);
         }
 
+        @Override
+        public double eval0() {
+            return PlotUtils.calculatorExpression(expression).realPart();
+        }
+
         @Override
         public double eval(double x) {
             return PlotUtils.calculatorExpression(expression, xVariable, x).realPart();
@@ -177,11 +205,16 @@ public class CalculatorArityPlotFragment extends AbstractCalculatorPlotFragment
 
         private ImaginaryArityFunction(int arity,
                              @NotNull Generic expression,
-                             @NotNull Constant xVariable,
+                             @Nullable  Constant xVariable,
                              @Nullable Constant yVariable) {
             super(arity, expression, xVariable, yVariable);
         }
 
+        @Override
+        public double eval0() {
+            return PlotUtils.calculatorExpression(expression).imaginaryPart();
+        }
+
         @Override
         public double eval(double x) {
             return PlotUtils.calculatorExpression(expression, xVariable, x).imaginaryPart();

android-app/src/main/java/org/solovyev/android/calculator/plot/CalculatorPlotFragment.java

@@ -57,6 +57,11 @@ public class CalculatorPlotFragment extends AbstractCalculatorPlotFragment {
         }
     }
 
+    @Override
+    protected boolean is3dPlotSupported() {
+        return false;
+    }
+
     @Nullable
     @Override
     protected PlotBoundaries getPlotBoundaries() {

android-app/src/main/java/org/solovyev/android/calculator/plot/FunctionLineColorType.java

@@ -0,0 +1,12 @@
+package org.solovyev.android.calculator.plot;
+
+/**
+ * User: serso
+ * Date: 1/5/13
+ * Time: 10:45 PM
+ */
+public enum FunctionLineColorType {
+
+    color_map,
+    solid;
+}

android-app/src/main/java/org/solovyev/android/calculator/plot/FunctionLineDef.java

@@ -30,6 +30,9 @@ public class FunctionLineDef {
     **********************************************************************
     */
 
+    @NotNull
+    private FunctionLineColorType lineColorType = FunctionLineColorType.solid;
+
     private int lineColor = Color.WHITE;
 
     @NotNull
@@ -57,6 +60,16 @@ public class FunctionLineDef {
         return result;
     }
 
+    @NotNull
+    public static FunctionLineDef newInstance(int lineColor, @NotNull FunctionLineStyle lineStyle, float lineWidth, @NotNull FunctionLineColorType lineColorType) {
+        final FunctionLineDef result = new FunctionLineDef();
+        result.lineColor = lineColor;
+        result.lineColorType = lineColorType;
+        result.lineStyle = lineStyle;
+        result.lineWidth = lineWidth;
+        return result;
+    }
+
     @NotNull
     public static FunctionLineDef newDefaultInstance() {
         return new FunctionLineDef();
@@ -76,6 +89,11 @@ public class FunctionLineDef {
         return lineWidth;
     }
 
+    @NotNull
+    public FunctionLineColorType getLineColorType() {
+        return lineColorType;
+    }
+
     public void applyToPaint(@NotNull Paint paint) {
         paint.setColor(lineColor);
         paint.setStyle(Paint.Style.STROKE);

android-app/src/main/java/org/solovyev/android/calculator/plot/GLView.java

@@ -7,8 +7,10 @@ import android.graphics.Bitmap;
 import android.os.Handler;
 import android.os.Message;
 import android.util.AttributeSet;
+import android.util.Log;
 import android.view.SurfaceHolder;
 import android.view.SurfaceView;
+import org.jetbrains.annotations.NotNull;
 import org.solovyev.android.AndroidUtils2;
 
 import javax.microedition.khronos.egl.*;
@@ -28,9 +30,10 @@ abstract class GLView extends SurfaceView implements SurfaceHolder.Callback {
     private EGLContext eglContext;
     private GL11 gl;
     protected int width, height;
-    private boolean mIsLooping;
+    private volatile boolean looping;
 
     abstract void onDrawFrame(GL10 gl);
+
     abstract void onSurfaceCreated(GL10 gl, int width, int height);
 
     public String captureScreenshot() {
@@ -48,13 +51,20 @@ abstract class GLView extends SurfaceView implements SurfaceHolder.Callback {
         buf.asIntBuffer().get(data);
         buf = null;
         Bitmap bitmap = Bitmap.createBitmap(width, height, Bitmap.Config.RGB_565);
-        bitmap.setPixels(data, size-width, -width, 0, 0, width, height);
+        bitmap.setPixels(data, size - width, -width, 0, 0, width, height);
         return bitmap;
     }
 
-    private Handler handler = new Handler() {
+    @NotNull
+    private final Handler uiHandler = new Handler() {
         public void handleMessage(Message msg) {
+            switch (msg.what) {
+                case 1:
                     glDraw();
+                    break;
+                default:
+                    Log.e("GLView", "Incorrect message id: " + msg.what);
+            }
         }
     };
 
@@ -69,7 +79,7 @@ abstract class GLView extends SurfaceView implements SurfaceHolder.Callback {
     }
 
     private void init() {
-        SurfaceHolder holder = getHolder();
+        final SurfaceHolder holder = getHolder();
         holder.setType(SurfaceHolder.SURFACE_TYPE_GPU);
         holder.addCallback(this);
     }
@@ -129,7 +139,7 @@ abstract class GLView extends SurfaceView implements SurfaceHolder.Callback {
             if (egl.eglGetError() == EGL11.EGL_CONTEXT_LOST) {
                 paused = true;
             }
-            if (mIsLooping) {
+            if (looping) {
                 requestDraw();
             }
         }
@@ -154,24 +164,24 @@ abstract class GLView extends SurfaceView implements SurfaceHolder.Callback {
     }
 
     public void startLooping() {
-        if (!mIsLooping) {
+        if (!looping) {
-            mIsLooping = true;
+            looping = true;
             glDraw();
         }
     }
 
     public void stopLooping() {
-        if (mIsLooping) {
+        if (looping) {
-            mIsLooping = false;
+            looping = false;
         }
     }
 
     public boolean isLooping() {
-        return mIsLooping;
+        return looping;
     }
 
     public void requestDraw() {
-        handler.sendEmptyMessage(1);
+        uiHandler.sendEmptyMessage(1);
     }
 
     static void bitmapBGRtoRGB(Bitmap bitmap, int width, int height) {
@@ -182,7 +192,7 @@ abstract class GLView extends SurfaceView implements SurfaceHolder.Callback {
         for (int i = 0; i < size; ++i) {
             //BGR-565 to RGB-565
             short v = data[i];
-            data[i] = (short) (((v&0x1f) << 11) | (v&0x7e0) | ((v&0xf800) >> 11));
+            data[i] = (short) (((v & 0x1f) << 11) | (v & 0x7e0) | ((v & 0xf800) >> 11));
         }
         buf.rewind();
         bitmap.copyPixelsFromBuffer(buf);

android-app/src/main/java/org/solovyev/android/calculator/plot/Graph3d.java

@@ -2,7 +2,9 @@
 
 package org.solovyev.android.calculator.plot;
 
+import android.graphics.Color;
 import org.javia.arity.Function;
+import org.jetbrains.annotations.NotNull;
 
 import javax.microedition.khronos.opengles.GL10;
 import javax.microedition.khronos.opengles.GL11;
@@ -82,17 +84,20 @@ class Graph3d {
         return bb;
     }
 
-    public void update(GL11 gl, Function f, float zoom) {
+    public void update(@NotNull GL11 gl, @NotNull FunctionPlotDef fpd, float zoom) {
+        final Function function = fpd.getFunction();
+        final FunctionLineDef lineDef = fpd.getLineDef();
         final int NTICK = useHighQuality3d ? 5 : 0;
         final float size = 4 * zoom;
         final float minX = -size, maxX = size, minY = -size, maxY = size;
 
         //Calculator.log("update VBOs " + vertexVbo + ' ' + colorVbo + ' ' + vertexElementVbo);
         nVertex = N * N + 6 + 8 + NTICK * 6;
-        int nFloats = nVertex * 3;
+
-        float vertices[] = new float[nFloats];
+        final float vertices[] = new float[nVertex * 3];
-        byte colors[] = new byte[nVertex << 2];
+        final byte colors[] = new byte[nVertex * 4];
-        if (f != null) {
+
+        if (fpd != null) {
             //Calculator.log("Graph3d update");
             float sizeX = maxX - minX;
             float sizeY = maxY - minY;
@@ -103,43 +108,74 @@ class Graph3d {
             float y = minY;
             float x = minX - stepX;
             int nRealPoints = 0;
+
+            final int arity = function.arity();
+
             for (int i = 0; i < N; i++, y += stepY) {
                 float xinc = (i & 1) == 0 ? stepX : -stepX;
+
                 x += xinc;
                 for (int j = 0; j < N; ++j, x += xinc, pos += 3) {
-                    float z = (float) f.eval(x, y);
+
+                    final float z;
+                    switch (arity) {
+                        case 2:
+                            z = (float) function.eval(x, y);
+                            break;
+                        case 1:
+                            // todo serso: optimize (can be calculated once before loop)
+                            z = (float) function.eval(x);
+                            break;
+                        case 0:
+                            // todo serso: optimize (can be calculated once)
+                            z = (float) function.eval();
+                            break;
+                        default:
+                            throw new IllegalArgumentException();
+                    }
+
                     vertices[pos] = x;
                     vertices[pos + 1] = y;
                     vertices[pos + 2] = z;
-                    if (z == z) { // not NAN
+
+                    if (!Float.isNaN(z)) {
                         sum += z * z;
                         ++nRealPoints;
                     }
                 }
             }
+
             float maxAbs = (float) Math.sqrt(sum / nRealPoints);
             maxAbs *= .9f;
             maxAbs = Math.min(maxAbs, 15);
             maxAbs = Math.max(maxAbs, .001f);
 
+            final int lineColor = lineDef.getLineColor();
             final int limitColor = N * N * 4;
             for (int i = 0, j = 2; i < limitColor; i += 4, j += 3) {
-                float z = vertices[j];
+                final float z = vertices[j];
-                if (z == z) {
+
+                    if (!Float.isNaN(z)) {
+                        if (lineDef.getLineColorType() == FunctionLineColorType.color_map) {
                             final float a = z / maxAbs;
                             final float abs = a < 0 ? -a : a;
                             colors[i] = floatToByte(a);
                             colors[i + 1] = floatToByte(1 - abs * .3f);
                             colors[i + 2] = floatToByte(-a);
+                        } else {
+                            colors[i] = (byte) Color.red(lineColor);
+                            colors[i + 1] = (byte) Color.green(lineColor);
+                            colors[i + 2] = (byte) Color.blue(lineColor);
+                        }
                         colors[i + 3] = (byte) 255;
                     } else {
                         vertices[j] = 0;
-                    z = 0;
                         colors[i] = 0;
                         colors[i + 1] = 0;
                         colors[i + 2] = 0;
                         colors[i + 3] = 0;
                     }
+
             }
         }
         int base = N * N * 3;
@@ -248,7 +284,15 @@ class Graph3d {
     }
 
     private byte floatToByte(float v) {
-        return (byte) (v <= 0 ? 0 : v >= 1 ? 255 : (int) (v * 255));
+        if (v <= 0) {
+            return (byte) 0;
+        } else {
+            if (v >= 1) {
+                return (byte) 255;
+            } else {
+                return (byte) (v * 255);
+            }
+        }
     }
 
     public void draw(GL11 gl) {

android-app/src/main/java/org/solovyev/android/calculator/plot/Graph3dView.java

@@ -3,16 +3,18 @@
 package org.solovyev.android.calculator.plot;
 
 import android.content.Context;
+import android.graphics.Color;
 import android.opengl.Matrix;
 import android.os.Build;
 import android.util.AttributeSet;
 import android.view.MotionEvent;
 import android.widget.ZoomButtonsController;
-import org.javia.arity.Function;
 import org.jetbrains.annotations.NotNull;
 
 import javax.microedition.khronos.opengles.GL10;
 import javax.microedition.khronos.opengles.GL11;
+import java.util.ArrayList;
+import java.util.Collections;
 import java.util.List;
 
 public class Graph3dView extends GLView implements GraphView {
@@ -24,7 +26,12 @@ public class Graph3dView extends GLView implements GraphView {
     private ZoomButtonsController zoomController = new ZoomButtonsController(this);
     private float zoomLevel = 1, targetZoom, zoomStep = 0, currentZoom;
     private FPS fps = new FPS();
-    private Graph3d graph;
+
+    @NotNull
+    private List<Graph3d> graphs = new ArrayList<Graph3d>();
+
+    @NotNull
+    private GraphViewHelper graphViewHelper = GraphViewHelper.newDefaultInstance();
 
     public Graph3dView(Context context, AttributeSet attrs) {
         super(context, attrs);
@@ -149,7 +156,6 @@ public class Graph3dView extends GLView implements GraphView {
     private float[] matrix1 = new float[16], matrix2 = new float[16], matrix3 = new float[16];
     private float angleX, angleY;
     private boolean isDirty;
-    private Function function;
     private static final float DISTANCE = 15f;
 
     void setRotation(float x, float y) {
@@ -164,14 +170,18 @@ public class Graph3dView extends GLView implements GraphView {
 
     @Override
     public void init(@NotNull FunctionViewDef functionViewDef) {
+        this.graphViewHelper = GraphViewHelper.newInstance(functionViewDef, Collections.<FunctionPlotDef>emptyList());
     }
 
     public void setFunctionPlotDefs(@NotNull List<FunctionPlotDef> functionPlotDefs) {
-        if (functionPlotDefs.size() > 0) {
+        for (FunctionPlotDef functionPlotDef: functionPlotDefs) {
-            function = functionPlotDefs.get(0).getFunction();
+            final int arity = functionPlotDef.getFunction().arity();
-        } else {
+            if (arity != 0 && arity != 1 && arity != 2) {
-            function = null;
+                throw new IllegalArgumentException("Function must have arity 0 or 1 or 2 for 3d plot!");
             }
+        }
+
+        this.graphViewHelper = this.graphViewHelper.copy(functionPlotDefs);
         zoomLevel = 1;
         isDirty = true;
     }
@@ -180,10 +190,13 @@ public class Graph3dView extends GLView implements GraphView {
     public void onSurfaceCreated(GL10 gl, int width, int height) {
         gl.glDisable(GL10.GL_DITHER);
         gl.glHint(GL10.GL_PERSPECTIVE_CORRECTION_HINT, GL10.GL_FASTEST);
-        gl.glClearColor(0, 0, 0, 1);
+
+        final int backgroundColor = graphViewHelper.getFunctionViewDef().getBackgroundColor();
+        gl.glClearColor(Color.red(backgroundColor) / 255f, Color.green(backgroundColor) / 255f, Color.blue(backgroundColor) / 255f, Color.alpha(backgroundColor) / 255f);
+
         gl.glShadeModel(useHighQuality3d ? GL10.GL_SMOOTH : GL10.GL_FLAT);
         gl.glDisable(GL10.GL_LIGHTING);
-        graph = new Graph3d((GL11) gl, useHighQuality3d);
+        ensureGraphsSize((GL11) gl);
         isDirty = true;
         angleX = .5f;
         angleY = 0;
@@ -201,7 +214,11 @@ public class Graph3dView extends GLView implements GraphView {
             currentZoom = zoomLevel;
         }
         if (isDirty) {
-            graph.update(gl, function, zoomLevel);
+            ensureGraphsSize(gl);
+            for (int i = 0; i < graphViewHelper.getFunctionPlotDefs().size(); i++) {
+                 graphs.get(i).update(gl, graphViewHelper.getFunctionPlotDefs().get(i), zoomLevel);
+
+            }
             isDirty = false;
         }
 
@@ -233,8 +250,16 @@ public class Graph3dView extends GLView implements GraphView {
         Matrix.multiplyMM(matrix3, 0, matrix2, 0, matrix1, 0);
         gl.glMultMatrixf(matrix3, 0);
         System.arraycopy(matrix3, 0, matrix1, 0, 16);
+        for (Graph3d graph : graphs) {
             graph.draw(gl);
         }
+    }
+
+    private void ensureGraphsSize(@NotNull GL11 gl) {
+        while (graphViewHelper.getFunctionPlotDefs().size() > graphs.size()) {
+            graphs.add(new Graph3d(gl, useHighQuality3d));
+        }
+    }
 
     private void initFrustum(GL10 gl, float distance) {
         gl.glMatrixMode(GL10.GL_PROJECTION);

android-app/src/main/java/org/solovyev/android/calculator/plot/PlotUtils.java

@@ -51,7 +51,7 @@ public final class PlotUtils {
 	public static boolean addXY(double minValue,
 								double maxValue,
 								@NotNull Generic expression,
-								@NotNull Constant variable,
+								@Nullable Constant variable,
 								@NotNull MyXYSeries realSeries,
 								@Nullable MyXYSeries imagSeries,
 								boolean addExtra,
@@ -82,7 +82,7 @@ public final class PlotUtils {
             boolean needToCalculateRealY = realSeries.needToAdd(step, x);
 
 			if (needToCalculateRealY) {
-				final Complex c = calculatorExpression(expression, variable, x);
+				final Complex c = variable == null ? calculatorExpression(expression) : calculatorExpression(expression, variable, x);
 				Double y = prepareY(c.realPart());
 
                 if (y != null) {
@@ -106,7 +106,7 @@ public final class PlotUtils {
 			} else {
 				boolean needToCalculateImagY = imagSeries != null && imagSeries.needToAdd(step, x);
 				if (needToCalculateImagY) {
-					final Complex c = calculatorExpression(expression, variable, x);
+					final Complex c = variable == null ? calculatorExpression(expression) : calculatorExpression(expression, variable, x);
 					Double y = prepareY(c.imaginaryPart());
 					if (y != null) {
                         imag.moveToNextPoint(x, y);
@@ -128,20 +128,28 @@ public final class PlotUtils {
 	}
 
     @NotNull
-    static String getImagFunctionName(@NotNull Constant variable) {
+    static String getImagFunctionName(@Nullable  Constant variable) {
+        if (variable != null) {
             return "g(" + variable.getName() + ")" + " = " + "Im(ƒ(" + variable.getName() + "))";
+        } else {
+            return "g = Im(ƒ)";
+        }
     }
 
     @NotNull
-    private static String getRealFunctionName(@NotNull Generic expression, @NotNull Constant variable) {
+    private static String getRealFunctionName(@NotNull Generic expression, @Nullable  Constant variable) {
+        if (variable != null) {
             return "ƒ(" + variable.getName() + ")" + " = " + expression.toString();
+        } else {
+            return "ƒ = " + expression.toString();
+        }
     }
 
     @NotNull
     static XYChart prepareChart(final double minValue,
                                 final double maxValue,
                                 @NotNull final Generic expression,
-                                @NotNull final Constant variable,
+                                @Nullable final Constant variable,
                                 int bgColor,
                                 boolean interpolate,
                                 int realLineColor,
@@ -159,8 +167,12 @@ public final class PlotUtils {
 
         final XYMultipleSeriesRenderer renderer = new XYMultipleSeriesRenderer();
         renderer.setShowGrid(true);
-        renderer.setXTitle(variable.getName());
+        renderer.setXTitle(variable != null ? variable.getName() : null);
+        if (variable != null) {
             renderer.setYTitle("f(" + variable.getName() + ")");
+        } else {
+            renderer.setYTitle("f");
+        }
         renderer.setChartTitleTextSize(25);
         renderer.setAxisTitleTextSize(25);
         renderer.setLabelsTextSize(25);
@@ -370,6 +382,15 @@ public final class PlotUtils {
         }
     }
 
+    @NotNull
+    public static Complex calculatorExpression(@NotNull Generic expression) {
+        try {
+            return unwrap(expression.numeric());
+        } catch (RuntimeException e) {
+            return NaN;
+        }
+    }
+
     @NotNull
 	public static Complex calculatorExpression(@NotNull Generic expression, @NotNull Constant xVar, double x) {
         try {

core/src/main/java/org/solovyev/android/calculator/CalculatorEventType.java

@@ -162,6 +162,9 @@ public enum CalculatorEventType {
     //org.solovyev.android.calculator.plot.PlotInput
     plot_graph,
 
+
+    plot_graph_3d,
+
     //String
     show_evaluation_error;
 

core/src/main/java/org/solovyev/android/calculator/CalculatorUtils.java

@@ -44,9 +44,9 @@ public final class CalculatorUtils {
     public static boolean isPlotPossible(@NotNull Generic expression, @NotNull JsclOperation operation) {
         boolean result = false;
 
-        if (operation == JsclOperation.simplify) {
+        if (operation == JsclOperation.simplify || operation == JsclOperation.numeric) {
             int size = getNotSystemConstants(expression).size();
-            if (size == 1 || size == 2) {
+            if (size == 0 || size == 1 || size == 2) {
                 result = true;
             }
         }