making depth range trick testable

jzy3d-core/src/main/java/org/jzy3d/plot3d/primitives/Wireframeable.java

@@ -170,5 +170,5 @@ public abstract class Wireframeable extends Drawable {
    * no z-fighting occurs between faces and lines. In case of higher value, line
    * will be display more often, but also lines that should be behind the polygon
    */
-  protected float NO_OVERLAP_DEPTH_RATIO = 0.1f;//0.1f;
+  public static float NO_OVERLAP_DEPTH_RATIO = 0.1f;//0.1f;
 }

jzy3d-core/src/main/java/org/jzy3d/plot3d/primitives/axis/AxisBox.java

@@ -81,6 +81,15 @@ public class AxisBox implements IAxis {
   public static final int AXE_X = 0;
   public static final int AXE_Y = 1;
   public static final int AXE_Z = 2;
+  
+  protected boolean depthRangeTrick = true;
+  
+  /**
+   * The higher the value, the more the line are far from the faces and hence
+   * no z-fighting occurs between faces and lines. In case of higher value, line
+   * will be display more often, but also lines that should be behind the polygon
+   */
+  public static float NO_OVERLAP_DEPTH_RATIO = 0.5f;
 
   protected List<AxeAnnotation> annotations = new ArrayList<AxeAnnotation>();
 
@@ -177,7 +186,8 @@ public class AxisBox implements IAxis {
     
     // Push far from camera, to ensure the axis grid
     // Will remain covered by surface
-    painter.glDepthRangef(0.5f, 1);
+    if(depthRangeTrick)
+      painter.glDepthRangef(NO_OVERLAP_DEPTH_RATIO, 1f);
 
     
     painter.glPolygonMode(PolygonMode.BACK, PolygonFill.LINE);
@@ -199,7 +209,9 @@ public class AxisBox implements IAxis {
     
     
     // Reset depth range
-    painter.glDepthRangef(0f, 1);
+    
+    if(depthRangeTrick)
+      painter.glDepthRangef(0f, 1f);
 
   }
 

jzy3d-emul-gl/src/test/java/org/jzy3d/emulgl/opengl/TestDepthRange.java

@@ -0,0 +1,134 @@
+package org.jzy3d.emulgl.opengl;
+
+import org.junit.Test;
+import org.jzy3d.chart.Chart;
+import org.jzy3d.chart.factories.EmulGLChartFactory;
+import org.jzy3d.colors.Color;
+import org.jzy3d.colors.ColorMapper;
+import org.jzy3d.colors.colormaps.ColorMapRainbow;
+import org.jzy3d.maths.Range;
+import org.jzy3d.painters.IPainter;
+import org.jzy3d.plot3d.builder.Mapper;
+import org.jzy3d.plot3d.builder.SurfaceBuilder;
+import org.jzy3d.plot3d.builder.concrete.OrthonormalGrid;
+import org.jzy3d.plot3d.primitives.Shape;
+import org.jzy3d.plot3d.primitives.Wireframeable;
+import org.jzy3d.plot3d.primitives.axis.AxisBox;
+import org.jzy3d.plot3d.rendering.canvas.Quality;
+import org.jzy3d.utils.LoggerUtils;
+import static org.mockito.Mockito.*;
+
+/**
+ * {@AxisBox} and 
+ * @author martin
+ *
+ */
+public class TestDepthRange {
+  @Test
+  public void whenRenderAxis_DepthRangeModifiedByAxis() {
+    LoggerUtils.minimal();
+
+    // When
+    EmulGLChartFactory factory = new EmulGLChartFactory();
+    Chart chart = factory.newChart(Quality.Advanced());
+    
+    Shape surface = surface();
+    chart.add(surface);
+    
+    IPainter painter = spy(chart.getView().getPainter());
+    
+    // ----------------------------------------------
+    // Then surface will NOT update depth range
+    
+    surface.setPolygonWireframeDepthTrick(false);
+    surface.draw(painter);
+    
+    verify(painter, never()).glDepthRangef(0, 1);
+    
+    // ----------------------------------------------
+    // Then axis will update depth range
+    
+    chart.getView().getAxis().draw(painter);
+
+    // Called that way to push the depth range farther
+    verify(painter, atLeast(1)).glDepthRangef(AxisBox.NO_OVERLAP_DEPTH_RATIO, 1);
+
+    // Called that way for reset
+    verify(painter, atLeast(1)).glDepthRangef(0, 1);
+  }
+  
+  @Test
+  public void whenRenderSurface_DepthRangeModifiedBySurface() {
+    LoggerUtils.minimal();
+
+    // When
+    EmulGLChartFactory factory = new EmulGLChartFactory();
+    Chart chart = factory.newChart(Quality.Advanced());
+    
+    Shape surface = surface();
+    chart.add(surface);
+    
+    IPainter painter = spy(chart.getView().getPainter());
+    
+    // ----------------------------------------------
+    // Then surface will NOT update depth range
+    
+    surface.setPolygonWireframeDepthTrick(false);
+    surface.draw(painter);
+    
+    verify(painter, never()).glDepthRangef(0, 1);
+
+    // ----------------------------------------------
+    // Then surface WILL update depth range
+    
+    surface.setPolygonWireframeDepthTrick(true);
+    surface.draw(painter);
+    
+    // config for face
+    verify(painter, atLeast(1)).glDepthRangef(0, 1-Wireframeable.NO_OVERLAP_DEPTH_RATIO);
+    // config for wireframe
+    verify(painter, atLeast(1)).glDepthRangef(Wireframeable.NO_OVERLAP_DEPTH_RATIO, 1);
+    // back to default config
+    verify(painter, atLeast(1)).glDepthRangef(0, 1);
+
+    
+    // ----------------------------------------------
+    // Then axis will update depth range
+    
+    chart.getView().getAxis().draw(painter);
+
+    // Called that way to push the depth range farther
+    verify(painter, atLeast(1)).glDepthRangef(AxisBox.NO_OVERLAP_DEPTH_RATIO, 1);
+
+    // Called that way for reset
+    verify(painter, atLeast(1)).glDepthRangef(0, 1);
+  }
+
+
+
+  private static Shape surface() {
+    Mapper mapper = new Mapper() {
+      @Override
+      public double f(double x, double y) {
+        return x * Math.sin(x * y);
+      }
+    };
+    Range range = new Range(-3, 3);
+    int steps = 50;
+
+    SurfaceBuilder builder = new SurfaceBuilder();
+    Shape surface = builder.orthonormal(new OrthonormalGrid(range, steps, range, steps), mapper);
+
+    ColorMapper colorMapper = new ColorMapper(new ColorMapRainbow(), surface.getBounds().getZmin(),
+        surface.getBounds().getZmax(), new Color(1, 1, 1, ALPHA_FACTOR));
+    surface.setColorMapper(colorMapper);
+    surface.setFaceDisplayed(true);
+    surface.setWireframeDisplayed(true);
+    surface.setWireframeColor(Color.BLACK);
+    return surface;
+  }
+
+  static final float ALPHA_FACTOR = 0.75f;
+
+
+}