GraphUI Scene: Expose Z-Epsilon API for default and current PMVMatrixSetup values; Button add Z-Epsilon API for ctor and setLabelZOffset(..)

2 files changed, 53 insertions, 6 deletions

diff --git a/src/graphui/classes/com/jogamp/graph/ui/Scene.java b/src/graphui/classes/com/jogamp/graph/ui/Scene.java
index 1de608d12..1a55b39c7 100644
--- a/src/graphui/classes/com/jogamp/graph/ui/Scene.java
+++ b/src/graphui/classes/com/jogamp/graph/ui/Scene.java
@@ -102,10 +102,22 @@ public final class Scene implements Container, GLEventListener {
     public static final float DEFAULT_SCENE_DIST = -1/5f;
     /** Default projection angle in radians is PI/4, i.e. 45.0 degrees. */
     public static final float DEFAULT_ANGLE = FloatUtil.QUARTER_PI;
-    /** Default projection z-near value is 0.1. */
+    /** Default projection z-near value is {@value}. */
     public static final float DEFAULT_ZNEAR = 0.1f;
-    /** Default projection z-far value is 7000. */
+    /** Default projection z-far value is {@value}. */
     public static final float DEFAULT_ZFAR = 7000.0f;
+    /** Default Z precision on 16-bit depth buffer using {@link #DEFAULT_SCENE_DIST} z-position and {@link #DEFAULT_ZNEAR}. Value is {@code 0.0000061033...}*/
+    public static final float DEFAULT_Z16_EPSILON = FloatUtil.getZBufferEpsilon(16 /* zBits */, DEFAULT_SCENE_DIST, DEFAULT_ZNEAR);
+
+    /**
+     * Return Z precision on using {@link PMVMatrixSetup#getSceneDist()} z-position and {@link PMVMatrixSetup#getZNear()}.
+     * @param zBits depth buffer bit-depth, minimum 16-bit
+     * @param setup {@link PMVMatrixSetup} for scene-distance as z-position and zNear
+     * @return the Z precision
+     */
+    public static float getZEpsilon(final int zBits, final PMVMatrixSetup setup) {
+        return FloatUtil.getZBufferEpsilon(zBits, setup.getSceneDist(), setup.getZNear());
+    }
 
     /** Minimum sample count {@value} for Graph Region AA {@link Region#getRenderModes() render-modes}: {@link Region#VBAA_RENDERING_BIT} or {@link Region#MSAA_RENDERING_BIT}. */
     public static final int MIN_SAMPLE_COUNT = 1;
@@ -813,6 +825,15 @@ public final class Scene implements Container, GLEventListener {
     public AABBox getBounds() { return planeBox; }
 
     /**
+     * Return Z precision on using current {@link #getPMVMatrixSetup()}'s {@link PMVMatrixSetup#getSceneDist()} z-position and {@link PMVMatrixSetup#getZNear()}.
+     * @param zBits depth buffer bit-depth, minimum 16-bit
+     * @return the Z precision
+     */
+    public float getZEpsilon(final int zBits) {
+        return FloatUtil.getZBufferEpsilon(zBits, pmvMatrixSetup.getSceneDist(), pmvMatrixSetup.getZNear());
+    }
+
+    /**
      *
      * @param pmv
      * @param viewport
diff --git a/src/graphui/classes/com/jogamp/graph/ui/shapes/Button.java b/src/graphui/classes/com/jogamp/graph/ui/shapes/Button.java
index 9ce04cb47..ec07d7c4a 100644
--- a/src/graphui/classes/com/jogamp/graph/ui/shapes/Button.java
+++ b/src/graphui/classes/com/jogamp/graph/ui/shapes/Button.java
@@ -36,6 +36,7 @@ import com.jogamp.graph.curve.opengl.TextRegionUtil;
 import com.jogamp.graph.font.Font;
 import com.jogamp.graph.geom.plane.AffineTransform;
 import com.jogamp.graph.ui.GraphShape;
+import com.jogamp.graph.ui.Scene;
 import com.jogamp.opengl.math.FloatUtil;
 import com.jogamp.opengl.math.Vec2f;
 import com.jogamp.opengl.math.Vec3f;
@@ -60,7 +61,7 @@ public class Button extends BaseButton {
     /** {@value} */
     public static final float DEFAULT_SPACING_Y = 0.42f;
 
-    private static final float DEFAULT_LABEL_ZOFFSET = 0.0001f; // 0.05f;
+    private static final float DEFAULT_LABEL_ZOFFSET = 0.00016f; // 16 zBits, -1 zDist, 0.1 zNear, i.e. FloatUtil.getZBufferEpsilon(16, -1f, 0.1f)
     private float labelZOffset;
 
     private final Label0 label;
@@ -72,10 +73,26 @@ public class Button extends BaseButton {
     private final AffineTransform tempT3 = new AffineTransform();
 
     public Button(final int renderModes, final Font labelFont,
-                  final String labelText, final float width,
-                  final float height) {
+                  final String labelText, final float width, final float height) {
+        this(renderModes, labelFont, labelText, width, height, DEFAULT_LABEL_ZOFFSET);
+    }
+
+    public Button(final int renderModes, final Font labelFont,
+                  final String labelText, final float width, final float height,
+                  final int zBits, final Scene.PMVMatrixSetup setup) {
+        this(renderModes, labelFont, labelText, width, height, Scene.getZEpsilon(zBits, setup));
+    }
+
+    public Button(final int renderModes, final Font labelFont,
+                  final String labelText, final float width, final float height,
+                  final int zBits, final Scene scene) {
+        this(renderModes, labelFont, labelText, width, height, scene.getZEpsilon(zBits));
+    }
+
+    public Button(final int renderModes, final Font labelFont, final String labelText,
+                  final float width, final float height, final float zOffset) {
         super(renderModes | Region.COLORCHANNEL_RENDERING_BIT, width, height);
-        this.labelZOffset = DEFAULT_LABEL_ZOFFSET;
+        this.labelZOffset = zOffset;
         this.label = new Label0(labelFont, labelText, new Vec4f( 1.66f, 1.66f, 1.66f, 1.0f )); // 0.60 * 1.66 ~= 1.0
     }
 
@@ -144,6 +161,15 @@ public class Button extends BaseButton {
         markShapeDirty();
         return this;
     }
+    public Button setLabelZOffset(final int zBits, final float zDist, final float zNear) {
+        return setLabelZOffset( FloatUtil.getZBufferEpsilon(zBits, zDist, zNear) );
+    }
+    public Button setLabelZOffset(final int zBits, final Scene.PMVMatrixSetup setup) {
+        return setLabelZOffset( Scene.getZEpsilon(zBits, setup) );
+    }
+    public Button setLabelZOffset(final int zBits, final Scene scene) {
+        return setLabelZOffset( scene.getZEpsilon(zBits) );
+    }
 
     public final float getSpacingX() { return spacingX; }
     public final float getSpacingY() { return spacingY; }