[Bf-blender-cvs] [0c1c619681f] greasepencil-object: Fix draw back error due z-depth precission

[Antonio Vazquez]

Commit: 0c1c619681fd12d4a35a3f2ec8bbc36b40ddf927
Author: Antonio Vazquez
Date:   Fri Jun 29 10:13:50 2018 +0200
Branches: greasepencil-object
https://developer.blender.org/rB0c1c619681fd12d4a35a3f2ec8bbc36b40ddf927

Fix draw back error due z-depth precission

The value 1.0 makes the image disappear.

===================================================================

M	source/blender/draw/engines/gpencil/shaders/gpencil_fill_frag.glsl
M	source/blender/draw/engines/gpencil/shaders/gpencil_point_geom.glsl
M	source/blender/draw/engines/gpencil/shaders/gpencil_stroke_geom.glsl

===================================================================

diff --git a/source/blender/draw/engines/gpencil/shaders/gpencil_fill_frag.glsl b/source/blender/draw/engines/gpencil/shaders/gpencil_fill_frag.glsl
index dfd1d1dc438..35f47d6c418 100644
--- a/source/blender/draw/engines/gpencil/shaders/gpencil_fill_frag.glsl
+++ b/source/blender/draw/engines/gpencil/shaders/gpencil_fill_frag.glsl
@@ -135,6 +135,6 @@ void main()
 		gl_FragDepth = gl_FragCoord.z;
 	}
 	if  (xraymode == GP_XRAY_BACK) {
-		gl_FragDepth = 1.0;
+		gl_FragDepth = 0.999999;
 	}
 }
diff --git a/source/blender/draw/engines/gpencil/shaders/gpencil_point_geom.glsl b/source/blender/draw/engines/gpencil/shaders/gpencil_point_geom.glsl
index d0dd5521f39..f092149430c 100644
--- a/source/blender/draw/engines/gpencil/shaders/gpencil_point_geom.glsl
+++ b/source/blender/draw/engines/gpencil/shaders/gpencil_point_geom.glsl
@@ -32,7 +32,7 @@ float getZdepth(vec4 point)
 		return (point.z / point.w);
 	}
 	if  (xraymode == GP_XRAY_BACK) {
-		return 1.0;
+		return 0.999999;
 	}
 
 	/* in front by default */
diff --git a/source/blender/draw/engines/gpencil/shaders/gpencil_stroke_geom.glsl b/source/blender/draw/engines/gpencil/shaders/gpencil_stroke_geom.glsl
index 0d74bded692..0bcfe8cddb7 100644
--- a/source/blender/draw/engines/gpencil/shaders/gpencil_stroke_geom.glsl
+++ b/source/blender/draw/engines/gpencil/shaders/gpencil_stroke_geom.glsl
@@ -39,7 +39,7 @@ float getZdepth(vec4 point)
 		return (point.z / point.w);
 	}
 	if  (xraymode == GP_XRAY_BACK) {
-		return 1.0;
+		return 0.999999;
 	}
 
 	/* in front by default */