UI: Number slider uniform filling

Now we always fill the slider with a vertical boundary. A bit hard to explain,
but very easy to see the difference.

I split the widget in three parts and used fragment shader discard to remove the
undesired bits. That means all the widget program is doing a bit extra
calculation.

Reviewers: fclem

Subscribers: billreynish

Differential Revision: https://developer.blender.org/D3186

1 files changed, 5 insertions, 0 deletions

diff --git a/source/blender/gpu/shaders/gpu_shader_2D_widget_base_frag.glsl b/source/blender/gpu/shaders/gpu_shader_2D_widget_base_frag.glsl
index 286a5373554..a356014d025 100644
--- a/source/blender/gpu/shaders/gpu_shader_2D_widget_base_frag.glsl
+++ b/source/blender/gpu/shaders/gpu_shader_2D_widget_base_frag.glsl
@@ -2,6 +2,7 @@ uniform vec3 checkerColorAndSize;
 
 noperspective in vec4 finalColor;
 noperspective in float butCo;
+flat in float discardFac;
 
 out vec4 fragColor;
 
@@ -22,6 +23,10 @@ vec4 do_checkerboard()
 
 void main()
 {
+	if (min(1.0, -butCo) > discardFac) {
+		discard;
+	}
+
 	fragColor = finalColor;
 
 	if (butCo > 0.5) {