[Bf-blender-cvs] [d6bc53b3be9] uvimage-editor-drawing: Reduce render artifacts introduced by snapping vertices to pixel coords

[Jeroen Bakker]

Commit: d6bc53b3be9adb40fd6c2347812156dcdc2592d1
Author: Jeroen Bakker
Date:   Thu Sep 10 15:16:56 2020 +0200
Branches: uvimage-editor-drawing
https://developer.blender.org/rBd6bc53b3be9adb40fd6c2347812156dcdc2592d1

Reduce render artifacts introduced by snapping vertices to pixel coords

Use floor instead of round

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M	source/blender/draw/engines/overlay/shaders/edit_uv_edges_vert.glsl

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diff --git a/source/blender/draw/engines/overlay/shaders/edit_uv_edges_vert.glsl b/source/blender/draw/engines/overlay/shaders/edit_uv_edges_vert.glsl
index 5e9d8054bc0..ec04ce36938 100644
--- a/source/blender/draw/engines/overlay/shaders/edit_uv_edges_vert.glsl
+++ b/source/blender/draw/engines/overlay/shaders/edit_uv_edges_vert.glsl
@@ -16,7 +16,7 @@ void main()
   /* Snap vertices to the pixel grid to reduce artifacts. */
   vec2 half_viewport_res = sizeViewport.xy * 0.5;
   vec2 half_pixel_offset = sizeViewportInv * 0.5;
-  gl_Position.xy = round(gl_Position.xy * half_viewport_res) / half_viewport_res +
+  gl_Position.xy = floor(gl_Position.xy * half_viewport_res) / half_viewport_res +
                    half_pixel_offset;
 
   bool is_select = (flag & VERT_UV_SELECT) != 0;