GooEngine: Enable GP screenspace thickness slider for all modes.

scripts/startup/bl_ui/properties_data_gpencil.py

@@ -365,7 +365,6 @@ class DATA_PT_gpencil_strokes(DataButtonsPanel, Panel):
         col = layout.column(align=True)
         col.prop(gpd, "stroke_thickness_space")
         sub = col.column()
-        sub.active = gpd.stroke_thickness_space == 'WORLDSPACE'
         sub.prop(gpd, "pixel_factor", text="Thickness Scale")
 
         col.prop(gpd, "edit_curve_resolution")

source/blender/draw/engines/gpencil/gpencil_cache_utils.c

@@ -274,7 +274,7 @@ GPENCIL_tLayer *gpencil_layer_cache_add(GPENCIL_PrivateData *pd,
                                                 pd->vertex_paint_opacity);
   /* Negate thickness sign to tag that strokes are in screen space.
    * Convert to world units (by default, 1 meter = 2000 pixels). */
-  float thickness_scale = (is_screenspace) ? -1.0f : (gpd->pixfactor / GPENCIL_PIXEL_FACTOR);
+  float thickness_scale = (is_screenspace) ? -gpd->pixfactor : (gpd->pixfactor / GPENCIL_PIXEL_FACTOR);
   float layer_opacity = gpencil_layer_final_opacity_get(pd, ob, gpl);
   float layer_tint[4];
   float layer_alpha;

source/blender/draw/engines/overlay/overlay_outline.cc

@@ -191,7 +191,7 @@ static void gpencil_layer_cache_populate(bGPDlayer *gpl,
   float object_scale = mat4_to_scale(iter->ob->object_to_world);
   /* Negate thickness sign to tag that strokes are in screen space.
    * Convert to world units (by default, 1 meter = 2000 pixels). */
-  float thickness_scale = (is_screenspace) ? -1.0f : (gpd->pixfactor / 2000.0f);
+  float thickness_scale = (is_screenspace) ? -gpd->pixfactor : (gpd->pixfactor / 2000.0f);
 
   GPUVertBuf *position_tx = DRW_cache_gpencil_position_buffer_get(iter->ob, iter->cfra);
   GPUVertBuf *color_tx = DRW_cache_gpencil_color_buffer_get(iter->ob, iter->cfra);

source/blender/draw/intern/shaders/common_gpencil_lib.glsl

@@ -69,7 +69,8 @@ float gpencil_stroke_thickness_modulate(float thickness, vec4 ndc_pos, vec4 view
   if (gpThicknessIsScreenSpace) {
     /* Multiply offset by view Z so that offset is constant in screenspace.
      * (e.i: does not change with the distance to camera) */
-    thickness *= ndc_pos.w;
+    thickness *= ndc_pos.w *
+                 -gpThicknessWorldScale;  // Multiply by positive world scale (default 1.0).
   }
   else {
     /* World space point size. */