Color Picker in texture mode sampling incorrect values (sample merged OFF, sampling from another object) #88300

New Issue

Jonas Meyer · 2021-05-15T00:40:24+02:00

Jonas Meyer commented

2021-05-15 00:40:24 +02:00

System Information
Operating system: Windows-10-10.0.19041-SP0 64 Bits
Graphics card: GeForce RTX 3080/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 462.31

Blender Version
Broken: version: 2.92.0, branch: master, commit date: 2021-02-24 16:25, hash: 02948a2cab
Worked: ?

Short description of error
The color picker in "Texture Painting" mode seems to only sample the correct color when the look is set to Noneunder the ColorManagement->Look->"None" and if the Viewport Shading->RenderPass is set to DiffuseColor.
Otherwise, the color values are simply wrong, they are either too bright or too dark.
In the provided scene the issue is quite clear, but in more complex scenes with more complex lighting and post-processing the sampling becomes completely broken giving values that aren't even close to what is shown on screen.

Expected Behaviour
The way I would expect the color picker to work is that it either samples the color as I as a user see it on my viewport.
Or that it samples the source texture at the pixel I am sampling without any extra lighting applied to it. ( This should be easily toggleable behavior but that is more of a feature request )ColorPicker_WrongSampling.blend
Right now it seems to do neither.

Exact steps for others to reproduce the error

Open attached .blend file.
Select the black cube and enter Texture Paint Mode.

**System Information** Operating system: Windows-10-10.0.19041-SP0 64 Bits Graphics card: GeForce RTX 3080/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 462.31 **Blender Version** Broken: version: 2.92.0, branch: master, commit date: 2021-02-24 16:25, hash: `02948a2cab` Worked: ? **Short description of error** The color picker in "Texture Painting" mode seems to only sample the correct color when the look is set to **None**under the **ColorManagement->Look->"None"** and if the Viewport **Shading->RenderPass** is set to **DiffuseColor**. Otherwise, the color values are simply wrong, they are either too bright or too dark. *In the provided scene the issue is quite clear, but in more complex scenes with more complex lighting and post-processing the sampling becomes **completely** broken giving values that aren't even close to what is shown on screen.* **Expected Behaviour** The way I would expect the color picker to work is that it either samples the color as **I** as a user see it on my viewport. Or that it samples the source texture at the pixel I am sampling without any extra lighting applied to it. *( This should be easily toggleable behavior but that is more of a feature request )*[ColorPicker_WrongSampling.blend](https://archive.blender.org/developer/F10104107/ColorPicker_WrongSampling.blend) Right now it seems to do neither. **Exact steps for others to reproduce the error** - Open attached .blend file. - Select the black cube and enter Texture Paint Mode. # Sample the color from the other cube *( I recommend sampling the green since the meshes are close to each other making it easy to see the color difference )*.

Jonas Meyer commented

2021-05-15 00:40:25 +02:00

Added subscriber: @JJG

Jonas Meyer commented

2021-05-15 01:02:03 +02:00

Here is a video I recorded of the problem to show to some friends where you can see the color picker doing all sorts of nonsense. That was before I made the reproduction steps.
#86196 seems related in so far that its talking about sampling in general behaving strangely, not specific to the 3D texture painting.There also appears to be an issue with the color picker sampling textures linearly despite what interpolation method is actually being used, in the videos case the texture interpolation is set to "Closest" but its using "Linear" instead. Should I make another ticket for this?{F10104126}*There also doesn't appear to be a way to make the embed display smaller, sorry for that.//

Here is a video I recorded of the problem to show to some friends where you can see the color picker doing all sorts of nonsense. That was before I made the reproduction steps. [#86196](https:*developer.blender.org/T86196) seems related in so far that its talking about sampling in general behaving strangely, not specific to the 3D texture painting.*There also appears to be an issue with the color picker sampling textures linearly despite what interpolation method is actually being used, in the videos case the texture interpolation is set to "Closest" but its using "Linear" instead. Should I make another ticket for this?*{[F10104126](https://archive.blender.org/developer/F10104126/colorPicker_wonkiness.mp4)}*There also doesn't appear to be a way to make the embed display smaller, sorry for that.//

Philipp Oeser commented

2021-05-20 10:02:30 +02:00

Added subscriber: @lichtwerk

Philipp Oeser commented

2021-05-20 10:02:30 +02:00

Changed status from 'Needs Triage' to: 'Confirmed'

Philipp Oeser self-assigned this 2021-05-20 10:02:30 +02:00

Philipp Oeser commented

2021-05-20 10:02:30 +02:00

I can sort of confirm.

But first of all, here is the scenario that actually works as intended:

use the {key S} Sample Color operator (not the eyedropper from the brush color), this operator has the Sample Merged option.
- with the option of, shading information is discarded and only the texture value is sampled

However, this only seems to work correctly when sampling from the same object, when picking from another object, behavior seems to be as if the Sample Merged option is ON (meaning it will just sample the OpneGL pixel value -- including all shading on top).

Will check on the case where we are picking from another object than is currently being painted on.
But @JJG: could you confirm that Sample Color works correctly for you when sampling from the same object?

There also appears to be an issue with the color picker sampling textures linearly despite what interpolation method is actually being used, in the videos case the texture interpolation is set to "Closest" but its using "Linear" instead. Should I make another ticket for this?

Yes, please

I can sort of confirm. But first of all, here is the scenario that actually works as intended: - use the {key S} `Sample Color` operator (not the eyedropper from the brush color), this operator has the `Sample Merged` option. - with the option of, shading information is discarded and only the texture value is sampled However, this only seems to work correctly when sampling from the **same object**, when picking from another object, behavior seems to be as if the `Sample Merged` option is ON (meaning it will just sample the OpneGL pixel value -- including all shading on top). Will check on the case where we are picking **from another object** than is currently being painted on. But @JJG: could you confirm that Sample Color works correctly for you when sampling **from the same object**? > There also appears to be an issue with the color picker sampling textures linearly despite what interpolation method is actually being used, in the videos case the texture interpolation is set to "Closest" but its using "Linear" instead. Should I make another ticket for this? > Yes, please

Philipp Oeser changed title from ~~Color Picker in texture mode sampling incorrect values~~ to Color Picker in texture mode sampling incorrect values (sample merged OFF, sampling from another object)

2021-05-20 10:03:02 +02:00

Jonas Meyer commented

2021-05-20 11:12:15 +02:00

Added subscriber: @jonas-19

Jonas Meyer commented

2021-05-20 11:12:15 +02:00

But @jonas-19 Meyer (JJG): could you confirm that Sample Color works correctly for you when sampling from the same object?

Will do later in the evening today.

> But @jonas-19 Meyer (JJG): could you confirm that Sample Color works correctly for you when sampling from the same object? Will do later in the evening today.

Philipp Oeser commented

2021-05-20 12:05:00 +02:00

Added subscribers: @mano-wii, @ideasman42

Philipp Oeser commented

2021-05-20 12:05:00 +02:00

So here is a bit of code that would enable picking colors directly from the textures of other objects.
Has rough edges though, not sure if this would really be the way to go:

P2128: T88300_snippet



diff --git a/source/blender/editors/sculpt_paint/paint_utils.c b/source/blender/editors/sculpt_paint/paint_utils.c
index 2484f382ed4..5f04c74f92e 100644
--- a/source/blender/editors/sculpt_paint/paint_utils.c
+++ b/source/blender/editors/sculpt_paint/paint_utils.c
@@ -478,26 +478,33 @@ void paint_sample_color(
 
   if (v3d && texpaint_proj) {
     /* first try getting a color directly from the mesh faces if possible */
-    ViewLayer *view_layer = CTX_data_view_layer(C);
-    Object *ob = OBACT(view_layer);
-    Object *ob_eval = DEG_get_evaluated_object(depsgraph, ob);
-    ImagePaintSettings *imapaint = &scene->toolsettings->imapaint;
-    bool use_material = (imapaint->mode == IMAGEPAINT_MODE_MATERIAL);
+    const int mval- [x] = {x, y};
+    Base *base = ED_view3d_give_base_under_cursor(C, mval);
+
+    if (base != NULL) {
+      Object *ob = base->object;
+      Object *ob_eval = DEG_get_evaluated_object(depsgraph, ob);
+
+      /* Cheat for picking from another than the active object
+       * imapaint_face_image() needs these initalized. */
+      BKE_texpaint_slots_refresh_object(scene, ob);
+
+      ImagePaintSettings *imapaint = &scene->toolsettings->imapaint;
+      bool use_material = (imapaint->mode == IMAGEPAINT_MODE_MATERIAL);
 
-    if (ob) {
       CustomData_MeshMasks cddata_masks = CD_MASK_BAREMESH;
       cddata_masks.pmask |= CD_MASK_ORIGINDEX;
       Mesh *me = (Mesh *)ob->data;
       Mesh *me_eval = mesh_get_eval_final(depsgraph, scene, ob_eval, &cddata_masks);
 
       ViewContext vc;
-      const int mval- [x] = {x, y};
       uint faceindex;
       uint totpoly = me->totpoly;
 
       if (CustomData_has_layer(&me_eval->ldata, CD_MLOOPUV)) {
         ED_view3d_viewcontext_init(C, &vc, depsgraph);
-
+        /* Cheat for picking from another than the active object. */
+        vc.obact = ob;
         view3d_operator_needs_opengl(C);
 
         if (imapaint_pick_face(&vc, mval, &faceindex, totpoly)) {
diff --git a/source/blender/editors/space_view3d/view3d_draw.c b/source/blender/editors/space_view3d/view3d_draw.c
index 0a89b7d0292..58e9a25db6e 100644
--- a/source/blender/editors/space_view3d/view3d_draw.c
+++ b/source/blender/editors/space_view3d/view3d_draw.c
@@ -2161,7 +2161,9 @@ static void validate_object_select_id(struct Depsgraph *depsgraph,
   else if ((obact_eval && (obact_eval->mode & OB_MODE_PARTICLE_EDIT)) && !XRAY_ENABLED(v3d)) {
     /* do nothing */
   }
-  else {
+  /* #88300: in case of sampling from another object, we dont want to return here
+   * DRW_select_buffer_context_create stuff below is still needed. */
+  else if (OBACT(view_layer) == obact){
     v3d->runtime.flag |= V3D_RUNTIME_DEPTHBUF_OVERRIDDEN;
     return;
   }

Will change this to TODO, current code was not really expecting this to work on objects other than the active.
(Of course, from the user perspective, this is totally unexpected)

Might be interesting to
CC @ideasman42
CC @mano-wii

So here is a bit of code that would enable picking colors directly from the textures of **other objects**. Has rough edges though, not sure if this would really be the way to go: [P2128: T88300_snippet](https://archive.blender.org/developer/P2128.txt) ``` diff --git a/source/blender/editors/sculpt_paint/paint_utils.c b/source/blender/editors/sculpt_paint/paint_utils.c index 2484f382ed4..5f04c74f92e 100644 --- a/source/blender/editors/sculpt_paint/paint_utils.c +++ b/source/blender/editors/sculpt_paint/paint_utils.c @@ -478,26 +478,33 @@ void paint_sample_color( if (v3d && texpaint_proj) { /* first try getting a color directly from the mesh faces if possible */ - ViewLayer *view_layer = CTX_data_view_layer(C); - Object *ob = OBACT(view_layer); - Object *ob_eval = DEG_get_evaluated_object(depsgraph, ob); - ImagePaintSettings *imapaint = &scene->toolsettings->imapaint; - bool use_material = (imapaint->mode == IMAGEPAINT_MODE_MATERIAL); + const int mval- [x] = {x, y}; + Base *base = ED_view3d_give_base_under_cursor(C, mval); + + if (base != NULL) { + Object *ob = base->object; + Object *ob_eval = DEG_get_evaluated_object(depsgraph, ob); + + /* Cheat for picking from another than the active object + * imapaint_face_image() needs these initalized. */ + BKE_texpaint_slots_refresh_object(scene, ob); + + ImagePaintSettings *imapaint = &scene->toolsettings->imapaint; + bool use_material = (imapaint->mode == IMAGEPAINT_MODE_MATERIAL); - if (ob) { CustomData_MeshMasks cddata_masks = CD_MASK_BAREMESH; cddata_masks.pmask |= CD_MASK_ORIGINDEX; Mesh *me = (Mesh *)ob->data; Mesh *me_eval = mesh_get_eval_final(depsgraph, scene, ob_eval, &cddata_masks); ViewContext vc; - const int mval- [x] = {x, y}; uint faceindex; uint totpoly = me->totpoly; if (CustomData_has_layer(&me_eval->ldata, CD_MLOOPUV)) { ED_view3d_viewcontext_init(C, &vc, depsgraph); - + /* Cheat for picking from another than the active object. */ + vc.obact = ob; view3d_operator_needs_opengl(C); if (imapaint_pick_face(&vc, mval, &faceindex, totpoly)) { diff --git a/source/blender/editors/space_view3d/view3d_draw.c b/source/blender/editors/space_view3d/view3d_draw.c index 0a89b7d0292..58e9a25db6e 100644 --- a/source/blender/editors/space_view3d/view3d_draw.c +++ b/source/blender/editors/space_view3d/view3d_draw.c @@ -2161,7 +2161,9 @@ static void validate_object_select_id(struct Depsgraph *depsgraph, else if ((obact_eval && (obact_eval->mode & OB_MODE_PARTICLE_EDIT)) && !XRAY_ENABLED(v3d)) { /* do nothing */ } - else { + /* #88300: in case of sampling from another object, we dont want to return here + * DRW_select_buffer_context_create stuff below is still needed. */ + else if (OBACT(view_layer) == obact){ v3d->runtime.flag |= V3D_RUNTIME_DEPTHBUF_OVERRIDDEN; return; } ``` Will change this to TODO, current code was not really expecting this to work on objects other than the active. (Of course, from the user perspective, this is totally unexpected) Might be interesting to CC @ideasman42 CC @mano-wii

Jonas Meyer commented

2021-05-20 18:28:15 +02:00

@lichtwerk I can confirm that the sampling works as long as it is the same object but gives incorrect values when trying to sample another object.

Philipp Oeser removed their assignment 2021-06-02 10:48:42 +02:00

Ken commented

2021-12-06 15:51:35 +01:00

Added subscriber: @KennethThomas

Julien Kaspar added this to the Sculpt, Paint & Texture project 2023-02-08 10:48:53 +01:00

Philipp Oeser removed the

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Color Picker in texture mode sampling incorrect values (sample merged OFF, sampling from another object) #88300

Sample the color from the other cube ( I recommend sampling the green since the meshes are close to each other making it easy to see the color difference ).