Grease Pencil: drawing shapes on surface causes intense viewport flickering #65955

New Issue

MACHIN3 · 2019-06-20T13:25:54+02:00

MACHIN3 commented

2019-06-20 13:25:54 +02:00

System Information
Operating system: Linux-4.13.10-041310-generic-x86_64-with-debian-stretch-sid 64 Bits
Graphics card: GeForce GTX 1050/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 390.67

Blender Version
Broken: version: 2.80 (sub 74), branch: master, commit date: 2019-06-19 18:29, hash: d30f72dfd8

Drawing GP shapes on the surface of an object causes viewport flickering.

See video demo .

grease_pencil_shape_on_surface_viewport_flicker.blend

Exact steps for others to reproduce the error

open the blend file
- everything is setup for surface drawing already
start drawing lines or other shapes
- the viewport should flicker(cyclce through various buffers?)

**System Information** Operating system: Linux-4.13.10-041310-generic-x86_64-with-debian-stretch-sid 64 Bits Graphics card: GeForce GTX 1050/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 390.67 **Blender Version** Broken: version: 2.80 (sub 74), branch: master, commit date: 2019-06-19 18:29, hash: `d30f72dfd8` Drawing GP shapes on the surface of an object causes viewport flickering. See [video demo ](https://www.youtube.com/watch?v=Wa7clEDLeFI). [grease_pencil_shape_on_surface_viewport_flicker.blend](https://archive.blender.org/developer/F7352773/grease_pencil_shape_on_surface_viewport_flicker.blend) **Exact steps for others to reproduce the error** * open the blend file * everything is setup for surface drawing already * start drawing lines or other shapes * the viewport should flicker(cyclce through various buffers?)

MACHIN3 commented

2019-06-20 13:25:54 +02:00

Added subscriber: @MACHIN3

Tchelet Levi commented

2019-06-20 16:46:23 +02:00

Added subscriber: @MizManFryinPan

Tchelet Levi commented

2019-06-20 16:46:23 +02:00

Can confirm. Doesn't work on 'd30f72dfd8ac'
Seems to have worked fine on Hash: '12da679fa094' though it could've also worked later on. Its just the latest one before today's build that I have on my computer.

Can confirm. Doesn't work on 'd30f72dfd8ac' Seems to have worked fine on Hash: '12da679fa094' though it could've also worked later on. Its just the latest one before today's build that I have on my computer.

Brecht Van Lommel commented

2019-06-20 16:53:40 +02:00

Added subscriber: @brecht

Clément Foucault was assigned by Brecht Van Lommel

2019-06-20 16:53:40 +02:00

Brecht Van Lommel commented

2019-06-20 16:53:40 +02:00

Caused by 741641f4c3.

Caused by 741641f4c3.

Clément Foucault commented

2019-06-21 00:53:23 +02:00

Ok it is caused by a VERY bad usage of DRW in GPencil. My patch just unveiled the problem.

Clément Foucault removed their assignment 2019-06-21 01:31:10 +02:00

Antonio Vazquez was assigned by Clément Foucault

2019-06-21 01:31:10 +02:00

Clément Foucault commented

2019-06-21 01:31:10 +02:00

Added subscribers: @antoniov, @fclem

Clément Foucault commented

2019-06-21 01:31:10 +02:00

@antoniov The issue comes from these lines. When drawing a line, the draw depth function is called first, and only used basic engine and GPencil. But then when the viewport is redrawn, an other set of engine is enabled which reset all engines data for this viewport.

This makes stl->storage->buffer_stroke false even if the stl->storage->buffer_stroke is still valid. That leads to memory leak and other
So the easy fix should be to free just after finishing drawing.

In the long run we should reuse the batches to avoid memory allocations.

Source of the issue.

        if (stl->storage->buffer_stroke) {
          GPU_BATCH_DISCARD_SAFE(e_data->batch_buffer_stroke);
          MEM_SAFE_FREE(e_data->batch_buffer_stroke);
          stl->storage->buffer_stroke = false;
        }

      ...
      /* temp textures for ping-pong buffers */
      e_data.temp_depth_tx_a = DRW_texture_pool_query_2d(
          size[0], size[1], GPU_DEPTH_COMPONENT24, &draw_engine_gpencil_type);
      ...

Don't use e_data for things that will change or can be volatile. Use stl->g_data for that and be sure to reset it before reuse

Pretty much all these vars should be inside stl->g_data

  /* textures */
  struct GPUTexture *background_depth_tx;
  struct GPUTexture *background_color_tx;

  struct GPUTexture *gpencil_blank_texture;

  /* runtime pointers texture */
  struct GPUTexture *input_depth_tx;
  struct GPUTexture *input_color_tx;

  /* working textures */
  struct GPUTexture *temp_color_tx_a;
  struct GPUTexture *temp_depth_tx_a;

  struct GPUTexture *temp_color_tx_b;
  struct GPUTexture *temp_depth_tx_b;

  struct GPUTexture *temp_color_tx_fx;
  struct GPUTexture *temp_depth_tx_fx;

  /* for buffer only one batch is nedeed because the drawing is only of one stroke */
  GPUBatch *batch_buffer_stroke;
  GPUBatch *batch_buffer_fill;
  GPUBatch *batch_buffer_ctrlpoint;

  /* grid geometry */
  GPUBatch *batch_grid;

If you are using temp textures, then you cannot assume they will be the same when the next redraw comes up. Use txl and real texture for that.

@antoniov The issue comes from these lines. When drawing a line, the draw depth function is called first, and only used basic engine and GPencil. But then when the viewport is redrawn, an other set of engine is enabled which reset all engines data for this viewport. This makes `stl->storage->buffer_stroke` false even if the stl->storage->buffer_stroke is still valid. That leads to memory leak and other So the easy fix should be to free just after finishing drawing. In the long run we should reuse the batches to avoid memory allocations. Source of the issue. ``` if (stl->storage->buffer_stroke) { GPU_BATCH_DISCARD_SAFE(e_data->batch_buffer_stroke); MEM_SAFE_FREE(e_data->batch_buffer_stroke); stl->storage->buffer_stroke = false; } ``` ``` ... /* temp textures for ping-pong buffers */ e_data.temp_depth_tx_a = DRW_texture_pool_query_2d( size[0], size[1], GPU_DEPTH_COMPONENT24, &draw_engine_gpencil_type); ... ``` Don't use e_data for things that will change or can be volatile. Use stl->g_data for that and be sure to reset it before reuse Pretty much all these vars should be inside stl->g_data ``` /* textures */ struct GPUTexture *background_depth_tx; struct GPUTexture *background_color_tx; struct GPUTexture *gpencil_blank_texture; /* runtime pointers texture */ struct GPUTexture *input_depth_tx; struct GPUTexture *input_color_tx; /* working textures */ struct GPUTexture *temp_color_tx_a; struct GPUTexture *temp_depth_tx_a; struct GPUTexture *temp_color_tx_b; struct GPUTexture *temp_depth_tx_b; struct GPUTexture *temp_color_tx_fx; struct GPUTexture *temp_depth_tx_fx; /* for buffer only one batch is nedeed because the drawing is only of one stroke */ GPUBatch *batch_buffer_stroke; GPUBatch *batch_buffer_fill; GPUBatch *batch_buffer_ctrlpoint; /* grid geometry */ GPUBatch *batch_grid; ``` If you are using temp textures, then you cannot assume they will be the same when the next redraw comes up. Use txl and real texture for that.

Antonio Vazquez commented

2019-06-21 08:21:20 +02:00

@fclem I will take a look of the bug, but not sure now it's the moment to make the other changes so near of 2.80 release date. I thinkis better wait for 2.81.

Antonio Vazquez commented

2019-06-21 08:24:52 +02:00

I have tested and in Windows 10 NVIDIA RTX2080TI I'm unable to reproduce it.

EDIT: With a new file I can reproduce it now.

I have tested and in Windows 10 NVIDIA RTX2080TI I'm unable to reproduce it. EDIT: With a new file I can reproduce it now.

Antonio Vazquez commented

2019-06-21 20:54:38 +02:00

Working in the fix in D5115

Working in the fix in [D5115](https://archive.blender.org/developer/D5115)

blender-admin commented

2019-06-22 16:47:18 +02:00

This issue was referenced by 8bf1977d31

This issue was referenced by 8bf1977d311fc7d8b5979fdd6ac5b982076b1e60

Antonio Vazquez commented

2019-06-22 16:50:22 +02:00

Changed status from 'Open' to: 'Resolved'

Antonio Vazquez closed this issue

2019-06-22 16:50:22 +02:00

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Grease Pencil: drawing shapes on surface causes intense viewport flickering #65955