Edge loops crashing blender (exeeding IMM_BUFFER_SIZE) #68950

New Issue

Olin · 2019-08-21T06:47:42+02:00

Olin commented

2019-08-21 06:47:42 +02:00

Operating system: Windows 10
Graphics card: AMD R9 270

Broken: 2.80
Worked: (optional)

Adding edge loops to cylinder completely crashes after a certain point

Based on the default startup or an attached .blend file (as simple as possible).
Delete the underappreciated default cube
add cylinder
set subdivisions to 500 in the little f9 menu
add edge loops with Ctrl+R and scroll up to increase number until blender just dies.
look at your beautiful desktop

Could not test with the absolutely latest blender because isp is having troubles but some nice people on reddit say they can reproduce it

Attached video shows me demonstrating.2019-08-20 22-07-03.mp4

Reddit Thread that started this all: https://www.reddit.com/r/blender/comments/ct4o6o/nice/

Operating system: Windows 10 Graphics card: AMD R9 270 Broken: 2.80 Worked: (optional) Adding edge loops to cylinder completely crashes after a certain point Based on the default startup or an attached .blend file (as simple as possible). Delete the underappreciated default cube add cylinder set subdivisions to 500 in the little f9 menu add edge loops with Ctrl+R and scroll up to increase number until blender just dies. look at your beautiful desktop Could not test with the absolutely latest blender because isp is having troubles but some nice people on reddit say they can reproduce it Attached video shows me demonstrating.[2019-08-20 22-07-03.mp4](https://archive.blender.org/developer/F7677211/2019-08-20_22-07-03.mp4) Reddit Thread that started this all: https://www.reddit.com/r/blender/comments/ct4o6o/nice/

Olin commented

2019-08-21 06:47:42 +02:00

Added subscriber: @Ferret-1

blender-admin commented

2019-08-21 06:47:42 +02:00

#69372 was marked as duplicate of this issue

Jesse Yurkovich commented

2019-08-21 08:33:16 +02:00

Added subscriber: @deadpin

Jesse Yurkovich commented

2019-08-21 08:33:16 +02:00

It looks like the vertex buffer limit has been exceeded which triggers an assert inside gpu_immediate.c (debug build)

Bumping to 6mb allows a 500 vertex cylinder to be edge-ring'd 500 times. The operator soft-max for cylinder creation and loop cut and slide are both 500 (gpu_immediate is used to draw the new edge-rings during the interactive portion of the operator while scrolling the mouse). The limit can still be exceeded if the user goes out of their way to exceed the cylinder max (e.g. a 2000 vert cylinder and then mouse-wheeling loop cuts again)

#if TRUST_NO_ONE
  assert(bytes_needed <= IMM_BUFFER_SIZE);
#endif

...
blender.exe!immBegin(GPUPrimType prim_type, unsigned int vertex_len) Line 215	C
blender.exe!EDBM_preselect_edgering_draw(EditMesh_PreSelEdgeRing * psel, const float[4] * matrix) Line 175	C
blender.exe!ringsel_draw(const bContext * UNUSED_C, ARegion * UNUSED_ar, void * arg) Line 105	C
blender.exe!ED_region_draw_cb_draw(const bContext * C, ARegion * ar, int type) Line 279	C

It looks like the vertex buffer limit has been exceeded which triggers an assert inside gpu_immediate.c (debug build) Bumping to 6mb allows a 500 vertex cylinder to be edge-ring'd 500 times. The operator soft-max for cylinder creation and loop cut and slide are both 500 (gpu_immediate is used to draw the new edge-rings during the interactive portion of the operator while scrolling the mouse). The limit can still be exceeded if the user goes out of their way to exceed the cylinder max (e.g. a 2000 vert cylinder and then mouse-wheeling loop cuts again) ``` #if TRUST_NO_ONE assert(bytes_needed <= IMM_BUFFER_SIZE); #endif ... blender.exe!immBegin(GPUPrimType prim_type, unsigned int vertex_len) Line 215 C blender.exe!EDBM_preselect_edgering_draw(EditMesh_PreSelEdgeRing * psel, const float[4] * matrix) Line 175 C blender.exe!ringsel_draw(const bContext * UNUSED_C, ARegion * UNUSED_ar, void * arg) Line 105 C blender.exe!ED_region_draw_cb_draw(const bContext * C, ARegion * ar, int type) Line 279 C ```

Philipp Oeser commented

2019-08-21 10:59:23 +02:00

Added subscribers: @fclem, @lichtwerk

Philipp Oeser commented

2019-08-21 10:59:23 +02:00

Can confirm what @deadpin said (thx investigating!)

Will raise awareness to @fclem [not sure this should be handled more gracefully, but will put on low prio for now...]

Can confirm what @deadpin said (thx investigating!) Will raise awareness to @fclem [not sure this should be handled more gracefully, but will put on low prio for now...]

Philipp Oeser changed title from ~~Edge loops crashing blender~~ to Edge loops crashing blender (exeeding IMM_BUFFER_SIZE)

2019-08-21 10:59:35 +02:00

Clément Foucault commented

2019-08-21 13:30:46 +02:00

This should be fixed by issuing multiple draw commands if the number of verts is too high.

This is an easy fix for a newcomer so I would leave it to someone else.

This should be fixed by issuing multiple draw commands if the number of verts is too high. This is an easy fix for a newcomer so I would leave it to someone else.

Huseyin Karakullukcu self-assigned this 2019-08-22 20:09:26 +02:00

Huseyin Karakullukcu commented

2019-08-22 20:44:23 +02:00

@fclem Is making IMM_BUFFER_SIZE stretchable, a better solution or not? I think it fixes this problem very easily with small amount code change.