Metal: Assert is triggered when drawing a Batch with an attribute format different from the type used in the Shader #111370

New Issue

Germano Cavalcante · 2023-08-22T05:02:30+02:00

2023-08-22 05:02:30 +02:00

System Information
Operating system: macOS-13.3.1-arm64-arm-64bit 64 Bits
Graphics card: Metal API Apple M1 1.2

Blender Version
Broken: version: 4.0.0 Alpha, branch: main, commit date: 2023-08-21 22:52, hash: d45f47a809dd
Worked: [couldn't check yet]

Short description of error
I'm not sure how serious the problem is.
Even with the assert, the drawing seems to work.
Below is a small code that demonstrates the problem:

import bpy
import gpu
from gpu.types import (
    GPUBatch,
    GPUIndexBuf,
    GPUVertBuf,
    GPUVertFormat,
)

def draw():
    x1=0
    y1=0
    x2=bpy.context.region.width
    y2=bpy.context.region.height

    # The size of each color in `vertex_colors` needs to be 4 and
    # the size of each vector in `vertices` needs to be 3
    # otherwise a assert will be triggered the Metal backend.
    vertex_colors = ((1.0, 0.0, 0.0, 1.0), (1.0, 1.0, 1.0, 1.0))
    vertices = ((x1, y1), (x2, y2))

    shader = gpu.shader.from_builtin('POLYLINE_SMOOTH_COLOR')
    shader.uniform_float("viewportSize", gpu.state.viewport_get()[2:])
    shader.uniform_float("lineWidth", 5)

    vbo_format = GPUVertFormat()
    vbo_format.attr_add(id='color', comp_type='F32', len=len(vertex_colors[0]), fetch_mode='FLOAT')
    vbo_format.attr_add(id='pos', comp_type='F32', len=len(vertices[0]), fetch_mode='FLOAT')

    vbo = GPUVertBuf(vbo_format, len(vertices))
    vbo.attr_fill('color', vertex_colors)
    vbo.attr_fill('pos', vertices)

    batch = GPUBatch(type='LINE_STRIP', buf=vbo)
    batch.draw(shader)
    del batch


bpy.types.SpaceView3D.draw_handler_add(draw, (), 'WINDOW', 'POST_PIXEL')

Note that the dimension of the vertices is 2D.
If converted to 3D (by adding a z value), the assert is no longer triggered.

Exact steps for others to reproduce the error

Open attached .blend file.
Run the script in the text editor
Update the 3D view (by zooming for example)

gpu_metal_assert__bug.blend

**System Information** Operating system: macOS-13.3.1-arm64-arm-64bit 64 Bits Graphics card: Metal API Apple M1 1.2 **Blender Version** Broken: version: 4.0.0 Alpha, branch: main, commit date: 2023-08-21 22:52, hash: `d45f47a809dd` Worked: [couldn't check yet] **Short description of error** I'm not sure how serious the problem is. Even with the assert, the drawing seems to work. Below is a small code that demonstrates the problem: ```python import bpy import gpu from gpu.types import ( GPUBatch, GPUIndexBuf, GPUVertBuf, GPUVertFormat, ) def draw(): x1=0 y1=0 x2=bpy.context.region.width y2=bpy.context.region.height # The size of each color in `vertex_colors` needs to be 4 and # the size of each vector in `vertices` needs to be 3 # otherwise a assert will be triggered the Metal backend. vertex_colors = ((1.0, 0.0, 0.0, 1.0), (1.0, 1.0, 1.0, 1.0)) vertices = ((x1, y1), (x2, y2)) shader = gpu.shader.from_builtin('POLYLINE_SMOOTH_COLOR') shader.uniform_float("viewportSize", gpu.state.viewport_get()[2:]) shader.uniform_float("lineWidth", 5) vbo_format = GPUVertFormat() vbo_format.attr_add(id='color', comp_type='F32', len=len(vertex_colors[0]), fetch_mode='FLOAT') vbo_format.attr_add(id='pos', comp_type='F32', len=len(vertices[0]), fetch_mode='FLOAT') vbo = GPUVertBuf(vbo_format, len(vertices)) vbo.attr_fill('color', vertex_colors) vbo.attr_fill('pos', vertices) batch = GPUBatch(type='LINE_STRIP', buf=vbo) batch.draw(shader) del batch bpy.types.SpaceView3D.draw_handler_add(draw, (), 'WINDOW', 'POST_PIXEL') ``` Note that the dimension of the vertices is 2D. If converted to 3D (by adding a z value), the assert is no longer triggered. **Exact steps for others to reproduce the error** - Open attached .blend file. - Run the script in the text editor - Update the 3D view (by zooming for example) [gpu_metal_assert__bug.blend](/attachments/40ab81e4-5bfd-41cd-a536-5ecb90bcdbdc)

gpu_metal_assert__bug.blend

891 KiB

Germano Cavalcante added the

labels 2023-08-22 05:02:31 +02:00

Germano Cavalcante added

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