1417182 - GLSL fragment shader Texture2D mis-sampled unless refactored to temporary variable

Status: UNCONFIRMED

(Core :: Graphics: CanvasWebGL, defect, P3)

Description

[jameswilddev]

User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.110 Safari/537.36 Edge/16.16299

Steps to reproduce:

I'm currently doing some graphics experiments, and have found a scenario in which Firefox's WebGL implementation on Windows acts strangely.

This graphics experiment can be seen at http://test.sunruse.co.uk/toon-engine-firefox-repro-1/

I've found a workaround for this; open the shader editor, and replace the following line:

gl_FragColor = vec4(pow(pow(texture2D(u_palette, texture2D(u_gbuffer, v_uv).rg).rgb, vec3(2.2)) * (texture2D(u_accumulator, v_uv).rgb + u_ambientColor), vec3(1.0 / 2.2)), 1.0);

With:

  vec2 paletteUV = texture2D(u_gbuffer, v_uv).rg;
gl_FragColor = vec4(pow(pow(texture2D(u_palette, paletteUV).rgb, vec3(2.2)) * (texture2D(u_accumulator, v_uv).rgb + u_ambientColor), vec3(1.0 / 2.2)), 1.0);

This should be functionally identical (getting a colour from a palette texture by reading from a G-buffer texture has been split into separately sampling the G-buffer and palette as two separate statements rather than in one expression).


Actual results:

In Firefox, the scene is blue with only outlines visible.


Expected results:

In Edge or Chrome, different parts of the scene have colour.

Comment 1

[Jerry Shih[:jerry] (UTC+8) (inactive)]

Michael, could you check this? Maybe it's related to libangle update.

Comment 2

[Daosheng Mu[:daoshengmu]]

I have checked it with Firefox beta(58) and Nightly (59) in Windows, it has already been fixed.


:jameswilddev, could you help us download Firefox Beta and try it again? Thanks!

Comment 3

[jameswilddev]

Just tried it and all looks good from here.  Thanks!