"TonemapShaderGLES2: Fragment shader compilation failed" on HTML5 with GLES2

[dsnopek]

Godot version

3.5.rc1

System information

Firefox 99 and Chrome 101

Issue description

When running a GLES2 game exported to HTML5 (by Godot 3.5-rc1) in either Firefox or Chrome, I get a whole bunch of errors, starting with "TonemapShaderGLES2: Fragment shader compilation failed"

This same game project doesn't have any issues when exported by Godot 3.4.4.

Here's a screenshot of the full set of error messages:

Steps to reproduce

I've tried to reproduce with a fresh project, but I can't seem to. I'll keep trying to figure it out, but I decided to post this issue right away just in case the error message is enough for someone to guess what's going wrong.

UPDATE:

• Create a fresh project
• Enable FXAA in project settings
• Export to HTML5
• Open in a web browser.

Minimal reproduction project

No response

[clayjohn]

Likely also a regression from #54585

Should be as simple as making the following changes (I'll make a PR shortly):

godot/drivers/gles2/shaders/tonemap.glsl

Line 207 in b0a2b34

color.a = a + color.a * (1 - a);

to

 color.a = a + color.a * (1.0 - a); 

and

godot/drivers/gles2/shaders/tonemap.glsl

Lines 245 to 248 in b0a2b34

	float lumaNW = dot(rgbNW.rgb, luma) - ((1 - rgbNW.a) / 8.0);
	float lumaNE = dot(rgbNE.rgb, luma) - ((1 - rgbNE.a) / 8.0);
	float lumaSW = dot(rgbSW.rgb, luma) - ((1 - rgbSW.a) / 8.0);
	float lumaSE = dot(rgbSE.rgb, luma) - ((1 - rgbSE.a) / 8.0);

to

 float lumaNW = dot(rgbNW.rgb, luma) - ((1.0 - rgbNW.a) / 8.0); 
 float lumaNE = dot(rgbNE.rgb, luma) - ((1.0 - rgbNE.a) / 8.0); 
 float lumaSW = dot(rgbSW.rgb, luma) - ((1.0 - rgbSW.a) / 8.0); 
 float lumaSE = dot(rgbSE.rgb, luma) - ((1.0 - rgbSE.a) / 8.0); 

and

godot/drivers/gles2/shaders/tonemap.glsl

Line 270 in b0a2b34

float lumaB = dot(rgbB.rgb, luma) - ((1 - rgbB.a) / 8.0);

to

float lumaB = dot(rgbB.rgb, luma) - ((1.0 - rgbB.a) / 8.0); 

[dsnopek]

Likely also a regression from #54585

Aha! Based on looking at that issue, I figured out what I was missing to reproduce: All you need to do is enable FXAA on a fresh project.

[akien-mga]

Fixed by #61171.