BoxBlur shader stop working in certain Bl version. #52431

New Issue

Mario Mey · 2017-08-17T20:49:30+02:00

Mario Mey commented

2017-08-17 20:49:30 +02:00

System Information
Debian 9 x64, nVidia GT620

Blender Version
Broken: 2.76 (from web)
Worked: 2.75a (from web)

Short description of error
This is a Filter 2D download from doesn't-know-where (I couldn't find source). It is a Blur filter with amount and multiplier values. It works pretty well in 2.75a. Since 2.76, it doesn't work anymore, the output is only a bit darker. No blur.
2dfilter_boxblur.blend

Shader code is:

/* Simple Box Blur
 * Higher amount = slower
 * multipler property does not affect performance
 */

uniform sampler2D bgl_RenderedTexture;
uniform float bgl_RenderedTextureWidth;
uniform float bgl_RenderedTextureHeight;
uniform float amount;
uniform float multiplier;

vec2 pix = vec2(1.0 / bgl_RenderedTextureWidth, 1.0 / bgl_RenderedTextureHeight) * multiplier;

void main() {
	vec4 sum = vec4(0);
	
	int i, j;
	
	for(i = -amount; i <= amount; i++){
		for(j = -amount; j <= amount; j++){
			sum += texture2D(bgl_RenderedTexture, gl_TexCoord[0].st + vec2(float(i), float(j)) * pix);
	}}
	gl_FragColor = sum / pow((amount + 1) * 2, 2);
}

Exact steps for others to reproduce the error
Open file with 2.75a, run Game.
Open file with 2.76, run Game.

**System Information** Debian 9 x64, nVidia GT620 **Blender Version** Broken: 2.76 (from web) Worked: 2.75a (from web) **Short description of error** This is a Filter 2D download from doesn't-know-where (I couldn't find source). It is a Blur filter with amount and multiplier values. It works pretty well in 2.75a. Since 2.76, it doesn't work anymore, the output is only a bit darker. No blur. [2dfilter_boxblur.blend](https://archive.blender.org/developer/F716574/2dfilter_boxblur.blend) Shader code is: ``` /* Simple Box Blur * Higher amount = slower * multipler property does not affect performance */ uniform sampler2D bgl_RenderedTexture; uniform float bgl_RenderedTextureWidth; uniform float bgl_RenderedTextureHeight; uniform float amount; uniform float multiplier; vec2 pix = vec2(1.0 / bgl_RenderedTextureWidth, 1.0 / bgl_RenderedTextureHeight) * multiplier; void main() { vec4 sum = vec4(0); int i, j; for(i = -amount; i <= amount; i++){ for(j = -amount; j <= amount; j++){ sum += texture2D(bgl_RenderedTexture, gl_TexCoord[0].st + vec2(float(i), float(j)) * pix); }} gl_FragColor = sum / pow((amount + 1) * 2, 2); } ``` **Exact steps for others to reproduce the error** Open file with 2.75a, run Game. Open file with 2.76, run Game.

Mario Mey commented

2017-08-17 20:49:30 +02:00

Changed status to: 'Open'

Mario Mey commented

2017-08-17 20:49:30 +02:00

Added subscriber: @MarioSottile

Sergey Sharybin commented

2017-09-11 13:11:44 +02:00

Added subscriber: @Sergey

Sergey Sharybin commented

2017-09-11 13:11:44 +02:00

Changed status from 'Open' to: 'Archived'

Sergey Sharybin closed this issue

2017-09-11 13:11:44 +02:00

Sergey Sharybin self-assigned this 2017-09-11 13:11:44 +02:00

Sergey Sharybin commented

2017-09-11 13:11:44 +02:00

Your uniform value for amount is set as float in shader, but declared as integer in camera properties. Now, thing is, before 2.76 (commit 97b431e4) all shader uniforms were binding as floats, but it's not what you always want so proper int/float binding was implemented. What happens in your scene is that binding uniform fails because BGE tries to bind it as integer, while it is float in shader itself.

Unfortunately, we can't do-version anything here to avoid regression, such things would require writing comprehensive GLSL compiler by ourselves.. Two things you can do:

Change uniform float amount; to uniform int amount; in the shader itself
Change amoumt from integer to float in logic editor.

So thanks for the report, but it's not really a bug..

Your uniform value for `amount` is set as `float` in shader, but declared as `integer` in camera properties. Now, thing is, before 2.76 (commit 97b431e4) all shader uniforms were binding as floats, but it's not what you always want so proper int/float binding was implemented. What happens in your scene is that binding uniform fails because BGE tries to bind it as integer, while it is float in shader itself. Unfortunately, we can't do-version anything here to avoid regression, such things would require writing comprehensive GLSL compiler by ourselves.. Two things you can do: - Change `uniform float amount;` to `uniform int amount;` in the shader itself - Change `amoumt` from integer to float in logic editor. So thanks for the report, but it's not really a bug..

Mario Mey commented

2017-09-11 23:22:53 +02:00

As the code is done, changing amount to float, it does weird results. "uniform int amout" is the real solution.

Anyway... by setting amount to 0 (no-blur), the result is darker than original. With 2 or 3, it has more or less the same brightness... I would like to fix it, but it is not a Blender bug, but this code bug. I will ask about it in IRC #gameblender.

Thanks.

As the code is done, changing amount to float, it does weird results. "uniform int amout" is the real solution. Anyway... by setting amount to 0 (no-blur), the result is darker than original. With 2 or 3, it has *more or less* the same brightness... I would like to fix it, but it is not a Blender bug, but this code bug. I will ask about it in IRC #gameblender. Thanks.

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BoxBlur shader stop working in certain Bl version. #52431