Decal with normal map only bugs

[Dreikblack]

1. Does not work on current beta build (invisible). Can be fixed with new Lighting.glsl shader which was not yet added to build.

2. On one side normal looks correct like scratch and on other like "vein":

3. If surface have normal map, decal looks wrong by having different color and visible borders. Most likely it's happens due full "rewrite" of surface normal map.

Can be decal normal map be just "above" or something like that to prevent it?

 

Map, mats, shader:

DecalNormals.zip

[Josh]

I just had to change the normal argument for RenderLighting to inout and it fixed the problem I think:

[Dreikblack]

What was fixed? I still have 2 and 3 issues with latest update and shader

[Josh]

Will take another look tomorrow.

[Josh]

On 3/14/2025 at 10:10 PM, Dreikblack said:

2. On one side normal looks correct like scratch and on other like "vein":

3. If surface have normal map, decal looks wrong by having different color and visible borders. Most likely it's happens due full "rewrite" of surface normal map. Can be decal normal map be just "above" or something like that to prevent it?

2. This looks correct. On the right side, most of the light come from the sun from the side, so the left side of the crack is lit. On the left face, the only light is coming from the diffuse skybox, so the bottom edge of the crack is lit. It can be helpful to set IBL lighting to zero when testing these things, to better see what is happening.

3. You can use an opacity map to control the alpha weight of the normal and other maps, when a base color texture is not in use.

[Dreikblack]

7 hours ago, Josh said:

2. This looks correct. On the right side, most of the light come from the sun from the side, so the left side of the crack is lit. On the left face, the only light is coming from the diffuse skybox, so the bottom edge of the crack is lit. It can be helpful to set IBL lighting to zero when testing these things, to better see what is happening.

It's not light.

0 IBL, only sun light:

And everything same, but decal rotated by 90:

It looks like normal map is reverted or something for some of decal "faces"

7 hours ago, Josh said:

3. You can use an opacity map to control the alpha weight of the normal and other maps, when a base color texture is not in use.

Opacity map does exactly nothing. Same effect if it's full red or black.

[Josh]

Looks like the tangent / bitangent might be flipped on some mapping axes...

normaltest.zip

[Josh]

Okay, this seems to be the magic formula:

if (dot(decalnormalmatrix[axis], facenormal) < 0.0f) decalnormalmatrix[axis] *= -1.0f;// flip if facing wrong way
//if (dot(decalnormalmatrix[2], facenormal) < 0.0f) decalnormalmatrix = -decalnormalmatrix;// flip if facing wrong way

 

[Josh]

Opacity map works as expected.

Imperfections.zip

[Josh]

(Crosses fingers)

[Dreikblack]

11 minutes ago, Josh said:

Opacity map works as expected.

So it's RGB channels and not just red? Now i have effect.

Is there a way to change total opacity for specific decal instance in runt time btw?

[Josh]

The shader reads the red channel of the opacity texture:

if (mtl.textureHandle[TEXTURE_OPACITY] != uvec2(0))
{
	color.a = texture(sampler2D(mtl.textureHandle[TEXTURE_OPACITY]), decalcoords).r;
}

 

[Josh]

9 minutes ago, Dreikblack said:

Is there a way to change total opacity for specific decal instance in runt time btw?

I updated the shader so it will consider the entity alpha as well.

if (mtl.textureHandle[TEXTURE_OPACITY] != uvec2(0))
{
	color.a *= texture(sampler2D(mtl.textureHandle[TEXTURE_OPACITY]), decalcoords).r;
}

 

[Dreikblack]

Now lightning is wrong and depends on decal rotation. y = 0:

y = 90:

And if i make full white ambient light dark sides are still dark

[Josh]

Okay, I got it all worked out. This normal map and scene were very useful for testing.

DecalTest.zip

[Dreikblack]

Now all faces are flipped for imperfection decal bump:

[Josh]

Perhaps the original normal map is wrong? You can see in my screenshot above that the decal normals match the object with that material applied to it.

+red should point to the right
+green should point up

[Dreikblack]

I used this one https://www.leadwerks.com/community/files/file/2664-scratches005/

[Josh]

You can see it appears the scratches are sticking out of the surface with this normal map, when applied to a box.

When I flip the normal map vertically it appears as expected.

[Dreikblack]

I guess i will just flip normal textures then. Maybe some of them made for renderers with flipped values or something