Issue with Normal Maps? - GameCreators Forum

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Mambazo

18

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Joined: 11th Dec 2005

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Posted: 7th Jun 2020 00:43

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Expected behaviour would be that all faces react the same way to the light source.

Is the box underside normal vector flipped?
Is the tangent generated for the face incorrect?
Is there an issue with the shader generated by SetObjectNormalMap()?

I dunno!

Video of issue:

Normal map used:

Code to recreate:

// show all errors
SetErrorMode(2)

// set window properties
SetWindowTitle( "normal_map_bug" )
SetWindowSize( 1024, 768, 0 )
SetVirtualResolution( 1024, 768 ) // doesn't have to match the window

// remove global light
SetSunActive(0)
SetAmbientColor( 0, 0, 0 )

// left box with marker
box1 = CreateObjectBox( 5, 5, 5 )
underside_marker = CreateObjectSphere( 0.5, 10, 10 )
SetObjectPosition( underside_marker, 0, -4, 0 )
SetObjectColorEmissive( underside_marker, 255, 0, 0 )
FixObjectToObject( underside_marker, box1 )
SetObjectPosition( box1, -6, 0, 0 )
SetObjectNormalMap( box1, LoadImage("normal_map_small.png") )

// right box
box2 = CreateObjectBox( 5, 5, 5 )
SetObjectPosition( box2, 6, 0, 0 )
SetObjectNormalMap( box2, LoadImage("normal_map_small.png") )

// light
light_y# = 5
light_z# = -5
light1 as integer = 1
CreatePointLight( light1, 0, light_y#, light_z#, 50, 255, 255, 255 )
SetPointLightMode( light1, 1 )
light_helper = CreateObjectSphere( 0.5, 10, 10 )
SetObjectColorEmissive( light_helper, 255, 255, 255 )
SetObjectPosition( light_helper, 0, light_y#, light_z# )

// camera
SetCameraPosition( 1, 0, 0, -20 )
SetCameraLookAt( 1, 0, 0, 0, 0 )

// action :P
do
    
    Print("Left Box underside (marked red) does not")
    Print("interact with the light correctly")
    
	RotateObjectLocalX( box1, 1 )
	RotateObjectLocalY( box2, 1 )
    
    Sync()
loop

+ Code Snippet

// show all errors
SetErrorMode(2)

// set window properties
SetWindowTitle( "normal_map_bug" )
SetWindowSize( 1024, 768, 0 )
SetVirtualResolution( 1024, 768 ) // doesn't have to match the window

// remove global light
SetSunActive(0)
SetAmbientColor( 0, 0, 0 )

// left box with marker
box1 = CreateObjectBox( 5, 5, 5 )
underside_marker = CreateObjectSphere( 0.5, 10, 10 )
SetObjectPosition( underside_marker, 0, -4, 0 )
SetObjectColorEmissive( underside_marker, 255, 0, 0 )
FixObjectToObject( underside_marker, box1 )
SetObjectPosition( box1, -6, 0, 0 )
SetObjectNormalMap( box1, LoadImage("normal_map_small.png") )

// right box
box2 = CreateObjectBox( 5, 5, 5 )
SetObjectPosition( box2, 6, 0, 0 )
SetObjectNormalMap( box2, LoadImage("normal_map_small.png") )

// light
light_y# = 5
light_z# = -5
light1 as integer = 1
CreatePointLight( light1, 0, light_y#, light_z#, 50, 255, 255, 255 )
SetPointLightMode( light1, 1 )
light_helper = CreateObjectSphere( 0.5, 10, 10 )
SetObjectColorEmissive( light_helper, 255, 255, 255 )
SetObjectPosition( light_helper, 0, light_y#, light_z# )

// camera
SetCameraPosition( 1, 0, 0, -20 )
SetCameraLookAt( 1, 0, 0, 0, 0 )

// action :P
do
    
    Print("Left Box underside (marked red) does not")
    Print("interact with the light correctly")
    
	RotateObjectLocalX( box1, 1 )
	RotateObjectLocalY( box2, 1 )
    
    Sync()
loop

If at first you don't succeed, sky-diving isn't for you.

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Bengismo

6

Years of Service

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Joined: 20th Nov 2017

Location: Yorkshire, England

Posted: 7th Jun 2020 02:03 Edited at: 7th Jun 2020 02:24

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This post has been marked by the post author as the answer.

Its a bug with the way in which AppGameKit creates the cube internally. Only the bottom face has the issue.

It can be fixed with a function:

// show all errors
SetErrorMode(2)

// set window properties
SetWindowTitle( "normal_map_bug" )
SetWindowSize( 1024, 768, 0 )
SetVirtualResolution( 1024, 768 ) // doesn't have to match the window

// remove global light
SetSunActive(0)
SetAmbientColor( 0, 0, 0 )

// left box with marker
box1 = CreateObjectBox( 5, 5, 5 )
box1 = correctbox(box1)
underside_marker = CreateObjectSphere( 0.5, 10, 10 )
SetObjectPosition( underside_marker, 0, -4, 0 )
SetObjectColorEmissive( underside_marker, 255, 0, 0 )
FixObjectToObject( underside_marker, box1 )
SetObjectPosition( box1, -6, 0, 0 )
SetObjectNormalMap( box1, LoadImage("normal_map_small.png") )

// right box
box2 = CreateObjectBox( 5, 5, 5 )
SetObjectPosition( box2, 6, 0, 0 )
SetObjectNormalMap( box2, LoadImage("normal_map_small.png") )

// light
light_y# = 5
light_z# = -8
light1 as integer = 1
CreatePointLight( light1, 0, light_y#, light_z#, 50, 255, 255, 255 )
SetPointLightMode( light1, 1 )
light_helper = CreateObjectSphere( 0.5, 10, 10 )
SetObjectColorEmissive( light_helper, 255, 255, 255 )
SetObjectPosition( light_helper, 0, light_y#, light_z# )

// camera
SetCameraPosition( 1, 0, 0, -20 )
SetCameraLookAt( 1, 0, 0, 0, 0 )

// action :P
do
    
    Print("Left Box underside (marked red) does not")
    Print("interact with the light correctly")
    
	RotateObjectLocalX( box1, 1 )
	RotateObjectLocalY( box2, 1 )
    
    Sync()
loop

function correctbox(id)
	mblk = CreateMemblockFromObjectMesh(id,1)
	deleteobject(id)
	//swap x and z

offset = 60+32*4*5
	off2c=8
	x# = GetMemblockFloat(mblk,offset)
	SetMemblockFloat(mblk,offset,-x#)
	z# = GetMemblockFloat(mblk,offset+off2c)
	SetMemblockFloat(mblk,offset+off2c,-z#)

inc offset,32
	x# = GetMemblockFloat(mblk,offset)
	SetMemblockFloat(mblk,offset,-x#)
	z# = GetMemblockFloat(mblk,offset+off2c)
	SetMemblockFloat(mblk,offset+off2c,-z#)

id = CreateObjectFromMeshMemblock(mblk)
	deletememblock(mblk)

endfunction	id

+ Code Snippet

// show all errors
SetErrorMode(2)

// set window properties
SetWindowTitle( "normal_map_bug" )
SetWindowSize( 1024, 768, 0 )
SetVirtualResolution( 1024, 768 ) // doesn't have to match the window

// remove global light
SetSunActive(0)
SetAmbientColor( 0, 0, 0 )

// left box with marker
box1 = CreateObjectBox( 5, 5, 5 )
box1 = correctbox(box1)
underside_marker = CreateObjectSphere( 0.5, 10, 10 )
SetObjectPosition( underside_marker, 0, -4, 0 )
SetObjectColorEmissive( underside_marker, 255, 0, 0 )
FixObjectToObject( underside_marker, box1 )
SetObjectPosition( box1, -6, 0, 0 )
SetObjectNormalMap( box1, LoadImage("normal_map_small.png") )

// right box
box2 = CreateObjectBox( 5, 5, 5 )
SetObjectPosition( box2, 6, 0, 0 )
SetObjectNormalMap( box2, LoadImage("normal_map_small.png") )

// light
light_y# = 5
light_z# = -8
light1 as integer = 1
CreatePointLight( light1, 0, light_y#, light_z#, 50, 255, 255, 255 )
SetPointLightMode( light1, 1 )
light_helper = CreateObjectSphere( 0.5, 10, 10 )
SetObjectColorEmissive( light_helper, 255, 255, 255 )
SetObjectPosition( light_helper, 0, light_y#, light_z# )

// camera
SetCameraPosition( 1, 0, 0, -20 )
SetCameraLookAt( 1, 0, 0, 0, 0 )



// action :P
do
    
    Print("Left Box underside (marked red) does not")
    Print("interact with the light correctly")
    
	RotateObjectLocalX( box1, 1 )
	RotateObjectLocalY( box2, 1 )
    
    Sync()
loop


function correctbox(id)
	mblk = CreateMemblockFromObjectMesh(id,1)
	deleteobject(id)
	//swap x and z

	offset = 60+32*4*5
	off2c=8
	x# = GetMemblockFloat(mblk,offset)
	SetMemblockFloat(mblk,offset,-x#)
	z# = GetMemblockFloat(mblk,offset+off2c)
	SetMemblockFloat(mblk,offset+off2c,-z#)

	inc offset,32
	x# = GetMemblockFloat(mblk,offset)
	SetMemblockFloat(mblk,offset,-x#)
	z# = GetMemblockFloat(mblk,offset+off2c)
	SetMemblockFloat(mblk,offset+off2c,-z#)

	inc offset,32
	x# = GetMemblockFloat(mblk,offset)
	SetMemblockFloat(mblk,offset,-x#)
	z# = GetMemblockFloat(mblk,offset+off2c)
	SetMemblockFloat(mblk,offset+off2c,-z#)

	inc offset,32
	x# = GetMemblockFloat(mblk,offset)
	SetMemblockFloat(mblk,offset,-x#)
	z# = GetMemblockFloat(mblk,offset+off2c)
	SetMemblockFloat(mblk,offset+off2c,-z#)

	id = CreateObjectFromMeshMemblock(mblk)
	deletememblock(mblk)

endfunction	id

it probably wants raising as an issue on github

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Mambazo

18

Years of Service

User Offline

Joined: 11th Dec 2005

Location:

Posted: 7th Jun 2020 11:33 Edited at: 7th Jun 2020 13:45

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I took the auto-generated shader and modified its check on the normal.y, seems to have fixed it without needing to modify the mesh.

From this:

+ Code Snippet

if( abs( normal.y ) > 0.999 ) {
	tangent = vec3( normal.y,0.0,0.0);
} else {
	tangent = normalize( vec3(-normal.z, 0.0, normal.x) );
}

To this:

+ Code Snippet

if( normal.y > 0.999 ) {
	tangent = vec3( normal.y,0.0,0.0);
} else {
	if( normal.y < -0.999 ) {
		tangent = vec3( -normal.y,0.0,0.0);
	} else {
		tangent = normalize( vec3(-normal.z, 0.0, normal.x) );
	}
}

Now I'm no so sure it is a mesh issue after all!

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AppGameKit Classic Chat / [SOLVED] Issue with Normal Maps?

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