UV coords modifying at runtime
Posted: Thu Aug 26, 2004 7:16 pm
OK I am sorry for the first text in french.
I will so try to barguain English.
Hello
Does somebody know how to modify the UV maps coords at runtime ?
I want to use an user-selected image (undetermined width and heigth) as a texture on a rotating parallelepiped.
The image dimensions may not match a 2^x number (64,128,256,...) and a black band appears on the left and/or under the image on the faces of the mesh.
I tried to "poke" the correct UV coords directly in data section where they are defined, just before creating mesh but it seems to have no effect.
Here is the piece of code (most of it is taken from PB help):
I hope my english is good enough to clearly describe my problem (I already found it difficult to explain in french, so...)
Thank You
Regards
Alban
Merci d'avance
A+
Alban
I will so try to barguain English.
Hello
Does somebody know how to modify the UV maps coords at runtime ?
I want to use an user-selected image (undetermined width and heigth) as a texture on a rotating parallelepiped.
The image dimensions may not match a 2^x number (64,128,256,...) and a black band appears on the left and/or under the image on the faces of the mesh.
I tried to "poke" the correct UV coords directly in data section where they are defined, just before creating mesh but it seems to have no effect.
Here is the piece of code (most of it is taken from PB help):
Code: Select all
If InitEngine3D()
UseJPEGImageDecoder()
InitSprite()
InitKeyboard()
InitMouse()
If OpenScreen(1024,768,32,"3d screen")
Gosub createMeshes
CreateCamera(0, 0, 0, 100, 100)
CameraBackColor(0,RGB(255,0,0))
CameraLocate(0,0,0,1000)
Repeat
ClearScreen(0, 0, 0)
ExamineKeyboard()
RotateEntity(0, 1, 0, 0)
RenderWorld()
FlipBuffers()
Until KeyboardPushed(#PB_Key_Escape)
EndIf
Else
MessageRequester("Error", "The 3D Engine can't be initialized",0)
EndIf
End
createMeshes:
; Create a cube, manually.. See the DataSetion, for more precisions
;
im=LoadImage(1,"MY_IMAGE.jpg") ; this can be any JPEG image
im_Id=ImageID()
larg=ImageWidth()
haut=ImageHeight()
; calculate the closest 2^x number matching the image dimensions
; for texture creating
text_dim=64
If larg>64 Or haut>64
text_dim=128
EndIf
If larg>128 Or haut>128
text_dim=256
EndIf
If larg>256 Or haut>256
text_dim=512
EndIf
If larg>512 Or haut>512
text_dim=1024
EndIf
;calculate ratio image dimension / texture size (=U and V coords)
percentw.f=larg/text_dim
percenth.f=haut/text_dim
;poke result in data section for the concerned points only (front face)
mem=?CubeTextureCoordinates
PokeF(mem+16,percenth.f)
PokeF(mem+48,percenth.f)
PokeF(mem+52,-percentw.f)
PokeF(mem+60,-percentw.f)
; Mesh creating
CreateMesh(0)
SetMeshData(0, 0, ?CubeVertices , 8)
SetMeshData(0, 1, ?CubeFacesIndexes , 12)
SetMeshData(0, 2, ?CubeTextureCoordinates, 8)
i=CreateTexture(0,text_dim,text_dim)
If StartDrawing(TextureOutput(0))
DrawImage(im,0,0)
StopDrawing()
Else
End
EndIf
CreateEntity(0, MeshID(0), CreateMaterial(0,TextureID(0)))
; aplatit le mesh façon fiche cartonnée
ResizeEntity(0,larg/2,haut/2,8)
Return
DataSection
CubeVertices:
Data.f 0, 0, 0 ; Vertex index 0
Data.f 1, 0, 0 ; Vertex index 1
Data.f 1, 0, 1 ; Vertex index 2
Data.f 0, 0, 1 ; Vertex index 3
Data.f 0, 1, 0 ; Vertex index 4 - Note: exactly the same as above, but with 'y'
Data.f 1, 1, 0 ; Vertex index 5
Data.f 1, 1, 1 ; Vertex index 6
Data.f 0, 1, 1 ; Vertex index 7
CubeFacesIndexes:
Data.w 0, 1, 2 ; bottom face (clockwise as it's reversed...)
Data.w 2, 3, 0
Data.w 6, 5, 4 ; top face
Data.w 4, 7, 6
Data.w 1, 5, 6 ; right face
Data.w 6, 2, 1
Data.w 7, 4, 0 ; left face
Data.w 0, 3, 7
Data.w 5, 1, 0 ; back face
Data.w 0, 4, 5
Data.w 2, 6, 7 ; front face
Data.w 7, 3, 2
CubeTextureCoordinates:
Data.f 0, 0 ; Vertex 0 ad 0,4
Data.f 0, 0 ; Vertex 1 ad 8,12
Data.f -1, 0 ; Vertex 2 ad 16,20
Data.f 0, 0 ; Vertex 3 ad 24,28
;
Data.f 0, 0 ; Vertex 4 ad 32,36
Data.f 0, 0 ; Vertex 5 ad 40,44
Data.f -1, 1 ; Vertex 6 ad 48,52
Data.f 0, 1 ; Vertex 7 ad 56,60
EndDataSection
Thank You
Regards
Alban
Merci d'avance
A+
Alban
