SetUV for OpenGL ?

BlitzMax Forums/BlitzMax Programming/SetUV for OpenGL ?

Stu_ovine (Posted 2008) [#1]

I've looked around the forum to find a way of scrolling a basic square (2d) texture. i.e. draw a quad in max2D, scroll the texture in a constant direction. I found SetUV for directX but do we have a counterpart for openGL ?

Gabriel (Posted 2008) [#2]

I haven't done any OpenGL in ages, but I think the UV coordinates are supplied with the command glTexCoord2f, something like this : glTexCoord2f(0.0f, 1.0f) It goes right before your call to glVertex3f to draw the vertex.

Stu_ovine (Posted 2008) [#3]

I want to still use drawimage (max2D), so the scrolling textures can be placed in front and behind other drawimage images. If thats possible of course.

Yan (Posted 2008) [#4]

This should contain all you need... 'Why scrolling a non ^2 image may give unexpected results Strict SetGraphicsDriver GLMax2DDriver() 'SetGraphicsDriver BufferedD3D7Max2DDriver() Graphics 800, 600, 0'32, -1 Local image:TImage = LoadImage(getenv_("BMXPATH") + "\samples\digesteroids\graphics\digestive.png") If image = Null Then RuntimeError "Couldn't load image" Local tw# = Pow2Size(image.width), th# = Pow2Size(image.height) Local scalex# = (tw# - image.width) / image.width Local scaley# = (th# - image.height) / image.height Local scrollx#, scrolly#, showtex SetBlend ALPHABLEND SetTextureRepeat(image, True) Repeat If KeyDown(KEY_LEFT) Then scrollx# :+ 0.01 If KeyDown(KEY_RIGHT) Then scrollx# :- 0.01 If KeyDown(KEY_UP) Then scrolly# :+ 0.01 If KeyDown(KEY_DOWN) Then scrolly# :- 0.01 If KeyHit(KEY_SPACE) Then showtex = 1 - showtex Cls If showtex SetAlpha 0.33 SetColor 0, 0, 100 DrawRect 12, 36, tw#, th# SetColor 255, 255, 255 SetUV(image, 1 + scrollx#, scrolly#, 1 + scalex# + scrollx#, 1 + scrolly#) SetScale scalex#, 1 DrawImage image, 12 + image.width, 36 SetUV(image, 1 + scrollx#, 1 + scrolly#, 1 + scalex# + scrollx#, 1 + scaley# + scrolly#) SetScale scalex#, scaley# DrawImage image, 12 + image.width, 36 + image.height SetUV(image, scrollx#, 1 + scrolly#, 1 + scrollx#, 1 + scaley# + scrolly#) SetScale 1, scaley# DrawImage image, 12, 36 + image.height EndIf SetAlpha 1 SetScale 1, 1 SetColor 0, 0, 100 DrawRect 12, 36, image.width, image.height SetColor 255, 255, 255 SetUV(image, scrollx#, scrolly#, 1 + scrollx#, 1 + scrolly#) DrawImage image, 12, 36 DrawText "Show Texture = " + showtex, 12, 12 DrawText "Hit SPACE to toggle texture, CURSOR keys to scroll image", 200, 576 Flip 1 Until KeyHit(KEY_ESCAPE) End Function SetTextureRepeat(image:TImage, rep=True)' Under DX, *ALL* images drawn will repeat ' Assert (image.width = Pow2Size(image.width)) And (image.height = Pow2Size(image.height)),.. ' "Image width and height must be a power of two" Local D3D7Driver:TD3D7Max2DDriver = TD3D7Max2DDriver(_max2dDriver) If rep ?Win32 If D3D7Driver 'DX D3D7Driver.device.SetTextureStageState 0, D3DTSS_ADDRESS, D3DTADDRESS_WRAP Else ? 'GL glBindTexture GL_TEXTURE_2D, TGLImageFrame(image.Frame(0)).name glTexParameteri GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT glTexParameteri GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT ?Win32 EndIf ? Else ?Win32 If D3D7Driver 'DX D3D7Driver.device.SetTextureStageState 0, D3DTSS_ADDRESS, D3DTADDRESS_CLAMP Else ? 'GL glBindTexture GL_TEXTURE_2D, TGLImageFrame(image.Frame(0)).name glTexParameteri GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE glTexParameteri GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE ?Win32 EndIf ? EndIf End Function Function SetUV(image:TImage, u0!, v0!, u1!, v1!, frame=0) Local twr! = Double(image.width) / Pow2Size(image.width) Local thr! = Double(image.height) / Pow2Size(image.height) u0! = twr! * u0! v0! = thr! * v0! u1! = twr! * u1! v1! = thr! * v1! ?Win32 If TGLMax2DDriver(_max2dDriver) ? 'GL Local GLImageFrame:TGLImageFrame = TGLImageFrame(image.Frame(frame)) GLImageFrame.u0# = u0! GLImageFrame.v0# = v0! GLImageFrame.u1# = u1! GLImageFrame.v1# = v1! ?Win32 Else 'DX TD3D7ImageFrame(image.Frame(frame)).SetUV(u0!, v0!, u1!, v1!) EndIf ? End Function Function Pow2Size(n) Local t = 1 While t < n t :* 2 Wend Return t End Function

Stu_ovine (Posted 2008) [#5]

Thats what I was after, many thanks

Stu_ovine (Posted 2008) [#6]

Does anyone have a version of this that will work with non ^2 images ? I have a small banner that I want to scroll , but its 78 pixels high :S

ImaginaryHuman (Posted 2008) [#7]

Are you just scrolling horizontally with no vertical wrapping?

Bremer (Posted 2008) [#8]

This seems to work fine, its the code posted by Yan but cut down to only have the openGL part. And with the example title image, which is much wider than its heigh, it seems to work just fine on my computer. SuperStrict SetGraphicsDriver GLMax2DDriver() Graphics 800, 600, 0 Local image:TImage = LoadImage(getenv_("BMXPATH") + "\samples\digesteroids\graphics\title.png") If image = Null Then RuntimeError "Couldn't load image" Local scrollx:Float, scrolly:Float SetBlend ALPHABLEND SetTextureRepeat(image) Repeat If KeyDown(KEY_LEFT) Then scrollx :+ 0.01 If KeyDown(KEY_RIGHT) Then scrollx :- 0.01 If KeyDown(KEY_UP) Then scrolly :+ 0.01 If KeyDown(KEY_DOWN) Then scrolly :- 0.01 Cls SetAlpha 1 SetScale 1, 1 SetColor 0, 0, 100 DrawRect 12, 36, image.width, image.height SetColor 255, 255, 255 SetUV(image, scrollx, scrolly, 1 + scrollx, 1 + scrolly) DrawImage image, 12, 36 DrawText "CURSOR keys to scroll image", 200, 576 Flip 1 Until KeyHit(KEY_ESCAPE) End Function SetTextureRepeat(image:TImage) glBindTexture GL_TEXTURE_2D, TGLImageFrame(image.Frame(0)).name glTexParameteri GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT glTexParameteri GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT End Function Function SetUV(image:TImage, u0:Float, v0:Float, u1:Float, v1:Float, frame:Int=0) Local GLImageFrame:TGLImageFrame = TGLImageFrame(image.Frame(frame)) GLImageFrame.u0 = u0 GLImageFrame.v0 = v0 GLImageFrame.u1 = u1 GLImageFrame.v1 = v1 End Function

Stu_ovine (Posted 2008) [#9]

I just want to scroll the Y. > Zawran - that doesn't wrap the none ^ 2 texture - it leaves a border around the outside of the picture when it wraps

Yan (Posted 2008) [#10]

Scale the original image (pixmap) up to the nearest ^2 vertically, then scale the image's Y axis down by the relevant amount when you draw it. 78 -> 128 = Y * (78 / 128) = SetScale 1, 0.6094

Bremer (Posted 2008) [#11]

hmm, there are no border on the outside here, but it might be that I do not know exactly what you are refereing to. Sorry I couldn't help then.

ImaginaryHuman (Posted 2008) [#12]

How big is the border? 1 pixel wide?

Stu_ovine (Posted 2008) [#13]

Scaling works a treat - Many thanks