Does EntityAlpha work ?

BlitzMax Forums/MiniB3D Module/Does EntityAlpha work ?

Warner

(Posted 2009) [#1]

I'm trying to get EntityAlpha to work, but somehow it doesn't seem to do anything? I am using the following code:

Import sidesign.minib3d

Graphics3D 800, 600

cam = CreateCamera()
cube = CreateCube()
cube2 = CreateCube()
MoveEntity cube, 0, 0, 5
MoveEntity cube2, 1, 1, 6
EntityAlpha cube, 0.5
EntityAlpha cube2, 0.5

Repeat

	RenderWorld
	Flip

Until KeyHit(key_escape)
End

ima747

(Posted 2009) [#2]

Works for me, check your video card drivers are up to date, are you using a system with intel graphics on board?

Warner

(Posted 2009) [#3]

I have a sis mirage 3, it is an onboard card in my laptop. The drivers are up to date. Is there any other way to achieve transparency ?

Uncle

(Posted 2009) [#4]

I just tested your code and it works fine for me as well. Can you post a screen shot of what your getting?

Warner

(Posted 2009) [#5]

It does this:

I've tried everything, even 'hacking' into the minib3d source to force enabling alphablending. Additive blending does work, strangely enough:

Import sidesign.minib3d

Graphics3D 800, 600

cam = CreateCamera()
cube = CreateCube()
cube2 = CreateCube()
EntityBlend cube, 3
EntityBlend cube2, 3

MoveEntity cube, 1, 1, 6
MoveEntity cube2, 0, 0, 5

Repeat

	RenderWorld
	Flip

Until KeyHit(key_escape)
End

Warner

(Posted 2009) [#6]

If I write a program that uses alpha in Max2D, using OpenGL, it does work:

SetGraphicsDriver GLMax2DDriver()

Graphics 800, 600

im = CreateImage(80, 80)
DrawOval 0, 0, 80, 80
GrabImage im, 0, 0

Cls

SetBlend ALPHABLEND
For i = 0 To 10
SetAlpha i / 10.0
DrawImage im, i * 80, 0
Next
SetAlpha 1.0
Flip

WaitKey
End

Am I right in thinking that it is not a driver issue then ?

EDIT:
I found out something very strange: some sort of alpha does seem to work, but only in a very small range around the camera. In a distance from 0..1 or 0..2 units, the objects are drawn with alpha.

ima747

(Posted 2009) [#7]

It's your on board graphics card and if you're drivers are up to date then it's a limitation/bug/in-compatability with your hardware.

Warner

(Posted 2009) [#8]

Fair enough. But why does the common alpha functions work ? I don't understand that. In DirectX (b3d) everything works as well. I can remember having trouble with minib3d EntityAlpha as well on my previous laptop, which had an NVidia FX GO card.

ima747

(Posted 2009) [#9]

minib3d uses OpenGL and as such many mobile and some onboard (*cough* intel graphics) graphics sets do not fully and or properly support OpenGL. Take a dig through the forum and you'll find many a post along the lines of "such and such doesn't work right on my laptop" that can be traced back to poor OpenGL support by the manufacturer. Expect everything to function better with a more standards compliant chipset.

All newer chip sets (last year or 2) to my knowledge work fine, it's only older ones that tend to have problems, with the exception of some intel onboard's but they're designed to hate most 3d it seems.

So postive side your code is fine, down side might be time to upgrade :0(

Warner

(Posted 2009) [#10]

Okay, thanks for explaining this.