Not drawing fully transparent

Member

Posts: 469
Joined: 2002.10

Post: #1

Mar 18, 2003 — 07:22 PM

when I draw a textured poly that has fully transparent parts I get dithering. Am I doing something wrong or is there no way to get fully transparent textures?
[Image: polkadotproblem.jpg]

---Kelvin--
15.4" MacBook Pro revA
1.83GHz/2GB/250GB

ghettotek

Unregistered

Post: #2

Mar 18, 2003 — 07:31 PM

can we see what code youre using?

OneSadCookie

Luminary

Posts: 5,125
Joined: 2002.04

Post: #3

Mar 18, 2003 — 07:38 PM

Make sure the color channels of the transparent parts match the color channels of the surrounding opaque parts.

What's causing those dots? They must be in your texture...

kelvin

Member

Posts: 469
Joined: 2002.10

Post: #4

Mar 18, 2003 — 07:50 PM

as far as I know, the dots are dithering.

for generating the texture here's my code:

Code:

[debugImage lockFocus];

            [[[[NSColor whiteColor] colorWithAlphaComponent:0.0] colorUsingColorSpaceName:NSDeviceRGBColorSpace] set];

            NSRectFill(NSMakeRect(0,0,size.width,size.height));

            [debugImage unlockFocus];

...

[debugImage lockFocus];

                    [[text_view layoutManager] drawGlyphsForGlyphRange:NSMakeRange(0,1)

                                                                atPoint:NSMakePoint(image_offset.x,

                                                                                    image_offset.y +

                                                                                    [aFont boundingRectForFont].origin.y)];

                    [debugImage unlockFocus];

---Kelvin--
15.4" MacBook Pro revA
1.83GHz/2GB/250GB

OneSadCookie

Luminary

Posts: 5,125
Joined: 2002.04

Post: #5

Mar 18, 2003 — 07:54 PM

Are you drawing to a 32-bit texture and rendering to a 16-bit screen on a Rage 128?

kelvin

Member

Posts: 469
Joined: 2002.10

Post: #6

Mar 18, 2003 — 08:14 PM

yes.

---Kelvin--
15.4" MacBook Pro revA
1.83GHz/2GB/250GB

OneSadCookie

Luminary

Posts: 5,125
Joined: 2002.04

Post: #7

Mar 18, 2003 — 08:30 PM

LOL

I didn't expect to be right

The Rage 128's dithering is appalling. Try matching your texture depth to your screen depth.

Tycho

Unregistered

Post: #8

Mar 18, 2003 — 09:06 PM

I don't have my Rage 128 anymore, but it always seemed that dithering looked WAY better in OS 9 than it did in OS X. In OS 9 it seemed to be using a sort of random diffuse dither while OS X used a sort of pattern based dithering if you know what I mean.

Skorche

Sage

Posts: 1,478
Joined: 2002.09

Post: #9

Mar 18, 2003 — 09:32 PM

Yuck, I guess I never noticed that on my family's G4, but then again I haven't really ever played openGL games under OSX.

Scott Lembcke - Howling Moon Software
Author of Chipmunk Physics - A fast and simple rigid body physics library in C.

kelvin

Member

Posts: 469
Joined: 2002.10

Post: #10

Mar 18, 2003 — 09:32 PM

My issue is: should ALL pixels with 0.0 alpha be transparent? guh... I need a new mac.

---Kelvin--
15.4" MacBook Pro revA
1.83GHz/2GB/250GB

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