From: Don Tidrow (dtidrow++at++nvl.army.mil)
Date: 12/05/2000 13:57:16
Since the original bounced for being too fat, let me try again without the
original texture image - if anybody wants to see it, I'll send it to them
directly.
-----FW: 12-bit intensity textures with alpha-----
Date: Tue, 05 Dec 2000 16:33:59 -0500 (EST)
From: Don Tidrow <dtidrow++at++nvl.army.mil>
To: info-performer++at++sgi.com
Subject: 12-bit intensity textures with alpha
I'm currently trying to load in a 16-bit image as an intensity texture with
alpha (12 bits intensity, 4 bits alpha) and am having problems. Here's what
I'm doing:
IMAGE *imgFile = iopen(argv[1], "r");
unsigned short* image;
if (imgFile)
{
unsigned int nc = imgFile->zsize,
sx = imgFile->xsize,
sy = imgFile->ysize,
bpp = BPP(imgFile->type);
image = (unsigned short*)
pfMalloc(imgFile->xsize*imgFile->ysize*
imgFile->zsize*BPP(imgFile->type),
pfGetSharedArena());
for(int i = 0; i < sy; ++i)
getrow(imgFile, image+i*sx, i, 0);
tex->setImage((unsigned int*)image, 1, sx, sy, 1); // hack for now
tex->setFormat(PFTEX_INTERNAL_FORMAT, PFTEX_I_12A_4);
tex->setFormat(PFTEX_EXTERNAL_FORMAT, PFTEX_PACK_16);
tex->setFormat(PFTEX_IMAGE_FORMAT, PFTEX_LUMINANCE_ALPHA);
// set up pfMaterial properties
mtl->setColor(PFMTL_AMBIENT, 0.0, 0.0, 0.0);
mtl->setColor(PFMTL_DIFFUSE, 0.0, 0.0, 0.0);
mtl->setColor(PFMTL_EMISSION, 0.5, 0.5, 0.5);
mtl->setColor(PFMTL_SPECULAR, 0.0, 0.0, 0.0);
...
}
The image being loaded is a ramp from 0 intensity in the upper left corner, to
4095 in the lower right corner, and alpha being set to 8 (ie. in the lower 4
bits of each image pixel) on all pixels (ramp.int, attached). When I apply this
texture to a quad, I get what's in image1.
Changing
tex->setFormat(PFTEX_IMAGE_FORMAT, PFTEX_LUMINANCE_ALPHA);
to
tex->setFormat(PFTEX_IMAGE_FORMAT, PFTEX_LUMINANCE);
results in image2. What I really want is a half-transparent version of image2 -
any suggestions on what changes I need to make, either in the code or in the
source image?
Don
-- In October 1997, three computer lab staffers disappeared from the server room while debugging a mysterious router problem.One year later, their packet logs were found...
The Blair Switch Project
-------------------------------------------------- | Don Tidrow | | Visual Simulation Developer | | US Army TACOM (currently working with NVESD) | | ph: (703)704-1361 fax: (703)704-1753 | --------------------------------------------------
--------------End of forwarded message-------------------------
-- In October 1997, three computer lab staffers disappeared from the server room while debugging a mysterious router problem.
One year later, their packet logs were found...
The Blair Switch Project
-------------------------------------------------- | Don Tidrow | | Visual Simulation Developer | | US Army TACOM (currently working with NVESD) | | ph: (703)704-1361 fax: (703)704-1753 | --------------------------------------------------
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