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Re: [KOS] display pvr_texture without white border?
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From: Nathan M. <gro...@gm...> - 2016-12-29 03:30:25
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Thanks alot, that was totally the problem! :)
On Wed, Dec 28, 2016 at 5:14 PM, Lawrence Sebald <blu...@gm...> wrote:
> Ah… Now that I see your post on another forum asking the same question, it
> makes a bit more sense.
>
> As was said over on that other forum, you either need to use a translucent
> or punch-thru polygon and have the background have alpha to make it
> transparent. To do this, you’ll need to use a PNG (or some other format
> that supports alpha), which if you’re using the image you posted over on
> that other forum, then you’re already doing. Just make the background
> transparent in your image editor instead of white.
>
> - Lawrence
>
> > On Dec 28, 2016, at 7:41 PM, Lawrence Sebald <blu...@gm...> wrote:
> >
> > I’m guessing your texture itself has a white border around whatever
> you’re drawing (i.e, it’s not actually 512x512 pixels in size, but you’ve
> extended the image by just resizing it and filling that in as white)?
> >
> > If so, what you need to do is adjust the u and v coordinates on each
> vertex. These two values are what portion of the texture you want to
> display. The left and top of the texture correspond to 0.0 of u and v
> respectively, whereas the full extent of the texture (in this case 512
> pixels over from the left and 512 pixels down from the top) correspond to
> 1.0 of u and v respectively.
> >
> > If your texture is actually 320x240 (for instance), then you’d want to
> adjust the u and v on the bottom and right side vertices (i.e, everything
> where you have 1.0) to be (320.0f / 512.0f) and (240.0f / 512.0f).
> >
> > Hopefully I’ve guessed what your issue is correctly and that helps
> understand the process.
> >
> > - Lawrence
> >
> >> On Dec 28, 2016, at 4:12 PM, Nathan Meier <gro...@gm...>
> wrote:
> >>
> >> I've been learning how to program with KOS. And currently I can display
> images and
> >> even move them around. But what I'm trying to figure out is how can I
> display the
> >> image without the white border behind it. Here's my current code for
> drawing one of the graphics:
> >>
> >> void draw_ground(void) {
> >> pvr_poly_cxt_t cxt;
> >> pvr_poly_hdr_t hdr;
> >> pvr_vertex_t vert;
> >>
> >> pvr_poly_cxt_txr(&cxt, PVR_LIST_OP_POLY, PVR_TXRFMT_RGB565, 512,
> 512, ground_tex, PVR_FILTER_BILINEAR);
> >> pvr_poly_compile(&hdr, &cxt);
> >> pvr_prim(&hdr, sizeof(hdr));
> >>
> >> vert.argb = PVR_PACK_COLOR(1.0f, 1.0f, 1.0f, 1.0f);
> >> vert.oargb = 0;
> >> vert.flags = PVR_CMD_VERTEX;
> >>
> >> vert.x = gx;
> >> vert.y = gy;
> >> vert.z = 1;
> >> vert.u = 0.0;
> >> vert.v = 0.0;
> >> pvr_prim(&vert, sizeof(vert));
> >>
> >> vert.x = gx + size;
> >> vert.y = gy;
> >> vert.z = 1;
> >> vert.u = 1.0;
> >> vert.v = 0.0;
> >> pvr_prim(&vert, sizeof(vert));
> >>
> >> vert.x = gx;
> >> vert.y = gy + size;
> >> vert.z = 1;
> >> vert.u = 0.0;
> >> vert.v = 1.0;
> >> pvr_prim(&vert, sizeof(vert));
> >>
> >> vert.x = gx + size;
> >> vert.y = gy + size;
> >> vert.z = 1;
> >> vert.u = 1.0;
> >> vert.v = 1.0;
> >> vert.flags = PVR_CMD_VERTEX_EOL;
> >> pvr_prim(&vert, sizeof(vert));
> >> }
> >>
> >> any help figuring this out would be appreciated.
> >> ------------------------------------------------------------
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> >
>
>
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