Re: Transparent textures from images
- To: mathgroup at smc.vnet.net
- Subject: [mg123408] Re: Transparent textures from images
- From: John Fultz <jfultz at wolfram.com>
- Date: Tue, 6 Dec 2011 03:12:22 -0500 (EST)
- Delivered-to: l-mathgroup@mail-archive0.wolfram.com
- Reply-to: jfultz at wolfram.com
Patrick, This is a bug in Mathematica. But, fortunately, it's a very easy bug to work around. Replace: Texture[img] with Texture[ImageData[img]] Sincerely, John Fultz jfultz at wolfram.com User Interface Group Wolfram Research, Inc. On Sat, 3 Dec 2011 04:14:01 -0500 (EST), Patrick Scheibe wrote: > Hi, > > I sent this already to Wolfram, but maybe someone wants to try this on a > windows machine. > Starting from an image with alpha-channel > > data = Table[{Sin[x], Sin[y], 1, Sin[x y]}, {y, 0, 2 Pi, > 2 Pi/127.}, {x, 0, 2 Pi, 2 Pi/127.}]; > img = Image[data, ColorSpace -> "RGB"] > AlphaChannel[img] > > When I use this now as texture on a cube, I expect the walls to be > transparent according to the alpha-channel > > vtc = {{0, 0}, {1, 0}, {1, 1}, {0, 1}}; > coords = {{{0, 0, 0}, {0, 1, 0}, {1, 1, 0}, {1, 0, 0}}, {{0, 0, > 0}, {1, 0, 0}, {1, 0, 1}, {0, 0, 1}}, {{1, 0, 0}, {1, 1, 0}, {1, > 1, 1}, {1, 0, 1}}, {{1, 1, 0}, {0, 1, 0}, {0, 1, 1}, {1, 1, > 1}}, {{0, 1, 0}, {0, 0, 0}, {0, 0, 1}, {0, 1, 1}}, {{0, 0, > 1}, {1, 0, 1}, {1, 1, 1}, {0, 1, 1}}}; > Graphics3D[{Texture[img], > Polygon[coords, VertexTextureCoordinates -> Table[vtc, {6}]]}, > Boxed -> False] > > This does not work here. I get a cube with a white painting where it > should be transparent. Using the pure {r,g,b,a} data I get the right > result: > > Graphics3D[{Texture[data], > Polygon[coords, VertexTextureCoordinates -> Table[vtc, {6}]]}, > Boxed -> False] > > Can someone check this or give me a hint which part I understood wrong? > > Cheers > Patrick
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