Texture Tag Output



  • Hi Dan, thanks for following up.

    With regard to the code posted I think there are two things to check:

    • the expression used to compute the linear interpolation is incorrect: it should rather be spot1.x + (spot2.x - spot1.x) / pointcount*x as well as for y

    • beware of properly specifying the ChannelData::texflag and specify the correct TEX flag.

    Last but not least, in Python you can only sample shaders being the BaseShader::Sample available. On C++ instead it's also possible sample BaseChannels via BaseChannel::Sample.

    Best, Riccardo



  • Thanks again, Riccardo. I really appreciate all of the help.

    I noticed the sampling coordinate issue right before I checked back here, sorry about such a simple mistake.

    If I had to redo the code in C++ that would be totally fine. BaseChannel::Sample would work to give me the end output once I pass it the correct UVW coordinate, right? Would there be a better way to get what the UVW coordinate would be at a given point in C++? I'm not seeing a simple way to pass the Texture Tag and there for the projection type to it. This seems like it's possibly pretty simply but I'm not properly understanding it.

    Dan

    Edit:

    I want to clarify that I'm looking to accomplish something similar to how the displacer object in this example is able to use the linked texture tag(set to spherical projection, and using any movements of the texture) to correctly displace the plane. I want to be able to get the same data that I assume the Displacer is getting access to so that I can create my own custom outputs.

    alt text



  • Hi Dan, thanks for providing further details on it and sorry for coming late here.

    Actually I spent some time to run some test and, in the end, I confirm that what you're looking for can be delivered also on Python if sampling shader is sufficient.

    In my tests, I also found that BaseChannel::Sample() has the same behavior or BaseShader::Sample() and both are "somehow" actually agnostic to tiling.
    What should be evaluated before hand is if we're sampling the "first" tile or its repetition and this can be done via a simple helper function that, for the sole UVW case (you can extend the cases by looking at the ShdProjectPoint here), looks like as:

    TEX_EPSILON = 0.0001
    
    def TestUVW(texdata, uvw):
        # check texdata
        if texdata is None or uvw is None:
            return False
    
        # update the UVW value by evaluting TextureTag offset/tiles
        if texdata["proj"] == c4d.P_UVW:
            uvw.x = (uvw.x - texdata["ox"]) * texdata["invLenx"];
            uvw.y = (uvw.y - texdata["oy"]) * texdata["invLeny"];
            
            # if tiling simply return
            if texdata["texflag"] & c4d.TEX_TILE:
                return True
    
            # return True only if UV coord are referring to the first tile, False otherwise
            return (uvw.x >= -TEX_EPSILON and uvw.x <= 1.0+TEX_EPSILON) and (uvw.y >= -TEX_EPSILON and uvw.y <= 1.0+TEX_EPSILON)
    
        return false
    

    Given that, the whole code to sample an object where UVW mapping and a non-tiling TextureTag are assigned looks as:

    import c4d
    
    TEX_EPSILON = 0.0001
    
    def TestUVW(texdata, uvw):
        # check texdata
        if texdata is None or uvw is None:
            return False
    
        # update the UVW value by evaluting TextureTag offset/tiles
        if texdata["proj"] == c4d.P_UVW:
            uvw.x = (uvw.x - texdata["ox"]) * texdata["invLenx"];
            uvw.y = (uvw.y - texdata["oy"]) * texdata["invLeny"];
            
            # if tiling simply return
            if texdata["texflag"] & c4d.TEX_TILE:
                return True
    
            # return True only if UV coord are referring to the first tile, False otherwise
            return (uvw.x >= -TEX_EPSILON and uvw.x <= 1.0+TEX_EPSILON) and (uvw.y >= -TEX_EPSILON and uvw.y <= 1.0+TEX_EPSILON)
    
        return false
    
    
    # Main function
    def main():
        if op is None:
            return
    
        # get the current TextureTag / Material / UVWTag
        currentTextureTag = op.GetTag(c4d.Ttexture)
        currentMaterial =  currentTextureTag[c4d.TEXTURETAG_MATERIAL]
        currentUVWTag = op.GetTag(c4d.Tuvw)
        # get the shader associated to the color slot
        shd = currentMaterial[c4d.MATERIAL_COLOR_SHADER]
        # init via  InitRenderStruct()
        initRS = c4d.modules.render.InitRenderStruct()
        c4d.INITRENDERRESULT_OK == shd.InitRender(initRS)
    
        # init the ChannelData
        chanData = c4d.modules.render.ChannelData()
        chanData.n = c4d.Vector(0.0, 0.0, 1.0)
        chanData.d = c4d.Vector(0.01,0.01,0.01)
        chanData.scale = 1.0
    
        # prepare the data for testing the UVW
        texdata = {
        "proj" : currentTextureTag[c4d.TEXTURETAG_PROJECTION],
        "ox" : currentTextureTag[c4d.TEXTURETAG_OFFSETX],
        "oy" : currentTextureTag[c4d.TEXTURETAG_OFFSETY],
        "invLenx" : currentTextureTag[c4d.TEXTURETAG_TILESX],
        "invLeny" : currentTextureTag[c4d.TEXTURETAG_TILESY],
        "texflag" : 0
        }
    
        # check the tiling state
        if currentTextureTag[c4d.TEXTURETAG_TILE]:
            texdata["texflag"] = texdata["texflag"] & TEX_TILE
    
        points = op.GetAllPoints()
        polygons = op.GetAllPolygons()
    
        pointcount = 10
        # loop over the data in the UVW set to retrieve the color
        uvwdict = currentUVWTag.GetSlow(0)
    
        spot1 = uvwdict["a"]
        spot2 = uvwdict["c"]
        print polygons[0]
        point1 = points[polygons[0].a]
        print point1
        point2 = points[polygons[0].c]
        print point2
        for i in xrange(pointcount+1):
            for j in xrange(pointcount+1):
                col = c4d.Vector(-1)
                localUVW = c4d.Vector (spot1.x + (spot2.x-spot1.x) / pointcount * i, spot1.y + (spot2.y - spot1.y) / pointcount * j, 0)
                localPOS = c4d.Vector (point1.x + (point2.x-point1.x) / pointcount * i, 0, point1.z + (point2.z - point1.z) / pointcount * j)
    
                if (TestUVW(texdata, localUVW)):
                    chanData.p = localUVW
                    col = shd.Sample(chanData)
    
                print  i, ",", j, " / ", localPOS, " / ", localUVW, "/", col
    
        # free the allocated resources
        shd.FreeRender()
    
    # Execute main()
    if __name__=='__main__':
        main()
    

    For all the points hitting the mapping with the shader, the color is returned, whilst for the remaining points (-1, -1, -1) is returned.

    Best, Riccardo



  • Hi Riccardo!

    No worries about the wait, I really appreciate all of the help you've been giving me. I'm going over the code you provided and working to implement one of the other projections to make sure I properly understand it.

    With the code you provided I'm confused about the handling of tiling. Why is it necessary to implement return True if it is tiling? Would just taking the modulo of the uvw.x and uvw.y not work? In my few tests it seems to do the job.



  • Hi Dan,

    the approach I depicted is just one of the many viable and shouldn't be deemed as "the" approach. I'm simply returning True to avoid checking for the passed uvw being in the "1st" tile.

    But, again, feel free to experiment and if you find a better approach just share your code for the sake of our community growth.

    Best, Riccardo



  • Hi again, Riccardo!

    If I figure it out I'll be sure to post it.

    I've been trying to get some of the other projection types to work but I've been having trouble with them. So I went to Flat Projection since it seems like the simplest one on the list.

    case P_FLAT: case P_SPATIAL:
        {
          Vector d = p * tdp->im;
          uv->x =  (d.x*0.5-tdp->ox)*lenxinv;
          uv->y = -(d.y*0.5+tdp->oy)*lenyinv;
          break;
        }
    

    Modifying your code with it though isn't giving me the sort of outputs I would be expecting.

    import c4d
    import math
    TEX_EPSILON = 0.0001
    
    def TestUVW(texdata, uvw):
        # check texdata
        if texdata is None or uvw is None:
            return False
    
        # update the UVW value by evaluting TextureTag offset/tiles
        if texdata["proj"] == c4d.P_UVW:
            uvw.x = (uvw.x - texdata["ox"]) * texdata["invLenx"];
            uvw.y = (uvw.y - texdata["oy"]) * texdata["invLeny"];
    
            # if tiling simply return
            if texdata["texflag"] & c4d.TEX_TILE:
                return True
    
            # return True only if UV coord are referring to the first tile, False otherwise
            return (uvw.x >= -TEX_EPSILON and uvw.x <= 1.0+TEX_EPSILON) and (uvw.y >= -TEX_EPSILON and uvw.y <= 1.0+TEX_EPSILON)
    
        return false
    
    #code I added
    def TestFlat(texdata,p):
        d = p * texdata["im"]
        uv = c4d.Vector()
        uv.x =  (d.x*.5-texdata["ox"])*texdata["invLenx"]
        uv.y = -(d.y*.5+texdata["oy"])*texdata["invLeny"]
        
        return uv
    # Main function
    def main():
        if op is None:
            return
    
        # get the current TextureTag / Material / UVWTag
        currentTextureTag = op.GetTag(c4d.Ttexture)
        currentMaterial =  currentTextureTag[c4d.TEXTURETAG_MATERIAL]
        currentUVWTag = op.GetTag(c4d.Tuvw)
        # get the shader associated to the color slot
        shd = currentMaterial[c4d.MATERIAL_COLOR_SHADER]
        # init via  InitRenderStruct()
        initRS = c4d.modules.render.InitRenderStruct()
        c4d.INITRENDERRESULT_OK == shd.InitRender(initRS)
    
        # init the ChannelData
        chanData = c4d.modules.render.ChannelData()
        chanData.n = c4d.Vector(0.0, 0.0, 1.0)
        chanData.d = c4d.Vector(0.01,0.01,0.01)
        chanData.scale = 1.0
      
        # prepare the data for testing the UVW
        invlenx = 0
        invleny =0
        if currentTextureTag[c4d.TEXTURETAG_LENGTHX] !=0:
            invlenx = 1.0/currentTextureTag[c4d.TEXTURETAG_LENGTHX]
        if currentTextureTag[c4d.TEXTURETAG_LENGTHY] !=0:
            invleny = 1.0/currentTextureTag[c4d.TEXTURETAG_LENGTHY]
        
        texdata = {
        "proj" : currentTextureTag[c4d.TEXTURETAG_PROJECTION],
        "ox" : currentTextureTag[c4d.TEXTURETAG_OFFSETX],
        "oy" : currentTextureTag[c4d.TEXTURETAG_OFFSETY],
        "invLenx" : invlenx,#currentTextureTag[c4d.TEXTURETAG_TILESX],
        "invLeny" : invleny,#currentTextureTag[c4d.TEXTURETAG_TILESY],
        "texflag" : 0,
        "lenx" : currentTextureTag[c4d.TEXTURETAG_LENGTHX],
        "leny" : currentTextureTag[c4d.TEXTURETAG_LENGTHY],
        "im":~currentTextureTag.GetMl()
        
        }
        
        # check the tiling state
        if currentTextureTag[c4d.TEXTURETAG_TILE]:
            texdata["texflag"] = texdata["texflag"] & c4d.TEX_TILE
    
        points = op.GetAllPoints()
        polygons = op.GetAllPolygons()
    
        pointcount = 10
        # loop over the data in the UVW set to retrieve the color
        uvwdict = currentUVWTag.GetSlow(0)
    
        spot1 = uvwdict["a"]
        spot2 = uvwdict["c"]
        point1 = points[polygons[0].a]
        point2 = points[polygons[0].c]
        check = c4d.Vector()
        for i in xrange(pointcount+1):
            for j in xrange(pointcount+1):
                col = c4d.Vector(-1)
                localUVW = c4d.Vector (spot1.x + (spot2.x-spot1.x) / pointcount * i, spot1.y + (spot2.y - spot1.y) / pointcount * j, 0)
                localPOS = c4d.Vector (point1.x + (point2.x-point1.x) / pointcount * i, 0, point1.z + (point2.z - point1.z) / pointcount * j)
            
                if texdata["proj"] == c4d.TEXTURETAG_PROJECTION_UVW:
                    if (TestUVW(texdata, localUVW)):
                        chanData.p = localUVW
                        col = shd.Sample(chanData)
                
                if texdata["proj"] == c4d.TEXTURETAG_PROJECTION_FLAT:
                        flatprojection = TestFlat(texdata,localUVW)
                        chanData.p = flatprojection
                        col = shd.Sample(chanData)
    
    
                print  i, ",", j, " / ", localPOS, " / ", localUVW, "/",flatprojection,"/", col
    
        # free the allocated resources
        shd.FreeRender()
    
    # Execute main()
    if __name__=='__main__':
        main()
    

    I took texdata["im"] to mean the inverted matrix of the Texture Tag because of the documentation saying "The inverse of the texture projection matrix. " Because of the default scale of 100 on the texture tag it was making everything really tiny, so I started to use GetNormalized on texdata["im"]. Even in that case it wasn't outputting what I was expecting.

    I modified your output to show what TestFlat() was returning and what was actually being sampled.

     print  i, ",", j, " / ", localPOS, " / ", localUVW, "/",flatprojection,"/", col
    

    Given a normal flat texture I thought that flatprojection would go from vector(.25,0,0) to vector(.75,1,0), but it's actually going from vector(0,-.5,0) to vector(.5,0,0). The latter seems consistent with the code I wrote, but that doesn't seem to be what give the correct output.

    Here is my current setup, with a simple gradient texture and a one polygon 200x200 plane.
    alt text

    Am I still missing something? Am I wrong about what matrix texdata["im"] is supposed to be? The flat projection could is simple enough that I don't see many places where I could have made a mistake.

    Dan



  • Hi Dan, thanks for following up and sorry for coming late here.

    With regard to your new post, there are a few points to clarify:

    • the snippet found in the TexData page in our documentation should be used to compute the UV value for a certain point not for testing a point being inside or outside first tile;

    That said, you are supposed i would suggest to write the coder above as:

    # return the UV of a certain point when flat projection is used
    def ComputeFlatMapping(mappingInfo, p):
        uv = c4d.Vector()
        # check projection being set to flat
        if mappingInfo["proj"] == c4d.TEXTURETAG_PROJECTION_FLAT:
            d = p * mappingInfo["im"]
            uv.x = (d.x * .5 - mappingInfo["ox"]) * mappingInfo["invLenx"] + 0.5
            uv.y = (d.y * .5 + mappingInfo["oy"]) * mappingInfo["invLeny"] + 0.5
        return uv
    

    and later on in the code do something like:

        # compute the UV value at two vertexes
            if currentTextureTag[c4d.TEXTURETAG_PROJECTION] == c4d.TEXTURETAG_PROJECTION_UVW:
                spot1 = uvwdict["a"]
                spot2 = uvwdict["c"]
            else:
                # non UVW cases should be generated on the fly during the sampling loop
                spot1 = 0
                spot2 = 0
    

    The whole code should then look like (I've cleaned and reorganized a few items there):

    import c4d
    import math
    TEX_EPSILON = 0.0001
    
    # test if a given uv value-set is inside first tile (0-1) or outside it
    def TestTiling(mappingInfo, uvw):
        # check passed arguments
        if mappingInfo is None or uvw is None:
            return False
    
        # update the UVW value by evaluating TextureTag offset/tiles
        if mappingInfo["proj"] == c4d.TEXTURETAG_PROJECTION_UVW:
            uvw.x = (uvw.x - mappingInfo["ox"]) * mappingInfo["invLenx"]
            uvw.y = (uvw.y - mappingInfo["oy"]) * mappingInfo["invLeny"]
    
        # if tiling simply return
        if mappingInfo["texflag"] & c4d.TEX_TILE:
            return True
    
        # return True only if UV coord are referring to the first tile, False otherwise
        return (uvw.x >= -TEX_EPSILON and uvw.x <= 1.0+TEX_EPSILON) and (uvw.y >= -TEX_EPSILON and uvw.y <= 1.0+TEX_EPSILON)
    
    # return the UV of a certain point when flat projection is used
    def ComputeFlatMapping(mappingInfo, p):
        uv = c4d.Vector()
        # check projection being set to flat
        if mappingInfo["proj"] == c4d.TEXTURETAG_PROJECTION_FLAT:
            d = p * mappingInfo["im"]
            uv.x = (d.x * .5 - mappingInfo["ox"]) * mappingInfo["invLenx"] + 0.5
            uv.y = (d.y * .5 + mappingInfo["oy"]) * mappingInfo["invLeny"] + 0.5
        return uv
    
    # Main function
    def main():
        if op is None:
            return
    
        # get the current TextureTag / Material / UVWTag
        currentTextureTag = op.GetTag(c4d.Ttexture)
        currentMaterial =  currentTextureTag[c4d.TEXTURETAG_MATERIAL]
    
        mappingInfo = {
            "proj" : currentTextureTag[c4d.TEXTURETAG_PROJECTION],
            "ox" : currentTextureTag[c4d.TEXTURETAG_OFFSETX],
            "oy" : currentTextureTag[c4d.TEXTURETAG_OFFSETY],
            "invLenx" : currentTextureTag[c4d.TEXTURETAG_TILESX],
            "invLeny" : currentTextureTag[c4d.TEXTURETAG_TILESY],
            "texflag" : 0,
            "lenx" : currentTextureTag[c4d.TEXTURETAG_LENGTHX],
            "leny" : currentTextureTag[c4d.TEXTURETAG_LENGTHY],
            "im":~currentTextureTag.GetMl()
        }
    
        # check the tiling state
        if currentTextureTag[c4d.TEXTURETAG_TILE] == 1:
            print "here tiling"
            mappingInfo["texflag"] = mappingInfo["texflag"] | c4d.TEX_TILE
    
        points = op.GetAllPoints()
        polygons = op.GetAllPolygons()
    
        intermediatePointsCnt = 10
        point1 = points[polygons[0].a]
        point2 = points[polygons[0].c]
    
        # get the first UVWTag
        currentUVWTag = op.GetTag(c4d.Tuvw)
        if currentUVWTag is None:
            return
    
        # access the tag values
        uvwdict = currentUVWTag.GetSlow(0)
    
        # compute the UV value at two vertexes
        if currentTextureTag[c4d.TEXTURETAG_PROJECTION] == c4d.TEXTURETAG_PROJECTION_UVW:
            spot1 = uvwdict["a"]
            spot2 = uvwdict["c"]
        else:
            # non UVW cases should be generated on the fly during the sampling loop
            spot1 = 0
            spot2 = 0
    
        # get the shader associated to the color slot
        shd = currentMaterial[c4d.MATERIAL_COLOR_SHADER]
        # init via  InitRenderStruct()
        initRS = c4d.modules.render.InitRenderStruct()
        c4d.INITRENDERRESULT_OK == shd.InitRender(initRS)
    
        # init the ChannelData
        chanData = c4d.modules.render.ChannelData()
        chanData.n = c4d.Vector(0.0, 0.0, 1.0)
        chanData.d = c4d.Vector(0.01,0.01,0.01)
        chanData.scale = 1.0
    
        for j in xrange(intermediatePointsCnt + 1):
            for i in xrange(intermediatePointsCnt + 1):
                col = c4d.Vector(-1)
                localPOS = c4d.Vector (point1.x + (point2.x - point1.x) / intermediatePointsCnt * i, 0, point1.z + (point2.z - point1.z) / intermediatePointsCnt * j)
                localUVW = c4d.Vector (spot1.x + (spot2.x - spot1.x) / intermediatePointsCnt * i, spot1.y + (spot2.y - spot1.y) / intermediatePointsCnt * j, 0)
                
                # if theoretical projection is used recompute the UVW for the sampled point
                if mappingInfo["proj"] == c4d.TEXTURETAG_PROJECTION_FLAT:
                    localUVW = ComputeFlatMapping(mappingInfo, localPOS)
    
                if mappingInfo["proj"] == c4d.TEXTURETAG_PROJECTION_UVW or mappingInfo["proj"] == c4d.TEXTURETAG_PROJECTION_FLAT:
                    if (TestTiling(mappingInfo, localUVW)):
                        chanData.p = localUVW
                        col = shd.Sample(chanData)
    
                print localPOS, "/", localUVW, "/",col
    
        # free the allocated resources
        shd.FreeRender()
    
    # Execute main()
    if __name__=='__main__':
        main()
    

    For the sake of completeness, please find also attached to the test scene used to verify the code .

    Hoping this helps you to further aim in the desired direction, give best.

    Riccardo



  • Hi again Riccardo, sorry about another late response but I was finally able to go through your code again. I see where I when wrong in understanding where the Flat projection stuff would take over.

    Going through your code I saw a few things that didn't make sense to me and I just want to make sure I went about them in the right way.

     if currentTextureTag[c4d.TEXTURETAG_PROJECTION] == c4d.TEXTURETAG_PROJECTION_UVW:
            spot1 = uvwdict["a"]
            spot2 = uvwdict["c"]
        else:
            # non UVW cases should be generated on the fly during the sampling loop
            spot1 = 0#These need to be swapped to c4d.Vector(0), since later on it's looking for a vector.
            spot2 = 0
    

    And then the second one:

    def ComputeFlatMapping(mappingInfo, p):
        uv = c4d.Vector()
        # check projection being set to flat
        if mappingInfo["proj"] == c4d.TEXTURETAG_PROJECTION_FLAT:
            d = p * mappingInfo["im"]
            uv.x = (d.x * .5 - mappingInfo["ox"]) * mappingInfo["invLenx"] + 0.5
            uv.y = (d.y * .5 + mappingInfo["oy"]) * mappingInfo["invLeny"] + 0.5 # this needs to be changed to "-(d.y * .5 + mappingInfo["oy"]) * mappingInfo["invLeny"] + 0.5"
        return uv
    

    Without changing it to minus in your checkerboard example doesn't seem to return the correct color samples. I was getting Vector(0,0,0) when I should have been getting Vector(1,1,1) and vice versa from what I could tell.

    Swapping uv.y to the minus seemed to fix that.

    Then I tried a new test with a new material, each quarter of it being a different color. Even with my 'fix' I was getting incorrect outputs.

    My new test

    What I'm getting as an output:

    Vector(-300, 0, 200) / Vector(0.793, 0.803, 0) / Vector(1, 0, 0)
    Vector(-400, 0, 300) / Vector(0.086, 0.803, 0) / Vector(0, 0, 0)
    Vector(-300, 0, 300) / Vector(0.44, 0.45, 0) / Vector(0, 0, 0)
    Vector(-200, 0, 300) / Vector(0.793, 0.096, 0) / Vector(1, 0, 0)
    Vector(-300, 0, 400) / Vector(0.086, 0.096, 0) / Vector(0, 0, 0)
    

    When I expect to get:

    Vector(-300, 0, 200) / Vector(0.793, 0.803, 0) / Vector(1, 0, 0)
    Vector(-400, 0, 300) / Vector(0.086, 0.803, 0) / Vector(0, 0, 0)
    Vector(-300, 0, 300) / Vector(0.44, 0.45, 0) / Vector(1, 1, 1)
    Vector(-200, 0, 300) / Vector(0.793, 0.096, 0) / Vector(0, 0, 1)
    Vector(-300, 0, 400) / Vector(0.086, 0.096, 0) / Vector(1, 1, 1)
    

    After all of that I still have one more question: where the end +.5 came from for the last bit of code. They are missing from the TexData example, but from what I can tell it needs them to function correctly.

          /*TexData example for Flat Projection*/
          Vector d = p * tdp->im;
          uv->x =  (d.x*0.5-tdp->ox)*lenxinv;
          uv->y = -(d.y*0.5+tdp->oy)*lenyinv;
    
            /* as opposed to  your code*/
            uv.x = (d.x * .5 - mappingInfo["ox"]) * mappingInfo["invLenx"] + 0.5
            uv.y = (d.y * .5 + mappingInfo["oy"]) * mappingInfo["invLeny"] + 0.5
    
    

    I'm just worried in doing the other projection types that there will be an unknown variable that I don't know that I need to add.

    Again, thank you so much for all of your help, Riccardo.



  • Hi Dan, thanks for following up.

    Here are my considerations based on your comments:

    1. Without changing it to minus in your checkerboard example doesn't seem to return the correct color samples. I was getting Vector(0,0,0) when I should have been getting Vector(1,1,1) and vice versa from what I could tell.

    I think it's a bug in how the Layer shader in your scene is sampled.
    Using a grandient-only shader (new scene) makes the script generating consistent results
    0_1552060778053_144ffd79-840d-4da0-9d57-e5678ee95a8c-image.png

    In this case the "relevant" values are:

    Vector(-300, 0, 200) / Vector(0.793, 0.803, 0) / Vector(1, 0, 0)
    Vector(-400, 0, 300) / Vector(0.086, 0.803, 0) / Vector(0, 1, 0)
    Vector(-300, 0, 300) / Vector(0.44, 0.45, 0) / Vector(0, 0, 1)
    Vector(-200, 0, 300) / Vector(0.793, 0.096, 0) / Vector(1, 1, 1)
    Vector(-300, 0, 400) / Vector(0.086, 0.096, 0) / Vector(0, 0, 1)
    
    1. Swapping uv.y to the minus seemed to fix that.

    I agree, my bad there! Correct code should look like:

    def ComputeFlatMapping(mappingInfo, p):
        uv = c4d.Vector()
        # check projection being set to flat
        if mappingInfo["proj"] == c4d.TEXTURETAG_PROJECTION_FLAT:
            d = p * mappingInfo["im"]
            uv.x = (d.x * .5 - mappingInfo["ox"]) * mappingInfo["invLenx"] + 0.5
            uv.y = -(d.y * .5 + mappingInfo["oy"]) * mappingInfo["invLeny"] + 0.5
        return uv
    
    1. After all of that I still have one more question: where the end +.5 came from for the last bit of code. They are missing from the TexData example, but from what I can tell it needs them to function correctly.

    Here I've just debugged the values returned by the code responsible for generating UV values and I found that the values were missing a +0.5 shift.

    Best, Riccardo



  • Hi Riccardo,

    Thanks for the first response. My bad with not catching that it was a layer shader bug, I figured I had done something wrong with the sampling. I'll start looking into the other projection samplings.

    Dan


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