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colorAtPoint [-coordU float] [-coordV float] [-maxU float] [-maxV float] [-minU float] [-minV float] [-output string] [-samplesU uint] [-samplesV uint]
colorAtPoint is NOT undoable, NOT queryable, and NOT editable.
The colorAtPoint command is used to query textures or ocean
shaders at passed in uv coordinates.
(For ocean shaders uv is x and z in worldspace ).
The return value is a floating point array whose size is
determined by either the number of input uv arguments passed in and the
the queried value. One can query alpha only, rgb only, or rgba values.
The returned array is only single indexed, so if rgb is specified then
the index for red values would be index * 3. Blue is index * 3 + 1, and
green is index * 3 + 2. For rgba use a multiple of 4 instead of 3.
For alpha only one can simply use the index.
There are two basic argument formats that may be used:
colorAtPoint -u 0 -v 0 -u .2 -v .1 etc.. for all points
or
colorAtPoint -mu 0 -mv 0 -xu 1 -xv 1 -su 10 -sv 10 // samples 100 points
If one is sampling several points and they are all in a regular grid
formation it is more efficient to call this routine with the latter
method, which uses a min/max uv and number of samples, rather than
a long argument list of uv coords.
- return values (-o A or RGB or RGBA )
- individual UV coordinates to sample (-u float -v float )
- (numbers of calls to -u and -v must match)
- uniform grid of points to sample (-su int -sv int)
- (may not use this in combination with -u or -v)
- bounds for sample grid (-mu float -mv float -xu float -xv float)
None
texture, color, alpha, uv, ocean, outColor, paramUV
coordU, coordV, maxU, maxV, minU, minV, output, samplesU, samplesV
| Long name (short name) |
Argument types |
Properties |
-coordU(-u)
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float
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Input u coordinate to sample texture at.
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-coordV(-v)
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float
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Input v coordinate to sample texture at.
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-maxU(-xu)
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float
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DEFAULT 1.0
Maximum u bounds to sample.
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-maxV(-xv)
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float
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DEFAULT 1.0
Maximum v bounds to sample.
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-minU(-mu)
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float
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DEFAULT 0.0
Minimum u bounds to sample.
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-minV(-mv)
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float
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DEFAULT 0.0
Minimum v bounds to sample.
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-output(-o)
|
string
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Type of data to output:
A = alpha only
RGB = color only
RGBA = color and alpha
|
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-samplesU(-su)
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uint
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DEFAULT 1
The number of points to sample in the U dimension.
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-samplesV(-sv)
|
uint
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DEFAULT 1
The number of points to sample in the V dimension.
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Flag can appear in Create mode of command
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Flag can appear in Edit mode of command
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Flag can appear in Query mode of command
|
Flag can be used more than once in a command.
|
// The return value is the array of values determined by the number of
// coord flag uses or samplesU * samplesV. The default return value is alpha.
// If instead the return value is RGB there will be 3 times as many values returned,
// and if it is RGBA there will be 4 times as many values.
createNode checker;
colorAtPoint checker1;
// returns the alpha value at uv (0.0,0.0) for texture checker1
// The return array will have one entry corresponding to this alpha.
colorAtPoint -u .5 -v .5 checker1;
// returns the alpha value at uv (0.5,0.5) for texture checker1
// The return array will have one entry corresponding to this alpha.
colorAtPoint -o RGB -u .5 -v .5 -u 0.0 -v 0.1 checker1;
// returns the colors at uv (0.5,0.5) and (0.0, 0.01) for texture checker1
// The return array will have 6 values in the following order: RGBRGB
colorAtPoint -o A -su 11 -sv 6 checker1;
// returns the alpha for 50 points in a uniform 11 by 6 grid mapped across
// uv (0.0, 0.0) to uv (1.0, 1.0) The 12th point would be the first point
// in the second row of samples where uv = (0.0, 0.2)
colorAtPoint -o A -su 3 -sv 3 -mu 0.3 -mv 0.3 -xu 0.4 -xv 0.4 checker1;
// returns the alpha for 9 points in a uniform 3 by 3 grid mapped across
// uv (0.3, 0.3) to uv (0.4, 0.4) The 4th point would be the first point
// in the second row of samples where uv = (0.35, 0.3).