Add fill-extrusion-vertical-gradient property #6841
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Is @mapbox/studio ok with including this? Seems like this is a desired option. |
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In general we're a little concerned about the spec getting bloated, but we're good with this addition; it'll be easy enough for us to support |
ryanhamley
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I rebased this PR against
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| @@ -24,7 +24,8 @@ export type FillExtrusionUniformsType = {| | |||
| 'u_matrix': UniformMatrix4f, | |||
| 'u_lightpos': Uniform3f, | |||
| 'u_lightintensity': Uniform1f, | |||
| 'u_lightcolor': Uniform3f | |||
| 'u_lightcolor': Uniform3f, | |||
| 'u_vertical_gradient': Uniform1f | |||
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this is just 1 or 0 right? in that case we can use an integer uniform Uniform1i to follow the convention of other uniforms used as booleans such as u_is_zoom_constant for symbol icons/sdfs
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This actually needs to be a float because the calculation in the shader has float constants.
| @@ -80,7 +84,8 @@ const extrusionTextureUniforms = (context: Context, locations: UniformLocations) | |||
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| const fillExtrusionUniformValues = ( | |||
| matrix: Float32Array, | |||
| painter: Painter | |||
| painter: Painter, | |||
| verticalGradient: number | |||
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For clarity, I lean towards passing this value to the *UniformValues functions as a boolean, and casting only as the value is bound to its uniform location.
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Uniform1i requires a number input so casting the boolean to a number only when binding to the location causes a Flow error. Is there a way around that?
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yep you use the + like here https://github.com/mapbox/mapbox-gl-js/blob/master/src/render/program/symbol_program.js#L116
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Ah yeah, I was mistakenly casting to a number elsewhere in the program, causing a flow error. This is fixed now.
| @@ -47,7 +48,11 @@ void main() { | |||
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| // Add gradient along z axis of side surfaces | |||
| if (normal.y != 0.0) { | |||
| directional *= clamp((t + base) * pow(height / 150.0, 0.5), mix(0.7, 0.98, 1.0 - u_lightintensity), 1.0); | |||
| // This avoids another branching statement, but multiplies by a constant of 0.84 if no vertical gradient, | |||
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do we have any idea where the magic -0.84 comes from? maybe nicki would know
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why would Nicki know? i have no idea where it comes from
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Nicki worked on the extrusion shaders w lbud
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@nickidlugash do you remember where this magic number came from?
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@ryanhamley @mollymerp I didn't work with lbud on this PR at all, but having worked on the initial implementation of this shader, my guess is that 0.84 is the lower clamp in the gradient logic when u_lightintensity is the default value of 0.5 (mix(0.7, 0.98, 0.5) = 0.84). I assume it's negative so that when u_vertical_gradient is 0, that first line just evaluates to 0.84.
0.7 and 0.98 are magic numbers that I came up with to keep the vertical gradient consistently subtle, regardless of how intense the light is.
I actually wonder though if it would be better not to multiply by a constant here if there is no vertical gradient (i.e. something like (1.0 - u_vertical_gradient) instead of the current top line). Multiplying by a constant seems like it would unnecessarily limit the range of light intensity such that you could never get as intense a light when intensity=1.
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I updated the way the gradient is calculated (removed the 0.84 constant) to allow the full spectrum of light intensity to be used in determining the final color.
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@lbud, @ryanhamley, @mollymerp, @nickidlugash Thanks so much for your awesome work on this. My team is looking forward to getting this into our project right away. |
This PR adds a new boolean data-constant paint property,
fill-extrusion-vertical-gradient( 🤔 a bit verbose — I'm open to better ideas). It defaults totrue(the current behavior), but if set tofalse, does not apply a vertical gradient along the sides of fill-extrusion features.Closes #5768.
I only ran benchmarks for
LayerFillExtrusionsince nothing else should be affected, and it shows no real change: https://bl.ocks.org/lbud/raw/d353b63e34c7fcb6e4ec2698370fd6b9/Launch Checklist
@mapbox/maps-designif this PR includes style spec changes