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Set PenSkin silhouette data directly #475

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Merged
merged 1 commit into from
Apr 2, 2020
Merged

Set PenSkin silhouette data directly #475

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32 changes: 17 additions & 15 deletions src/PenSkin.js
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Original file line number Diff line number Diff line change
Expand Up @@ -109,6 +109,12 @@ class PenSkin extends Skin {
/** @type {boolean} */
this._silhouetteDirty = false;

/** @type {Uint8Array} */
this._silhouettePixels = null;

/** @type {ImageData} */
this._silhouetteImageData = null;

/** @type {object} */
this._lineOnBufferDrawRegionId = {
enter: () => this._enterDrawLineOnBuffer(),
Expand Down Expand Up @@ -597,6 +603,9 @@ class PenSkin extends Skin {
gl.clearColor(0, 0, 0, 0);
gl.clear(gl.COLOR_BUFFER_BIT);

this._silhouettePixels = new Uint8Array(Math.floor(width * height * 4));
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Nit: the math.floor isn't necessary here

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It seems to be used in every other place in the codebase that constructs a Uint8Array, specifically to prevent issues with Edge.

If I removed it here, I don't think it would cause any trouble (width and height should be integers), and newer versions of Edge (I tested it on Microsoft Edge 44.18362.449.0, Microsoft EdgeHTML 18.18363) have no trouble with floating-point values in typed array constructors, but it'd break the convention that the rest of the codebase is using. Is that okay?

(P.S. it may be worth revisiting this in the future by either testing whether Edge 15, the minimum version Scratch officially supports, supports floating-point values in TypedArray constructors, or by bumping the minimum supported Edge version in the FAQ to something newer.)

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Oops - thanks for the reminder! I had completely forgotten about that.

this._silhouetteImageData = this._canvas.getContext('2d').createImageData(width, height);
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Yes. We should definitely reuse these.


this._silhouetteDirty = true;
}

Expand Down Expand Up @@ -634,24 +643,17 @@ class PenSkin extends Skin {
// Render export texture to another framebuffer
const gl = this._renderer.gl;

const bounds = this._bounds;

this._renderer.enterDrawRegion(this._toBufferDrawRegionId);

// Sample the framebuffer's pixels into the silhouette instance
const skinPixels = new Uint8Array(Math.floor(this._canvas.width * this._canvas.height * 4));
gl.readPixels(0, 0, this._canvas.width, this._canvas.height, gl.RGBA, gl.UNSIGNED_BYTE, skinPixels);

const skinCanvas = this._canvas;
skinCanvas.width = bounds.width;
skinCanvas.height = bounds.height;

const skinContext = skinCanvas.getContext('2d');
const skinImageData = skinContext.createImageData(bounds.width, bounds.height);
skinImageData.data.set(skinPixels);
skinContext.putImageData(skinImageData, 0, 0);

this._silhouette.update(this._canvas, true /* isPremultiplied */);
gl.readPixels(
0, 0,
this._canvas.width, this._canvas.height,
gl.RGBA, gl.UNSIGNED_BYTE, this._silhouettePixels
);

this._silhouetteImageData.data.set(this._silhouettePixels);
this._silhouette.update(this._silhouetteImageData, true /* isPremultiplied */);

this._silhouetteDirty = false;
}
Expand Down