const _createBlendMode = (functions, equations) => ({
functionName: "blendFunc" + (functions.length < 3 ? "" : "Separate"),
functions,
equationName: "blendEquation" + (!equations || equations.length < 2 ? "" : "Separate"),
equations: equations || [WebGL2RenderingContext.FUNC_ADD],
});
/**
* @typedef {Object} BlendModeInfo
* @property {string} functionName
* @property {Array<number>} functions
* @property {string} equationName
* @property {Array<number>} equations
*/
/**
* @typedef {function} createBlendMode
* @param {Array<number>} functions
* @param {Array<number>} equations
* @returns {BlendModeInfo}
*/
/**
* <pre>
* Blend modes
* - OVERLAY is an alias of NORMAL_PM, not a real overlay blend
* - Multiplicative modes (MULTIPLY, MULTIPLY_PM, SCREEN, SCREEN_PM, SHADOW, EXCLUSION):
* textures are premultiplied, so soft (semi-transparent) edges darken or fringe;
* image.alpha scales only the output alpha, so modes using DST_COLOR / SRC_COLOR
* ignore it for the rgb channels
* </pre>
* @typedef {Object} BlendMode
* @property {createBlendMode} createBlendMode
* @property {BlendModeInfo} NONE
* @property {BlendModeInfo} NORMAL_PM
* @property {BlendModeInfo} ADD_PM
* @property {BlendModeInfo} MULTIPLY_PM Multiplicative: textures are premultiplied, so soft edges darken or fringe; image.alpha only scales the output alpha, so the DST_COLOR / SRC_COLOR factors ignore it
* @property {BlendModeInfo} SCREEN_PM Multiplicative: textures are premultiplied, so soft edges darken or fringe; image.alpha only scales the output alpha, so the DST_COLOR / SRC_COLOR factors ignore it
* @property {BlendModeInfo} ADD_NPM
* @property {BlendModeInfo} SRC_IN
* @property {BlendModeInfo} SRC_OUT
* @property {BlendModeInfo} SRC_ATOP
* @property {BlendModeInfo} DST_OVER
* @property {BlendModeInfo} DST_IN
* @property {BlendModeInfo} DST_OUT
* @property {BlendModeInfo} DST_ATOP
* @property {BlendModeInfo} XOR
* @property {BlendModeInfo} NORMAL
* @property {BlendModeInfo} ADD
* @property {BlendModeInfo} MULTIPLY Multiplicative: textures are premultiplied, so soft edges darken or fringe; image.alpha only scales the output alpha, so the DST_COLOR / SRC_COLOR factors ignore it
* @property {BlendModeInfo} SCREEN Multiplicative: textures are premultiplied, so soft edges darken or fringe; image.alpha only scales the output alpha, so the DST_COLOR / SRC_COLOR factors ignore it
* @property {BlendModeInfo} OVERLAY Alias of NORMAL_PM, not a real overlay blend
* @property {BlendModeInfo} EXCLUSION Multiplicative: textures are premultiplied, so soft edges darken or fringe; image.alpha only scales the output alpha, so the DST_COLOR / SRC_COLOR factors ignore it
* @property {BlendModeInfo} LIGHTEN
* @property {BlendModeInfo} DARKEN
* @property {BlendModeInfo} SHADOW Multiplicative: textures are premultiplied, so soft edges darken or fringe; image.alpha only scales the output alpha, so the DST_COLOR / SRC_COLOR factors ignore it
*/
export const BlendMode = {
createBlendMode: _createBlendMode,
NONE: _createBlendMode([0, 0]),
NORMAL_PM: _createBlendMode([WebGL2RenderingContext.ONE, WebGL2RenderingContext.ONE_MINUS_SRC_ALPHA]),
ADD_PM: _createBlendMode([WebGL2RenderingContext.ONE, WebGL2RenderingContext.ONE]),
MULTIPLY_PM: _createBlendMode([
WebGL2RenderingContext.DST_COLOR,
WebGL2RenderingContext.ONE_MINUS_SRC_ALPHA,
WebGL2RenderingContext.ONE,
WebGL2RenderingContext.ONE_MINUS_SRC_ALPHA,
]),
SCREEN_PM: _createBlendMode([
WebGL2RenderingContext.ONE,
WebGL2RenderingContext.ONE_MINUS_SRC_COLOR,
WebGL2RenderingContext.ONE,
WebGL2RenderingContext.ONE_MINUS_SRC_ALPHA,
]),
ADD_NPM: _createBlendMode([
WebGL2RenderingContext.SRC_ALPHA,
WebGL2RenderingContext.ONE,
WebGL2RenderingContext.ONE,
WebGL2RenderingContext.ONE,
]),
SRC_IN: _createBlendMode([WebGL2RenderingContext.DST_ALPHA, WebGL2RenderingContext.ZERO]),
SRC_OUT: _createBlendMode([WebGL2RenderingContext.ONE_MINUS_DST_ALPHA, WebGL2RenderingContext.ZERO]),
SRC_ATOP: _createBlendMode([WebGL2RenderingContext.DST_ALPHA, WebGL2RenderingContext.ONE_MINUS_SRC_ALPHA]),
DST_OVER: _createBlendMode([WebGL2RenderingContext.ONE_MINUS_DST_ALPHA, WebGL2RenderingContext.ONE]),
DST_IN: _createBlendMode([WebGL2RenderingContext.ZERO, WebGL2RenderingContext.SRC_ALPHA]),
DST_OUT: _createBlendMode([WebGL2RenderingContext.ZERO, WebGL2RenderingContext.ONE_MINUS_SRC_ALPHA]),
DST_ATOP: _createBlendMode([WebGL2RenderingContext.ONE_MINUS_DST_ALPHA, WebGL2RenderingContext.SRC_ALPHA]),
XOR: _createBlendMode([WebGL2RenderingContext.ONE_MINUS_DST_ALPHA, WebGL2RenderingContext.ONE_MINUS_SRC_ALPHA]),
NORMAL: _createBlendMode([
WebGL2RenderingContext.SRC_ALPHA,
WebGL2RenderingContext.ONE_MINUS_SRC_ALPHA,
WebGL2RenderingContext.ONE,
WebGL2RenderingContext.ONE_MINUS_SRC_ALPHA,
]),
ADD: _createBlendMode([
WebGL2RenderingContext.SRC_ALPHA,
WebGL2RenderingContext.DST_ALPHA,
WebGL2RenderingContext.ONE,
WebGL2RenderingContext.DST_ALPHA,
]),
MULTIPLY: _createBlendMode([WebGL2RenderingContext.DST_COLOR, WebGL2RenderingContext.ZERO]),
SCREEN: _createBlendMode([
WebGL2RenderingContext.SRC_ALPHA,
WebGL2RenderingContext.ONE_MINUS_SRC_COLOR,
WebGL2RenderingContext.ONE,
WebGL2RenderingContext.ONE_MINUS_SRC_COLOR,
]),
OVERLAY: _createBlendMode([WebGL2RenderingContext.ONE, WebGL2RenderingContext.ONE_MINUS_SRC_ALPHA]),
EXCLUSION: _createBlendMode([WebGL2RenderingContext.ONE_MINUS_DST_COLOR, WebGL2RenderingContext.ONE_MINUS_SRC_COLOR]),
LIGHTEN: _createBlendMode([WebGL2RenderingContext.ONE, WebGL2RenderingContext.ONE], [WebGL2RenderingContext.MAX]),
DARKEN: _createBlendMode([WebGL2RenderingContext.ONE, WebGL2RenderingContext.ONE], [WebGL2RenderingContext.MIN]),
SHADOW: _createBlendMode([WebGL2RenderingContext.DST_COLOR, WebGL2RenderingContext.SRC_COLOR]),
};
Extensions