import mapWebGLBlendModesToPixi from './utils/mapWebGLBlendModesToPixi';
import System from '../System';
import State from './State';
import { BLEND_MODES } from '@pixi/constants';
const BLEND = 0;
const OFFSET = 1;
const CULLING = 2;
const DEPTH_TEST = 3;
const WINDING = 4;
/**
* System plugin to the renderer to manage WebGL state machines.
*
* @class
* @extends PIXI.System
* @memberof PIXI.systems
*/
export default class StateSystem extends System
{
/**
* @param {PIXI.Renderer} renderer - The renderer this System works for.
*/
constructor(renderer)
{
super(renderer);
/**
* GL context
* @member {WebGLRenderingContext}
* @readonly
*/
this.gl = null;
/**
* State ID
* @member {number}
* @readonly
*/
this.stateId = 0;
/**
* Polygon offset
* @member {number}
* @readonly
*/
this.polygonOffset = 0;
/**
* Blend mode
* @member {number}
* @default PIXI.BLEND_MODES.NONE
* @readonly
*/
this.blendMode = BLEND_MODES.NONE;
/**
* Whether current blend equation is different
* @member {boolean}
* @protected
*/
this._blendEq = false;
/**
* Collection of calls
* @member {function[]}
* @readonly
*/
this.map = [];
// map functions for when we set state..
this.map[BLEND] = this.setBlend;
this.map[OFFSET] = this.setOffset;
this.map[CULLING] = this.setCullFace;
this.map[DEPTH_TEST] = this.setDepthTest;
this.map[WINDING] = this.setFrontFace;
/**
* Collection of check calls
* @member {function[]}
* @readonly
*/
this.checks = [];
/**
* Default WebGL State
* @member {PIXI.State}
* @readonly
*/
this.defaultState = new State();
this.defaultState.blend = true;
this.defaultState.depth = true;
}
contextChange(gl)
{
this.gl = gl;
this.blendModes = mapWebGLBlendModesToPixi(gl);
this.setState(this.defaultState);
this.reset();
}
/**
* Sets the current state
*
* @param {*} state - The state to set.
*/
setState(state)
{
state = state || this.defaultState;
// TODO maybe to an object check? ( this.state === state )?
if (this.stateId !== state.data)
{
let diff = this.stateId ^ state.data;
let i = 0;
// order from least to most common
while (diff)
{
if (diff & 1)
{
// state change!
this.map[i].call(this, !!(state.data & (1 << i)));
}
diff = diff >> 1;
i++;
}
this.stateId = state.data;
}
// based on the above settings we check for specific modes..
// for example if blend is active we check and set the blend modes
// or of polygon offset is active we check the poly depth.
for (let i = 0; i < this.checks.length; i++)
{
this.checks[i](this, state);
}
}
/**
* Sets the state, when previous state is unknown
*
* @param {*} state - The state to set
*/
forceState(state)
{
state = state || this.defaultState;
for (let i = 0; i < this.map.length; i++)
{
this.map[i].call(this, !!(state.data & (1 << i)));
}
for (let i = 0; i < this.checks.length; i++)
{
this.checks[i](this, state);
}
this.stateId = state.data;
}
/**
* Enables or disabled blending.
*
* @param {boolean} value - Turn on or off webgl blending.
*/
setBlend(value)
{
this.updateCheck(StateSystem.checkBlendMode, value);
this.gl[value ? 'enable' : 'disable'](this.gl.BLEND);
}
/**
* Enables or disable polygon offset fill
*
* @param {boolean} value - Turn on or off webgl polygon offset testing.
*/
setOffset(value)
{
this.updateCheck(StateSystem.checkPolygonOffset, value);
this.gl[value ? 'enable' : 'disable'](this.gl.POLYGON_OFFSET_FILL);
}
/**
* Sets whether to enable or disable depth test.
*
* @param {boolean} value - Turn on or off webgl depth testing.
*/
setDepthTest(value)
{
this.gl[value ? 'enable' : 'disable'](this.gl.DEPTH_TEST);
}
/**
* Sets whether to enable or disable cull face.
*
* @param {boolean} value - Turn on or off webgl cull face.
*/
setCullFace(value)
{
this.gl[value ? 'enable' : 'disable'](this.gl.CULL_FACE);
}
/**
* Sets the gl front face.
*
* @param {boolean} value - true is clockwise and false is counter-clockwise
*/
setFrontFace(value)
{
this.gl.frontFace(this.gl[value ? 'CW' : 'CCW']);
}
/**
* Sets the blend mode.
*
* @param {number} value - The blend mode to set to.
*/
setBlendMode(value)
{
if (value === this.blendMode)
{
return;
}
this.blendMode = value;
const mode = this.blendModes[value];
const gl = this.gl;
if (mode.length === 2)
{
gl.blendFunc(mode[0], mode[1]);
}
else
{
gl.blendFuncSeparate(mode[0], mode[1], mode[2], mode[3]);
}
if (mode.length === 6)
{
this._blendEq = true;
gl.blendEquationSeparate(mode[4], mode[5]);
}
else if (this._blendEq)
{
this._blendEq = false;
gl.blendEquationSeparate(gl.FUNC_ADD, gl.FUNC_ADD);
}
}
/**
* Sets the polygon offset.
*
* @param {number} value - the polygon offset
* @param {number} scale - the polygon offset scale
*/
setPolygonOffset(value, scale)
{
this.gl.polygonOffset(value, scale);
}
// used
/**
* Resets all the logic and disables the vaos
*/
reset()
{
this.gl.pixelStorei(this.gl.UNPACK_FLIP_Y_WEBGL, false);
this.forceState(0);
this._blendEq = true;
this.blendMode = -1;
this.setBlendMode(0);
}
/**
* checks to see which updates should be checked based on which settings have been activated.
* For example, if blend is enabled then we should check the blend modes each time the state is changed
* or if polygon fill is activated then we need to check if the polygon offset changes.
* The idea is that we only check what we have too.
*
* @param {Function} func the checking function to add or remove
* @param {boolean} value should the check function be added or removed.
*/
updateCheck(func, value)
{
const index = this.checks.indexOf(func);
if (value && index === -1)
{
this.checks.push(func);
}
else if (!value && index !== -1)
{
this.checks.splice(index, 1);
}
}
/**
* A private little wrapper function that we call to check the blend mode.
*
* @static
* @private
* @param {PIXI.StateSystem} System the System to perform the state check on
* @param {PIXI.State} state the state that the blendMode will pulled from
*/
static checkBlendMode(system, state)
{
system.setBlendMode(state.blendMode);
}
/**
* A private little wrapper function that we call to check the polygon offset.
*
* @static
* @private
* @param {PIXI.StateSystem} System the System to perform the state check on
* @param {PIXI.State} state the state that the blendMode will pulled from
*/
static checkPolygonOffset(system, state)
{
system.setPolygonOffset(state.polygonOffset, 0);
}
}
