import System from '../System';
import GLBuffer from './GLBuffer';
import { ENV } from '@pixi/constants';
import { settings } from '../settings';
const byteSizeMap = { 5126: 4, 5123: 2, 5121: 1 };
/**
* @class
* @extends PIXI.System
* @memberof PIXI.systems
*/
export default class GeometrySystem extends System
{
/**
* @param {PIXI.Renderer} renderer - The renderer this System works for.
*/
constructor(renderer)
{
super(renderer);
this._activeGeometry = null;
this._activeVao = null;
/**
* `true` if we has `*_vertex_array_object` extension
* @member {boolean}
* @readonly
*/
this.hasVao = true;
/**
* `true` if has `ANGLE_instanced_arrays` extension
* @member {boolean}
* @readonly
*/
this.hasInstance = true;
/**
* A cache thats stores vaos linked to geometries.
* @member {Object}
* @private
*/
this.cache = {};
/**
* A cache of currently bound buffer..
*/
this.boundBuffers = {};
}
/**
* Sets up the renderer context and necessary buffers.
*
* @private
*/
contextChange()
{
const gl = this.gl = this.renderer.gl;
this.CONTEXT_UID = this.renderer.CONTEXT_UID;
// webgl2
if (!gl.createVertexArray)
{
// webgl 1!
let nativeVaoExtension = this.renderer.context.extensions.vertexArrayObject;
if (settings.PREFER_ENV === ENV.WEBGL_LEGACY)
{
nativeVaoExtension = null;
}
if (nativeVaoExtension)
{
gl.createVertexArray = () =>
nativeVaoExtension.createVertexArrayOES();
gl.bindVertexArray = (vao) =>
nativeVaoExtension.bindVertexArrayOES(vao);
gl.deleteVertexArray = (vao) =>
nativeVaoExtension.deleteVertexArrayOES(vao);
}
else
{
this.hasVao = false;
gl.createVertexArray = () =>
{
// empty
};
gl.bindVertexArray = () =>
{
// empty
};
gl.deleteVertexArray = () =>
{
// empty
};
}
}
if (!gl.vertexAttribDivisor)
{
const instanceExt = gl.getExtension('ANGLE_instanced_arrays');
if (instanceExt)
{
gl.vertexAttribDivisor = (a, b) =>
instanceExt.vertexAttribDivisorANGLE(a, b);
gl.drawElementsInstanced = (a, b, c, d, e) =>
instanceExt.drawElementsInstancedANGLE(a, b, c, d, e);
gl.drawArraysInstanced = (a, b, c, d) =>
instanceExt.drawArraysInstancedANGLE(a, b, c, d);
}
else
{
this.hasInstance = false;
}
}
}
/**
* Binds geometry so that is can be drawn. Creating a Vao if required
* @private
* @param {PIXI.Geometry} geometry instance of geometry to bind
* @param {PIXI.Shader} shader instance of shader to bind
*/
bind(geometry, shader)
{
shader = shader || this.renderer.shader.shader;
const { gl } = this;
// not sure the best way to address this..
// currently different shaders require different VAOs for the same geometry
// Still mulling over the best way to solve this one..
// will likely need to modify the shader attribute locations at run time!
let vaos = geometry.glVertexArrayObjects[this.CONTEXT_UID];
if (!vaos)
{
geometry.glVertexArrayObjects[this.CONTEXT_UID] = vaos = {};
}
const vao = vaos[shader.program.id] || this.initGeometryVao(geometry, shader.program);
this._activeGeometry = geometry;
if (this._activeVao !== vao)
{
this._activeVao = vao;
if (this.hasVao)
{
gl.bindVertexArray(vao);
}
else
{
this.activateVao(geometry, shader.program);
}
}
// TODO - optimise later!
// don't need to loop through if nothing changed!
// maybe look to add an 'autoupdate' to geometry?
this.updateBuffers();
}
/**
* Reset and unbind any active VAO and geometry
*/
reset()
{
this.unbind();
}
/**
* Update buffers
* @private
*/
updateBuffers()
{
const geometry = this._activeGeometry;
const { gl } = this;
for (let i = 0; i < geometry.buffers.length; i++)
{
const buffer = geometry.buffers[i];
const glBuffer = buffer._glBuffers[this.CONTEXT_UID];
if (buffer._updateID !== glBuffer.updateID)
{
glBuffer.updateID = buffer._updateID;
// TODO can cache this on buffer! maybe added a getter / setter?
const type = buffer.index ? gl.ELEMENT_ARRAY_BUFFER : gl.ARRAY_BUFFER;
const drawType = buffer.static ? gl.STATIC_DRAW : gl.DYNAMIC_DRAW;
if (this.boundBuffers[type] !== glBuffer)
{
this.boundBuffers[type] = glBuffer;
gl.bindBuffer(type, glBuffer.buffer);
}
this._boundBuffer = glBuffer;
if (glBuffer.byteLength >= buffer.data.byteLength)
{
// offset is always zero for now!
gl.bufferSubData(type, 0, buffer.data);
}
else
{
glBuffer.byteLength = buffer.data.byteLength;
gl.bufferData(type, buffer.data, drawType);
}
}
}
}
/**
* Check compability between a geometry and a program
* @private
* @param {PIXI.Geometry} geometry - Geometry instance
* @param {PIXI.Program} program - Program instance
*/
checkCompatibility(geometry, program)
{
// geometry must have at least all the attributes that the shader requires.
const geometryAttributes = geometry.attributes;
const shaderAttributes = program.attributeData;
for (const j in shaderAttributes)
{
if (!geometryAttributes[j])
{
throw new Error(`shader and geometry incompatible, geometry missing the "${j}" attribute`);
}
}
}
/**
* Takes a geometry and program and generates a unique signature for them.
*
* @param {PIXI.Geometry} geometry to get signature from
* @param {PIXI.Program} prgram to test geometry against
* @returns {String} Unique signature of the geometry and program
* @private
*/
getSignature(geometry, program)
{
const attribs = geometry.attributes;
const shaderAttributes = program.attributeData;
const strings = [geometry.id];
for (const i in attribs)
{
if (shaderAttributes[i])
{
strings.push(i);
}
}
return strings.join('-');
}
/**
* Creates a Vao with the same structure as the geometry and stores it on the geometry.
* @private
* @param {PIXI.Geometry} geometry - Instance of geometry to to generate Vao for
* @param {PIXI.Program} program - Instance of program
*/
initGeometryVao(geometry, program)
{
this.checkCompatibility(geometry, program);
const gl = this.gl;
const CONTEXT_UID = this.CONTEXT_UID;
const signature = this.getSignature(geometry, program);
if (this.cache[signature])
{
const vao = this.cache[signature];
geometry.glVertexArrayObjects[this.CONTEXT_UID][program.id] = vao;
return vao;
}
const buffers = geometry.buffers;
const attributes = geometry.attributes;
const tempStride = {};
const tempStart = {};
for (const j in buffers)
{
tempStride[j] = 0;
tempStart[j] = 0;
}
for (const j in attributes)
{
if (!attributes[j].size && program.attributeData[j])
{
attributes[j].size = program.attributeData[j].size;
}
tempStride[attributes[j].buffer] += attributes[j].size * byteSizeMap[attributes[j].type];
}
for (const j in attributes)
{
const attribute = attributes[j];
const attribSize = attribute.size;
if (attribute.stride === undefined)
{
if (tempStride[attribute.buffer] === attribSize * byteSizeMap[attribute.type])
{
attribute.stride = 0;
}
else
{
attribute.stride = tempStride[attribute.buffer];
}
}
if (attribute.start === undefined)
{
attribute.start = tempStart[attribute.buffer];
tempStart[attribute.buffer] += attribSize * byteSizeMap[attribute.type];
}
}
// first update - and create the buffers!
// only create a gl buffer if it actually gets
for (let i = 0; i < buffers.length; i++)
{
const buffer = buffers[i];
if (!buffer._glBuffers[CONTEXT_UID])
{
buffer._glBuffers[CONTEXT_UID] = new GLBuffer(gl.createBuffer());
}
}
// TODO - maybe make this a data object?
// lets wait to see if we need to first!
const vao = gl.createVertexArray();
gl.bindVertexArray(vao);
this.activateVao(geometry, program);
gl.bindVertexArray(null);
// add it to the cache!
geometry.glVertexArrayObjects[this.CONTEXT_UID][program.id] = vao;
return vao;
}
/**
* Activate vertex array object
*
* @private
* @param {PIXI.Geometry} geometry - Geometry instance
* @param {PIXI.Program} program - Shader program instance
*/
activateVao(geometry, program)
{
const gl = this.gl;
const CONTEXT_UID = this.CONTEXT_UID;
const buffers = geometry.buffers;
const attributes = geometry.attributes;
if (geometry.indexBuffer)
{
// first update the index buffer if we have one..
gl.bindBuffer(gl.ELEMENT_ARRAY_BUFFER, geometry.indexBuffer._glBuffers[CONTEXT_UID].buffer);
}
let lastBuffer = null;
// add a new one!
for (const j in attributes)
{
const attribute = attributes[j];
const buffer = buffers[attribute.buffer];
const glBuffer = buffer._glBuffers[CONTEXT_UID];
if (program.attributeData[j])
{
if (lastBuffer !== glBuffer)
{
gl.bindBuffer(gl.ARRAY_BUFFER, glBuffer.buffer);
lastBuffer = glBuffer;
}
const location = program.attributeData[j].location;
// TODO introduce state again
// we can optimise this for older devices that have no VAOs
gl.enableVertexAttribArray(location);
gl.vertexAttribPointer(location,
attribute.size,
attribute.type || gl.FLOAT,
attribute.normalized,
attribute.stride,
attribute.start);
if (attribute.instance)
{
// TODO calculate instance count based of this...
if (this.hasInstance)
{
gl.vertexAttribDivisor(location, 1);
}
else
{
throw new Error('geometry error, GPU Instancing is not supported on this device');
}
}
}
}
}
/**
* Draw the geometry
*
* @param {Number} type - the type primitive to render
* @param {Number} [size] - the number of elements to be rendered
* @param {Number} [start] - Starting index
* @param {Number} [instanceCount] - the number of instances of the set of elements to execute
*/
draw(type, size, start, instanceCount)
{
const { gl } = this;
const geometry = this._activeGeometry;
// TODO.. this should not change so maybe cache the function?
if (geometry.indexBuffer)
{
if (geometry.instanced)
{
/* eslint-disable max-len */
gl.drawElementsInstanced(type, size || geometry.indexBuffer.data.length, gl.UNSIGNED_SHORT, (start || 0) * 2, instanceCount || 1);
/* eslint-enable max-len */
}
else
{
gl.drawElements(type, size || geometry.indexBuffer.data.length, gl.UNSIGNED_SHORT, (start || 0) * 2);
}
}
else if (geometry.instanced)
{
// TODO need a better way to calculate size..
gl.drawArraysInstanced(type, start, size || geometry.getSize(), instanceCount || 1);
}
else
{
gl.drawArrays(type, start, size || geometry.getSize());
}
return this;
}
/**
* Unbind/reset everything
* @private
*/
unbind()
{
this.gl.bindVertexArray(null);
this._activeVao = null;
this._activeGeometry = null;
}
}
