openlayers
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Build tools and sources for developing OpenLayers based mapping applications
387 lines (333 loc) • 10.7 kB
JavaScript
goog.provide('ol.webgl.Context');
goog.require('ol');
goog.require('ol.Disposable');
goog.require('ol.array');
goog.require('ol.events');
goog.require('ol.obj');
goog.require('ol.webgl');
goog.require('ol.webgl.ContextEventType');
/**
* @classdesc
* A WebGL context for accessing low-level WebGL capabilities.
*
* @constructor
* @extends {ol.Disposable}
* @param {HTMLCanvasElement} canvas Canvas.
* @param {WebGLRenderingContext} gl GL.
*/
ol.webgl.Context = function(canvas, gl) {
/**
* @private
* @type {HTMLCanvasElement}
*/
this.canvas_ = canvas;
/**
* @private
* @type {WebGLRenderingContext}
*/
this.gl_ = gl;
/**
* @private
* @type {Object.<string, ol.WebglBufferCacheEntry>}
*/
this.bufferCache_ = {};
/**
* @private
* @type {Object.<string, WebGLShader>}
*/
this.shaderCache_ = {};
/**
* @private
* @type {Object.<string, WebGLProgram>}
*/
this.programCache_ = {};
/**
* @private
* @type {WebGLProgram}
*/
this.currentProgram_ = null;
/**
* @private
* @type {WebGLFramebuffer}
*/
this.hitDetectionFramebuffer_ = null;
/**
* @private
* @type {WebGLTexture}
*/
this.hitDetectionTexture_ = null;
/**
* @private
* @type {WebGLRenderbuffer}
*/
this.hitDetectionRenderbuffer_ = null;
/**
* @type {boolean}
*/
this.hasOESElementIndexUint = ol.array.includes(
ol.WEBGL_EXTENSIONS, 'OES_element_index_uint');
// use the OES_element_index_uint extension if available
if (this.hasOESElementIndexUint) {
var ext = gl.getExtension('OES_element_index_uint');
ol.DEBUG && console.assert(ext,
'Failed to get extension "OES_element_index_uint"');
}
ol.events.listen(this.canvas_, ol.webgl.ContextEventType.LOST,
this.handleWebGLContextLost, this);
ol.events.listen(this.canvas_, ol.webgl.ContextEventType.RESTORED,
this.handleWebGLContextRestored, this);
};
ol.inherits(ol.webgl.Context, ol.Disposable);
/**
* Just bind the buffer if it's in the cache. Otherwise create
* the WebGL buffer, bind it, populate it, and add an entry to
* the cache.
* @param {number} target Target.
* @param {ol.webgl.Buffer} buf Buffer.
*/
ol.webgl.Context.prototype.bindBuffer = function(target, buf) {
var gl = this.getGL();
var arr = buf.getArray();
var bufferKey = String(ol.getUid(buf));
if (bufferKey in this.bufferCache_) {
var bufferCacheEntry = this.bufferCache_[bufferKey];
gl.bindBuffer(target, bufferCacheEntry.buffer);
} else {
var buffer = gl.createBuffer();
gl.bindBuffer(target, buffer);
ol.DEBUG && console.assert(target == ol.webgl.ARRAY_BUFFER ||
target == ol.webgl.ELEMENT_ARRAY_BUFFER,
'target is supposed to be an ARRAY_BUFFER or ELEMENT_ARRAY_BUFFER');
var /** @type {ArrayBufferView} */ arrayBuffer;
if (target == ol.webgl.ARRAY_BUFFER) {
arrayBuffer = new Float32Array(arr);
} else if (target == ol.webgl.ELEMENT_ARRAY_BUFFER) {
arrayBuffer = this.hasOESElementIndexUint ?
new Uint32Array(arr) : new Uint16Array(arr);
}
gl.bufferData(target, arrayBuffer, buf.getUsage());
this.bufferCache_[bufferKey] = {
buf: buf,
buffer: buffer
};
}
};
/**
* @param {ol.webgl.Buffer} buf Buffer.
*/
ol.webgl.Context.prototype.deleteBuffer = function(buf) {
var gl = this.getGL();
var bufferKey = String(ol.getUid(buf));
ol.DEBUG && console.assert(bufferKey in this.bufferCache_,
'attempted to delete uncached buffer');
var bufferCacheEntry = this.bufferCache_[bufferKey];
if (!gl.isContextLost()) {
gl.deleteBuffer(bufferCacheEntry.buffer);
}
delete this.bufferCache_[bufferKey];
};
/**
* @inheritDoc
*/
ol.webgl.Context.prototype.disposeInternal = function() {
ol.events.unlistenAll(this.canvas_);
var gl = this.getGL();
if (!gl.isContextLost()) {
var key;
for (key in this.bufferCache_) {
gl.deleteBuffer(this.bufferCache_[key].buffer);
}
for (key in this.programCache_) {
gl.deleteProgram(this.programCache_[key]);
}
for (key in this.shaderCache_) {
gl.deleteShader(this.shaderCache_[key]);
}
// delete objects for hit-detection
gl.deleteFramebuffer(this.hitDetectionFramebuffer_);
gl.deleteRenderbuffer(this.hitDetectionRenderbuffer_);
gl.deleteTexture(this.hitDetectionTexture_);
}
};
/**
* @return {HTMLCanvasElement} Canvas.
*/
ol.webgl.Context.prototype.getCanvas = function() {
return this.canvas_;
};
/**
* Get the WebGL rendering context
* @return {WebGLRenderingContext} The rendering context.
* @api
*/
ol.webgl.Context.prototype.getGL = function() {
return this.gl_;
};
/**
* Get the frame buffer for hit detection.
* @return {WebGLFramebuffer} The hit detection frame buffer.
*/
ol.webgl.Context.prototype.getHitDetectionFramebuffer = function() {
if (!this.hitDetectionFramebuffer_) {
this.initHitDetectionFramebuffer_();
}
return this.hitDetectionFramebuffer_;
};
/**
* Get shader from the cache if it's in the cache. Otherwise, create
* the WebGL shader, compile it, and add entry to cache.
* @param {ol.webgl.Shader} shaderObject Shader object.
* @return {WebGLShader} Shader.
*/
ol.webgl.Context.prototype.getShader = function(shaderObject) {
var shaderKey = String(ol.getUid(shaderObject));
if (shaderKey in this.shaderCache_) {
return this.shaderCache_[shaderKey];
} else {
var gl = this.getGL();
var shader = gl.createShader(shaderObject.getType());
gl.shaderSource(shader, shaderObject.getSource());
gl.compileShader(shader);
ol.DEBUG && console.assert(
gl.getShaderParameter(shader, ol.webgl.COMPILE_STATUS) ||
gl.isContextLost(),
gl.getShaderInfoLog(shader) || 'illegal state, shader not compiled or context lost');
this.shaderCache_[shaderKey] = shader;
return shader;
}
};
/**
* Get the program from the cache if it's in the cache. Otherwise create
* the WebGL program, attach the shaders to it, and add an entry to the
* cache.
* @param {ol.webgl.Fragment} fragmentShaderObject Fragment shader.
* @param {ol.webgl.Vertex} vertexShaderObject Vertex shader.
* @return {WebGLProgram} Program.
*/
ol.webgl.Context.prototype.getProgram = function(
fragmentShaderObject, vertexShaderObject) {
var programKey =
ol.getUid(fragmentShaderObject) + '/' + ol.getUid(vertexShaderObject);
if (programKey in this.programCache_) {
return this.programCache_[programKey];
} else {
var gl = this.getGL();
var program = gl.createProgram();
gl.attachShader(program, this.getShader(fragmentShaderObject));
gl.attachShader(program, this.getShader(vertexShaderObject));
gl.linkProgram(program);
ol.DEBUG && console.assert(
gl.getProgramParameter(program, ol.webgl.LINK_STATUS) ||
gl.isContextLost(),
gl.getProgramInfoLog(program) || 'illegal state, shader not linked or context lost');
this.programCache_[programKey] = program;
return program;
}
};
/**
* FIXME empy description for jsdoc
*/
ol.webgl.Context.prototype.handleWebGLContextLost = function() {
ol.obj.clear(this.bufferCache_);
ol.obj.clear(this.shaderCache_);
ol.obj.clear(this.programCache_);
this.currentProgram_ = null;
this.hitDetectionFramebuffer_ = null;
this.hitDetectionTexture_ = null;
this.hitDetectionRenderbuffer_ = null;
};
/**
* FIXME empy description for jsdoc
*/
ol.webgl.Context.prototype.handleWebGLContextRestored = function() {
};
/**
* Creates a 1x1 pixel framebuffer for the hit-detection.
* @private
*/
ol.webgl.Context.prototype.initHitDetectionFramebuffer_ = function() {
var gl = this.gl_;
var framebuffer = gl.createFramebuffer();
gl.bindFramebuffer(gl.FRAMEBUFFER, framebuffer);
var texture = ol.webgl.Context.createEmptyTexture(gl, 1, 1);
var renderbuffer = gl.createRenderbuffer();
gl.bindRenderbuffer(gl.RENDERBUFFER, renderbuffer);
gl.renderbufferStorage(gl.RENDERBUFFER, gl.DEPTH_COMPONENT16, 1, 1);
gl.framebufferTexture2D(
gl.FRAMEBUFFER, gl.COLOR_ATTACHMENT0, gl.TEXTURE_2D, texture, 0);
gl.framebufferRenderbuffer(gl.FRAMEBUFFER, gl.DEPTH_ATTACHMENT,
gl.RENDERBUFFER, renderbuffer);
gl.bindTexture(gl.TEXTURE_2D, null);
gl.bindRenderbuffer(gl.RENDERBUFFER, null);
gl.bindFramebuffer(gl.FRAMEBUFFER, null);
this.hitDetectionFramebuffer_ = framebuffer;
this.hitDetectionTexture_ = texture;
this.hitDetectionRenderbuffer_ = renderbuffer;
};
/**
* Use a program. If the program is already in use, this will return `false`.
* @param {WebGLProgram} program Program.
* @return {boolean} Changed.
* @api
*/
ol.webgl.Context.prototype.useProgram = function(program) {
if (program == this.currentProgram_) {
return false;
} else {
var gl = this.getGL();
gl.useProgram(program);
this.currentProgram_ = program;
return true;
}
};
/**
* @param {WebGLRenderingContext} gl WebGL rendering context.
* @param {number=} opt_wrapS wrapS.
* @param {number=} opt_wrapT wrapT.
* @return {WebGLTexture} The texture.
* @private
*/
ol.webgl.Context.createTexture_ = function(gl, opt_wrapS, opt_wrapT) {
var texture = gl.createTexture();
gl.bindTexture(gl.TEXTURE_2D, texture);
gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.LINEAR);
gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.LINEAR);
if (opt_wrapS !== undefined) {
gl.texParameteri(
ol.webgl.TEXTURE_2D, ol.webgl.TEXTURE_WRAP_S, opt_wrapS);
}
if (opt_wrapT !== undefined) {
gl.texParameteri(
ol.webgl.TEXTURE_2D, ol.webgl.TEXTURE_WRAP_T, opt_wrapT);
}
return texture;
};
/**
* @param {WebGLRenderingContext} gl WebGL rendering context.
* @param {number} width Width.
* @param {number} height Height.
* @param {number=} opt_wrapS wrapS.
* @param {number=} opt_wrapT wrapT.
* @return {WebGLTexture} The texture.
*/
ol.webgl.Context.createEmptyTexture = function(
gl, width, height, opt_wrapS, opt_wrapT) {
var texture = ol.webgl.Context.createTexture_(gl, opt_wrapS, opt_wrapT);
gl.texImage2D(
gl.TEXTURE_2D, 0, gl.RGBA, width, height, 0, gl.RGBA, gl.UNSIGNED_BYTE,
null);
return texture;
};
/**
* @param {WebGLRenderingContext} gl WebGL rendering context.
* @param {HTMLCanvasElement|HTMLImageElement|HTMLVideoElement} image Image.
* @param {number=} opt_wrapS wrapS.
* @param {number=} opt_wrapT wrapT.
* @return {WebGLTexture} The texture.
*/
ol.webgl.Context.createTexture = function(gl, image, opt_wrapS, opt_wrapT) {
var texture = ol.webgl.Context.createTexture_(gl, opt_wrapS, opt_wrapT);
gl.texImage2D(
gl.TEXTURE_2D, 0, gl.RGBA, gl.RGBA, gl.UNSIGNED_BYTE, image);
return texture;
};