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/**
* Methods related to textures
* @name ___METHODS_FOR_TEXTURES___
* @memberof rglwidgetClass
* @kind function
* @instance
*/
rglwidgetClass.prototype.getTexFilter = function(filter) {
var gl = this.gl || this.initGL();
switch(filter) {
case "nearest": return gl.NEAREST;
case "linear": return gl.LINEAR;
case "nearest.mipmap.nearest": return gl.NEAREST_MIPMAP_NEAREST;
case "linear.mipmap.nearest": return gl.LINEAR_MIPMAP_NEAREST;
case "nearest.mipmap.linear": return gl.NEAREST_MIPMAP_LINEAR;
case "linear.mipmap.linear": return gl.LINEAR_MIPMAP_LINEAR;
default: console.error("Unknown filter: "+filter);
}
};
/**
* Handle a texture after its image has been loaded
* @param { Object } texture - the gl texture object
* @param { Object } textureCanvas - the canvas holding the image
*/
rglwidgetClass.prototype.handleLoadedTexture = function(texture, textureCanvas) {
var gl = this.gl || this.initGL();
gl.pixelStorei(gl.UNPACK_FLIP_Y_WEBGL, true);
gl.bindTexture(gl.TEXTURE_2D, texture);
gl.texImage2D(gl.TEXTURE_2D, 0, gl.RGBA, gl.RGBA, gl.UNSIGNED_BYTE, textureCanvas);
gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.LINEAR);
gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.LINEAR_MIPMAP_NEAREST);
gl.generateMipmap(gl.TEXTURE_2D);
gl.bindTexture(gl.TEXTURE_2D, null);
};
/**
* Get maximum dimension of texture in current browser.
* @returns {number}
*/
rglwidgetClass.prototype.getMaxTexSize = function() {
var gl = this.gl || this.initGL();
return Math.min(4096, gl.getParameter(gl.MAX_TEXTURE_SIZE));
};
/**
* Load an image to a texture
* @param { string } uri - The image location
* @param { Object } texture - the gl texture object
*/
rglwidgetClass.prototype.loadImageToTexture = function(uri, texture) {
var canvas = this.textureCanvas,
ctx = canvas.getContext("2d"),
image = new Image(),
self = this;
image.onload = function() {
var w = image.width,
h = image.height,
canvasX = self.getPowerOfTwo(w),
canvasY = self.getPowerOfTwo(h),
maxTexSize = self.getMaxTexSize();
while (canvasX > 1 && canvasY > 1 && (canvasX > maxTexSize || canvasY > maxTexSize)) {
canvasX /= 2;
canvasY /= 2;
}
canvas.width = canvasX;
canvas.height = canvasY;
ctx.imageSmoothingEnabled = true;
ctx.drawImage(image, 0, 0, canvasX, canvasY);
self.handleLoadedTexture(texture, canvas);
self.texturesLoading -= 1;
if (!self.texturesLoading)
self.drawScene();
};
if (!self.texturesLoading)
self.texturesLoading = 0; // may have been undefined
self.texturesLoading += 1;
image.src = uri;
};
/**
* Draw text to the texture canvas
* @returns { Object } object with text measurements
* @param { string } text - the text
* @param { number } cex - expansion
* @param { string } family - font family
* @param { number } font - font number
*/
rglwidgetClass.prototype.drawTextToCanvas = function(text, cex, family, font) {
var canvasX, canvasY,
scaling = 20,
textColour = "white",
backgroundColour = "rgba(0,0,0,0)",
canvas = this.textureCanvas,
ctx = canvas.getContext("2d"),
i, textHeight = 0, textHeights = [], width, widths = [],
offsetx, offsety = 0, line, lines = [], offsetsx = [],
offsetsy = [], lineoffsetsy = [], fontStrings = [],
maxTexSize = this.getMaxTexSize(),
getFontString = function(i) {
textHeights[i] = scaling*cex[i];
var fontString = textHeights[i] + "px",
family0 = family[i],
font0 = font[i];
if (family0 === "sans")
family0 = "sans-serif";
else if (family0 === "mono")
family0 = "monospace";
fontString = fontString + " " + family0;
if (font0 === 2 || font0 === 4)
fontString = "bold " + fontString;
if (font0 === 3 || font0 === 4)
fontString = "italic " + fontString;
return fontString;
};
cex = rglwidgetClass.repeatToLen(cex, text.length);
family = rglwidgetClass.repeatToLen(family, text.length);
font = rglwidgetClass.repeatToLen(font, text.length);
canvasX = 1;
line = -1;
offsetx = maxTexSize;
for (i = 0; i < text.length; i++) {
ctx.font = fontStrings[i] = getFontString(i);
width = widths[i] = ctx.measureText(text[i]).width;
if (offsetx + width > maxTexSize) {
offsety = offsety + 2*textHeight;
if (line >= 0)
lineoffsetsy[line] = offsety;
line += 1;
if (offsety > maxTexSize)
console.error("Too many strings for texture.");
textHeight = 0;
offsetx = 0;
}
textHeight = Math.max(textHeight, textHeights[i]);
offsetsx[i] = offsetx;
offsetx += width;
canvasX = Math.max(canvasX, offsetx);
lines[i] = line;
}
offsety = lineoffsetsy[line] = offsety + 2*textHeight;
for (i = 0; i < text.length; i++) {
offsetsy[i] = lineoffsetsy[lines[i]];
}
canvasX = this.getPowerOfTwo(canvasX);
canvasY = this.getPowerOfTwo(offsety);
canvas.width = canvasX;
canvas.height = canvasY;
ctx.fillStyle = backgroundColour;
ctx.fillRect(0, 0, ctx.canvas.width, ctx.canvas.height);
ctx.textBaseline = "alphabetic";
for(i = 0; i < text.length; i++) {
ctx.font = fontStrings[i];
ctx.fillStyle = textColour;
ctx.textAlign = "left";
ctx.fillText(text[i], offsetsx[i], offsetsy[i]);
}
return {canvasX:canvasX, canvasY:canvasY,
widths:widths, textHeights:textHeights,
offsetsx:offsetsx, offsetsy:offsetsy};
};
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