littlejsengine
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LittleJS - Tiny and Fast HTML5 Game Engine
1,151 lines (1,058 loc) • 44.8 kB
JavaScript
/**
* LittleJS Drawing System
* - Hybrid system with both Canvas2D and WebGL available
* - Super fast tile sheet rendering with WebGL
* - Can apply rotation, mirror, color and additive color
* - Font rendering system with built in engine font
* - Many useful utility functions
*
* LittleJS uses a hybrid rendering solution with the best of both Canvas2D and WebGL.
* There are 3 canvas/contexts available to draw to...
* mainCanvas - 2D background canvas, non WebGL stuff like tile layers are drawn here.
* glCanvas - Used by the accelerated WebGL batch rendering system.
*
* The WebGL rendering system is very fast with some caveats...
* - Switching blend modes (additive) or textures causes another draw call which is expensive in excess
* - Group additive rendering together using renderOrder to mitigate this issue
*
* The LittleJS rendering solution is intentionally simple, feel free to adjust it for your needs!
* @namespace Draw
*/
'use strict';
/** The primary 2D canvas visible to the user
* @type {HTMLCanvasElement}
* @memberof Draw */
let mainCanvas;
/** 2d context for mainCanvas
* @type {CanvasRenderingContext2D}
* @memberof Draw */
let mainContext;
/** The default 2d context to use for drawing, usually mainContext
* @type {CanvasRenderingContext2D|OffscreenCanvasRenderingContext2D}
* @memberof Draw */
let drawContext;
/** Offscreen canvas that can be used for image processing
* @type {OffscreenCanvas}
* @memberof Draw */
let workCanvas;
/** Offscreen canvas that can be used for image processing
* @type {OffscreenCanvasRenderingContext2D}
* @memberof Draw */
let workContext;
/** Offscreen canvas with willReadFrequently that can be used for image processing
* @type {OffscreenCanvas}
* @memberof Draw */
let workReadCanvas;
/** Offscreen canvas with willReadFrequently that can be used for image processing
* @type {OffscreenCanvasRenderingContext2D}
* @memberof Draw */
let workReadContext;
/** The size of the main canvas (and other secondary canvases)
* @type {Vector2}
* @memberof Draw */
let mainCanvasSize = vec2();
/** Array containing texture info for batch rendering system
* @type {Array<TextureInfo>}
* @memberof Draw */
let textureInfos = [];
/** Keeps track of how many draw calls there were each frame for debugging
* @type {number}
* @memberof Draw */
let drawCount;
///////////////////////////////////////////////////////////////////////////////
/**
* Create a tile info object using a grid based system
* - This can take vecs or floats for easier use and conversion
* - If an index is passed in, the tile size and index will determine the position
* @param {Vector2|number} [index=0] - Index of the tile in 1d or 2d form
* @param {Vector2|number} [size] - Size of tile in pixels
* @param {TextureInfo|number} [texture] - Texture index or info to use
* @param {number} [padding] - How many pixels padding around tiles
* @param {number} [bleed] - How many pixels smaller to draw tiles
* @return {TileInfo}
* @example
* tile(2) // a tile at index 2 using the default tile size of 16
* tile(5, 8) // a tile at index 5 using a tile size of 8
* tile(1, 16, 3) // a tile at index 1 of size 16 on texture 3
* tile(vec2(4,8), vec2(30,10)) // a tile at index (4,8) with a size of (30,10)
* @memberof Draw */
function tile(index=new Vector2, size=tileDefaultSize, texture=0, padding=tileDefaultPadding, bleed=tileDefaultBleed)
{
ASSERT(isVector2(index) || typeof index === 'number', 'index must be a vec2 or number');
ASSERT(isVector2(size) || typeof size === 'number', 'size must be a vec2 or number');
ASSERT(isNumber(texture) || texture instanceof TextureInfo, 'texture must be a number or TextureInfo');
ASSERT(isNumber(padding), 'padding must be a number');
if (headlessMode) return new TileInfo;
if (typeof size === 'number')
{
// if size is a number, make it a vector
ASSERT(size > 0);
size = new Vector2(size, size);
}
// create tile info object
const textureInfo = typeof texture === 'number' ?
textureInfos[texture] : texture;
// get the position of the tile
const sizePaddedX = size.x + padding*2;
const sizePaddedY = size.y + padding*2;
let x, y;
if (typeof index === 'number')
{
const cols = textureInfo.size.x / sizePaddedX |0;
x = index % cols;
y = index / cols |0;
}
else
{
x = index.x;
y = index.y;
}
const pos = new Vector2(x*sizePaddedX + padding, y*sizePaddedY + padding);
return new TileInfo(pos, size, textureInfo, padding, bleed);
}
/**
* Tile Info - Stores info about how to draw a tile
* @memberof Draw
*/
class TileInfo
{
/** Create a tile info object
* @param {Vector2} [pos=vec2()] - Top left corner of tile in pixels
* @param {Vector2} [size] - Size of tile in pixels
* @param {TextureInfo} [textureInfo] - Texture info to use
* @param {number} [padding] - How many pixels padding around tiles
* @param {number} [bleed] - How many pixels smaller to draw tiles
*/
constructor(pos=vec2(), size=tileDefaultSize, textureInfo=textureInfos[0], padding=tileDefaultPadding, bleed=tileDefaultBleed)
{
/** @property {Vector2} - Top left corner of tile in pixels */
this.pos = pos.copy();
/** @property {Vector2} - Size of tile in pixels */
this.size = size.copy();
/** @property {number} - How many pixels padding around tiles */
this.padding = padding;
/** @property {TextureInfo} - The texture info for this tile */
this.textureInfo = textureInfo;
/** @property {number} - Shrinks tile by this many pixels to prevent neighbors bleeding */
this.bleed = bleed;
}
/** Returns a copy of this tile offset by a vector
* @param {Vector2} offset - Offset to apply in pixels
* @return {TileInfo}
*/
offset(offset)
{ return new TileInfo(this.pos.add(offset), this.size, this.textureInfo, this.padding, this.bleed); }
/** Returns a copy of this tile offset by a number of animation frames
* @param {number} frame - Offset to apply in animation frames
* @return {TileInfo}
*/
frame(frame)
{
ASSERT(typeof frame === 'number');
const w = this.size.x + this.padding*2;
const x = frame*w;
ASSERT(x < this.textureInfo.size.x, 'frame extends beyond texture width!');
return this.offset(new Vector2(x));
}
/**
* Set this tile to use a full image in a texture info
* @param {TextureInfo} [textureInfo]
* @return {TileInfo}
*/
setFullImage(textureInfo=this.textureInfo)
{
this.textureInfo = textureInfo;
this.pos = new Vector2;
this.size = textureInfo.size.copy();
this.bleed = this.padding = 0;
return this;
}
/**
* Returns a tile info for an index using this tile as reference
* @param {Vector2|number} [index=0]
* @return {TileInfo}
*/
tile(index)
{ return tile(index, this.size, this.textureInfo, this.padding, this.bleed); }
}
/**
* Tile Info - Stores info about each texture
* @memberof Draw
*/
class TextureInfo
{
/**
* Create a TextureInfo, called automatically by the engine
* @param {HTMLImageElement|OffscreenCanvas} image
* @param {boolean} [useWebGL] - Should use WebGL if available?
*/
constructor(image, useWebGL=true)
{
/** @property {HTMLImageElement|OffscreenCanvas} - image source */
this.image = image;
/** @property {Vector2} - size of the image */
this.size = image ? vec2(image.width, image.height) : vec2();
/** @property {Vector2} - inverse of the size, cached for rendering */
this.sizeInverse = image ? vec2(1/image.width, 1/image.height) : vec2();
/** @property {WebGLTexture} - WebGL texture */
this.glTexture = undefined;
useWebGL && this.createWebGLTexture();
}
/** Creates the WebGL texture, updates if already created */
createWebGLTexture() { glRegisterTextureInfo(this); }
/** Destroys the WebGL texture */
destroyWebGLTexture() { glUnregisterTextureInfo(this); }
/** Check if the texture is webgl enabled
* @return {boolean} */
hasWebGL() { return !!this.glTexture; }
}
///////////////////////////////////////////////////////////////////////////////
// Drawing functions
/** Draw textured tile centered in world space
* @param {Vector2} pos - Center of the tile in world space
* @param {Vector2} [size=vec2(1)] - Size of the tile in world space
* @param {TileInfo} [tileInfo] - Tile info to use, untextured if undefined
* @param {Color} [color=WHITE] - Color to modulate with
* @param {number} [angle] - Angle to rotate by
* @param {boolean} [mirror] - Is image flipped along the Y axis?
* @param {Color} [additiveColor] - Additive color to be applied if any
* @param {boolean} [useWebGL=glEnable] - Use accelerated WebGL rendering?
* @param {boolean} [screenSpace=false] - Are the pos and size are in screen space?
* @param {CanvasRenderingContext2D|OffscreenCanvasRenderingContext2D} [context] - Canvas 2D context to draw to
* @memberof Draw */
function drawTile(pos, size=vec2(1), tileInfo, color=WHITE,
angle=0, mirror, additiveColor, useWebGL=glEnable, screenSpace, context)
{
ASSERT(isVector2(pos), 'pos must be a vec2');
ASSERT(isVector2(size), 'size must be a vec2');
ASSERT(isColor(color), 'color is invalid');
ASSERT(isNumber(angle), 'angle must be a number');
ASSERT(!additiveColor || isColor(additiveColor), 'additiveColor must be a color');
ASSERT(!context || !useWebGL, 'context only supported in canvas 2D mode');
const textureInfo = tileInfo?.textureInfo;
const bleed = tileInfo?.bleed ?? 0;
if (useWebGL && glEnable)
{
ASSERT(!!glContext, 'WebGL is not enabled!');
if (screenSpace)
[pos, size, angle] = screenToWorldTransform(pos, size, angle);
if (textureInfo)
{
// calculate uvs and render
const sizeInverse = textureInfo.sizeInverse;
const x = tileInfo.pos.x * sizeInverse.x;
const y = tileInfo.pos.y * sizeInverse.y;
const w = tileInfo.size.x * sizeInverse.x;
const h = tileInfo.size.y * sizeInverse.y;
glSetTexture(textureInfo.glTexture);
if (bleed)
{
const bleedX = sizeInverse.x*bleed;
const bleedY = sizeInverse.y*bleed;
glDraw(pos.x, pos.y, mirror ? -size.x : size.x, size.y, angle,
x + bleedX, y + bleedY,
x - bleedX + w, y - bleedY + h,
color.rgbaInt(), additiveColor && additiveColor.rgbaInt());
}
else
{
glDraw(pos.x, pos.y, mirror ? -size.x : size.x, size.y, angle,
x, y, x + w, y + h,
color.rgbaInt(), additiveColor && additiveColor.rgbaInt());
}
}
else
{
// if no tile info, force untextured
glDraw(pos.x, pos.y, size.x, size.y, angle, 0, 0, 0, 0, 0, color.rgbaInt());
}
}
else
{
// normal canvas 2D rendering method (slower)
++drawCount;
size = new Vector2(size.x, -size.y); // flip upside down sprites
drawCanvas2D(pos, size, angle, mirror, (context)=>
{
if (textureInfo)
{
// calculate uvs and render
const x = tileInfo.pos.x, y = tileInfo.pos.y;
const w = tileInfo.size.x, h = tileInfo.size.y;
drawImageColor(context, textureInfo.image, x, y, w, h, -.5, -.5, 1, 1, color, additiveColor, bleed);
}
else
{
// if no tile info, use untextured rect
const c = additiveColor ? color.add(additiveColor) : color;
context.fillStyle = c.toString();
context.fillRect(-.5, -.5, 1, 1);
}
}, screenSpace, context);
}
}
/** Draw colored rect centered on pos
* @param {Vector2} pos
* @param {Vector2} [size=vec2(1)]
* @param {Color} [color=WHITE]
* @param {number} [angle]
* @param {boolean} [useWebGL=glEnable]
* @param {boolean} [screenSpace]
* @param {CanvasRenderingContext2D|OffscreenCanvasRenderingContext2D} [context]
* @memberof Draw */
function drawRect(pos, size, color, angle, useWebGL, screenSpace, context)
{
drawTile(pos, size, undefined, color, angle, false, undefined, useWebGL, screenSpace, context);
}
/** Draw a rect centered on pos with a gradient from top to bottom
* @param {Vector2} pos
* @param {Vector2} [size=vec2(1)]
* @param {Color} [colorTop=WHITE]
* @param {Color} [colorBottom=BLACK]
* @param {number} [angle]
* @param {boolean} [useWebGL=glEnable]
* @param {boolean} [screenSpace]
* @param {CanvasRenderingContext2D|OffscreenCanvasRenderingContext2D} [context]
* @memberof Draw */
function drawRectGradient(pos, size, colorTop=WHITE, colorBottom=BLACK, angle=0, useWebGL=glEnable, screenSpace=false, context)
{
ASSERT(isVector2(pos), 'pos must be a vec2');
ASSERT(isVector2(size), 'size must be a vec2');
ASSERT(isColor(colorTop) && isColor(colorBottom), 'color is invalid');
ASSERT(isNumber(angle), 'angle must be a number');
ASSERT(!context || !useWebGL, 'context only supported in canvas 2D mode');
if (useWebGL && glEnable)
{
ASSERT(!!glContext, 'WebGL is not enabled!');
if (screenSpace)
{
// convert to world space
pos = screenToWorld(pos);
size = size.scale(1/cameraScale);
angle += cameraAngle;
}
// build 4 corner points for the rectangle
const points = [], colors = [];
const halfSizeX = size.x/2, halfSizeY = size.y/2;
const colorTopInt = colorTop.rgbaInt();
const colorBottomInt = colorBottom.rgbaInt();
const c = cos(-angle), s = sin(-angle);
for (let i=4; i--;)
{
const x = i & 1 ? halfSizeX : -halfSizeX;
const y = i & 2 ? halfSizeY : -halfSizeY;
const rx = x * c - y * s;
const ry = x * s + y * c;
const color = i & 2 ? colorTopInt : colorBottomInt;
points.push(vec2(pos.x + rx, pos.y + ry));
colors.push(color);
}
glDrawColoredPoints(points, colors);
}
else
{
// normal canvas 2D rendering method (slower)
++drawCount;
size = new Vector2(size.x, -size.y); // fix upside down sprites
drawCanvas2D(pos, size, angle, false, (context)=>
{
// if no tile info, use untextured rect
const gradient = context.createLinearGradient(0, -.5, 0, .5);
gradient.addColorStop(0, colorTop.toString());
gradient.addColorStop(1, colorBottom.toString());
context.fillStyle = gradient;
context.fillRect(-.5, -.5, 1, 1);
}, screenSpace, context);
}
}
/** Draw connected lines between a series of points
* @param {Array<Vector2>} points
* @param {number} [width]
* @param {Color} [color=WHITE]
* @param {boolean} [wrap] - Should the last point connect to the first?
* @param {Vector2} [pos=vec2()] - Offset to apply
* @param {number} [angle] - Angle to rotate by
* @param {boolean} [useWebGL=glEnable]
* @param {boolean} [screenSpace]
* @param {CanvasRenderingContext2D|OffscreenCanvasRenderingContext2D} [context]
* @memberof Draw */
function drawLineList(points, width=.1, color, wrap=false, pos=vec2(), angle=0, useWebGL=glEnable, screenSpace, context)
{
ASSERT(isArray(points), 'points must be an array');
ASSERT(isNumber(width), 'width must be a number');
ASSERT(isColor(color), 'color is invalid');
ASSERT(isVector2(pos), 'pos must be a vec2');
ASSERT(isNumber(angle), 'angle must be a number');
ASSERT(!context || !useWebGL, 'context only supported in canvas 2D mode');
if (useWebGL && glEnable)
{
ASSERT(!!glContext, 'WebGL is not enabled!');
let size = vec2(1);
if (screenSpace)
[pos, size, angle] = screenToWorldTransform(pos, size, angle);
glDrawOutlineTransform(points, color.rgbaInt(), width, pos.x, pos.y, size.x, size.y, angle, wrap);
}
else
{
// normal canvas 2D rendering method (slower)
++drawCount;
drawCanvas2D(pos, vec2(1), angle, false, (context)=>
{
context.strokeStyle = color.toString();
context.lineWidth = width;
context.beginPath();
for (let i=0; i<points.length; ++i)
{
const point = points[i];
context.lineTo(point.x, point.y);
}
wrap && context.closePath();
context.stroke();
}, screenSpace, context);
}
}
/** Draw colored line between two points
* @param {Vector2} posA
* @param {Vector2} posB
* @param {number} [width]
* @param {Color} [color=WHITE]
* @param {Vector2} [pos=vec2()] - Offset to apply
* @param {number} [angle] - Angle to rotate by
* @param {boolean} [useWebGL=glEnable]
* @param {boolean} [screenSpace]
* @param {CanvasRenderingContext2D|OffscreenCanvasRenderingContext2D} [context]
* @memberof Draw */
function drawLine(posA, posB, width=.1, color, pos=vec2(), angle=0, useWebGL, screenSpace, context)
{
const halfDelta = vec2((posB.x - posA.x)/2, (posB.y - posA.y)/2);
const size = vec2(width, halfDelta.length()*2);
pos = pos.add(posA.add(halfDelta));
if (screenSpace)
halfDelta.y *= -1; // flip angle Y if screen space
angle += halfDelta.angle();
drawRect(pos, size, color, angle, useWebGL, screenSpace, context);
}
/** Draw colored regular polygon using passed in number of sides
* @param {Vector2} pos
* @param {Vector2} [size=vec2(1)]
* @param {number} [sides]
* @param {Color} [color=WHITE]
* @param {number} [angle]
* @param {number} [lineWidth]
* @param {Color} [lineColor=BLACK]
* @param {boolean} [useWebGL=glEnable]
* @param {boolean} [screenSpace]
* @param {CanvasRenderingContext2D|OffscreenCanvasRenderingContext2D} [context]
* @memberof Draw */
function drawRegularPoly(pos, size=vec2(1), sides=3, color=WHITE, lineWidth=0, lineColor=BLACK, angle=0, useWebGL=glEnable, screenSpace=false, context)
{
ASSERT(isVector2(size), 'size must be a vec2');
ASSERT(isNumber(sides), 'sides must be a number');
// build regular polygon points
const points = [];
const sizeX = size.x/2, sizeY = size.y/2;
for (let i=sides; i--;)
{
const a = (i/sides)*PI*2;
points.push(vec2(sin(a)*sizeX, cos(a)*sizeY));
}
drawPoly(points, color, lineWidth, lineColor, pos, angle, useWebGL, screenSpace, context);
}
/** Draw colored polygon using passed in points
* @param {Array<Vector2>} points - Array of Vector2 points
* @param {Color} [color=WHITE]
* @param {number} [lineWidth]
* @param {Color} [lineColor=BLACK]
* @param {Vector2} [pos=vec2()] - Offset to apply
* @param {number} [angle] - Angle to rotate by
* @param {boolean} [useWebGL=glEnable]
* @param {boolean} [screenSpace]
* @param {CanvasRenderingContext2D|OffscreenCanvasRenderingContext2D} [context]
* @memberof Draw */
function drawPoly(points, color=WHITE, lineWidth=0, lineColor=BLACK, pos=vec2(), angle=0, useWebGL=glEnable, screenSpace=false, context=undefined)
{
ASSERT(isVector2(pos), 'pos must be a vec2');
ASSERT(isArray(points), 'points must be an array');
ASSERT(isColor(color) && isColor(lineColor), 'color is invalid');
ASSERT(isNumber(lineWidth), 'lineWidth must be a number');
ASSERT(isNumber(angle), 'angle must be a number');
ASSERT(!context || !useWebGL, 'context only supported in canvas 2D mode');
if (useWebGL && glEnable)
{
ASSERT(!!glContext, 'WebGL is not enabled!');
let size = vec2(1);
if (screenSpace)
[pos, size, angle] = screenToWorldTransform(pos, size, angle);
glDrawPointsTransform(points, color.rgbaInt(), pos.x, pos.y, size.x, size.y, angle);
if (lineWidth > 0)
glDrawOutlineTransform(points, lineColor.rgbaInt(), lineWidth, pos.x, pos.y, size.x, size.y, angle);
}
else
{
drawCanvas2D(pos, vec2(1), angle, false, context=>
{
context.fillStyle = color.toString();
context.beginPath();
for (const point of points)
context.lineTo(point.x, point.y);
context.closePath();
context.fill();
if (lineWidth)
{
context.strokeStyle = lineColor.toString();
context.lineWidth = lineWidth;
context.stroke();
}
}, screenSpace, context);
}
}
/** Draw colored ellipse using passed in point
* @param {Vector2} pos
* @param {Vector2} [size=vec2(1)] - Width and height diameter
* @param {Color} [color=WHITE]
* @param {number} [angle]
* @param {number} [lineWidth]
* @param {Color} [lineColor=BLACK]
* @param {boolean} [useWebGL=glEnable]
* @param {boolean} [screenSpace]
* @param {CanvasRenderingContext2D|OffscreenCanvasRenderingContext2D} [context]
* @memberof Draw */
function drawEllipse(pos, size=vec2(1), color=WHITE, angle=0, lineWidth=0, lineColor=BLACK, useWebGL=glEnable, screenSpace=false, context)
{
ASSERT(isVector2(pos), 'pos must be a vec2');
ASSERT(isVector2(size), 'size must be a vec2');
ASSERT(isColor(color) && isColor(lineColor), 'color is invalid');
ASSERT(isNumber(angle), 'angle must be a number');
ASSERT(isNumber(lineWidth), 'lineWidth must be a number');
ASSERT(lineWidth >= 0, 'lineWidth must be a positive value or 0');
ASSERT(!context || !useWebGL, 'context only supported in canvas 2D mode');
// clamp line width to prevent artifacts
lineWidth = clamp(lineWidth, 0, Math.min(size.x, size.y));
if (useWebGL && glEnable)
{
// draw as a regular polygon
const sides = glCircleSides;
drawRegularPoly(pos, size, sides, color, lineWidth, lineColor, angle, useWebGL, screenSpace, context);
}
else
{
drawCanvas2D(pos, vec2(1), angle, false, context=>
{
context.fillStyle = color.toString();
context.beginPath();
context.ellipse(0, 0, size.x/2, size.y/2, 0, 0, 9);
context.fill();
if (lineWidth)
{
context.strokeStyle = lineColor.toString();
context.lineWidth = lineWidth;
context.stroke();
}
}, screenSpace, context);
}
}
/** Draw colored circle using passed in point
* @param {Vector2} pos
* @param {number} [size=1] - Diameter
* @param {Color} [color=WHITE]
* @param {number} [lineWidth=0]
* @param {Color} [lineColor=BLACK]
* @param {boolean} [useWebGL=glEnable]
* @param {boolean} [screenSpace]
* @param {CanvasRenderingContext2D|OffscreenCanvasRenderingContext2D} [context]
* @memberof Draw */
function drawCircle(pos, size=1, color=WHITE, lineWidth=0, lineColor=BLACK, useWebGL=glEnable, screenSpace=false, context)
{
ASSERT(isNumber(size), 'size must be a number');
drawEllipse(pos, vec2(size), color, 0, lineWidth, lineColor, useWebGL, screenSpace, context);
}
/**
* @callback Canvas2DDrawFunction - A function that draws to a 2D canvas context
* @param {CanvasRenderingContext2D|OffscreenCanvasRenderingContext2D} context
* @memberof Draw
*/
/** Draw directly to a 2d canvas context in world space
* @param {Vector2} pos
* @param {Vector2} size
* @param {number} angle
* @param {boolean} [mirror]
* @param {Canvas2DDrawFunction} [drawFunction]
* @param {boolean} [screenSpace=false]
* @param {CanvasRenderingContext2D|OffscreenCanvasRenderingContext2D} [context=drawContext]
* @memberof Draw */
function drawCanvas2D(pos, size, angle=0, mirror=false, drawFunction, screenSpace=false, context=drawContext)
{
ASSERT(isVector2(pos), 'pos must be a vec2');
ASSERT(isVector2(size), 'size must be a vec2');
ASSERT(isNumber(angle), 'angle must be a number');
ASSERT(typeof drawFunction === 'function', 'drawFunction must be a function');
if (!screenSpace)
{
pos = worldToScreen(pos);
size = size.scale(cameraScale);
angle -= cameraAngle;
}
context.save();
context.translate(pos.x+.5, pos.y+.5);
context.rotate(angle);
context.scale(mirror ? -size.x : size.x, -size.y);
drawFunction(context);
context.restore();
}
///////////////////////////////////////////////////////////////////////////////
// Text Drawing Functions
/** Draw text on main canvas in world space
* Automatically splits new lines into rows
* @param {string|number} text
* @param {Vector2} pos
* @param {number} [size]
* @param {Color} [color=WHITE]
* @param {number} [lineWidth]
* @param {Color} [lineColor=BLACK]
* @param {CanvasTextAlign} [textAlign='center']
* @param {string} [font=fontDefault]
* @param {string} [fontStyle]
* @param {number} [maxWidth]
* @param {number} [angle]
* @param {CanvasRenderingContext2D|OffscreenCanvasRenderingContext2D} [context=drawContext]
* @memberof Draw */
function drawText(text, pos, size=1, color, lineWidth=0, lineColor, textAlign, font, fontStyle, maxWidth, angle=0, context=drawContext)
{
// convert to screen space
pos = worldToScreen(pos);
size *= cameraScale;
lineWidth *= cameraScale;
angle -= cameraAngle;
angle *= -1;
drawTextScreen(text, pos, size, color, lineWidth, lineColor, textAlign, font, fontStyle, maxWidth, angle, context);
}
/** Draw text in screen space
* Automatically splits new lines into rows
* @param {string|number} text
* @param {Vector2} pos
* @param {number} size
* @param {Color} [color=WHITE]
* @param {number} [lineWidth]
* @param {Color} [lineColor=BLACK]
* @param {CanvasTextAlign} [textAlign]
* @param {string} [font=fontDefault]
* @param {string} [fontStyle]
* @param {number} [maxWidth]
* @param {number} [angle]
* @param {CanvasRenderingContext2D|OffscreenCanvasRenderingContext2D} [context=drawContext]
* @memberof Draw */
function drawTextScreen(text, pos, size, color=WHITE, lineWidth=0, lineColor=BLACK, textAlign='center', font=fontDefault, fontStyle='', maxWidth, angle=0, context=drawContext)
{
ASSERT(isString(text), 'text must be a string');
ASSERT(isVector2(pos), 'pos must be a vec2');
ASSERT(isNumber(size), 'size must be a number');
ASSERT(isColor(color), 'color must be a color');
ASSERT(isNumber(lineWidth), 'lineWidth must be a number');
ASSERT(isColor(lineColor), 'lineColor must be a color');
ASSERT(['left','center','right'].includes(textAlign), 'align must be left, center, or right');
ASSERT(isString(font), 'font must be a string');
ASSERT(isString(fontStyle), 'fontStyle must be a string');
ASSERT(isNumber(angle), 'angle must be a number');
context.fillStyle = color.toString();
context.strokeStyle = lineColor.toString();
context.lineWidth = lineWidth;
context.textAlign = textAlign;
context.font = fontStyle + ' ' + size + 'px '+ font;
context.textBaseline = 'middle';
const lines = (text+'').split('\n');
const posY = pos.y - (lines.length-1) * size/2; // center vertically
context.save();
context.translate(pos.x, posY);
context.rotate(-angle);
let yOffset = 0;
lines.forEach(line=>
{
lineWidth && context.strokeText(line, 0, yOffset, maxWidth);
context.fillText(line, 0, yOffset, maxWidth);
yOffset += size;
});
context.restore();
}
///////////////////////////////////////////////////////////////////////////////
// Drawing utilities
/** Load a texture at a specific index
* @param {number} textureIndex - Index to store the texture at
* @param {string} [src] - Image source path
* @return {Promise} Promise that resolves when texture is loaded
* @memberof Draw */
async function loadTexture(textureIndex, src)
{
ASSERT(isNumber(textureIndex), 'textureIndex must be a number');
ASSERT(!textureInfos[textureIndex], 'textureIndex is already loaded!');
ASSERT(!src || isString(src), 'image src must be a string');
const image = new Image;
if (src)
{
await new Promise(resolve =>
{
image.onerror = image.onload = resolve;
image.crossOrigin = 'anonymous';
image.src = src;
});
}
textureInfos[textureIndex] = new TextureInfo(image);
}
/** Convert from screen to world space coordinates
* @param {Vector2} screenPos
* @return {Vector2}
* @memberof Draw */
function screenToWorld(screenPos)
{
ASSERT(isVector2(screenPos), 'screenPos must be a vec2');
let x = (screenPos.x - mainCanvasSize.x/2 + .5) / cameraScale;
let y = (screenPos.y - mainCanvasSize.y/2 + .5) / -cameraScale;
if (cameraAngle)
{
// apply camera rotation
const c = cos(-cameraAngle), s = sin(-cameraAngle);
const xr = x * c - y * s, yr = x * s + y * c;
x = xr; y = yr;
}
return new Vector2(x + cameraPos.x, y + cameraPos.y);
}
/** Convert from world to screen space coordinates
* @param {Vector2} worldPos
* @return {Vector2}
* @memberof Draw */
function worldToScreen(worldPos)
{
ASSERT(isVector2(worldPos), 'worldPos must be a vec2');
let x = worldPos.x - cameraPos.x;
let y = worldPos.y - cameraPos.y;
if (cameraAngle)
{
// apply inverse camera rotation
const c = cos(cameraAngle), s = sin(cameraAngle);
const xr = x * c - y * s, yr = x * s + y * c;
x = xr; y = yr;
}
return new Vector2
(
x * cameraScale + mainCanvasSize.x/2 - .5,
y * -cameraScale + mainCanvasSize.y/2 - .5
);
}
/** Convert from screen to world space coordinates for a directional vector (no translation)
* @param {Vector2} screenDelta
* @return {Vector2}
* @memberof Draw */
function screenToWorldDelta(screenDelta)
{
ASSERT(isVector2(screenDelta), 'screenDelta must be a vec2');
let x = screenDelta.x / cameraScale;
let y = screenDelta.y / -cameraScale;
if (cameraAngle)
{
// apply camera rotation
const c = cos(-cameraAngle), s = sin(-cameraAngle);
const xr = x * c - y * s, yr = x * s + y * c;
x = xr; y = yr;
}
return new Vector2(x, y);
}
/** Convert from screen to world space coordinates for a directional vector (no translation)
* @param {Vector2} worldDelta
* @return {Vector2}
* @memberof Draw */
function worldToScreenDelta(worldDelta)
{
ASSERT(isVector2(worldDelta), 'worldDelta must be a vec2');
let x = worldDelta.x;
let y = worldDelta.y;
if (cameraAngle)
{
// apply inverse camera rotation
const c = cos(cameraAngle), s = sin(cameraAngle);
const xr = x * c - y * s, yr = x * s + y * c;
x = xr; y = yr;
}
return new Vector2(x * cameraScale, y * -cameraScale);
}
/** Convert screen space transform to world space
* @param {Vector2} screenPos
* @param {Vector2} screenSize
* @param {number} [screenAngle]
* @return {[Vector2, Vector2, number]} - [pos, size, angle]
* @memberof Draw */
function screenToWorldTransform(screenPos, screenSize, screenAngle=0)
{
ASSERT(isVector2(screenPos), 'screenPos must be a vec2');
ASSERT(isVector2(screenSize), 'screenSize must be a vec2');
ASSERT(isNumber(screenAngle), 'screenAngle must be a number');
return [
screenToWorld(screenPos),
screenSize.scale(1/cameraScale),
screenAngle + cameraAngle
];
}
/** Get the size of the camera window in world space
* @return {Vector2}
* @memberof Draw */
function getCameraSize() { return mainCanvasSize.scale(1/cameraScale); }
/** Check if a box, point, or circle is on screen with a circle test
* If size is a Vector2, uses the length as diameter
* This can be used to cull offscreen objects from render or update
* @param {Vector2} pos - world space position
* @param {Vector2|number} size - world space size or diameter
* @return {boolean}
* @memberof Draw */
function isOnScreen(pos, size=0)
{
ASSERT(isVector2(pos), 'pos must be a vec2');
ASSERT(isVector2(size) || isNumber(size), 'size must be a vec2 or number');
// optimized circle on screen test
// pos = worldToScreen(pos);
let x = pos.x - cameraPos.x;
let y = pos.y - cameraPos.y;
if (cameraAngle)
{
// apply inverse camera rotation
const c = cos(cameraAngle), s = sin(cameraAngle);
const xr = x * c - y * s, yr = x * s + y * c;
x = xr; y = yr;
}
x *= cameraScale*2; y *= -cameraScale*2;
if (size instanceof Vector2)
size = size.length(); // use length of vector as diameter
size *= cameraScale;
// check against screen bounds
const w = mainCanvasSize.x, h = mainCanvasSize.y;
return x + size > -w && x - size < w &&
y + size > -h && y - size < h;
}
/** Enable normal or additive blend mode
* @param {boolean} [additive]
* @param {CanvasRenderingContext2D|OffscreenCanvasRenderingContext2D} [context]
* @memberof Draw */
function setBlendMode(additive=false, context=drawContext)
{
glAdditive = additive;
context.globalCompositeOperation = additive ? 'lighter' : 'source-over';
}
/** Combines LittleJS canvases onto the main canvas
* This is necessary for things like screenshots and video
* @memberof Draw */
function combineCanvases()
{
const w = mainCanvasSize.x, h = mainCanvasSize.y;
workCanvas.width = w;
workCanvas.height = h;
workContext.fillRect(0,0,w,h); // remove background alpha
glCopyToContext(workContext);
workContext.drawImage(mainCanvas, 0, 0);
mainContext.drawImage(workCanvas, 0, 0);
}
/** Helper function to draw an image with color and additive color applied
* This is slower then normal drawImage when color is applied
* @param {CanvasRenderingContext2D|OffscreenCanvasRenderingContext2D} context
* @param {HTMLImageElement|OffscreenCanvas} image
* @param {number} sx
* @param {number} sy
* @param {number} sWidth
* @param {number} sHeight
* @param {number} dx
* @param {number} dy
* @param {number} dWidth
* @param {number} dHeight
* @param {Color} color
* @param {Color} [additiveColor]
* @param {number} [bleed] - How many pixels to shrink the source, used to fix bleeding
* @memberof Draw */
function drawImageColor(context, image, sx, sy, sWidth, sHeight, dx, dy, dWidth, dHeight, color, additiveColor, bleed=0)
{
function isWhite(c) { return c.r >= 1 && c.g >= 1 && c.b >= 1; }
function isBlack(c) { return c.r <= 0 && c.g <= 0 && c.b <= 0 && c.a <= 0; }
const sx2 = bleed;
const sy2 = bleed;
sWidth = max(1,sWidth|0);
sHeight = max(1,sHeight|0);
const sWidth2 = sWidth - 2*bleed;
const sHeight2 = sHeight - 2*bleed;
if (!canvasColorTiles || (additiveColor ? isWhite(color.add(additiveColor)) && additiveColor.a <= 0 : isWhite(color)))
{
// white texture with no additive alpha, no need to tint
context.globalAlpha = color.a;
context.drawImage(image, sx+sx2, sy+sy2, sWidth2, sHeight2, dx, dy, dWidth, dHeight);
context.globalAlpha = 1;
}
else
{
// copy to offscreen canvas
workReadCanvas.width = sWidth;
workReadCanvas.height = sHeight;
workReadContext.drawImage(image, sx|0, sy|0, sWidth, sHeight, 0, 0, sWidth, sHeight);
// tint image using offscreen work context
const imageData = workReadContext.getImageData(0, 0, sWidth, sHeight);
const data = imageData.data;
if (additiveColor && !isBlack(additiveColor))
{
// slower path with additive color
const colorMultiply = [color.r, color.g, color.b, color.a];
const colorAdd = [additiveColor.r * 255, additiveColor.g * 255, additiveColor.b * 255, additiveColor.a * 255];
for (let i = 0; i < data.length; ++i)
data[i] = data[i] * colorMultiply[i&3] + colorAdd[i&3] |0;
workReadContext.putImageData(imageData, 0, 0);
context.drawImage(workReadCanvas, sx2, sy2, sWidth2, sHeight2, dx, dy, dWidth, dHeight);
}
else
{
// faster path with no additive color
for (let i = 0; i < data.length; i+=4)
{
data[i ] *= color.r;
data[i+1] *= color.g;
data[i+2] *= color.b;
}
workReadContext.putImageData(imageData, 0, 0);
context.globalAlpha = color.a;
context.drawImage(workReadCanvas, sx2, sy2, sWidth2, sHeight2, dx, dy, dWidth, dHeight);
context.globalAlpha = 1;
}
}
}
/** Returns true if fullscreen mode is active
* @return {boolean}
* @memberof Draw */
function isFullscreen() { return !!document.fullscreenElement; }
/** Toggle fullscreen mode
* @memberof Draw */
function toggleFullscreen()
{
const rootElement = mainCanvas.parentElement;
if (isFullscreen())
{
if (document.exitFullscreen)
document.exitFullscreen();
}
else if (rootElement.requestFullscreen)
rootElement.requestFullscreen();
}
/** Set the cursor style
* @param {string} [cursorStyle] - CSS cursor style (auto, none, crosshair, etc)
* @memberof Draw */
function setCursor(cursorStyle = 'auto')
{
const rootElement = mainCanvas.parentElement;
rootElement.style.cursor = cursorStyle;
}
///////////////////////////////////////////////////////////////////////////////
/** Engine font image, 8x8 font provided by the engine
* @type {FontImage}
* @memberof Draw */
let engineFontImage;
/**
* Font Image Object - Draw text by using tiles in an image
* - 96 characters (from space to tilde) are stored in an image
* - A 8x8 default engine font is supplied for general use
* - This system is WebGL enabled for fast text rendering
* - Fonts can also be colored and scaled along each axis
*
* @memberof Draw
* @example
* // use built in font
* const font = engineFontImage;
*
* // draw text
* font.drawTextScreen('LittleJS\nHello World!', vec2(200, 50));
*/
class FontImage
{
/** Create an image font
* @param {TileInfo} tileInfo - Tile info of first character in font
*/
constructor(tileInfo)
{
ASSERT(!!tileInfo, 'tileInfo is required for FontImage');
/** @property {TileInfo} - Tile info for the font */
this.tileInfo = tileInfo.frame(0);
}
/** Draw text in world space using the image font
* @param {string|number} text
* @param {Vector2} pos
* @param {Vector2|number} [size]
* @param {boolean} [center=true]
* @param {Color} [color=WHITE]
* @param {boolean} [useWebGL=glEnable]
* @param {CanvasRenderingContext2D|OffscreenCanvasRenderingContext2D} [context]
*/
drawText(text, pos, size=1, center, color, useWebGL, context)
{
ASSERT(isVector2(size) || typeof size === 'number', 'size must be a vec2 or number');
if (typeof size === 'number')
{
// if size is a number, make it a vector
ASSERT(size > 0);
size *= cameraScale;
size = new Vector2(size, size);
}
else
size = size.scale(cameraScale);
this.drawTextScreen(text, worldToScreen(pos), size, center, color, useWebGL, context);
}
/** Draw text in screen space using the image font
* @param {string|number} text
* @param {Vector2} pos
* @param {Vector2|number} size
* @param {boolean} [center]
* @param {Color} [color=WHITE]
* @param {boolean} [useWebGL=glEnable]
* @param {CanvasRenderingContext2D|OffscreenCanvasRenderingContext2D} [context]
*/
drawTextScreen(text, pos, size, center=true, color=WHITE, useWebGL=glEnable, context)
{
ASSERT(isString(text), 'text must be a string');
ASSERT(isVector2(pos), 'pos must be a vec2');
ASSERT(isVector2(size) || typeof size === 'number', 'size must be a vec2 or number');
ASSERT(isColor(color), 'color must be a color');
// if size is a number, make it a vector
size = typeof size === 'number' ? new Vector2(size, size) : size;
// precache objects for drawing
const drawPos = new Vector2;
const tileInfo = this.tileInfo;
const padding = tileInfo.padding;
const sizePaddedX = tileInfo.size.x + padding*2;
const sizePaddedY = tileInfo.size.y + padding*2;
const cols = tileInfo.textureInfo.size.x / sizePaddedX |0;
// draw each line of text
(text+'').split('\n').forEach((line, j)=>
{
const centerOffset = center ? (line.length-1) * size.x / 2 : 0;
for (let i=line.length; i--;)
{
// get the character index
const charCode = line.charCodeAt(i);
const index = charCode < 32 || charCode > 127 ?
95 : charCode - 32; // handle out of range characters
// get the position of the tile
const x = index % cols;
const y = index / cols |0;
tileInfo.pos.x = x*sizePaddedX + padding;
tileInfo.pos.y = y*sizePaddedY + padding;
// draw the tile
drawPos.x = pos.x + i * size.x - centerOffset |0;
drawPos.y = pos.y + j * size.y |0;
drawTile(drawPos, size, tileInfo, color, 0, false, undefined, useWebGL, true, context);
}
});
}
}
// load engine font, called automatically on startup
async function fontImageInit()
{
const image = new Image;
await new Promise(resolve =>
{
image.onerror = image.onload = resolve;
image.crossOrigin = 'anonymous';
image.src = 'data:image/png;base64,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';
});
const tilePos=vec2(), tileSize=vec2(8), padding=1, bleed=0;
const textureInfo = new TextureInfo(image);
const tileInfo = new TileInfo(tilePos, tileSize, textureInfo, padding, bleed);
engineFontImage = new FontImage(tileInfo);
}