littlejsengine
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LittleJS - Tiny and Fast HTML5 Game Engine
1,239 lines (1,141 loc) • 59.6 kB
JavaScript
/**
* LittleJS Drawing System
* - Hybrid rendering with both Canvas2D and WebGL support
* - Optimized tile sheet sprite rendering using WebGL batching
* - Primitive drawing for polygons, ellipses, and lines
* - Tile-based rendering with TileInfo and TextureInfo classes
* - Text rendering with custom fonts and ImageFont support
* - Color and additive color blending for effects
* - Rotation, mirroring, and scaling transformations
* - Camera system with position, scale, and rotation
* - Multiple canvas support (main, WebGL, work canvases)
* - Gradient fills and outlined shapes
* - Image manipulation and color tinting
*
* Rendering Architecture:
* - glCanvas: WebGL canvas for accelerated sprite batch rendering
* - mainCanvas: Canvas2D overlay for text, UI, and custom drawing
* - All draw functions default to WebGL when enabled, can force Canvas2D with useWebGL parameter
*
* @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;
/** Keeps track of how many primitives were drawn each frame for debugging
* A single draw call can render many primitives (e.g. a WebGL sprite batch).
* @type {number}
* @memberof Draw */
let primitiveCount;
// internal predicates for tint short-circuiting in canvas2D draw paths
// isWhite ignores alpha because alpha is applied via globalAlpha, not multiply
// isBlack includes alpha so additive colors that only contribute alpha are not skipped
/** @param {Color} c */ function isWhite(c) { return c.r >= 1 && c.g >= 1 && c.b >= 1; }
/** @param {Color} c */ function isBlack(c) { return c.r <= 0 && c.g <= 0 && c.b <= 0 && c.a <= 0; }
///////////////////////////////////////////////////////////////////////////////
/**
* 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=0, 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;
ASSERT(textureInfo instanceof TextureInfo, 'tile texture is not loaded');
ASSERT(textureInfo.size.x > 0, 'tile texture is not loaded');
// 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 all sides of each tile (increases grid size, does not affect tile size)
* @param {number} [bleed] - How many pixels smaller to shrink UVS of tiles (does not affect grid size, only UVs)
*/
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.size.x <= this.textureInfo.size.x, 'frame extends beyond texture width!');
return this.offset(new Vector2(x));
}
/**
* Returns a tile info for an index using this tile as reference
* @param {Vector2|number} [index=0]
* @return {TileInfo}
*/
index(index)
{ return tile(index, this.size, this.textureInfo, this.padding, this.bleed); }
/**
* 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;
}
}
/**
* 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?
* @param {boolean} [wrap] - Should the texture wrap (REPEAT) or clamp (CLAMP_TO_EDGE)?
*/
constructor(image, useWebGL=true, wrap=false)
{
/** @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;
/** @property {boolean} - true for REPEAT wrap mode, false for CLAMP_TO_EDGE */
this.wrap = wrap;
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; }
/** Set the wrap mode for this texture
* @param {boolean} [wrap] - true for REPEAT, false for CLAMP_TO_EDGE */
setWrap(wrap=true)
{
this.wrap = wrap;
glSetTextureWrap(this.glTexture, wrap);
}
}
///////////////////////////////////////////////////////////////////////////////
// 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=false, 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
{
// untextured: fold color+additive to match the Canvas2D path's
// color.add(additiveColor) on line ~337.
const combined = additiveColor ? color.add(additiveColor) : color;
glDrawUntextured(pos.x, pos.y, size.x, size.y, angle, combined.rgbaInt());
}
}
else
{
// normal canvas 2D rendering method (slower)
++drawCount;
++primitiveCount;
drawCanvas2D(pos, size, angle, mirror, (context)=>
{
if (textureInfo)
{
// un-flip Y so the image renders right-side up under drawCanvas2D's Y flip
context.scale(1, -1);
// 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 (Y-symmetric, no compensation needed)
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=CLEAR_WHITE]
* @param {number} [angle]
* @param {boolean} [useWebGL=glEnable]
* @param {boolean} [screenSpace]
* @param {CanvasRenderingContext2D|OffscreenCanvasRenderingContext2D} [context]
* @memberof Draw */
function drawRectGradient(pos, size, colorTop=WHITE, colorBottom=CLEAR_WHITE, 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;
++primitiveCount;
drawCanvas2D(pos, size, angle, false, (context)=>
{
// gradient endpoints are flipped to match the Y flip inside drawCanvas2D
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 a texture tiled (wrapped) across a rectangle in world space.
* Useful for backgrounds, repeating patterns, and seamless fills.
* The whole texture is tiled — sub-region (TileInfo) wrapping is not supported.
* @param {Vector2} pos - Center of the rect in world space
* @param {Vector2} size - Size of the rect in world space
* @param {Vector2} wrapCount - How many times the texture repeats (x, y)
* @param {TextureInfo|number} [texture=0] - TextureInfo or texture index into textureInfos
* @param {Color} [color=WHITE] - Color to modulate with
* @param {number} [angle=0] - Angle to rotate by
* @param {Color} [additiveColor] - Additive color to be applied if any
* @param {boolean} [useWebGL=glEnable] - Use accelerated WebGL rendering?
* @param {boolean} [screenSpace=false] - Are pos and size in screen space?
* @param {CanvasRenderingContext2D|OffscreenCanvasRenderingContext2D} [context] - Canvas 2D context to draw to
* @memberof Draw */
function drawTextureWrapped(pos, size, wrapCount, texture=0, color=WHITE,
angle=0, additiveColor, useWebGL=glEnable, screenSpace=false, context)
{
ASSERT(isVector2(pos), 'pos must be a vec2');
ASSERT(isVector2(size), 'size must be a vec2');
ASSERT(isVector2(wrapCount), 'wrapCount 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');
ASSERT(!(texture instanceof TileInfo),
'pass a TextureInfo or texture index, not a TileInfo — use tileInfo.textureInfo');
// short-circuit before texture lookup — textureInfos[0] is undefined in headless mode
if (headlessMode) return;
// resolve texture argument: TextureInfo or index
const textureInfo = typeof texture === 'number' ? textureInfos[texture] : texture;
ASSERT(textureInfo instanceof TextureInfo, 'texture not loaded');
ASSERT(textureInfo.size.x > 0, 'texture not loaded');
ASSERT(textureInfo.wrap,
'drawTextureWrapped requires a wrap-enabled texture; call textureInfo.setWrap(true) first');
if (useWebGL && glEnable)
{
ASSERT(!!glContext, 'WebGL is not enabled!');
if (screenSpace)
[pos, size, angle] = screenToWorldTransform(pos, size, angle);
glSetTexture(textureInfo.glTexture);
glDraw(pos.x, pos.y, size.x, size.y, angle,
0, 0, wrapCount.x, wrapCount.y,
color.rgbaInt(), additiveColor && additiveColor.rgbaInt());
return;
}
// Canvas2D path — increment counts here (WebGL counts via glFlush)
++drawCount;
++primitiveCount;
if (!screenSpace)
{
pos = worldToScreen(pos);
size = size.scale(cameraScale);
angle -= cameraAngle;
}
// pick image source: raw, or tinted bake. Match drawImageColor's
// "no tint needed" predicate so behavior stays consistent.
const noTint = !canvasColorTiles ||
(additiveColor
? isWhite(color.add(additiveColor)) && additiveColor.a <= 0
: isWhite(color));
// alpha is baked into pixels by bakeTintedImage's additive branch;
// in that case globalAlpha must NOT also apply color.a
const alphaBaked = !noTint && additiveColor && !isBlack(additiveColor);
const source = noTint
? textureInfo.image
: bakeTintedImage(textureInfo.image, color, additiveColor);
context = context || drawContext;
context.save();
context.translate(pos.x + .5, pos.y + .5);
context.rotate(angle);
context.globalAlpha = alphaBaked ? 1 : color.a;
const pattern = context.createPattern(source, 'repeat');
// map pattern-source pixels into user space so the rect contains
// wrapCount.x × wrapCount.y repeats
const m = new DOMMatrix()
.translate(-size.x/2, -size.y/2)
.scale(size.x / (wrapCount.x * source.width),
size.y / (wrapCount.y * source.height));
pattern.setTransform(m);
context.fillStyle = pattern;
context.fillRect(-size.x/2, -size.y/2, size.x, size.y);
context.globalAlpha = 1;
context.restore();
}
/** 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=WHITE, wrap=false, pos=vec2(), angle=0, useWebGL=glEnable, screenSpace=false, 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;
++primitiveCount;
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=WHITE, pos=vec2(), angle=0, useWebGL=glEnable, screenSpace=false, 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} [lineWidth]
* @param {Color} [lineColor=BLACK]
* @param {number} [angle]
* @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, 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);
}
/** Draw an ellipse filled with a radial gradient from the center to the rim
* - Best when batched with other untextured polys
* - If drawing mostly textured sprites, bake the gradient into a texture and use drawTile instead
* - Stacking gradients at the exact same position may show a faint vertical artifact
* @param {Vector2} pos
* @param {Vector2} [size=vec2(1)] - Width and height diameter
* @param {Color} [colorInner=WHITE]
* @param {Color} [colorOuter=CLEAR_WHITE]
* @param {number} [angle]
* @param {boolean} [useWebGL=glEnable]
* @param {boolean} [screenSpace]
* @param {CanvasRenderingContext2D|OffscreenCanvasRenderingContext2D} [context]
* @memberof Draw */
let drawEllipseGradientOffset = 0;
function drawEllipseGradient(pos, size=vec2(1), colorInner=WHITE, colorOuter=CLEAR_WHITE, 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(colorInner) && isColor(colorOuter), 'color is invalid');
ASSERT(isNumber(angle), 'angle must be a number');
ASSERT(!context || !useWebGL, 'context only supported in canvas 2D mode');
if (headlessMode) return;
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;
}
// fan as tristrip; rotate the boundary vertex by one slice per call
// so back-to-back gradients at the same position have their hole
// (from gpu edge-rule on the boundary line-degen) at different rim
// verts and don't visibly stack
const sides = glCircleSides;
const radiusX = size.x/2, radiusY = size.y/2;
const innerInt = colorInner.rgbaInt();
const outerInt = colorOuter.rgbaInt();
const offset = drawEllipseGradientOffset++;
const c = cos(-angle), s = sin(-angle);
const rim = (a) =>
{
const lx = sin(a)*radiusX, ly = cos(a)*radiusY;
return vec2(pos.x + lx*c - ly*s, pos.y + lx*s + ly*c);
};
const startA = (offset%sides)/sides*PI*2;
const points = [rim(startA)];
const colors = [outerInt];
for (let i=sides; i--;)
{
const a = ((i+offset)%sides)/sides*PI*2;
points.push(pos);
colors.push(innerInt);
points.push(rim(a));
colors.push(outerInt);
}
glDrawColoredPoints(points, colors);
}
else
{
// normal canvas 2D rendering method (slower)
++drawCount;
++primitiveCount;
drawCanvas2D(pos, size, angle, false, (context)=>
{
const gradient = context.createRadialGradient(0, 0, 0, 0, 0, .5);
gradient.addColorStop(0, colorInner.toString());
gradient.addColorStop(1, colorOuter.toString());
context.fillStyle = gradient;
context.beginPath();
context.ellipse(0, 0, .5, .5, 0, 0, 9);
context.fill();
}, screenSpace, context);
}
}
/** Draw a circle filled with a radial gradient from the center to the rim
* - Best when batched with other untextured polys
* - If drawing mostly textured sprites, bake the gradient into a texture and use drawTile instead
* - Stacking gradients at the exact same position may show a faint vertical artifact
* @param {Vector2} pos
* @param {number} [size=1] - Diameter
* @param {Color} [colorInner=WHITE]
* @param {Color} [colorOuter=CLEAR_WHITE]
* @param {boolean} [useWebGL=glEnable]
* @param {boolean} [screenSpace]
* @param {CanvasRenderingContext2D|OffscreenCanvasRenderingContext2D} [context]
* @memberof Draw */
function drawCircleGradient(pos, size=1, colorInner=WHITE, colorOuter=CLEAR_WHITE, useWebGL=glEnable, screenSpace=false, context)
{
ASSERT(isNumber(size), 'size must be a number');
drawEllipseGradient(pos, vec2(size), colorInner, colorOuter, 0, 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.
* The Y axis is flipped so world-Y-up coordinates render right-side up
* (matches the WebGL path). Callers whose drawing depends on Y direction
* (e.g. linear gradients) should flip their own Y endpoints accordingly.
* @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=WHITE, lineWidth=0, lineColor=BLACK, textAlign='center', font=fontDefault, 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(isStringLike(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(isStringLike(font), 'font must be a string');
ASSERT(isStringLike(fontStyle), 'fontStyle must be a string');
ASSERT(isNumber(angle), 'angle must be a number');
const lines = (text+'').split('\n');
const posY = pos.y - (lines.length-1) * size/2; // center vertically
// save before style mutations so caller's context state is preserved
context.save();
context.fillStyle = color.toString();
context.strokeStyle = lineColor.toString();
context.lineWidth = lineWidth;
context.textAlign = textAlign;
context.font = fontStyle + ' ' + size + 'px '+ font;
context.textBaseline = 'middle';
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 || isStringLike(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); }
/** Fit the camera to a rectangle in world space by setting cameraPos and cameraScale
* - worldMargin pads the content rectangle in world units, so the gap scales with the content on resize
* - screenInset reserves space in screen pixels on each viewport edge (for example a HUD band) and
* re-centers the content away from that edge, so the reserved band stays a fixed pixel size on resize
* - worldMargin and screenInset may each be a number for all sides, a Vector2 (x=left/right, y=top/bottom),
* or an object with any of {top, right, bottom, left}
* @param {Vector2} center - Center of the rectangle in world space
* @param {Vector2} size - Size of the rectangle in world space
* @param {number|Vector2|Object} [worldMargin] - World space padding added around the content rectangle
* @param {number|Vector2|Object} [screenInset] - Screen space padding in pixels reserved on each viewport edge
* @return {number} - The new camera scale
* @memberof Draw */
function cameraFit(center, size, worldMargin, screenInset)
{
ASSERT(isVector2(center), 'center must be a vec2');
ASSERT(isVector2(size), 'size must be a vec2');
// pad the content
const margin = padSides(worldMargin);
const inset = padSides(screenInset);
const worldW = size.x + margin.left + margin.right;
const worldH = size.y + margin.top + margin.bottom;
const viewW = mainCanvasSize.x - inset.left - inset.right;
const viewH = mainCanvasSize.y - inset.top - inset.bottom;
// bail on a degenerate rect or viewport rather than NaN the camera
if (!(worldW > 0 && worldH > 0 && viewW > 0 && viewH > 0))
return cameraScale;
// scale to fit the padded content
cameraScale = min(viewW / worldW, viewH / worldH);
// calculate offset vectors
const marginVector = vec2(margin.right - margin.left, margin.top - margin.bottom).scale(.5);
const insetVector = vec2(inset.right - inset.left, inset.top - inset.bottom).scale(.5 / cameraScale);
// apply the offsets and return camera scale
cameraPos = center.add(marginVector).add(insetVector);
return cameraScale;
function padSides(p)
{
// normalize a padding option to {top, right, bottom, left}
if (p === undefined || isNumber(p))
p = vec2(p);
if (isVector2(p))
return { top: p.y, right: p.x, bottom: p.y, left: p.x };
return {
top: p.top || 0,
right: p.right || 0,
bottom: p.bottom || 0,
left: p.left || 0,
};
}
}
/** 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');
// cameraScale of 0 collapses world coords; nothing is visible
if (!cameraScale) return false;
// 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 additive blending
* @param {boolean} [additive]
* @memberof Draw */
function setAdditiveBlendMode(additive=true)
{
glAdditive = additive;
drawContext.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;
// remove background alpha — explicit fillStyle so a previous caller
// leaving workContext.fillStyle transparent can't silently no-op this
workContext.fillStyle = '#000';
workContext.fillRect(0,0,w,h);
glCopyToContext(workContext);
workContext.drawImage(mainCanvas, 0, 0);
mainContext.drawImage(workCanvas, 0, 0);
}
// Internal: bake a color/additive-color tint into workReadCanvas at the
// image's native resolution. Returns the work canvas, suitable for
// passing to context.createPattern. Used by drawTextureWrapped's
// Canvas2D path. Caller is responsible for short-circuiting when no
// tint is needed (i.e. color is white and additiveColor is black/none).
function bakeTintedImage(image, color, additiveColor)
{
const w = image.width|0, h = image.height|0;
workReadCanvas.width = w;
workReadCanvas.height = h;
workReadContext.drawImage(image, 0, 0);
const imageData = workReadContext.getImageData(0, 0, w, h);
const data = imageData.data;
if (additiveColor && !isBlack(additiveColor))
{
// multiply + additive (slower)
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;
}
else
{
// RGB only, faster — alpha left intact for the caller
for (let i = 0; i < data.length; i+=4)
{
data[i ] *= color.r;
data[i+1]