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1334import earcut from "earcut"
import type { Color } from "../math/color"
import { Matrix } from "../math/matrix"
import type { Paint } from "../math/paint"
import type { Path } from "../math/path"
import { Rectangle } from "../math/rectangle"
import type { Vector2 } from "../math/vector2"
import type {
Font,
ImageAsset,
Renderer,
RendererBackend,
RendererCapabilities,
} from "./renderer"
import { BatchManager, type DrawOperation } from "./batchmanager"
import { RendererError } from "../error/renderererror"
/**
* Vertex data for path rendering
*/
interface PathVertex {
x: number
y: number
}
/**
* Tessellated path data ready for GPU rendering
*/
interface TessellatedPath {
vertices: Float32Array
indices: Uint16Array
vertexCount: number
indexCount: number
}
/**
* WebGL texture wrapper
*/
interface WebGLTexture2D {
texture: WebGLTexture
width: number
height: number
}
/**
* WebGL renderer implementation
* Provides hardware-accelerated rendering using WebGL
*/
export class WebGLRenderer implements Renderer {
private _canvas: HTMLCanvasElement | null = null
private _gl: WebGLRenderingContext | null = null
private _isInitialized = false
private _width = 0
private _height = 0
// Shader programs
private _pathProgram: WebGLProgram | null = null
private _imageProgram: WebGLProgram | null = null
private _textProgram: WebGLProgram | null = null
// Buffers
private _pathVertexBuffer: WebGLBuffer | null = null
private _pathIndexBuffer: WebGLBuffer | null = null
private _imageVertexBuffer: WebGLBuffer | null = null
// Texture cache
private _textureCache = new Map<ImageAsset, WebGLTexture2D>()
// Transform stack
private _transformStack: Matrix[] = []
private _currentTransform: Matrix = new Matrix()
// Opacity stack
private _opacityStack: number[] = []
private _currentOpacity = 1.0
// Batching
private _batchManager = new BatchManager()
private _batchingEnabled = true
readonly backend: RendererBackend = "webgl"
readonly capabilities: RendererCapabilities = {
maxTextureSize: 2048, // Will be updated during initialization
supportsBlendModes: true,
supportsFilters: false,
supportsAdvancedPaths: false,
supportsHardwareAcceleration: true,
}
get isInitialized(): boolean {
return this._isInitialized
}
get width(): number {
return this._width
}
get height(): number {
return this._height
}
/**
* Initialize the renderer with a canvas element
*/
async initialize(canvas: HTMLCanvasElement): Promise<void> {
this._canvas = canvas
// Get WebGL context
const gl = canvas.getContext("webgl", {
alpha: true,
antialias: true,
premultipliedAlpha: true,
}) as WebGLRenderingContext | null
if (!gl) {
// Try experimental WebGL
const experimentalGl = canvas.getContext("experimental-webgl", {
alpha: true,
antialias: true,
premultipliedAlpha: true,
}) as WebGLRenderingContext | null
if (!experimentalGl) {
throw RendererError.initFailed(
"webgl",
"Failed to get WebGL rendering context from canvas. WebGL may not be supported in this environment.",
)
}
this._gl = experimentalGl
} else {
this._gl = gl
}
this._width = canvas.width
this._height = canvas.height
// Update capabilities
const maxTextureSize = this._gl.getParameter(
this._gl.MAX_TEXTURE_SIZE,
) as number
;(this.capabilities as { maxTextureSize: number }).maxTextureSize =
maxTextureSize
// Initialize shaders and buffers
try {
await this._initializeShaders()
this._initializeBuffers()
} catch (error) {
throw RendererError.initFailed(
"webgl",
`Failed to initialize WebGL shaders or buffers: ${error instanceof Error ? error.message : String(error)}`,
error instanceof Error ? error : undefined,
)
}
// Set up initial GL state
this._gl.viewport(0, 0, this._width, this._height)
this._gl.enable(this._gl.BLEND)
this._gl.blendFunc(this._gl.SRC_ALPHA, this._gl.ONE_MINUS_SRC_ALPHA)
this._isInitialized = true
}
/**
* Resize the renderer viewport
*/
resize(width: number, height: number): void {
if (!this._canvas || !this._gl) {
throw new Error("Renderer not initialized")
}
this._canvas.width = width
this._canvas.height = height
this._width = width
this._height = height
this._gl.viewport(0, 0, width, height)
}
/**
* Begin a new frame
*/
beginFrame(): void {
// Reset transform and opacity stacks
this._transformStack = []
this._currentTransform = new Matrix()
this._opacityStack = []
this._currentOpacity = 1.0
// Clear any pending batches from previous frame
this._batchManager.clear()
}
/**
* End the current frame
*/
endFrame(): void {
if (!this._gl) {
throw new Error("Renderer not initialized")
}
// Flush any remaining batched operations
this._flushBatches()
// Flush any pending GPU operations
this._gl.flush()
}
/**
* Clear the canvas with an optional color
*/
clear(color?: Color): void {
if (!this._gl) {
throw new Error("Renderer not initialized")
}
const gl = this._gl
if (color) {
gl.clearColor(color.r, color.g, color.b, color.a)
} else {
gl.clearColor(0, 0, 0, 0)
}
gl.clear(gl.COLOR_BUFFER_BIT)
}
/**
* Clear a specific region of the canvas
*/
clearRegion(region: Rectangle, color?: Color): void {
if (!this._gl) {
throw new Error("Renderer not initialized")
}
const gl = this._gl
// Enable scissor test to limit clearing to the region
gl.enable(gl.SCISSOR_TEST)
gl.scissor(
Math.floor(region.x),
Math.floor(this._height - region.y - region.height),
Math.ceil(region.width),
Math.ceil(region.height),
)
if (color) {
gl.clearColor(color.r, color.g, color.b, color.a)
} else {
gl.clearColor(0, 0, 0, 0)
}
gl.clear(gl.COLOR_BUFFER_BIT)
// Disable scissor test
gl.disable(gl.SCISSOR_TEST)
}
/**
* Draw a path with the specified paint
*/
drawPath(path: Path, paint: Paint): void {
if (!this._gl || !this._pathProgram) {
throw new Error("Renderer not initialized")
}
if (path.isEmpty()) {
return
}
// If batching is enabled, add to batch queue
if (this._batchingEnabled && this._batchManager.isEnabled) {
this._batchManager.addOperation({
type: "path",
path,
paint,
transform: this._currentTransform.clone(),
opacity: this._currentOpacity,
})
return
}
// Otherwise, draw immediately
this._drawPathImmediate(path, paint)
}
/**
* Draw a path immediately without batching
*/
private _drawPathImmediate(path: Path, paint: Paint): void {
if (!this._gl || !this._pathProgram) {
return
}
const gl = this._gl
// Tessellate the path
const tessellated = this._tessellatePath(path)
if (tessellated.indexCount === 0) {
return
}
// Use path shader program
gl.useProgram(this._pathProgram)
// Upload vertex data
gl.bindBuffer(gl.ARRAY_BUFFER, this._pathVertexBuffer)
gl.bufferData(gl.ARRAY_BUFFER, tessellated.vertices, gl.DYNAMIC_DRAW)
gl.bindBuffer(gl.ELEMENT_ARRAY_BUFFER, this._pathIndexBuffer)
gl.bufferData(
gl.ELEMENT_ARRAY_BUFFER,
tessellated.indices,
gl.DYNAMIC_DRAW,
)
// Set up vertex attributes
const positionLoc = gl.getAttribLocation(
this._pathProgram,
"a_position",
)
gl.enableVertexAttribArray(positionLoc)
gl.vertexAttribPointer(positionLoc, 2, gl.FLOAT, false, 0, 0)
// Set uniforms
this._setPathUniforms(paint)
// Set blend mode
this._setBlendMode(paint.blendMode)
// Draw
gl.drawElements(
gl.TRIANGLES,
tessellated.indexCount,
gl.UNSIGNED_SHORT,
0,
)
// Reset blend mode
gl.blendFunc(gl.SRC_ALPHA, gl.ONE_MINUS_SRC_ALPHA)
}
/**
* Draw a path stroke with the specified paint and width
* Tessellates the stroke path with proper miter joins and butt caps
*/
drawStroke(path: Path, paint: Paint, strokeWidth: number): void {
if (!this._gl || !this._pathProgram) {
throw new Error("Renderer not initialized")
}
if (path.isEmpty() || strokeWidth <= 0) {
return
}
// If batching is enabled, add to batch queue
if (this._batchingEnabled && this._batchManager.isEnabled) {
this._batchManager.addOperation({
type: "stroke",
path,
paint,
transform: this._currentTransform.clone(),
opacity: this._currentOpacity,
strokeWidth,
})
return
}
// Otherwise, draw immediately
this._drawStrokeImmediate(path, paint, strokeWidth)
}
/**
* Draw a stroke immediately without batching
*/
private _drawStrokeImmediate(
path: Path,
paint: Paint,
strokeWidth: number,
): void {
if (!this._gl || !this._pathProgram) {
return
}
// For simplicity, we'll tessellate the stroke path
// In production, use a proper stroke tessellation library
const strokePath = this._tessellateStroke(path, strokeWidth)
if (strokePath.indexCount === 0) {
return
}
const gl = this._gl
// Use path shader program
gl.useProgram(this._pathProgram)
// Upload vertex data
gl.bindBuffer(gl.ARRAY_BUFFER, this._pathVertexBuffer)
gl.bufferData(gl.ARRAY_BUFFER, strokePath.vertices, gl.DYNAMIC_DRAW)
gl.bindBuffer(gl.ELEMENT_ARRAY_BUFFER, this._pathIndexBuffer)
gl.bufferData(
gl.ELEMENT_ARRAY_BUFFER,
strokePath.indices,
gl.DYNAMIC_DRAW,
)
// Set up vertex attributes
const positionLoc = gl.getAttribLocation(
this._pathProgram,
"a_position",
)
gl.enableVertexAttribArray(positionLoc)
gl.vertexAttribPointer(positionLoc, 2, gl.FLOAT, false, 0, 0)
// Set uniforms
this._setPathUniforms(paint)
// Set blend mode
this._setBlendMode(paint.blendMode)
// Draw
gl.drawElements(
gl.TRIANGLES,
strokePath.indexCount,
gl.UNSIGNED_SHORT,
0,
)
// Reset blend mode
gl.blendFunc(gl.SRC_ALPHA, gl.ONE_MINUS_SRC_ALPHA)
}
/**
* Draw an image with the specified transformation
*/
drawImage(image: ImageAsset, transform: Matrix): void {
if (!this._gl || !this._imageProgram) {
throw new Error("Renderer not initialized")
}
const gl = this._gl
// Get or create texture
let texture = this._textureCache.get(image)
if (!texture) {
texture = this._createTexture(image)
this._textureCache.set(image, texture)
}
// Use image shader program
gl.useProgram(this._imageProgram)
// Create quad vertices with transformation
const vertices = this._createImageQuad(image, transform)
// Upload vertex data
gl.bindBuffer(gl.ARRAY_BUFFER, this._imageVertexBuffer)
gl.bufferData(gl.ARRAY_BUFFER, vertices, gl.DYNAMIC_DRAW)
// Set up vertex attributes
const positionLoc = gl.getAttribLocation(
this._imageProgram,
"a_position",
)
const texCoordLoc = gl.getAttribLocation(
this._imageProgram,
"a_texCoord",
)
gl.enableVertexAttribArray(positionLoc)
gl.vertexAttribPointer(positionLoc, 2, gl.FLOAT, false, 16, 0)
gl.enableVertexAttribArray(texCoordLoc)
gl.vertexAttribPointer(texCoordLoc, 2, gl.FLOAT, false, 16, 8)
// Bind texture
gl.activeTexture(gl.TEXTURE0)
gl.bindTexture(gl.TEXTURE_2D, texture.texture)
// Set uniforms
this._setImageUniforms()
// Draw
gl.drawArrays(gl.TRIANGLE_STRIP, 0, 4)
}
/**
* Draw text at the specified position
*/
drawText(text: string, font: Font, position: Vector2, paint: Paint): void {
// WebGL text rendering is complex and typically done via texture atlas
// For now, we'll throw an error indicating it's not implemented
// In a full implementation, this would render text to a texture and draw that
throw new Error("Text rendering not yet implemented in WebGL renderer")
}
/**
* Save the current rendering state
*/
save(): void {
this._transformStack.push(this._currentTransform.clone())
this._opacityStack.push(this._currentOpacity)
}
/**
* Restore the previous rendering state
*/
restore(): void {
const transform = this._transformStack.pop()
if (transform) {
this._currentTransform = transform
}
const opacity = this._opacityStack.pop()
if (opacity !== undefined) {
this._currentOpacity = opacity
}
}
/**
* Apply a transformation matrix to the current rendering context
*/
transform(matrix: Matrix): void {
// Multiply current transform by the new matrix
this._currentTransform = this._currentTransform.multiply(matrix)
}
/**
* Set the global opacity for subsequent draw operations
*/
setOpacity(opacity: number): void {
this._currentOpacity = Math.max(0, Math.min(1, opacity))
}
/**
* Initialize shader programs
*/
private async _initializeShaders(): Promise<void> {
if (!this._gl) {
throw new Error("WebGL context not available")
}
const gl = this._gl
// Create path shader program
this._pathProgram = this._createProgram(
PATH_VERTEX_SHADER,
PATH_FRAGMENT_SHADER,
)
// Create image shader program
this._imageProgram = this._createProgram(
IMAGE_VERTEX_SHADER,
IMAGE_FRAGMENT_SHADER,
)
}
/**
* Initialize buffers
*/
private _initializeBuffers(): void {
if (!this._gl) {
throw new Error("WebGL context not available")
}
const gl = this._gl
this._pathVertexBuffer = gl.createBuffer()
this._pathIndexBuffer = gl.createBuffer()
this._imageVertexBuffer = gl.createBuffer()
if (
!this._pathVertexBuffer ||
!this._pathIndexBuffer ||
!this._imageVertexBuffer
) {
throw new Error("Failed to create WebGL buffers")
}
}
/**
* Create a shader program from vertex and fragment shader source
*/
private _createProgram(
vertexSource: string,
fragmentSource: string,
): WebGLProgram {
if (!this._gl) {
throw new Error("WebGL context not available")
}
const gl = this._gl
const vertexShader = this._compileShader(gl.VERTEX_SHADER, vertexSource)
const fragmentShader = this._compileShader(
gl.FRAGMENT_SHADER,
fragmentSource,
)
const program = gl.createProgram()
if (!program) {
throw new Error("Failed to create shader program")
}
gl.attachShader(program, vertexShader)
gl.attachShader(program, fragmentShader)
gl.linkProgram(program)
if (!gl.getProgramParameter(program, gl.LINK_STATUS)) {
const info = gl.getProgramInfoLog(program)
throw new Error(`Failed to link shader program: ${info}`)
}
return program
}
/**
* Compile a shader
*/
private _compileShader(type: number, source: string): WebGLShader {
if (!this._gl) {
throw new Error("WebGL context not available")
}
const gl = this._gl
const shader = gl.createShader(type)
if (!shader) {
throw new Error("Failed to create shader")
}
gl.shaderSource(shader, source)
gl.compileShader(shader)
if (!gl.getShaderParameter(shader, gl.COMPILE_STATUS)) {
const info = gl.getShaderInfoLog(shader)
throw new Error(`Failed to compile shader: ${info}`)
}
return shader
}
/**
* Tessellate a path into triangles for GPU rendering
* Uses earcut library for robust polygon triangulation
*/
private _tessellatePath(path: Path): TessellatedPath {
const pathPoints: number[] = []
let currentX = 0
let currentY = 0
let startX = 0
let startY = 0
// Convert path commands to flat coordinate array
for (const cmd of path.commands) {
switch (cmd.type) {
case "M":
currentX = cmd.x
currentY = cmd.y
startX = cmd.x
startY = cmd.y
pathPoints.push(currentX, currentY)
break
case "L":
currentX = cmd.x
currentY = cmd.y
pathPoints.push(currentX, currentY)
break
case "C":
// Approximate cubic bezier with line segments
// Using 10 segments for smooth curves
{
const steps = 10
const x0 = currentX
const y0 = currentY
for (let i = 1; i <= steps; i++) {
const t = i / steps
const mt = 1 - t
const mt2 = mt * mt
const mt3 = mt2 * mt
const t2 = t * t
const t3 = t2 * t
const x =
mt3 * x0 +
3 * mt2 * t * cmd.cp1x +
3 * mt * t2 * cmd.cp2x +
t3 * cmd.x
const y =
mt3 * y0 +
3 * mt2 * t * cmd.cp1y +
3 * mt * t2 * cmd.cp2y +
t3 * cmd.y
pathPoints.push(x, y)
}
currentX = cmd.x
currentY = cmd.y
}
break
case "Q":
// Approximate quadratic bezier with line segments
{
const steps = 10
const x0 = currentX
const y0 = currentY
for (let i = 1; i <= steps; i++) {
const t = i / steps
const mt = 1 - t
const x =
mt * mt * x0 +
2 * mt * t * cmd.cpx +
t * t * cmd.x
const y =
mt * mt * y0 +
2 * mt * t * cmd.cpy +
t * t * cmd.y
pathPoints.push(x, y)
}
currentX = cmd.x
currentY = cmd.y
}
break
case "Z":
// Close path if not already at start
if (
Math.abs(currentX - startX) > 0.001 ||
Math.abs(currentY - startY) > 0.001
) {
pathPoints.push(startX, startY)
}
currentX = startX
currentY = startY
break
}
}
// Need at least 3 points (6 coordinates) to form a triangle
if (pathPoints.length < 6) {
return {
vertices: new Float32Array(0),
indices: new Uint16Array(0),
vertexCount: 0,
indexCount: 0,
}
}
// Use earcut to triangulate the polygon
const indices = earcut(pathPoints)
return {
vertices: new Float32Array(pathPoints),
indices: new Uint16Array(indices),
vertexCount: pathPoints.length / 2,
indexCount: indices.length,
}
}
/**
* Tessellate a stroke path into triangles for GPU rendering
* Implements proper stroke expansion with miter joins and butt caps
*/
private _tessellateStroke(
path: Path,
strokeWidth: number,
): TessellatedPath {
const halfWidth = strokeWidth / 2
const pathPoints: { x: number; y: number }[] = []
let currentX = 0
let currentY = 0
let startX = 0
let startY = 0
// Extract path points with curve approximation
for (const cmd of path.commands) {
switch (cmd.type) {
case "M":
currentX = cmd.x
currentY = cmd.y
startX = cmd.x
startY = cmd.y
pathPoints.push({ x: currentX, y: currentY })
break
case "L":
currentX = cmd.x
currentY = cmd.y
pathPoints.push({ x: currentX, y: currentY })
break
case "C":
// Approximate cubic bezier
{
const steps = 10
const x0 = currentX
const y0 = currentY
for (let i = 1; i <= steps; i++) {
const t = i / steps
const mt = 1 - t
const mt2 = mt * mt
const mt3 = mt2 * mt
const t2 = t * t
const t3 = t2 * t
const x =
mt3 * x0 +
3 * mt2 * t * cmd.cp1x +
3 * mt * t2 * cmd.cp2x +
t3 * cmd.x
const y =
mt3 * y0 +
3 * mt2 * t * cmd.cp1y +
3 * mt * t2 * cmd.cp2y +
t3 * cmd.y
pathPoints.push({ x, y })
}
currentX = cmd.x
currentY = cmd.y
}
break
case "Q":
// Approximate quadratic bezier
{
const steps = 10
const x0 = currentX
const y0 = currentY
for (let i = 1; i <= steps; i++) {
const t = i / steps
const mt = 1 - t
const x =
mt * mt * x0 +
2 * mt * t * cmd.cpx +
t * t * cmd.x
const y =
mt * mt * y0 +
2 * mt * t * cmd.cpy +
t * t * cmd.y
pathPoints.push({ x, y })
}
currentX = cmd.x
currentY = cmd.y
}
break
case "Z":
// Close path
if (
pathPoints.length > 0 &&
pathPoints[0] &&
(Math.abs(currentX - startX) > 0.001 ||
Math.abs(currentY - startY) > 0.001)
) {
pathPoints.push({ x: startX, y: startY })
}
currentX = startX
currentY = startY
break
}
}
if (pathPoints.length < 2) {
return {
vertices: new Float32Array(0),
indices: new Uint16Array(0),
vertexCount: 0,
indexCount: 0,
}
}
// Generate stroke geometry with proper joins
const vertices: number[] = []
const indices: number[] = []
for (let i = 0; i < pathPoints.length; i++) {
const current = pathPoints[i]
if (!current) continue
const prev = pathPoints[i - 1]
const next = pathPoints[i + 1]
// Calculate tangent vectors
let tangentX = 0
let tangentY = 0
if (i === 0) {
// First point - use forward direction
if (next) {
tangentX = next.x - current.x
tangentY = next.y - current.y
}
} else if (i === pathPoints.length - 1) {
// Last point - use backward direction
if (prev) {
tangentX = current.x - prev.x
tangentY = current.y - prev.y
}
} else {
// Middle point - use average of forward and backward directions
if (prev && next) {
const dx1 = current.x - prev.x
const dy1 = current.y - prev.y
const dx2 = next.x - current.x
const dy2 = next.y - current.y
// Normalize both directions
const len1 = Math.sqrt(dx1 * dx1 + dy1 * dy1)
const len2 = Math.sqrt(dx2 * dx2 + dy2 * dy2)
if (len1 > 0 && len2 > 0) {
tangentX = dx1 / len1 + dx2 / len2
tangentY = dy1 / len1 + dy2 / len2
}
}
}
// Normalize tangent
const tangentLen = Math.sqrt(
tangentX * tangentX + tangentY * tangentY,
)
if (tangentLen > 0) {
tangentX /= tangentLen
tangentY /= tangentLen
}
// Calculate perpendicular (normal) direction
const normalX = -tangentY
const normalY = tangentX
// Add vertices on both sides of the stroke
const baseIndex = vertices.length / 2
vertices.push(
current.x + normalX * halfWidth,
current.y + normalY * halfWidth,
)
vertices.push(
current.x - normalX * halfWidth,
current.y - normalY * halfWidth,
)
// Create triangles for the stroke segment
if (i > 0) {
indices.push(baseIndex - 2, baseIndex - 1, baseIndex)
indices.push(baseIndex - 1, baseIndex + 1, baseIndex)
}
}
return {
vertices: new Float32Array(vertices),
indices: new Uint16Array(indices),
vertexCount: vertices.length / 2,
indexCount: indices.length,
}
}
/**
* Set uniforms for path rendering
*/
private _setPathUniforms(paint: Paint): void {
if (!this._gl || !this._pathProgram) {
return
}
const gl = this._gl
// Projection matrix (orthographic)
const projectionLoc = gl.getUniformLocation(
this._pathProgram,
"u_projection",
)
const projection = this._createProjectionMatrix()
gl.uniformMatrix3fv(projectionLoc, false, projection)
// Transform matrix
const transformLoc = gl.getUniformLocation(
this._pathProgram,
"u_transform",
)
const transform = this._matrixToArray(this._currentTransform)
gl.uniformMatrix3fv(transformLoc, false, transform)
// Color
const colorLoc = gl.getUniformLocation(this._pathProgram, "u_color")
if (paint.type === "solid" && paint.color) {
gl.uniform4f(
colorLoc,
paint.color.r,
paint.color.g,
paint.color.b,
paint.color.a * this._currentOpacity,
)
} else {
gl.uniform4f(colorLoc, 1, 1, 1, this._currentOpacity)
}
}
/**
* Set uniforms for image rendering
*/
private _setImageUniforms(): void {
if (!this._gl || !this._imageProgram) {
return
}
const gl = this._gl
// Projection matrix
const projectionLoc = gl.getUniformLocation(
this._imageProgram,
"u_projection",
)
const projection = this._createProjectionMatrix()
gl.uniformMatrix3fv(projectionLoc, false, projection)
// Texture sampler
const textureLoc = gl.getUniformLocation(
this._imageProgram,
"u_texture",
)
gl.uniform1i(textureLoc, 0)
// Opacity
const opacityLoc = gl.getUniformLocation(
this._imageProgram,
"u_opacity",
)
gl.uniform1f(opacityLoc, this._currentOpacity)
}
/**
* Create orthographic projection matrix
*/
private _createProjectionMatrix(): Float32Array {
// Orthographic projection for 2D rendering
const left = 0
const right = this._width
const bottom = this._height
const top = 0
return new Float32Array([
2 / (right - left),
0,
0,
0,
2 / (top - bottom),
0,
(right + left) / (left - right),
(top + bottom) / (bottom - top),
1,
])
}
/**
* Convert Matrix to Float32Array for WebGL
*/
private _matrixToArray(matrix: Matrix): Float32Array {
return new Float32Array([
matrix.a,
matrix.b,
0,
matrix.c,
matrix.d,
0,
matrix.tx,
matrix.ty,
1,
])
}
/**
* Create a WebGL texture from an image asset
*/
private _createTexture(image: ImageAsset): WebGLTexture2D {
if (!this._gl) {
throw new Error("WebGL context not available")
}
const gl = this._gl
const texture = gl.createTexture()
if (!texture) {
throw new Error("Failed to create texture")
}
gl.bindTexture(gl.TEXTURE_2D, texture)
gl.texImage2D(
gl.TEXTURE_2D,
0,
gl.RGBA,
gl.RGBA,
gl.UNSIGNED_BYTE,
image.data,
)
// Set texture parameters
gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_S, gl.CLAMP_TO_EDGE)
gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_T, gl.CLAMP_TO_EDGE)
gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.LINEAR)
gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.LINEAR)
return {
texture,
width: image.width,
height: image.height,
}
}
/**
* Create vertex data for an image quad
*/
private _createImageQuad(
image: ImageAsset,
transform: Matrix,
): Float32Array {
// Create a quad with position and texture coordinates
// Format: [x, y, u, v] per vertex
const w = image.width
const h = image.height
// Apply transform to corners
const corners = [
this._transformPoint(0, 0, transform),
this._transformPoint(w, 0, transform),
this._transformPoint(0, h, transform),
this._transformPoint(w, h, transform),
]
const c0 = corners[0]
const c1 = corners[1]
const c2 = corners[2]
const c3 = corners[3]
if (!c0 || !c1 || !c2 || !c3) {
throw new Error("Failed to transform image corners")
}
return new Float32Array([
c0.x,
c0.y,
0,
0, // Top-left
c1.x,
c1.y,
1,
0, // Top-right
c2.x,
c2.y,
0,
1, // Bottom-left
c3.x,
c3.y,
1,
1, // Bottom-right
])
}
/**
* Transform a point by a matrix
*/
private _transformPoint(
x: number,
y: number,
matrix: Matrix,
): { x: number; y: number } {
return {
x: matrix.a * x + matrix.c * y + matrix.tx,
y: matrix.b * x + matrix.d * y + matrix.ty,
}
}
/**
* Set blend mode
*/
private _setBlendMode(blendMode: Paint["blendMode"]): void {
if (!this._gl) {
return
}
const gl = this._gl
switch (blendMode) {
case "normal":
gl.blendFunc(gl.SRC_ALPHA, gl.ONE_MINUS_SRC_ALPHA)
break
case "multiply":
gl.blendFunc(gl.DST_COLOR, gl.ONE_MINUS_SRC_ALPHA)
break
case "screen":
gl.blendFunc(gl.ONE, gl.ONE_MINUS_SRC_COLOR)
break
case "lighten":
gl.blendFunc(gl.SRC_ALPHA, gl.ONE)
break
default:
gl.blendFunc(gl.SRC_ALPHA, gl.ONE_MINUS_SRC_ALPHA)
}
}
/**
* Get the current viewport bounds in world coordinates
* For WebGL, this is the canvas dimensions
*/
getViewportBounds(): Rectangle {
if (!this._gl) {
throw new Error("Renderer not initialized")
}
// Return the canvas bounds in screen space
// This assumes the renderer is rendering in screen space coordinates
return new Rectangle(0, 0, this._width, this._height)
}
/**
* Flush all batched draw operations
* Groups operations by paint to minimize state changes
*/
private _flushBatches(): void {
if (!this._gl) {
return
}
const batches = this._batchManager.flush()
// Process each batch
for (const batch of batches) {
// Process all operations in this batch
for (const op of batch.operations) {
// Save current transform and opacity
const savedTransform = this._currentTransform
const savedOpacity = this._currentOpacity
// Set transform and opacity for this operation
this._currentTransform = op.transform
this._currentOpacity = op.opacity
// Draw the operation
if (op.type === "path") {
this._drawPathImmediate(op.path, op.paint)
} else if (
op.type === "stroke" &&
op.strokeWidth !== undefined
) {
this._drawStrokeImmediate(op.path, op.paint, op.strokeWidth)
}
// Restore transform and opacity
this._currentTransform = savedTransform
this._currentOpacity = savedOpacity
}
}
}
/**
* Enable or disable draw call batching
*/
setBatchingEnabled(enabled: boolean): void {
this._batchingEnabled = enabled
this._batchManager.setEnabled(enabled)
// If disabling, flush any pending batches
if (!enabled) {
this._flushBatches()
}
}
/**
* Check if batching is enabled
*/
get isBatchingEnabled(): boolean {
return this._batchingEnabled
}
/**
* Get batching statistics
*/
getBatchStats(): { batchCount: number; operationCount: number } {
return {
batchCount: this._batchManager.batchCount,
operationCount: this._batchManager.operationCount,
}
}
}
// Shader source code
const PATH_VERTEX_SHADER = `
attribute vec2 a_position;
uniform mat3 u_projection;
uniform mat3 u_transform;
void main() {
vec3 pos = u_projection * u_transform * vec3(a_position, 1.0);
gl_Position = vec4(pos.xy, 0.0, 1.0);
}
`
const PATH_FRAGMENT_SHADER = `
precision mediump float;
uniform vec4 u_color;
void main() {
gl_FragColor = u_color;
}
`
const IMAGE_VERTEX_SHADER = `
attribute vec2 a_position;
attribute vec2 a_texCoord;
uniform mat3 u_projection;
varying vec2 v_texCoord;
void main() {
vec3 pos = u_projection * vec3(a_position, 1.0);
gl_Position = vec4(pos.xy, 0.0, 1.0);
v_texCoord = a_texCoord;
}
`
const IMAGE_FRAGMENT_SHADER = `
precision mediump float;
uniform sampler2D u_texture;
uniform float u_opacity;
varying vec2 v_texCoord;
void main() {
vec4 color = texture2D(u_texture, v_texCoord);
gl_FragColor = vec4(color.rgb, color.a * u_opacity);
}
`