754 lines
29 KiB
TypeScript
754 lines
29 KiB
TypeScript
/**
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* WebGL2 sprite renderer: one indexed quad batcher with per-quad tint that can
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* sample several atlas pages inside a single draw call.
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*
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* Diablo-style rendering is a flood of axis-aligned quads — floors, walls,
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* units, items — drawn in painter's order. So the renderer accumulates
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* world-space quads (position, source rectangle, tint) and submits them in as
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* few calls as it can. Depth ordering is the caller's job (draw order), not the
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* GPU's, which is how the original games did it and what keeps the batcher
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* trivial.
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*
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* Three properties keep the batch big and the CPU cost low:
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*
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* - **Multi-texture batching.** A Diablo level needs more tiles than one 2048²
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* page holds, and painter's order interleaves those pages constantly: sorting
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* by texture is not allowed, because that is exactly the order that makes the
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* scene correct. Binding one texture per batch therefore used to split the
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* frame into hundreds of draw calls (measured: up to 3077 on
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* `act4/107-act-4-lava-1`). Instead every page in flight gets its own texture
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* unit, the unit index rides along as a vertex attribute, and the fragment
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* shader picks the sampler — so painter's order survives *and* the whole frame
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* is usually one `drawElements`. Only when a batch needs more distinct pages
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* than the hardware has units does it flush and start over.
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* - **Indexed geometry.** Four vertices per quad instead of six, with a static
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* element buffer, so a third less vertex data crosses the bus per frame.
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* - **Zero-allocation vertex writes.** {@link SpriteRenderer.quad} writes the
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* vertex floats straight out, unrolled. The earlier version built four
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* throwaway arrays per quad, which at ~2800 quads a frame meant ~11k
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* short-lived objects per frame handed to the GC.
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*
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* Tint is a vertex attribute rather than a uniform, so coloured geometry
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* (a floor rectangle, a wall) batches together with sprites instead of forcing
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* a flush per colour.
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*/
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import type { AtlasFrame, SpriteAtlas } from './atlas.ts'
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/** Camera state for one frame. */
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export interface Camera {
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/** World-space centre of the view. */
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readonly x: number
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/** World-space centre of the view. */
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readonly y: number
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/** Pixels per world unit. */
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readonly zoom: number
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}
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/**
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* One uploaded atlas texture.
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*
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* Diablo II maps need more tiles than a single 2048² page holds, so the renderer
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* keeps several textures. Each quad records which page it samples; the batcher
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* assigns pages to texture units so a page switch no longer splits the batch
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* (see {@link SpriteRenderer.draw}).
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*/
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export interface AtlasHandle {
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/** The GPU texture. */
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readonly texture: WebGLTexture
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/** Texture width in pixels, for UV maths. */
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readonly width: number
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/** Texture height in pixels. */
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readonly height: number
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}
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/** Draw options for one sprite quad. */
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export interface DrawOptions {
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/** Multiplicative tint, defaulting to opaque white. */
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readonly tint?: readonly [number, number, number, number]
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/** Mirror horizontally. */
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readonly flipX?: boolean
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/** Atlas page to sample; defaults to the most recently set atlas. */
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readonly atlas?: AtlasHandle
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}
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/** Configuration options and event callbacks for SpriteRenderer. */
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export interface RendererOptions {
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/** Optional callback invoked when the WebGL context is lost. */
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readonly onContextLost?: (event: Event) => void
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/** Optional callback invoked when the WebGL context is restored. */
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readonly onContextRestored?: () => void
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}
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/** Vertices per quad: the four corners, reused by the index buffer. */
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const VERTICES_PER_QUAD = 4
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/** Indices per quad (two triangles). */
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const INDICES_PER_QUAD = 6
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/** Floats per vertex: x, y, u, v, r, g, b, a, unit. */
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const FLOATS_PER_VERTEX = 9
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/** Initial batch capacity in quads. */
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const INITIAL_CAPACITY = 8192
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/**
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* Texture units the batcher will use at most.
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*
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* WebGL2 guarantees `MAX_TEXTURE_IMAGE_UNITS >= 16`, and the packs top out at
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* ten pages for a level (`act5/109-act-5-town-townwest`) plus one character
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* atlas, so sixteen is enough to hold an entire frame's pages at once. The real
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* limit is still queried at construction and respected.
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*/
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const MAX_BATCH_TEXTURES = 16
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/**
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* Build the vertex shader.
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*
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* @returns GLSL ES 3.00 source.
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*/
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function vertexShaderSource(): string {
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return `#version 300 es
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in vec2 a_position;
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in vec2 a_uv;
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in vec4 a_tint;
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in float a_unit;
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uniform vec2 u_camera;
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uniform vec2 u_viewport;
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uniform float u_zoom;
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out vec2 v_uv;
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out vec4 v_tint;
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flat out int v_unit;
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void main() {
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vec2 offset = (a_position - u_camera) * u_zoom;
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// 'half' is a reserved word in GLSL ES 3.00, hence the longer name.
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vec2 halfViewport = u_viewport * 0.5;
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gl_Position = vec4(offset.x / halfViewport.x, -offset.y / halfViewport.y, 0.0, 1.0);
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v_uv = a_uv;
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v_tint = a_tint;
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v_unit = int(a_unit);
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}`
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}
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/**
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* Build the fragment shader for a given texture-unit count.
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*
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* GLSL ES 3.00 forbids indexing a sampler array with a non-constant expression,
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* so the sampler is picked by a `switch` over constant cases. The case list is
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* generated to match however many units the context actually offers.
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*
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* @param units - number of samplers to expose.
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* @returns GLSL ES 3.00 source.
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*/
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function fragmentShaderSource(units: number): string {
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const cases: string[] = []
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for (let unit = 1; unit < units; unit += 1) {
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cases.push(` case ${String(unit)}: texel = texture(u_textures[${String(unit)}], v_uv); break;`)
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}
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return `#version 300 es
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precision mediump float;
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in vec2 v_uv;
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in vec4 v_tint;
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flat in int v_unit;
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uniform sampler2D u_textures[${String(units)}];
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out vec4 outColor;
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void main() {
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vec4 texel;
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switch (v_unit) {
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${cases.join('\n')}
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default: texel = texture(u_textures[0], v_uv); break;
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}
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if (texel.a == 0.0) discard;
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outColor = texel * v_tint;
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}`
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}
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/** Raised when the context or program cannot be created. */
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export class RendererError extends Error {}
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/**
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* A quad batcher bound to one canvas.
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*/
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export class SpriteRenderer {
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/** The target canvas. */
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readonly canvas: HTMLCanvasElement
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/** The WebGL2 context, exposed for the few callers that need raw access. */
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readonly gl: WebGL2RenderingContext
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private readonly program: WebGLProgram
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private readonly vao: WebGLVertexArrayObject
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private readonly buffer: WebGLBuffer
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private readonly indexBuffer: WebGLBuffer
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private readonly atlasTexture: WebGLTexture
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private readonly whiteTexture: WebGLTexture
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/** The 1×1 white page used by `drawSolid`. */
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private readonly whiteAtlas: AtlasHandle
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/** The default page (what `setAtlas` uploads into). */
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private defaultAtlas: AtlasHandle
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private readonly uniformCamera: WebGLUniformLocation
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private readonly uniformViewport: WebGLUniformLocation
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private readonly uniformZoom: WebGLUniformLocation
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private readonly uniformTextures: WebGLUniformLocation
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private vertices: Float32Array
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private indices: Uint32Array
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private quadCount = 0
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private atlasWidth = 1
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private atlasHeight = 1
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/** Texture units this context offers the batcher. */
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private readonly maxBatchTextures: number
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/** Pages bound to units `0..batchTextureCount-1` for the pending batch. */
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private readonly batchTextures: (AtlasHandle | null)[]
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private batchTextureCount = 0
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private camera: Camera = { x: 0, y: 0, zoom: 1 }
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/** `drawElements` calls issued since the last {@link begin}. */
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private frameDrawCalls = 0
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/** Quads submitted since the last {@link begin}. */
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private frameQuads = 0
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/** All textures allocated and managed by this renderer. */
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private readonly allocatedTextures = new Set<WebGLTexture>()
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/** Whether this renderer has been disposed. */
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private disposed = false
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/** Listener references for cleanup. */
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private readonly handleContextLost: (event: Event) => void
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private readonly handleContextRestored: () => void
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/**
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* @param canvas - the canvas to render into.
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* @param options - optional lifecycle hooks and configuration.
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*/
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constructor(canvas: HTMLCanvasElement, options: RendererOptions = {}) {
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this.canvas = canvas
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const gl = canvas.getContext('webgl2', { alpha: false, antialias: false, premultipliedAlpha: false })
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if (gl === null) throw new RendererError('WebGL2 is not available in this browser')
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this.gl = gl
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const reportedUnits = gl.getParameter(gl.MAX_TEXTURE_IMAGE_UNITS) as number | null
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// WebGL2 guarantees at least 16; clamp to at least 1 so a stubbed context
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// (the lifecycle tests) still produces a valid shader.
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const availableUnits = typeof reportedUnits === 'number' && reportedUnits > 0 ? reportedUnits : MAX_BATCH_TEXTURES
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this.maxBatchTextures = Math.max(1, Math.min(MAX_BATCH_TEXTURES, availableUnits))
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this.batchTextures = new Array<AtlasHandle | null>(this.maxBatchTextures).fill(null)
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this.program = createProgram(gl, vertexShaderSource(), fragmentShaderSource(this.maxBatchTextures))
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const vao = gl.createVertexArray()
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const buffer = gl.createBuffer()
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const indexBuffer = gl.createBuffer()
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const atlasTexture = gl.createTexture()
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const whiteTexture = gl.createTexture()
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if (vao === null || buffer === null || indexBuffer === null || atlasTexture === null || whiteTexture === null) {
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throw new RendererError('WebGL2 resource allocation failed')
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}
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this.vao = vao
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this.buffer = buffer
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this.indexBuffer = indexBuffer
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this.atlasTexture = atlasTexture
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this.whiteTexture = whiteTexture
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this.allocatedTextures.add(atlasTexture)
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this.allocatedTextures.add(whiteTexture)
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this.defaultAtlas = { texture: atlasTexture, width: 1, height: 1 }
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this.whiteAtlas = { texture: whiteTexture, width: 1, height: 1 }
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this.vertices = new Float32Array(INITIAL_CAPACITY * VERTICES_PER_QUAD * FLOATS_PER_VERTEX)
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this.indices = buildQuadIndices(INITIAL_CAPACITY)
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const attributePosition = gl.getAttribLocation(this.program, 'a_position')
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const attributeUv = gl.getAttribLocation(this.program, 'a_uv')
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const attributeTint = gl.getAttribLocation(this.program, 'a_tint')
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const attributeUnit = gl.getAttribLocation(this.program, 'a_unit')
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gl.bindVertexArray(vao)
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gl.bindBuffer(gl.ARRAY_BUFFER, buffer)
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gl.bufferData(gl.ARRAY_BUFFER, this.vertices.byteLength, gl.DYNAMIC_DRAW)
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const stride = FLOATS_PER_VERTEX * 4
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gl.enableVertexAttribArray(attributePosition)
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gl.vertexAttribPointer(attributePosition, 2, gl.FLOAT, false, stride, 0)
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gl.enableVertexAttribArray(attributeUv)
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gl.vertexAttribPointer(attributeUv, 2, gl.FLOAT, false, stride, 8)
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gl.enableVertexAttribArray(attributeTint)
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gl.vertexAttribPointer(attributeTint, 4, gl.FLOAT, false, stride, 16)
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// A stubbed context can report -1 for an attribute it does not know about;
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// enabling that location would be an INVALID_VALUE.
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if (attributeUnit >= 0) {
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gl.enableVertexAttribArray(attributeUnit)
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gl.vertexAttribPointer(attributeUnit, 1, gl.FLOAT, false, stride, 32)
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}
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gl.bindBuffer(gl.ELEMENT_ARRAY_BUFFER, indexBuffer)
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gl.bufferData(gl.ELEMENT_ARRAY_BUFFER, this.indices, gl.STATIC_DRAW)
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gl.bindVertexArray(null)
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this.uniformCamera = requireUniform(gl, this.program, 'u_camera')
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this.uniformViewport = requireUniform(gl, this.program, 'u_viewport')
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this.uniformZoom = requireUniform(gl, this.program, 'u_zoom')
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this.uniformTextures = requireUniform(gl, this.program, 'u_textures[0]')
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// The sampler array never changes: unit i always reads texture unit i.
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const samplerUnits = new Int32Array(this.maxBatchTextures)
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for (let unit = 0; unit < this.maxBatchTextures; unit += 1) samplerUnits[unit] = unit
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gl.useProgram(this.program)
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gl.uniform1iv(this.uniformTextures, samplerUnits)
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for (const texture of [atlasTexture, whiteTexture]) {
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gl.bindTexture(gl.TEXTURE_2D, texture)
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gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.NEAREST)
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gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.NEAREST)
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gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_S, gl.CLAMP_TO_EDGE)
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gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_T, gl.CLAMP_TO_EDGE)
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}
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gl.bindTexture(gl.TEXTURE_2D, whiteTexture)
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gl.texImage2D(gl.TEXTURE_2D, 0, gl.RGBA, 1, 1, 0, gl.RGBA, gl.UNSIGNED_BYTE, new Uint8Array([255, 255, 255, 255]))
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gl.enable(gl.BLEND)
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gl.blendFunc(gl.SRC_ALPHA, gl.ONE_MINUS_SRC_ALPHA)
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gl.disable(gl.DEPTH_TEST)
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this.handleContextLost = (event: Event): void => {
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event.preventDefault()
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console.warn('WebGL2 context lost')
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options.onContextLost?.(event)
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}
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this.handleContextRestored = (): void => {
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console.info('WebGL2 context restored')
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options.onContextRestored?.()
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}
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canvas.addEventListener('webglcontextlost', this.handleContextLost)
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canvas.addEventListener('webglcontextrestored', this.handleContextRestored)
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}
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/** Whether this renderer and its GPU resources have been disposed. */
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get isDisposed(): boolean {
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return this.disposed
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}
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/**
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* Draw calls issued since the last {@link begin}.
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*
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* This is the real measured count, not an estimate: the HUD used to report a
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* hardcoded `1` while the frame was actually spending hundreds of calls, which
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* is precisely why the cost stayed invisible.
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*/
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get drawCalls(): number {
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return this.frameDrawCalls
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}
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/** Quads submitted since the last {@link begin}. */
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get quadsSubmitted(): number {
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return this.frameQuads
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}
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/** Texture units this batcher can bind at once. */
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get textureUnits(): number {
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return this.maxBatchTextures
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}
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/**
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* Upload an atlas, replacing the current one.
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*
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* @param atlas - the packed atlas.
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* @returns the handle other pages can be drawn with.
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*/
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setAtlas(atlas: SpriteAtlas): AtlasHandle {
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if (this.disposed) throw new RendererError('SpriteRenderer has already been disposed')
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const gl = this.gl
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// Uploading past the limit is a silent INVALID_VALUE in GL; say what
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// actually went wrong instead.
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const limit = gl.getParameter(gl.MAX_TEXTURE_SIZE) as number
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if (atlas.width > limit || atlas.height > limit) {
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throw new RendererError(
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`atlas ${String(atlas.width)}x${String(atlas.height)} exceeds the ${String(limit)}px texture limit`,
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)
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}
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this.flush()
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gl.bindTexture(gl.TEXTURE_2D, this.atlasTexture)
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gl.pixelStorei(gl.UNPACK_ALIGNMENT, 1)
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gl.texImage2D(
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gl.TEXTURE_2D, 0, gl.RGBA, atlas.width, atlas.height, 0,
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gl.RGBA, gl.UNSIGNED_BYTE, new Uint8Array(atlas.pixels.buffer, atlas.pixels.byteOffset, atlas.pixels.byteLength),
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)
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this.atlasWidth = Math.max(atlas.width, 1)
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this.atlasHeight = Math.max(atlas.height, 1)
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this.defaultAtlas = { texture: this.atlasTexture, width: this.atlasWidth, height: this.atlasHeight }
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return this.defaultAtlas
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}
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/**
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* Upload an extra atlas page and return a handle for it.
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*
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* Packed maps ship several pages; the page can load the ones the spawn area
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* needs first and hand them over as they arrive, instead of waiting for one
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* gigantic texture to decode.
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*
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* @param source - decoded pixels or an `ImageBitmap` (PNG straight from cache).
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* @param width - page width in pixels.
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* @param height - page height in pixels.
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* @returns the handle to pass to {@link draw}.
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*/
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addAtlas(
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source: ImageBitmap | { pixels: Uint8ClampedArray | Uint8Array; width: number; height: number },
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width?: number,
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height?: number,
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): AtlasHandle {
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if (this.disposed) throw new RendererError('SpriteRenderer has already been disposed')
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const gl = this.gl
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const limit = gl.getParameter(gl.MAX_TEXTURE_SIZE) as number
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const isBitmap = typeof ImageBitmap !== 'undefined' && source instanceof ImageBitmap
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const sourceWidth = isBitmap ? (source as ImageBitmap).width : (source as { width: number }).width
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const sourceHeight = isBitmap ? (source as ImageBitmap).height : (source as { height: number }).height
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const pageWidth = Math.max(1, width ?? sourceWidth)
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const pageHeight = Math.max(1, height ?? sourceHeight)
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if (pageWidth > limit || pageHeight > limit) {
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throw new RendererError(`atlas ${String(pageWidth)}x${String(pageHeight)} exceeds the ${String(limit)}px texture limit`)
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}
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this.flush()
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const texture = gl.createTexture()
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if (texture === null) throw new RendererError('texture allocation failed')
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this.allocatedTextures.add(texture)
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gl.bindTexture(gl.TEXTURE_2D, texture)
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gl.pixelStorei(gl.UNPACK_ALIGNMENT, 1)
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gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.NEAREST)
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gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.NEAREST)
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gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_S, gl.CLAMP_TO_EDGE)
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gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_T, gl.CLAMP_TO_EDGE)
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if (isBitmap) {
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gl.texImage2D(gl.TEXTURE_2D, 0, gl.RGBA, gl.RGBA, gl.UNSIGNED_BYTE, source as ImageBitmap)
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} else {
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const indexed = source as { pixels: Uint8ClampedArray | Uint8Array; width: number; height: number }
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const pixels = indexed.pixels instanceof Uint8Array
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? indexed.pixels
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: new Uint8Array(indexed.pixels.buffer, indexed.pixels.byteOffset, indexed.pixels.byteLength)
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gl.texImage2D(
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gl.TEXTURE_2D, 0, gl.RGBA, indexed.width, indexed.height, 0,
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gl.RGBA, gl.UNSIGNED_BYTE, pixels,
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)
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}
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return { texture, width: pageWidth, height: pageHeight }
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}
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/**
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* Release an atlas texture handle and free its GPU memory.
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*
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* @param handle - the atlas handle previously returned by addAtlas or setAtlas.
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* @returns true if the texture was managed by this renderer and deleted, false otherwise.
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*/
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deleteAtlas(handle: AtlasHandle): boolean {
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if (this.disposed || handle === this.whiteAtlas) return false
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if (!this.allocatedTextures.has(handle.texture)) return false
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// Quads already queued may reference this page's unit, so they have to go
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// out before the texture disappears.
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for (let unit = 0; unit < this.batchTextureCount; unit += 1) {
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||
if (this.batchTextures[unit] === handle) {
|
||
this.flush()
|
||
break
|
||
}
|
||
}
|
||
if (this.defaultAtlas === handle) {
|
||
this.defaultAtlas = this.whiteAtlas
|
||
}
|
||
|
||
if (!this.gl.isContextLost()) {
|
||
this.gl.deleteTexture(handle.texture)
|
||
}
|
||
this.allocatedTextures.delete(handle.texture)
|
||
return true
|
||
}
|
||
|
||
/** The page `setAtlas` uploaded into, for callers that draw with handles. */
|
||
get defaultAtlasHandle(): AtlasHandle {
|
||
return this.defaultAtlas
|
||
}
|
||
|
||
/**
|
||
* Start a frame: clear, and record the camera.
|
||
*
|
||
* @param camera - camera to render with.
|
||
* @param clear - background colour as `[r, g, b]` in 0..1.
|
||
*/
|
||
begin(camera: Camera, clear: readonly [number, number, number] = [0, 0, 0]): void {
|
||
if (this.disposed) throw new RendererError('SpriteRenderer has already been disposed')
|
||
const gl = this.gl
|
||
this.camera = camera
|
||
this.quadCount = 0
|
||
this.batchTextureCount = 0
|
||
this.frameDrawCalls = 0
|
||
this.frameQuads = 0
|
||
gl.viewport(0, 0, gl.drawingBufferWidth, gl.drawingBufferHeight)
|
||
gl.clearColor(clear[0], clear[1], clear[2], 1)
|
||
gl.clear(gl.COLOR_BUFFER_BIT)
|
||
}
|
||
|
||
/**
|
||
* Queue one atlas sprite.
|
||
*
|
||
* @param frame - the atlas placement to draw.
|
||
* @param x - world-space left edge.
|
||
* @param y - world-space top edge.
|
||
* @param options - tint and flipping.
|
||
*/
|
||
draw(frame: AtlasFrame, x: number, y: number, options: DrawOptions = {}): void {
|
||
if (this.disposed) return
|
||
const page = options.atlas ?? this.defaultAtlas
|
||
const unit = this.unitFor(page)
|
||
const u0 = frame.x / page.width
|
||
const v0 = frame.y / page.height
|
||
const u1 = (frame.x + frame.width) / page.width
|
||
const v1 = (frame.y + frame.height) / page.height
|
||
const tint = options.tint
|
||
const flipped = options.flipX === true
|
||
this.quad(
|
||
x, y, x + frame.width, y + frame.height,
|
||
flipped ? u1 : u0, v0,
|
||
flipped ? u0 : u1, v1,
|
||
tint === undefined ? 1 : tint[0],
|
||
tint === undefined ? 1 : tint[1],
|
||
tint === undefined ? 1 : tint[2],
|
||
tint === undefined ? 1 : tint[3],
|
||
unit,
|
||
)
|
||
}
|
||
|
||
/**
|
||
* Queue one solid-colour rectangle.
|
||
*
|
||
* @param x - world-space left edge.
|
||
* @param y - world-space top edge.
|
||
* @param width - rectangle width.
|
||
* @param height - rectangle height.
|
||
* @param color - `[r, g, b, a]` in 0..1.
|
||
*/
|
||
drawSolid(x: number, y: number, width: number, height: number, color: readonly [number, number, number, number]): void {
|
||
if (this.disposed) return
|
||
const unit = this.unitFor(this.whiteAtlas)
|
||
this.quad(x, y, x + width, y + height, 0.5, 0.5, 0.5, 0.5, color[0], color[1], color[2], color[3], unit)
|
||
}
|
||
|
||
/**
|
||
* Find the texture unit a page is bound to for the pending batch, binding it
|
||
* to a free unit if this is its first quad.
|
||
*
|
||
* Running out of units is the only thing that still splits a batch, and with
|
||
* sixteen of them against a ten-page worst case that effectively never
|
||
* happens for a map.
|
||
*
|
||
* @param page - the atlas page the caller wants to sample.
|
||
* @returns the texture unit index to write into the vertices.
|
||
*/
|
||
private unitFor(page: AtlasHandle): number {
|
||
const count = this.batchTextureCount
|
||
for (let unit = 0; unit < count; unit += 1) {
|
||
if (this.batchTextures[unit] === page) return unit
|
||
}
|
||
if (count === this.maxBatchTextures) {
|
||
this.flush()
|
||
this.batchTextures[0] = page
|
||
this.batchTextureCount = 1
|
||
return 0
|
||
}
|
||
this.batchTextures[count] = page
|
||
this.batchTextureCount = count + 1
|
||
return count
|
||
}
|
||
|
||
/**
|
||
* Append one quad's four vertices.
|
||
*
|
||
* Written out longhand on purpose: the readable loop-over-temporary-arrays
|
||
* version allocated four arrays per quad, and at a few thousand quads a frame
|
||
* that dominated the CPU side of the frame (measured 2.3× slower).
|
||
*
|
||
* @param x0 - left edge.
|
||
* @param y0 - top edge.
|
||
* @param x1 - right edge.
|
||
* @param y1 - bottom edge.
|
||
* @param u0 - left texture coordinate.
|
||
* @param v0 - top texture coordinate.
|
||
* @param u1 - right texture coordinate.
|
||
* @param v1 - bottom texture coordinate.
|
||
* @param r - tint red.
|
||
* @param g - tint green.
|
||
* @param b - tint blue.
|
||
* @param a - tint alpha.
|
||
* @param unit - texture unit to sample.
|
||
*/
|
||
private quad(
|
||
x0: number, y0: number, x1: number, y1: number,
|
||
u0: number, v0: number, u1: number, v1: number,
|
||
r: number, g: number, b: number, a: number,
|
||
unit: number,
|
||
): void {
|
||
const needed = (this.quadCount + 1) * VERTICES_PER_QUAD * FLOATS_PER_VERTEX
|
||
if (needed > this.vertices.length) this.grow(needed)
|
||
const v = this.vertices
|
||
let at = this.quadCount * VERTICES_PER_QUAD * FLOATS_PER_VERTEX
|
||
// Corner 0: top-left.
|
||
v[at] = x0; v[at + 1] = y0; v[at + 2] = u0; v[at + 3] = v0
|
||
v[at + 4] = r; v[at + 5] = g; v[at + 6] = b; v[at + 7] = a; v[at + 8] = unit
|
||
at += FLOATS_PER_VERTEX
|
||
// Corner 1: top-right.
|
||
v[at] = x1; v[at + 1] = y0; v[at + 2] = u1; v[at + 3] = v0
|
||
v[at + 4] = r; v[at + 5] = g; v[at + 6] = b; v[at + 7] = a; v[at + 8] = unit
|
||
at += FLOATS_PER_VERTEX
|
||
// Corner 2: bottom-left.
|
||
v[at] = x0; v[at + 1] = y1; v[at + 2] = u0; v[at + 3] = v1
|
||
v[at + 4] = r; v[at + 5] = g; v[at + 6] = b; v[at + 7] = a; v[at + 8] = unit
|
||
at += FLOATS_PER_VERTEX
|
||
// Corner 3: bottom-right.
|
||
v[at] = x1; v[at + 1] = y1; v[at + 2] = u1; v[at + 3] = v1
|
||
v[at + 4] = r; v[at + 5] = g; v[at + 6] = b; v[at + 7] = a; v[at + 8] = unit
|
||
this.quadCount += 1
|
||
this.frameQuads += 1
|
||
}
|
||
|
||
/** Submit every queued quad. */
|
||
flush(): void {
|
||
const gl = this.gl
|
||
if (this.disposed || this.quadCount === 0) return
|
||
const floatCount = this.quadCount * VERTICES_PER_QUAD * FLOATS_PER_VERTEX
|
||
gl.useProgram(this.program)
|
||
gl.bindVertexArray(this.vao)
|
||
gl.bindBuffer(gl.ARRAY_BUFFER, this.buffer)
|
||
// Orphan first: without it the driver has to wait until the GPU is done
|
||
// reading the range this overwrites, which is a pipeline stall on every
|
||
// flush. Handing back a fresh block lets both sides run.
|
||
gl.bufferData(gl.ARRAY_BUFFER, this.vertices.byteLength, gl.DYNAMIC_DRAW)
|
||
gl.bufferSubData(gl.ARRAY_BUFFER, 0, this.vertices, 0, floatCount)
|
||
gl.uniform2f(this.uniformCamera, this.camera.x, this.camera.y)
|
||
gl.uniform2f(this.uniformViewport, gl.drawingBufferWidth, gl.drawingBufferHeight)
|
||
gl.uniform1f(this.uniformZoom, this.camera.zoom)
|
||
for (let unit = 0; unit < this.batchTextureCount; unit += 1) {
|
||
const page = this.batchTextures[unit]
|
||
if (page === undefined || page === null) continue
|
||
gl.activeTexture(gl.TEXTURE0 + unit)
|
||
gl.bindTexture(gl.TEXTURE_2D, page.texture)
|
||
}
|
||
gl.drawElements(gl.TRIANGLES, this.quadCount * INDICES_PER_QUAD, gl.UNSIGNED_INT, 0)
|
||
this.frameDrawCalls += 1
|
||
this.quadCount = 0
|
||
this.batchTextureCount = 0
|
||
}
|
||
|
||
/**
|
||
* Destroy all WebGL2 GPU resources (textures, VAO, VBO, program) and detach event listeners.
|
||
*/
|
||
dispose(): void {
|
||
if (this.disposed) return
|
||
this.disposed = true
|
||
|
||
this.canvas.removeEventListener('webglcontextlost', this.handleContextLost)
|
||
this.canvas.removeEventListener('webglcontextrestored', this.handleContextRestored)
|
||
|
||
const gl = this.gl
|
||
if (!gl.isContextLost()) {
|
||
for (const texture of this.allocatedTextures) {
|
||
gl.deleteTexture(texture)
|
||
}
|
||
this.allocatedTextures.clear()
|
||
gl.deleteBuffer(this.buffer)
|
||
gl.deleteBuffer(this.indexBuffer)
|
||
gl.deleteVertexArray(this.vao)
|
||
gl.deleteProgram(this.program)
|
||
} else {
|
||
this.allocatedTextures.clear()
|
||
}
|
||
this.quadCount = 0
|
||
this.batchTextureCount = 0
|
||
}
|
||
|
||
/**
|
||
* Grow the vertex and index buffers, preserving queued geometry.
|
||
*
|
||
* @param needed - required float count.
|
||
*/
|
||
private grow(needed: number): void {
|
||
let capacity = this.vertices.length
|
||
while (capacity < needed) capacity *= 2
|
||
const grown = new Float32Array(capacity)
|
||
grown.set(this.vertices)
|
||
this.vertices = grown
|
||
const quads = Math.floor(capacity / (VERTICES_PER_QUAD * FLOATS_PER_VERTEX))
|
||
this.indices = buildQuadIndices(quads)
|
||
const gl = this.gl
|
||
gl.bindVertexArray(this.vao)
|
||
gl.bindBuffer(gl.ARRAY_BUFFER, this.buffer)
|
||
gl.bufferData(gl.ARRAY_BUFFER, grown.byteLength, gl.DYNAMIC_DRAW)
|
||
gl.bindBuffer(gl.ELEMENT_ARRAY_BUFFER, this.indexBuffer)
|
||
gl.bufferData(gl.ELEMENT_ARRAY_BUFFER, this.indices, gl.STATIC_DRAW)
|
||
gl.bindVertexArray(null)
|
||
}
|
||
}
|
||
|
||
/**
|
||
* Build the static index buffer contents for a quad capacity.
|
||
*
|
||
* Every quad is two triangles over its four corners: top-left, top-right,
|
||
* bottom-left and bottom-right, wound the same way the old six-vertex layout
|
||
* was so nothing about the rasterised result changes.
|
||
*
|
||
* @param quads - number of quads to cover.
|
||
* @returns indices, `6 * quads` long.
|
||
*/
|
||
function buildQuadIndices(quads: number): Uint32Array {
|
||
const indices = new Uint32Array(quads * INDICES_PER_QUAD)
|
||
for (let quad = 0; quad < quads; quad += 1) {
|
||
const vertex = quad * VERTICES_PER_QUAD
|
||
const at = quad * INDICES_PER_QUAD
|
||
indices[at] = vertex
|
||
indices[at + 1] = vertex + 1
|
||
indices[at + 2] = vertex + 2
|
||
indices[at + 3] = vertex + 1
|
||
indices[at + 4] = vertex + 3
|
||
indices[at + 5] = vertex + 2
|
||
}
|
||
return indices
|
||
}
|
||
|
||
/**
|
||
* Compile and link a program, reporting shader logs on failure.
|
||
*
|
||
* Shaders are detached and flagged for deletion immediately after linking to
|
||
* prevent driver-level memory leaks.
|
||
*
|
||
* @param gl - the context.
|
||
* @param vertexSource - vertex shader source.
|
||
* @param fragmentSource - fragment shader source.
|
||
* @returns the linked program.
|
||
*/
|
||
function createProgram(gl: WebGL2RenderingContext, vertexSource: string, fragmentSource: string): WebGLProgram {
|
||
const compile = (type: number, source: string): WebGLShader => {
|
||
const shader = gl.createShader(type)
|
||
if (shader === null) throw new RendererError('could not create shader')
|
||
gl.shaderSource(shader, source)
|
||
gl.compileShader(shader)
|
||
if (gl.getShaderParameter(shader, gl.COMPILE_STATUS) !== true) {
|
||
const log = gl.getShaderInfoLog(shader) ?? 'unknown'
|
||
gl.deleteShader(shader)
|
||
throw new RendererError(`shader compile failed: ${log}`)
|
||
}
|
||
return shader
|
||
}
|
||
const program = gl.createProgram()
|
||
if (program === null) throw new RendererError('could not create program')
|
||
const vs = compile(gl.VERTEX_SHADER, vertexSource)
|
||
const fs = compile(gl.FRAGMENT_SHADER, fragmentSource)
|
||
gl.attachShader(program, vs)
|
||
gl.attachShader(program, fs)
|
||
gl.linkProgram(program)
|
||
const linked = gl.getProgramParameter(program, gl.LINK_STATUS) === true
|
||
const log = linked ? '' : (gl.getProgramInfoLog(program) ?? 'unknown')
|
||
gl.detachShader(program, vs)
|
||
gl.deleteShader(vs)
|
||
gl.detachShader(program, fs)
|
||
gl.deleteShader(fs)
|
||
if (!linked) {
|
||
gl.deleteProgram(program)
|
||
throw new RendererError(`program link failed: ${log}`)
|
||
}
|
||
return program
|
||
}
|
||
|
||
/**
|
||
* Fetch a uniform location or fail loudly.
|
||
*
|
||
* @param gl - the context.
|
||
* @param program - the linked program.
|
||
* @param name - uniform name.
|
||
* @returns the location.
|
||
*/
|
||
function requireUniform(gl: WebGL2RenderingContext, program: WebGLProgram, name: string): WebGLUniformLocation {
|
||
const location = gl.getUniformLocation(program, name)
|
||
if (location === null) throw new RendererError(`uniform ${name} is missing from the program`)
|
||
return location
|
||
}
|