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import type { Dictionary } from "./util";
import type { Shader, UniformMatrix3fv } from "./shader";
import { Texture } from "./texture";
import { DefaultRenderable } from "./renderer";
import { IndexBuffer, VertexBuffer } from "./buffer";
import { VertexBufferLayout, VertexArray } from "./vertexBufferLayout";
import { fontPng } from "../assets";
export enum Align {
Begin,
End,
Middle,
}
export class GlypInfo {
x: number;
y: number;
width: number;
}
export class FontInfo {
letterHeight: number;
spaceWidth: number;
spacing: number;
textureWidth: number;
textureHeight: number;
glyphInfos: Dictionary<GlypInfo>;
}
export class LabelFactory {
texture: Texture;
font: FontInfo;
shader: Shader;
constructor(gl: WebGLRenderingContext, loc: string, font: FontInfo, shader: Shader) {
this.texture = Texture.fromImage(gl, loc, 'font');
this.font = font;
this.shader = shader;
}
build(gl: WebGLRenderingContext, transform?: UniformMatrix3fv): Label {
return new Label(gl, this.shader, this.texture, this.font, transform);
}
}
export class Label {
inner: DefaultRenderable;
font: FontInfo;
constructor(gl: WebGLRenderingContext, shader: Shader, tex: Texture, font: FontInfo, transform?: UniformMatrix3fv) {
this.font = font;
const uniforms = transform ? { "u_trans": transform, "u_trans_next": transform, } : {};
const ib = new IndexBuffer(gl, []);
const vb_pos = new VertexBuffer(gl, []);
const vb_tex = new VertexBuffer(gl, []);
const layout_pos = new VertexBufferLayout();
layout_pos.push(gl.FLOAT, 2, 4, "a_position");
const layout_tex = new VertexBufferLayout();
layout_tex.push(gl.FLOAT, 2, 4, "a_texCoord");
const vao = new VertexArray();
vao.addBuffer(vb_pos, layout_pos);
vao.addBuffer(vb_tex, layout_tex);
this.inner = new DefaultRenderable(ib, vao, shader, [tex], uniforms);
}
getRenderable(): DefaultRenderable {
return this.inner;
}
setText(gl: WebGLRenderingContext, text: string, h_align = Align.Begin, v_align = Align.Begin) {
const idxs = [];
const verts_pos = [];
const verts_tex = [];
let xPos = 0;
switch (h_align) {
case Align.Begin:
break;
case Align.End:
xPos = -1 * [...text].map(n => this.font.glyphInfos[n] ? this.font.glyphInfos[n].width : this.font.spaceWidth).reduce((a, b) => a + b, 0) / this.font.letterHeight;
break;
case Align.Middle:
xPos = -1 * [...text].map(n => this.font.glyphInfos[n] ? this.font.glyphInfos[n].width : this.font.spaceWidth).reduce((a, b) => a + b, 0) / this.font.letterHeight / 2;
break;
}
let yStart = 0;
switch (v_align) {
case Align.Begin:
break;
case Align.End:
yStart = 1;
break;
case Align.Middle:
yStart = 0.5;
break;
}
let j = 0;
for (let i = 0; i < text.length; i++) {
const info = this.font.glyphInfos[text[i]];
if (info) {
const dx = info.width / this.font.letterHeight;
// apply half-pixel correction to prevent texture bleeding
// we should address the center of each texel, not the border
// https://gamedev.stackexchange.com/questions/46963/how-to-avoid-texture-bleeding-in-a-texture-atlas
const x0 = (info.x + 0.5) / this.font.textureWidth;
const y0 = (info.y + 0.5) / this.font.textureHeight;
const letterWidth = (info.width - 1) / this.font.textureWidth;
const letterHeight = (this.font.letterHeight - 1) / this.font.textureHeight;
verts_pos.push(xPos, yStart);
verts_pos.push(xPos + dx, yStart);
verts_pos.push(xPos, yStart-1);
verts_pos.push(xPos + dx, yStart-1);
verts_tex.push(x0, y0);
verts_tex.push(x0 + letterWidth, y0);
verts_tex.push(x0, y0 + letterHeight);
verts_tex.push(x0 + letterWidth, y0 + letterHeight);
xPos += dx;
idxs.push(j+0, j+1, j+2, j+1, j+2, j+3);
j += 4;
} else {
// Just move xPos
xPos += this.font.spaceWidth / this.font.letterHeight;
}
}
this.inner.updateIndexBuffer(gl, idxs);
this.inner.updateVAOBuffer(gl, 0, verts_pos);
this.inner.updateVAOBuffer(gl, 1, verts_tex);
}
}
export function defaultLabelFactory(gl: WebGLRenderingContext, shader: Shader): LabelFactory {
const fontInfo = {
letterHeight: 8,
spaceWidth: 8,
spacing: -1,
textureWidth: 64,
textureHeight: 40,
glyphInfos: {
'a': { x: 0, y: 0, width: 8, },
'b': { x: 8, y: 0, width: 8, },
'c': { x: 16, y: 0, width: 8, },
'd': { x: 24, y: 0, width: 8, },
'e': { x: 32, y: 0, width: 8, },
'f': { x: 40, y: 0, width: 8, },
'g': { x: 48, y: 0, width: 8, },
'h': { x: 56, y: 0, width: 8, },
'i': { x: 0, y: 8, width: 8, },
'j': { x: 8, y: 8, width: 8, },
'k': { x: 16, y: 8, width: 8, },
'l': { x: 24, y: 8, width: 8, },
'm': { x: 32, y: 8, width: 8, },
'n': { x: 40, y: 8, width: 8, },
'o': { x: 48, y: 8, width: 8, },
'p': { x: 56, y: 8, width: 8, },
'q': { x: 0, y: 16, width: 8, },
'r': { x: 8, y: 16, width: 8, },
's': { x: 16, y: 16, width: 8, },
't': { x: 24, y: 16, width: 8, },
'u': { x: 32, y: 16, width: 8, },
'v': { x: 40, y: 16, width: 8, },
'w': { x: 48, y: 16, width: 8, },
'x': { x: 56, y: 16, width: 8, },
'y': { x: 0, y: 24, width: 8, },
'z': { x: 8, y: 24, width: 8, },
'0': { x: 16, y: 24, width: 8, },
'1': { x: 24, y: 24, width: 8, },
'2': { x: 32, y: 24, width: 8, },
'3': { x: 40, y: 24, width: 8, },
'4': { x: 48, y: 24, width: 8, },
'5': { x: 56, y: 24, width: 8, },
'6': { x: 0, y: 32, width: 8, },
'7': { x: 8, y: 32, width: 8, },
'8': { x: 16, y: 32, width: 8, },
'9': { x: 24, y: 32, width: 8, },
'-': { x: 32, y: 32, width: 8, },
'*': { x: 40, y: 32, width: 8, },
'!': { x: 48, y: 32, width: 8, },
'?': { x: 56, y: 32, width: 8, },
},
};
return new LabelFactory(gl, fontPng, fontInfo, shader);
}
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