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import { Shaders } from './shaders';
import { mat4, vec2 } from 'gl-matrix';
export class Renderer {
public readonly coordScale = 32;
private readonly viewScale = 2;
private readonly gl: WebGLRenderingContext;
private readonly shaders: Shaders;
private readonly center: vec2 = vec2.create();
private readonly translation: vec2 = vec2.create();
private readonly viewport: mat4 = mat4.create();
constructor(private readonly canvas: HTMLCanvasElement) {
this.gl = this.mkContext();
this.shaders = new Shaders(this.gl);
this.gl.clearColor(0.0, 0.0, 0.0, 1.0);
this.gl.enable(this.gl.BLEND);
this.gl.blendFunc(this.gl.ONE, this.gl.ONE_MINUS_SRC_ALPHA);
this.gl.pixelStorei(this.gl.UNPACK_PREMULTIPLY_ALPHA_WEBGL, 1);
this.setSize();
}
public createBuffer(): WebGLBuffer {
const ret = this.gl.createBuffer();
if (!ret)
throw new Error('unable to create buffer');
return ret;
}
public getContext(): WebGLRenderingContext {
return this.gl;
}
public getVertexPosLoc(): number {
return this.shaders.vertexPosLoc;
}
public getTextureCoordLoc(): number {
return this.shaders.textureCoordLoc;
}
public getSamplerLoc(): WebGLUniformLocation {
return this.shaders.samplerLoc;
}
public setCenter(v: vec2|number[]) {
this.snapToGrid(this.center, v);
}
public setTranslation(v: vec2|number[]) {
vec2.sub(this.translation, v, this.center);
this.snapToGrid(this.translation, this.translation);
this.gl.uniform2fv(this.shaders.translateLoc, this.translation);
}
public clear(): void {
this.gl.clear(this.gl.COLOR_BUFFER_BIT);
this.setTranslation([0, 0]);
}
public snapToGrid(out: vec2, a: vec2|number[]): void {
vec2.scale(out, a, this.coordScale);
vec2.round(out, out);
vec2.scale(out, out, 1 / this.coordScale);
}
private mkContext(): WebGLRenderingContext {
const gl = (
this.canvas.getContext('webgl') || this.canvas.getContext('experimental-webgl')
);
if (!gl)
throw new Error('unable to initialize WebGL context');
return gl;
}
private setSize(): void {
const w = this.canvas.width;
const h = this.canvas.height;
this.gl.viewport(0, 0, w, h);
this.clear();
const scale = this.viewScale * this.coordScale;
mat4.identity(this.viewport);
mat4.scale(this.viewport, this.viewport, [2 * scale / w, -2 * scale / h, 1.0]);
this.gl.uniformMatrix4fv(this.shaders.viewportLoc, false, this.viewport);
}
}
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