轻量封装WebGPU渲染系统示例＜11＞- WebGP实现的简单PBR效果(源码)

当前示例源码github地址:

https://github.com/vilyLei/voxwebgpu/blob/main/src/voxgpu/sample/SimplePBRTest.ts

此示例渲染系统实现的特性:

1. 用户态与系统态隔离。

2. 高频调用与低频调用隔离。

3. 面向用户的易用性封装。

4. 渲染数据和渲染机制分离。

5. 用户操作和渲染系统调度并行机制。

当前示例运行效果:

顶点shader:

@group(0) @binding(0) var objMat : mat4x4;
@group(0) @binding(1) var viewMat : mat4x4;
@group(0) @binding(2) var projMat : mat4x4;

struct VertexOutput {
  @builtin(position) Position : vec4,
  @location(0) pos: vec4,
  @location(1) uv : vec2,
  @location(2) normal : vec3,
  @location(3) camPos : vec3
}

fn inverseM33(m: mat3x3)-> mat3x3 {
    let a00 = m[0][0]; let a01 = m[0][1]; let a02 = m[0][2];
    let a10 = m[1][0]; let a11 = m[1][1]; let a12 = m[1][2];
    let a20 = m[2][0]; let a21 = m[2][1]; let a22 = m[2][2];
    let b01 = a22 * a11 - a12 * a21;
    let b11 = -a22 * a10 + a12 * a20;
    let b21 = a21 * a10 - a11 * a20;
    let det = a00 * b01 + a01 * b11 + a02 * b21;
    return mat3x3(
		vec3(b01, (-a22 * a01 + a02 * a21), (a12 * a01 - a02 * a11)) / det,
                vec3(b11, (a22 * a00 - a02 * a20), (-a12 * a00 + a02 * a10)) / det,
                vec3(b21, (-a21 * a00 + a01 * a20), (a11 * a00 - a01 * a10)) / det);
}
fn m44ToM33(m: mat4x4) -> mat3x3 {
	return mat3x3(m[0].xyz, m[1].xyz, m[2].xyz);
}

fn inverseM44(m: mat4x4)-> mat4x4 {
    let a00 = m[0][0]; let a01 = m[0][1]; let a02 = m[0][2]; let a03 = m[0][3];
    let a10 = m[1][0]; let a11 = m[1][1]; let a12 = m[1][2]; let a13 = m[1][3];
    let a20 = m[2][0]; let a21 = m[2][1]; let a22 = m[2][2]; let a23 = m[2][3];
    let a30 = m[3][0]; let a31 = m[3][1]; let a32 = m[3][2]; let a33 = m[3][3];
    let b00 = a00 * a11 - a01 * a10;
    let b01 = a00 * a12 - a02 * a10;
    let b02 = a00 * a13 - a03 * a10;
    let b03 = a01 * a12 - a02 * a11;
    let b04 = a01 * a13 - a03 * a11;
    let b05 = a02 * a13 - a03 * a12;
    let b06 = a20 * a31 - a21 * a30;
    let b07 = a20 * a32 - a22 * a30;
    let b08 = a20 * a33 - a23 * a30;
    let b09 = a21 * a32 - a22 * a31;
    let b10 = a21 * a33 - a23 * a31;
    let b11 = a22 * a33 - a23 * a32;
    let det = b00 * b11 - b01 * b10 + b02 * b09 + b03 * b08 - b04 * b07 + b05 * b06;
	return mat4x4(
		vec4(a11 * b11 - a12 * b10 + a13 * b09,
		a02 * b10 - a01 * b11 - a03 * b09,
		a31 * b05 - a32 * b04 + a33 * b03,
		a22 * b04 - a21 * b05 - a23 * b03) / det,
			vec4(a12 * b08 - a10 * b11 - a13 * b07,
		a00 * b11 - a02 * b08 + a03 * b07,
		a32 * b02 - a30 * b05 - a33 * b01,
		a20 * b05 - a22 * b02 + a23 * b01) / det,
		vec4(a10 * b10 - a11 * b08 + a13 * b06,
		a01 * b08 - a00 * b10 - a03 * b06,
		a30 * b04 - a31 * b02 + a33 * b00,
		a21 * b02 - a20 * b04 - a23 * b00) / det,
		vec4(a11 * b07 - a10 * b09 - a12 * b06,
		a00 * b09 - a01 * b07 + a02 * b06,
		a31 * b01 - a30 * b03 - a32 * b00,
		a20 * b03 - a21 * b01 + a22 * b00) / det);
}
@vertex
fn main(
  @location(0) position : vec3,
  @location(1) uv : vec2,
  @location(2) normal : vec3
) -> VertexOutput {
  let wpos = objMat * vec4(position.xyz, 1.0);
  var output : VertexOutput;
  output.Position = projMat * viewMat * wpos;
  output.uv = uv;

  let invMat33 = inverseM33( m44ToM33( objMat ) );
  output.normal = normalize( normal * invMat33 );
  output.camPos = (inverseM44(viewMat) * vec4(0.0,0.0,0.0, 1.0)).xyz;
  output.pos = wpos;
  return output;
}

片段shader:

@group(0) @binding(3) var albedo: vec4f;
@group(0) @binding(4) var param: vec4f;

const PI = 3.141592653589793;
const PI2 = 6.283185307179586;
const PI_HALF = 1.5707963267948966;
const RECIPROCAL_PI = 0.3183098861837907;
const RECIPROCAL_PI2 = 0.15915494309189535;
const EPSILON = 1e-6;

fn approximationSRGBToLinear(srgbColor: vec3) -> vec3 {
    return pow(srgbColor, vec3(2.2));
}
fn approximationLinearToSRCB(linearColor: vec3) -> vec3 {
    return pow(linearColor, vec3(1.0/2.2));
}

fn accurateSRGBToLinear(srgbColor: vec3) -> vec3 {
    let linearRGBLo = srgbColor / 12.92;
    let linearRGBHi = pow((srgbColor + vec3(0.055)) / vec3(1.055), vec3(2.4));
	if( all( srgbColor <= vec3(0.04045) ) ) {
		return linearRGBLo;
	}
    return linearRGBHi;
}
fn accurateLinearToSRGB(linearColor: vec3) -> vec3 {
    let srgbLo = linearColor * 12.92;
    let srgbHi = (pow(abs(linearColor), vec3(1.0 / 2.4)) * 1.055) - 0.055;
    if(all(linearColor <= vec3(0.0031308))) {
		return srgbLo;
	}
    return srgbHi;
}

// Trowbridge-Reitz(Generalized-Trowbridge-Reitz,GTR)
fn DistributionGTR1(NdotH: f32, roughness: f32) -> f32 {
    if (roughness >= 1.0) {
		return 1.0/PI;
	}
    let a2 = roughness * roughness;
    let t = 1.0 + (a2 - 1.0)*NdotH*NdotH;
    return (a2 - 1.0) / (PI * log(a2) *t);
}
fn DistributionGTR2(NdotH: f32, roughness: f32) -> f32 {
    let a2 = roughness * roughness;
    let t = 1.0 + (a2 - 1.0) * NdotH * NdotH;
    return a2 / (PI * t * t);
}


fn DistributionGGX(N: vec3, H: vec3, roughness: f32) -> f32 {
    let a = roughness*roughness;
    let a2 = a*a;
    let NdotH = max(dot(N, H), 0.0);
    let NdotH2 = NdotH*NdotH;

    let nom   = a2;
    var denom = (NdotH2 * (a2 - 1.0) + 1.0);
    denom = PI * denom * denom;

    return nom / max(denom, 0.0000001); // prevent divide by zero for roughness=0.0 and NdotH=1.0
}


fn GeometryImplicit(NdotV: f32, NdotL: f32) -> f32 {
    return NdotL * NdotV;
}

// ----------------------------------------------------------------------------
fn GeometrySchlickGGX(NdotV: f32, roughness: f32) -> f32 {
    let r = (roughness + 1.0);
    let k = (r*r) / 8.0;

    let nom   = NdotV;
    let denom = NdotV * (1.0 - k) + k;

    return nom / denom;
}
// ----------------------------------------------------------------------------
fn GeometrySmith(N: vec3, V: vec3, L: vec3, roughness: f32) -> f32 {
    let NdotV = max(dot(N, V), 0.0);
    let NdotL = max(dot(N, L), 0.0);
    let ggx2 = GeometrySchlickGGX(NdotV, roughness);
    let ggx1 = GeometrySchlickGGX(NdotL, roughness);

    return ggx1 * ggx2;
}

// @param cosTheta is clamp(dot(H, V), 0.0, 1.0)
fn fresnelSchlick(cosTheta: f32, F0: vec3) -> vec3 {
    return F0 + (1.0 - F0) * pow(max(1.0 - cosTheta, 0.0), 5.0);
}
fn fresnelSchlick2(specularColor: vec3, L: vec3, H: vec3) -> vec3 {
   return specularColor + (1.0 - specularColor) * pow(1.0 - saturate(dot(L, H)), 5.0);
}
//fresnelSchlick2(specularColor, L, H) * ((SpecularPower + 2) / 8 ) * pow(saturate(dot(N, H)), SpecularPower) * dotNL;

const OneOnLN2_x6 = 8.656171;// == 1/ln(2) * 6 (6 is SpecularPower of 5 + 1)
// dot -> dot(N,V) or
fn fresnelSchlick3(specularColor: vec3, dot: f32, glossiness: f32) -> vec3 {
	return specularColor + (max(vec3(glossiness), specularColor) - specularColor) * exp2(-OneOnLN2_x6 * dot);
}
fn fresnelSchlickWithRoughness(specularColor: vec3, L: vec3, N: vec3, gloss: f32) -> vec3 {
   return specularColor + (max(vec3(gloss), specularColor) - specularColor) * pow(1.0 - saturate(dot(L, N)), 5.0);
}

const A = 2.51f;
const B = 0.03f;
const C = 2.43f;
const D = 0.59f;
const E = 0.14f;
fn ACESToneMapping(color: vec3, adapted_lum: f32) -> vec3 {

	let c = color * adapted_lum;
	return (c * (A * c + B)) / (c * (C * c + D) + E);
}

//color = color / (color + vec3(1.0));
fn reinhard(v: vec3) -> vec3 {
    return v / (vec3(1.0) + v);
}
fn reinhard_extended(v: vec3, max_white: f32) -> vec3 {
    let numerator = v * (1.0f + (v / vec3(max_white * max_white)));
    return numerator / (1.0f + v);
}
fn luminance(v: vec3) -> f32 {
    return dot(v, vec3(0.2126f, 0.7152f, 0.0722f));
}

fn change_luminance(c_in: vec3, l_out: f32) -> vec3 {
    let l_in = luminance(c_in);
    return c_in * (l_out / l_in);
}
fn reinhard_extended_luminance(v: vec3, max_white_l: f32) -> vec3 {
    let l_old = luminance(v);
    let numerator = l_old * (1.0f + (l_old / (max_white_l * max_white_l)));
    let l_new = numerator / (1.0f + l_old);
    return change_luminance(v, l_new);
}
fn ReinhardToneMapping( color: vec3, toneMappingExposure: f32 ) -> vec3 {

	let c = color * toneMappingExposure;
	return saturate( c / ( vec3( 1.0 ) + c ) );

}
// expects values in the range of [0,1]x[0,1], returns values in the [0,1] range.
// do not collapse into a single function per: http://byteblacksmith.com/improvements-to-the-canonical-one-liner-glsl-rand-for-opengl-es-2-0/
const highp_a = 12.9898;
const highp_b = 78.233;
const highp_c = 43758.5453;
fn rand( uv: vec2 ) -> f32 {
	let dt = dot( uv.xy, vec2( highp_a, highp_b ) );
	let sn = modf( dt / PI ).fract;
	return fract(sin(sn) * highp_c);
}
// // based on https://www.shadertoy.com/view/MslGR8
fn dithering( color: vec3, fragCoord: vec2 ) -> vec3 {
    //Calculate grid position
    let grid_position = rand( fragCoord );

    //Shift the individual colors differently, thus making it even harder to see the dithering pattern
    var dither_shift_RGB = vec3( 0.25 / 255.0, -0.25 / 255.0, 0.25 / 255.0 );

    //modify shift acording to grid position.
    dither_shift_RGB = mix( 2.0 * dither_shift_RGB, -2.0 * dither_shift_RGB, grid_position );

    //shift the color by dither_shift
    return color + dither_shift_RGB;
}

const dis = 700.0;
const disZ = 400.0;
const u_lightPositions = array, 4>(
	vec3(-dis, dis, disZ),
	vec3(dis, dis, disZ),
	vec3(-dis, -dis, disZ),
	vec3(dis, -dis, disZ)
);
const colorValue = 300.0;
const u_lightColors = array, 4>(
	vec3(colorValue, colorValue, colorValue),
	vec3(colorValue, colorValue, colorValue),
	vec3(colorValue, colorValue, colorValue),
	vec3(colorValue, colorValue, colorValue),
);

fn calcPBRColor3(Normal: vec3, WorldPos: vec3, camPos: vec3) -> vec3 {

	var color = vec3(0.0);

    var ao = param.x;
    var roughness = param.y;
    var metallic = param.z;

	var N = normalize(Normal);
    var V = normalize(camPos.xyz - WorldPos);
    var dotNV = clamp(dot(N, V), 0.0, 1.0);

    // calculate reflectance at normal incidence; if dia-electric (like plastic) use F0
    // of 0.04 and if it's a metal, use the albedo color as F0 (metallic workflow)
    var F0 = vec3(0.04);
    F0 = mix(F0, albedo.xyz, metallic);

    // reflectance equation
    var Lo = vec3(0.0);
    
	for (var i: i32 = 0; i < 4; i++) {
		// calculate per-light radiance
        let L = normalize(u_lightPositions[i].xyz - WorldPos);
        let H = normalize(V + L);
        let distance = length(u_lightPositions[i].xyz - WorldPos);

        let attenuation = 1.0 / (1.0 + 0.001 * distance + 0.0003 * distance * distance);
        let radiance = u_lightColors[i].xyz * attenuation;

        // Cook-Torrance BRDF
        let NDF = DistributionGGX(N, H, roughness);
        let G   = GeometrySmith(N, V, L, roughness);
        //vec3 F    = fresnelSchlick(clamp(dot(H, V), 0.0, 1.0), F0);
        let F    = fresnelSchlick3(F0,clamp(dot(H, V), 0.0, 1.0), 0.9);
        //vec3 F    = fresnelSchlick3(F0,dotNV, 0.9);

        let nominator    = NDF * G * F;
        let denominator = 4.0 * max(dot(N, V), 0.0) * max(dot(N, L), 0.0);
        let specular = nominator / max(denominator, 0.001); // prevent divide by zero for NdotV=0.0 or NdotL=0.0

        // kS is equal to Fresnel
        let kS = F;
        // for energy conservation, the diffuse and specular light can't
        // be above 1.0 (unless the surface emits light); to preserve this
        // relationship the diffuse component (kD) should equal 1.0 - kS.
        var kD = vec3(1.0) - kS;
        // multiply kD by the inverse metalness such that only non-metals
        // have diffuse lighting, or a linear blend if partly metal (pure metals
        // have no diffuse light).
        kD *= 1.0 - metallic;

        // scale light by NdotL
        let NdotL = max(dot(N, L), 0.0);

        // add to outgoing radiance Lo
        // note that we already multiplied the BRDF by the Fresnel (kS) so we won't multiply by kS again
        Lo += (kD * albedo.xyz / PI + specular) * radiance * NdotL;
	}
	// ambient lighting (note that the next IBL tutorial will replace
    // this ambient lighting with environment lighting).
    let ambient = vec3(0.03) * albedo.xyz * ao;

    color = ambient + Lo;
    // HDR tonemapping
    color = reinhard( color );
    // gamma correct
    color = pow(color, vec3(1.0/2.2));
	return color;
}

@fragment
fn main(
  @location(0) pos: vec4,
  @location(1) uv: vec2,
  @location(2) normal: vec3,
  @location(3) camPos: vec3
) -> @location(0) vec4 {
  var color4 = vec4(calcPBRColor3(normal, pos.xyz, camPos), 1.0);
  return color4;
}

此示例基于此渲染系统实现，当前示例TypeScript源码如下：

export class SimplePBRTest {

	private mRscene = new RendererScene();

	geomData = new GeomDataBuilder();

	initialize(): void {
		console.log("SimplePBRTest::initialize() ...");

		const rc = this.mRscene;
		rc.initialize();
		this.initEvent();
		this.initScene();
	}
	private initEvent(): void {
		const rc = this.mRscene;
		rc.addEventListener(MouseEvent.MOUSE_DOWN, this.mouseDown);
		new MouseInteraction().initialize(rc, 0, false).setAutoRunning(true);
	}

	private mouseDown = (evt: MouseEvent): void => {

	}
	private createMaterial(shdSrc: WGRShderSrcType, color?: Color4, arm?: number[]): WGMaterial {

		color = color ? color : new Color4();

		let pipelineDefParam = {
			depthWriteEnabled: true,
			blendModes: [] as string[]
		};

		const material = new WGMaterial({
			shadinguuid: "simple-pbr-materialx",
			shaderCodeSrc: shdSrc,
			pipelineDefParam
		});

		let albedoV = new WGRStorageValue(new Float32Array([color.r, color.g, color.b, 1]));

		// arm[0]: ao, arm[1]: roughness, arm[2]: metallic
		let armV = new WGRStorageValue(new Float32Array([arm[0], arm[1], arm[2], 1]));
		material.uniformValues = [albedoV, armV];

		return material;
	}

	private createGeom(rgd: GeomRDataType, normalEnabled = false): WGGeometry {

		const geometry = new WGGeometry()
			.addAttribute({ position: rgd.vs })
			.addAttribute({ uv: rgd.uvs })
			.setIndices(rgd.ivs);
		if (normalEnabled) {
			geometry.addAttribute({ normal: rgd.nvs });
		}
		return geometry;
	}
	private initScene(): void {

		const rc = this.mRscene;
		const geometry = this.createGeom(this.geomData.createSphere(50), true);

		const shdSrc = {
			vertShaderSrc: { code: vertWGSL, uuid: "vertShdCode" },
			fragShaderSrc: { code: fragWGSL, uuid: "fragShdCode" }
		};

		let tot = 5;
		const size = new Vector3(150, 150, 150);
		const pos = new Vector3().copyFrom(size).scaleBy(-0.5 * (tot - 1));
		let pv = new Vector3();
		for (let i = 0; i < tot; ++i) {
			for (let j = 0; j < tot; ++j) {
				// params[0]: ao, params[1]: roughness, params[2]: metallic
				let params = [1.5, (i / tot) * 0.95 + 0.05, (j / tot) * 0.95 + 0.05];
				let material = this.createMaterial(shdSrc, new Color4(0.5, 0.0, 0.0), params);
				let entity = new Entity3D();
				entity.materials = [material];
				entity.geometry = geometry;
				pv.setXYZ(i * size.x, j * size.y, size.z).addBy(pos);
				entity.transform.setPosition(pv);
				rc.addEntity(entity);
			}
		}
	}

	run(): void {
		this.mRscene.run();
	}
}