轻量封装WebGPU渲染系统示例＜30＞- 绘制线段(源码)

原理说明：

WebGPU提供了绘制基本线条非机制，只要render pipeline primitive对应的 topology属性指定为line-list或者line-strip即可绘制对应的线条。

当前示例源码github地址:

https://github.com/vilyLei/voxwebgpu/blob/feature/rendering/src/voxgpu/sample/LineEntityTest.ts

当前示例运行效果:

WGSL顶点着色器代码：

@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) vertColor : vec4
}
@vertex
fn main(
  @location(0) position : vec3,
  @location(1) color : vec3,
) -> VertexOutput {

  let wpos = objMat * vec4(position.xyz, 1.0);
  var output : VertexOutput;
  output.Position = projMat * viewMat * wpos;
  output.vertColor = vec4f(color.xyz, 1.0);
  return output;
}

WGSL片段着色器代码：

@group(0) @binding(3) var color: vec4f;
@fragment
fn main(
  @location(0) vertColor: vec4
) -> @location(0) vec4 {
  var color4 = vertColor * color;
  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 LineEntityTest {
	private mRscene = new RendererScene();
	initialize(): void {

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

		let linePositions = [new Vector3(), new Vector3(-100), new Vector3(-150, -180), new Vector3(-150, -180, -100)];
		let line = new Line3DEntity({linePositions});
		line.setColor([1.0,0.0,0.0]);
		rsc.addEntity( line );

		linePositions = [new Vector3(), new Vector3(100), new Vector3(150, 180), new Vector3(150, 180, 100)];
		let lineColors = [new Color4(1.0), new Color4(0.0,1.0), new Color4(0.0,0.0,1.0), new Color4(1.0,0.0,1.0)];
		let colorLine = new Line3DEntity({linePositions, lineColors});
		rsc.addEntity( colorLine );
	}

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