Add files

src/graphics/rendering/uniforms-provider.ts

@@ -0,0 +1,94 @@
+import { mat2d, vec2 } from 'gl-matrix';
+
+export class UniformsProvider {
+  private scaleWorldLengthToNDC = 1;
+  private transformWorldToNDC = mat2d.create();
+
+  private viewAreaBottomLeft = vec2.create();
+  private worldAreaInView = vec2.create();
+  private squareToAspectRatio = vec2.create();
+  private uvToWorld = mat2d.create();
+  private cursorPosition = vec2.create();
+
+  public softShadowsEnabled?: boolean;
+
+  public constructor(private gl: WebGL2RenderingContext) {}
+
+  public getUniforms(uniforms: any): any {
+    const cursorPosition = this.uvToWorldCoordinate(this.cursorPosition);
+    return {
+      ...uniforms,
+      cursorPosition,
+      uvToWorld: this.uvToWorld,
+      worldAreaInView: this.worldAreaInView,
+      squareToAspectRatio: this.squareToAspectRatio,
+      scaleWorldLengthToNDC: this.scaleWorldLengthToNDC,
+      transformWorldToNDC: this.transformWorldToNDC,
+      squareToAspectRatioTimes2: vec2.scale(vec2.create(), this.squareToAspectRatio, 2),
+      softShadowsEnabled: this.softShadowsEnabled,
+    };
+  }
+
+  private getScreenToWorldTransform(screenSize: vec2) {
+    const transform = mat2d.fromTranslation(mat2d.create(), this.viewAreaBottomLeft);
+    mat2d.scale(
+      transform,
+      transform,
+      vec2.divide(vec2.create(), this.worldAreaInView, screenSize)
+    );
+    mat2d.translate(transform, transform, vec2.fromValues(0.5, 0.5));
+
+    return transform;
+  }
+
+  public uvToWorldCoordinate(screenUvPosition: vec2): vec2 {
+    const resolution = vec2.fromValues(this.gl.canvas.width, this.gl.canvas.height);
+
+    return vec2.transformMat2d(
+      vec2.create(),
+      vec2.multiply(vec2.create(), screenUvPosition, resolution),
+      this.getScreenToWorldTransform(resolution)
+    );
+  }
+
+  public setViewArea(topLeft: vec2, size: vec2) {
+    this.worldAreaInView = size;
+
+    // world coordinates
+    this.viewAreaBottomLeft = vec2.add(
+      vec2.create(),
+      topLeft,
+      vec2.fromValues(0, -size.y)
+    );
+
+    const scaleLongerEdgeTo1 =
+      1 / Math.max(this.worldAreaInView.x, this.worldAreaInView.y);
+
+    this.squareToAspectRatio = vec2.fromValues(
+      this.worldAreaInView.x * scaleLongerEdgeTo1,
+      this.worldAreaInView.y * scaleLongerEdgeTo1
+    );
+
+    this.scaleWorldLengthToNDC = scaleLongerEdgeTo1 * 2;
+
+    mat2d.fromScaling(
+      this.transformWorldToNDC,
+      vec2.fromValues(this.scaleWorldLengthToNDC, this.scaleWorldLengthToNDC)
+    );
+    mat2d.translate(
+      this.transformWorldToNDC,
+      this.transformWorldToNDC,
+      vec2.fromValues(
+        -this.viewAreaBottomLeft.x - 0.5 * this.worldAreaInView.x,
+        -this.viewAreaBottomLeft.y - 0.5 * this.worldAreaInView.y
+      )
+    );
+
+    this.uvToWorld = mat2d.fromTranslation(mat2d.create(), this.viewAreaBottomLeft);
+    mat2d.scale(this.uvToWorld, this.uvToWorld, this.worldAreaInView);
+  }
+
+  public setCursorPosition(position: vec2): void {
+    this.cursorPosition = position;
+  }
+}