Add new extrusion types, refactor code. (#323)

2023-08-25 21:02:23 +02:00
parent 4b42cfc1fc
commit be07a8fc4c
7 changed files with 674 additions and 92 deletions
--- a/orx-mesh-generators/src/commonMain/kotlin/ExtrusionScaled.kt
+++ b/orx-mesh-generators/src/commonMain/kotlin/ExtrusionScaled.kt
@@ -0,0 +1,116 @@
+package org.openrndr.extra.meshgenerators
+
+import org.openrndr.math.Matrix44
+import org.openrndr.math.Vector3
+import org.openrndr.shape.Path3D
+import org.openrndr.shape.ShapeContour
+
+/**
+ * Extrude a [contour] along a [path] specifying the number of steps.
+ * The [scale] argument can be used to make variable width shapes.
+ * For example `scale = { t: Double -> 0.5 - 0.5 * cos(t * 2 * PI) }`
+ * produces an extruded shape that begins and ends with hairline thickness.
+ *
+ * @param contour the cross-section of the mesh
+ * @param path the 3D path
+ * @param stepCount the number of steps along the [path]
+ * @param up0 the initial up-vector
+ * @param contourDistanceTolerance precision for calculating steps along
+ * [contour]. Lower tolerance results in higher precision.
+ * @param pathDistanceTolerance precision for calculating steps along
+ * [path]. Lower tolerance results in higher precision.
+ * @param steps the resulting positions in the path
+ * @param frames a list of matrices holding the transformation matrices along
+ * the path
+ * @param startCap adds a start cap if set to true
+ * @param endCap adds an end cap if set to true
+ * @param scale A function that takes a curve `t` value and returns
+ * a scaling factor for [contour] at that point.
+ * @param writer the vertex writer function
+ */
+fun extrudeContourStepsScaled(
+    contour: ShapeContour,
+    path: Path3D,
+    stepCount: Int,
+    up0: Vector3,
+    contourDistanceTolerance: Double = 0.5,
+    pathDistanceTolerance: Double = 0.5,
+    steps: List<Vector3> = path.equidistantPositions(
+        stepCount,
+        pathDistanceTolerance
+    ),
+    frames: List<Matrix44> = steps.frames(up0),
+    startCap: Boolean = true,
+    endCap: Boolean = true,
+    scale: (Double) -> Double = { _ -> 1.0 },
+    writer: VertexWriter
+) {
+    val finalFrames = if (path.closed) frames + frames.first() else frames
+
+    val linearContour = contour.sampleLinear(contourDistanceTolerance)
+    val linearContourPoints2D = linearContour.adaptivePositions()
+
+    val crossSections = List(finalFrames.size) {
+        val t = it / (finalFrames.size - 1.0)
+        linearContourPoints2D.map { p -> p * scale(t) }
+    }
+    if (!path.closed) {
+        if (startCap) {
+            triangulationWithFrame(
+                ShapeContour.fromPoints(crossSections.first(), true).shape.triangulation,
+                finalFrames.first(), false, writer
+            )
+        }
+        if (endCap) {
+            triangulationWithFrame(
+                ShapeContour.fromPoints(crossSections.last(), true).shape.triangulation,
+                finalFrames.last(), false, writer
+            )
+        }
+    }
+
+    // Then add sides
+    (finalFrames zip crossSections).windowed(2, 1).forEach {
+        contourSegment(it[0].second, it[1].second, it[0].first, it[1].first, writer)
+    }
+}
+
+/**
+ * Extrude a [contour] along a [path] specifying the number of steps.
+ * The [scale] argument can be used to make variable width shapes.
+ * For example `scale = { t: Double -> 0.5 - 0.5 * cos(t * 2 * PI) }`
+ * produces an extruded shape that begins and ends with hairline thickness.
+ *
+ * @param contour the cross-section of the mesh
+ * @param path the 3D path
+ * @param stepCount the number of steps along the [path]
+ * @param up0 the initial up-vector
+ * @param contourDistanceTolerance precision for calculating steps along
+ * [contour]. Lower tolerance results in higher precision.
+ * @param pathDistanceTolerance precision for calculating steps along
+ * @param scale A function that converts `t` into a radius
+ * [path]. Lower tolerance results in higher precision.
+ */
+fun TriangleMeshBuilder.extrudeContourStepsScaled(
+    contour: ShapeContour,
+    path: Path3D,
+    stepCount: Int,
+    up0: Vector3,
+    contourDistanceTolerance: Double = 0.5,
+    pathDistanceTolerance: Double = 0.5,
+    startCap: Boolean = true,
+    endCap: Boolean = true,
+    scale: (Double) -> Double = { _ -> 1.0 }
+) = extrudeContourStepsScaled(
+    contour,
+    path,
+    stepCount,
+    up0,
+    contourDistanceTolerance,
+    pathDistanceTolerance,
+    startCap = startCap,
+    endCap = endCap,
+    scale = scale,
+    writer = this::write
+)
+