82 lines
3.4 KiB
Kotlin
82 lines
3.4 KiB
Kotlin
package org.openrndr.extras.meshgenerators
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import org.openrndr.draw.VertexBuffer
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import org.openrndr.math.Vector2
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import org.openrndr.math.Vector3
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import org.openrndr.math.mix
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import org.openrndr.math.transforms.rotateZ
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fun cylinderMesh(sides: Int = 16, segments: Int = 16, radius: Double = 1.0, length: Double, invert: Boolean = false): VertexBuffer {
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val vertexCount = 6 * sides * segments
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val vb = meshVertexBuffer(vertexCount)
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vb.put {
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generateCylinder(sides, segments, radius, length, invert, bufferWriter(this))
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}
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return vb
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}
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fun generateCylinder(sides: Int, segments: Int, radius: Double, length: Double, invert: Boolean = false, vertexWriter: VertexWriter) {
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return generateTaperedCylinder(sides, segments, radius, radius, length, invert, vertexWriter)
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}
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fun generateTaperedCylinder(sides: Int, segments: Int, radiusStart: Double, radiusEnd:Double, length: Double, invert: Boolean = false, vertexWriter: VertexWriter) {
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val dphi = (Math.PI * 2) / sides
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val ddeg = (360.0) / sides
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val invertFactor = if (invert) -1.0 else 1.0
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val dr = radiusEnd - radiusStart
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val baseNormal = Vector2(length, dr).normalized.perpendicular.let { Vector3(x=it.y, y=0.0, z=it.x)}
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//val baseNormal = Vector3(1.0, 0.0, 0.0)
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for (segment in 0 until segments) {
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val radius0 = mix(radiusStart, radiusEnd, segment*1.0/segments)
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val radius1 = mix(radiusStart, radiusEnd, (segment+1)*1.0/segments)
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val z0 = (length / segments) * segment - length/2.0
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val z1 = (length / segments) * (segment + 1) - length/2.0
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for (side in 0 until sides) {
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val x00 = Math.cos(side * dphi) * radius0
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val x10 = Math.cos(side * dphi + dphi) * radius0
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val y00 = Math.sin(side * dphi) * radius0
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val y10 = Math.sin(side * dphi + dphi) * radius0
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val x01 = Math.cos(side * dphi) * radius1
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val x11 = Math.cos(side * dphi + dphi) * radius1
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val y01 = Math.sin(side * dphi) * radius1
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val y11 = Math.sin(side * dphi + dphi) * radius1
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val u0 = (segment + 0.0) / segments
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val u1 = (segment + 1.0) / segments
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val v0 = (side + 0.0) / sides
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val v1 = (side + 1.0) / sides
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val n0 = (rotateZ(side * ddeg) * baseNormal.xyz0).xyz.normalized * invertFactor
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val n1 = (rotateZ((side+1) * ddeg) * baseNormal.xyz0).xyz.normalized * invertFactor
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if (!invert) {
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vertexWriter(Vector3(x00, y00, z0), n0, Vector2(u0, v0))
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vertexWriter(Vector3(x10, y10, z0), n1, Vector2(u0, v1))
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vertexWriter(Vector3(x11, y11, z1), n1, Vector2(u1, v1))
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vertexWriter(Vector3(x11, y11, z1), n1, Vector2(u1, v1))
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vertexWriter(Vector3(x01, y01, z1), n0, Vector2(u1, v0))
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vertexWriter(Vector3(x00, y00, z0), n0, Vector2(u0, v0))
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} else {
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vertexWriter(Vector3(x00, y00, z0), n0, Vector2(u0, v0))
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vertexWriter(Vector3(x01, y01, z1), n0, Vector2(u1, v0))
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vertexWriter(Vector3(x11, y11, z1), n1, Vector2(u1, v1))
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vertexWriter(Vector3(x11, y11, z1), n1, Vector2(u1, v1))
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vertexWriter(Vector3(x10, y10, z0), n1, Vector2(u0, v1))
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vertexWriter(Vector3(x00, y00, z0), n0, Vector2(u0, v0))
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}
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}
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}
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} |