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// Copyright (C) 2019 Klaralvdalens Datakonsult AB (KDAB).
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GPL-3.0-only
import Qt3D.Core 2.14
import Qt3D.Render 2.14
import Qt3D.Extras 2.14
import Qt3D.Input 2.14
Entity {
property alias computeMode: particlesComputeJob.runType
function triggerCompute(frames) {
particlesComputeJob.trigger(frames)
}
components: [
RenderSettings {
ComputeFrameGraph {
camera: sceneCamera
}
// explicitly set RenderingPolicy to AlwaysRender, as changes in the
// scene won't be reflected in actual Qt scene-graph changes (due to
// GPU compute calls)
renderPolicy: RenderSettings.Always
},
InputSettings {}
]
FirstPersonCameraController { camera: sceneCamera }
Camera {
id: sceneCamera
projectionType: CameraLens.PerspectiveProjection
viewCenter: Qt.vector3d(0, 0, 0)
position: Qt.vector3d(0, 20, -800)
nearPlane: 0.1
farPlane: 1000
fieldOfView: 60
}
property int particlesCount: 1024 * 1024
readonly property int floatSize: 4
function buildParticlesBuffer() {
var byteSizeOfParticleData = 8;
var bufferData = new Float32Array(particlesCount * byteSizeOfParticleData);
for (var x = 0; x < 1024; ++x) {
for (var z = 0; z < 1024; ++z) {
var i = x * 1024 + z;
var positionIdx = i * byteSizeOfParticleData;
var colorIdx = i * byteSizeOfParticleData + 8;
bufferData[positionIdx] = -1024 + x * 2;
bufferData[positionIdx + 1] = 0;
bufferData[positionIdx + 2] = -1024 + z * 2;
bufferData[positionIdx + 3] = 1.0;
bufferData[colorIdx] = 0.25 + Math.sin(x / 1024) * 0.75;
bufferData[colorIdx + 1] = 0.25 + Math.sin(z / 1024) * 0.75;
bufferData[colorIdx + 2] = 0.25 + Math.sin(x / 1024) * 0.75;
bufferData[colorIdx + 3] = 1.0;
}
}
return bufferData
}
Buffer {
id: particleBuffer
// struct ParticleData
// {
// vec3 position; // Aligned to 4 floats
// vec3 color; // Aligned to 4 floats
// };
data: buildParticlesBuffer()
}
Attribute {
id: particlePositionDataAttribute
name: "particlePosition"
attributeType: Attribute.VertexAttribute
vertexBaseType: Attribute.Float
vertexSize: 3
divisor: 1
byteStride: 8 * floatSize
buffer: particleBuffer
}
Attribute {
id: particleColorDataAttribute
name: "particleColor"
attributeType: Attribute.VertexAttribute
vertexBaseType: Attribute.Float
vertexSize: 3
divisor: 1
byteOffset: 4 * floatSize
byteStride: 8 * floatSize
buffer: particleBuffer
}
ComputeMaterial {
id: computeMaterial
dataBuffer: particleBuffer
}
ComputeCommand {
id: particlesComputeJob
onRunTypeChanged: {
// Don't forget to re-enable the command
// when switching back to continuous
if (runType === ComputeCommand.Continuous)
enabled = true
}
}
Entity {
id: particleComputeEntity
components: [
particlesComputeJob,
computeMaterial
]
}
SphereGeometry {
id: sphereGeometry
rings: 10
slices: 10
radius: 1
// Additional Attributes
attributes: [
particlePositionDataAttribute,
particleColorDataAttribute
]
}
Entity {
id: particleRenderEntity
readonly property GeometryRenderer particlesRenderer: GeometryRenderer {
instanceCount: particlesCount
indexOffset: 0
firstInstance: 0
primitiveType: GeometryRenderer.Triangles
geometry: sphereGeometry
}
components: [
particlesRenderer,
computeMaterial
]
}
}
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