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| |
| #include "../shared/examplefw.h" |
| #include <QRandomGenerator> |
| |
| // Compute shader example. Writes to a storage buffer from a compute shader, |
| // then uses the same buffer as vertex buffer in the vertex stage. This would |
| // be typical when implementing particles for example. Here we just simply move |
| // the positions back and forth along the X axis. |
| |
| // Note that the example relies on gl_PointSize which is not supported |
| // everywhere. So in some cases the points will be of size 1. |
| |
| struct { |
| QVector<QRhiResource *> releasePool; |
| QRhiBuffer *sbuf = nullptr; |
| QRhiBuffer *computeUniBuf = nullptr; |
| QRhiShaderResourceBindings *computeBindings = nullptr; |
| QRhiComputePipeline *computePipeline = nullptr; |
| QRhiShaderResourceBindings *graphicsBindings = nullptr; |
| QRhiGraphicsPipeline *graphicsPipeline = nullptr; |
| QRhiResourceUpdateBatch *initialUpdates = nullptr; |
| float step = 0.2f; |
| } d; |
| |
| // these struct must match the std140 packing rules |
| struct Data { |
| float pos[2]; |
| float dir; |
| quint32 pad[1]; |
| }; |
| struct ComputeUBuf { |
| float step; |
| quint32 count; |
| }; |
| |
| const int DATA_COUNT = 256 * 128; |
| |
| const int COMPUTE_UBUF_SIZE = 8; |
| |
| void Window::customInit() |
| { |
| if (!m_r->isFeatureSupported(QRhi::Compute)) |
| qFatal("Compute is not supported"); |
| |
| if (!m_r->isFeatureSupported(QRhi::VertexShaderPointSize)) |
| qWarning("Point sizes other than 1 not supported"); |
| |
| // compute pass |
| |
| d.sbuf = m_r->newBuffer(QRhiBuffer::Immutable, |
| QRhiBuffer::StorageBuffer | QRhiBuffer::VertexBuffer, |
| sizeof(Data) * DATA_COUNT); |
| d.sbuf->build(); |
| d.releasePool << d.sbuf; |
| |
| d.computeUniBuf = m_r->newBuffer(QRhiBuffer::Dynamic, QRhiBuffer::UniformBuffer, COMPUTE_UBUF_SIZE); |
| d.computeUniBuf->build(); |
| d.releasePool << d.computeUniBuf; |
| |
| d.initialUpdates = m_r->nextResourceUpdateBatch(); |
| |
| QByteArray data; |
| data.resize(sizeof(Data) * DATA_COUNT); |
| Data *p = reinterpret_cast<Data *>(data.data()); |
| QRandomGenerator *rgen = QRandomGenerator::global(); |
| for (int i = 0; i < DATA_COUNT; ++i) { |
| p->pos[0] = rgen->bounded(1000) / 500.0f - 1.0f; |
| p->pos[1] = rgen->bounded(1000) / 500.0f - 1.0f; |
| p->dir = rgen->bounded(2) ? 1 : -1; |
| ++p; |
| } |
| d.initialUpdates->uploadStaticBuffer(d.sbuf, data.constData()); |
| |
| ComputeUBuf ud; |
| ud.step = d.step; |
| ud.count = DATA_COUNT; |
| d.initialUpdates->updateDynamicBuffer(d.computeUniBuf, 0, COMPUTE_UBUF_SIZE, &ud); |
| |
| d.computeBindings = m_r->newShaderResourceBindings(); |
| d.computeBindings->setBindings({ |
| QRhiShaderResourceBinding::bufferLoadStore(0, QRhiShaderResourceBinding::ComputeStage, d.sbuf), |
| QRhiShaderResourceBinding::uniformBuffer(1, QRhiShaderResourceBinding::ComputeStage, d.computeUniBuf) |
| }); |
| d.computeBindings->build(); |
| d.releasePool << d.computeBindings; |
| |
| d.computePipeline = m_r->newComputePipeline(); |
| d.computePipeline->setShaderResourceBindings(d.computeBindings); |
| d.computePipeline->setShaderStage({ QRhiShaderStage::Compute, getShader(QLatin1String(":/buffer.comp.qsb")) }); |
| d.computePipeline->build(); |
| d.releasePool << d.computePipeline; |
| |
| // graphics pass |
| |
| d.graphicsBindings = m_r->newShaderResourceBindings(); |
| d.graphicsBindings->build(); |
| d.releasePool << d.graphicsBindings; |
| |
| d.graphicsPipeline = m_r->newGraphicsPipeline(); |
| d.graphicsPipeline->setTopology(QRhiGraphicsPipeline::Points); |
| d.graphicsPipeline->setShaderStages({ |
| { QRhiShaderStage::Vertex, getShader(QLatin1String(":/main.vert.qsb")) }, |
| { QRhiShaderStage::Fragment, getShader(QLatin1String(":/main.frag.qsb")) } |
| }); |
| QRhiVertexInputLayout inputLayout; |
| inputLayout.setBindings({ |
| { 2 * sizeof(float) } |
| }); |
| inputLayout.setAttributes({ |
| { 0, 0, QRhiVertexInputAttribute::Float2, 0 }, |
| }); |
| d.graphicsPipeline->setVertexInputLayout(inputLayout); |
| d.graphicsPipeline->setShaderResourceBindings(d.graphicsBindings); |
| d.graphicsPipeline->setRenderPassDescriptor(m_rp); |
| d.graphicsPipeline->build(); |
| d.releasePool << d.graphicsPipeline; |
| } |
| |
| void Window::customRelease() |
| { |
| qDeleteAll(d.releasePool); |
| d.releasePool.clear(); |
| } |
| |
| void Window::customRender() |
| { |
| const QSize outputSizeInPixels = m_sc->currentPixelSize(); |
| QRhiCommandBuffer *cb = m_sc->currentFrameCommandBuffer(); |
| QRhiResourceUpdateBatch *u = m_r->nextResourceUpdateBatch(); |
| if (d.initialUpdates) { |
| u->merge(d.initialUpdates); |
| d.initialUpdates->release(); |
| d.initialUpdates = nullptr; |
| } |
| |
| #if 0 |
| u->updateDynamicBuffer(d.computeUniBuf, 0, sizeof(float), &d.step); |
| d.step += 0.01f; |
| #endif |
| |
| // compute pass |
| cb->beginComputePass(u); |
| cb->setComputePipeline(d.computePipeline); |
| cb->setShaderResources(); |
| cb->dispatch(DATA_COUNT / 256, 1, 1); |
| cb->endComputePass(); |
| |
| // graphics pass |
| cb->beginPass(m_sc->currentFrameRenderTarget(), m_clearColor, { 1.0f, 0 }); |
| cb->setGraphicsPipeline(d.graphicsPipeline); |
| cb->setViewport({ 0, 0, float(outputSizeInPixels.width()), float(outputSizeInPixels.height()) }); |
| QRhiCommandBuffer::VertexInput vbufBinding(d.sbuf, 0); |
| cb->setVertexInput(0, 1, &vbufBinding); |
| cb->draw(DATA_COUNT); |
| cb->endPass(); |
| } |