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// Copyright (C) 2019 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause
#include "../shared/examplefw.h"
#include "../shared/cube.h"
#include <QRandomGenerator>
// Instanced draw example. When running with OpenGL, at least 3.3 or ES 3.0 is
// needed.
const int INSTANCE_COUNT = 1024;
struct {
QList<QRhiResource *> releasePool;
QRhiBuffer *vbuf = nullptr;
QRhiBuffer *instBuf = nullptr;
QRhiBuffer *ubuf = nullptr;
QRhiShaderResourceBindings *srb = nullptr;
QRhiGraphicsPipeline *ps = nullptr;
QRhiResourceUpdateBatch *initialUpdates = nullptr;
QMatrix4x4 winProj;
} d;
void Window::customInit()
{
if (!m_r->isFeatureSupported(QRhi::Instancing))
qFatal("Instanced drawing is not supported");
d.initialUpdates = m_r->nextResourceUpdateBatch();
d.vbuf = m_r->newBuffer(QRhiBuffer::Immutable, QRhiBuffer::VertexBuffer, sizeof(cube));
d.vbuf->create();
d.releasePool << d.vbuf;
d.initialUpdates->uploadStaticBuffer(d.vbuf, cube);
// transform + color (mat4 + vec3), interleaved, for each instance
d.instBuf = m_r->newBuffer(QRhiBuffer::Immutable, QRhiBuffer::VertexBuffer, INSTANCE_COUNT * 19 * sizeof(float));
d.instBuf->create();
d.releasePool << d.instBuf;
d.ubuf = m_r->newBuffer(QRhiBuffer::Dynamic, QRhiBuffer::UniformBuffer, 64 + 12);
d.ubuf->create();
d.releasePool << d.ubuf;
d.srb = m_r->newShaderResourceBindings();
d.releasePool << d.srb;
d.srb->setBindings({
QRhiShaderResourceBinding::uniformBuffer(0, QRhiShaderResourceBinding::VertexStage, d.ubuf)
});
d.srb->create();
d.ps = m_r->newGraphicsPipeline();
d.releasePool << d.ps;
d.ps->setShaderStages({
{ QRhiShaderStage::Vertex, getShader(QLatin1String(":/inst.vert.qsb")) },
{ QRhiShaderStage::Fragment, getShader(QLatin1String(":/inst.frag.qsb")) }
});
QRhiVertexInputLayout inputLayout;
inputLayout.setBindings({
{ 3 * sizeof(float) }, // cube vertices
{ 19 * sizeof(float), QRhiVertexInputBinding::PerInstance }, // per-instance transform and color
});
inputLayout.setAttributes({
{ 0, 0, QRhiVertexInputAttribute::Float3, 0 }, // position
{ 1, 1, QRhiVertexInputAttribute::Float4, 0, 0 }, // instMat
{ 1, 2, QRhiVertexInputAttribute::Float4, 4 * sizeof(float), 1 },
{ 1, 3, QRhiVertexInputAttribute::Float4, 8 * sizeof(float), 2 },
{ 1, 4, QRhiVertexInputAttribute::Float4, 12 * sizeof(float), 3 },
{ 1, 5, QRhiVertexInputAttribute::Float3, 16 * sizeof(float) }, // instColor
});
d.ps->setVertexInputLayout(inputLayout);
d.ps->setShaderResourceBindings(d.srb);
d.ps->setRenderPassDescriptor(m_rp);
d.ps->create();
QByteArray instData;
instData.resize(INSTANCE_COUNT * 19 * sizeof(float));
float *p = reinterpret_cast<float *>(instData.data());
QRandomGenerator *rgen = QRandomGenerator::global();
for (int i = 0; i < INSTANCE_COUNT; ++i) {
QMatrix4x4 m;
m.translate(rgen->bounded(8000) / 100.0f - 40.0f,
rgen->bounded(8000) / 100.0f - 40.0f,
0.0f);
memcpy(p, m.constData(), 16 * sizeof(float));
p += 16;
// color
*p++ = i / float(INSTANCE_COUNT);
*p++ = 0.0f;
*p++ = 0.0f;
}
d.initialUpdates->uploadStaticBuffer(d.instBuf, instData.constData());
}
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 (d.winProj != m_proj) {
d.winProj = m_proj;
QMatrix4x4 mvp = m_proj;
mvp.scale(0.05f);
u->updateDynamicBuffer(d.ubuf, 0, 64, mvp.constData());
}
cb->beginPass(m_sc->currentFrameRenderTarget(), m_clearColor, { 1.0f, 0 }, u);
cb->setGraphicsPipeline(d.ps);
cb->setViewport({ 0, 0, float(outputSizeInPixels.width()), float(outputSizeInPixels.height()) });
cb->setShaderResources();
const QRhiCommandBuffer::VertexInput vbufBinding[] = {
{ d.vbuf, 0 },
{ d.instBuf, 0 }
};
cb->setVertexInput(0, 2, vbufBinding);
cb->draw(36, INSTANCE_COUNT);
cb->endPass();
}
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