qt-everywhere-src-5.15.1/qtbase/tests/manual/rhi/cubemap_render/cubemap_render.cpp - orbit - Git at Google

 /****************************************************************************
 **
 ** Copyright (C) 2020 The Qt Company Ltd.
 ** Contact: https://www.qt.io/licensing/
 **
 ** This file is part of the examples of the Qt Toolkit.
 **
 ** $QT_BEGIN_LICENSE:BSD$
 ** Commercial License Usage
 ** Licensees holding valid commercial Qt licenses may use this file in
 ** accordance with the commercial license agreement provided with the
 ** Software or, alternatively, in accordance with the terms contained in
 ** a written agreement between you and The Qt Company. For licensing terms
 ** and conditions see https://www.qt.io/terms-conditions. For further
 ** information use the contact form at https://www.qt.io/contact-us.
 **
 ** BSD License Usage
 ** Alternatively, you may use this file under the terms of the BSD license
 ** as follows:
 **
 ** "Redistribution and use in source and binary forms, with or without
 ** modification, are permitted provided that the following conditions are
 ** met:
 **   * Redistributions of source code must retain the above copyright
 **     notice, this list of conditions and the following disclaimer.
 **   * Redistributions in binary form must reproduce the above copyright
 **     notice, this list of conditions and the following disclaimer in
 **     the documentation and/or other materials provided with the
 **     distribution.
 **   * Neither the name of The Qt Company Ltd nor the names of its
 **     contributors may be used to endorse or promote products derived
 **     from this software without specific prior written permission.
 **
 **
 ** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 ** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 ** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 ** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 ** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 ** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 ** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 ** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 ** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 ** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 ** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
 **
 ** $QT_END_LICENSE$
 **
 ****************************************************************************/

 // Demonstrates rendering to two cubemaps in two different ways:
 //   - one by one, to each face,
 //   - if the supported max number of color attachments is greater than 4: in
 //     one go with all 6 faces attached as render targets.
 //
 // Finally, show what we got in a skybox-ish thing. Press the arrow keys to
 // switch between the two cubemaps. (the only difference should be their
 // background clear color)

 #define EXAMPLEFW_KEYPRESS_EVENTS
 #include "../shared/examplefw.h"
 #include "../shared/cube.h"

 // each face is 512x512
 static const QSize cubemapSize(512, 512);

 // each cubemap face gets a 256x256 quad in the center
 static float halfQuadVertexData[] =
 { // Y up, CCW
   -0.5f,    0.5f,
   -0.5f,   -0.5f,
    0.5f,   -0.5f,
    0.5f,    0.5f,
 };

 static quint16 halfQuadIndexData[] =
 {
     0, 1, 2, 0, 2, 3
 };

 struct {
     QVector<QRhiResource *> releasePool;

     QRhiTexture *cubemap1 = nullptr;
     QRhiTexture *cubemap2 = nullptr;
     bool canDoMrt = false;

     QRhiBuffer *half_quad_vbuf = nullptr;
     QRhiBuffer *half_quad_ibuf = nullptr;

     QRhiBuffer *oneface_ubuf = nullptr;
     int ubufSizePerFace;
     QRhiTextureRenderTarget *oneface_rt[6];
     QRhiRenderPassDescriptor *oneface_rp = nullptr;
     QRhiShaderResourceBindings *oneface_srb = nullptr;
     QRhiGraphicsPipeline *oneface_ps = nullptr;

     QRhiBuffer *mrt_ubuf = nullptr;
     QRhiTextureRenderTarget *mrt_rt = nullptr;
     QRhiRenderPassDescriptor *mrt_rp = nullptr;
     QRhiShaderResourceBindings *mrt_srb = nullptr;
     QRhiGraphicsPipeline *mrt_ps = nullptr;

     QRhiBuffer *vbuf = nullptr;
     QRhiBuffer *ubuf = nullptr;
     QRhiSampler *sampler = nullptr;
     QRhiShaderResourceBindings *srb = nullptr;
     QRhiGraphicsPipeline *ps = nullptr;

     QRhiResourceUpdateBatch *initialUpdates = nullptr;
     QMatrix4x4 winProj;
     float rx = 0;
 } d;

 void initializePerFaceRendering(QRhi *rhi)
 {
     d.cubemap1 = rhi->newTexture(QRhiTexture::RGBA8, cubemapSize, 1, QRhiTexture::CubeMap | QRhiTexture::RenderTarget);
     d.cubemap1->build();
     d.releasePool << d.cubemap1;

     d.ubufSizePerFace = rhi->ubufAligned(64 + 12);
     d.oneface_ubuf = rhi->newBuffer(QRhiBuffer::Dynamic, QRhiBuffer::UniformBuffer, d.ubufSizePerFace * 6);
     d.oneface_ubuf->build();
     d.releasePool << d.oneface_ubuf;

     for (int face = 0; face < 6; ++face) {
         QRhiColorAttachment att(d.cubemap1);
         att.setLayer(face);
         QRhiTextureRenderTargetDescription rtDesc(att);
         d.oneface_rt[face] = rhi->newTextureRenderTarget(rtDesc);
         if (face == 0) {
             d.oneface_rp = d.oneface_rt[0]->newCompatibleRenderPassDescriptor();
             d.releasePool << d.oneface_rp;
         }
         d.oneface_rt[face]->setRenderPassDescriptor(d.oneface_rp);
         d.oneface_rt[face]->build();
         d.releasePool << d.oneface_rt[face];
     }

     d.oneface_srb = rhi->newShaderResourceBindings();
     const QRhiShaderResourceBinding::StageFlags visibility =
             QRhiShaderResourceBinding::VertexStage | QRhiShaderResourceBinding::FragmentStage;
     d.oneface_srb->setBindings({
         QRhiShaderResourceBinding::uniformBufferWithDynamicOffset(0, visibility, d.oneface_ubuf, 64 + 12)
     });
     d.oneface_srb->build();
     d.releasePool << d.oneface_srb;

     d.oneface_ps = rhi->newGraphicsPipeline();
     d.oneface_ps->setShaderStages({
         { QRhiShaderStage::Vertex, getShader(QLatin1String(":/cubemap_oneface.vert.qsb")) },
         { QRhiShaderStage::Fragment, getShader(QLatin1String(":/cubemap_oneface.frag.qsb")) }
     });
     QRhiVertexInputLayout inputLayout;
     inputLayout.setBindings({
         { 2 * sizeof(float) }
     });
     inputLayout.setAttributes({
         { 0, 0, QRhiVertexInputAttribute::Float2, 0 },
     });
     d.oneface_ps->setVertexInputLayout(inputLayout);
     d.oneface_ps->setShaderResourceBindings(d.oneface_srb);
     d.oneface_ps->setRenderPassDescriptor(d.oneface_rp);
     d.oneface_ps->build();
     d.releasePool << d.oneface_ps;

     // wasteful to duplicate the mvp as well but will do for now
     for (int face = 0; face < 6; ++face) {
         const int offset = d.ubufSizePerFace * face;
         QMatrix4x4 identity;
         d.initialUpdates->updateDynamicBuffer(d.oneface_ubuf, offset, 64, identity.constData());
         // will use a different color for each face
         QColor c;
         switch (face) {
         case 0:
             c = Qt::red;
             break;
         case 1:
             c = Qt::green;
             break;
         case 2:
             c = Qt::blue;
             break;
         case 3:
             c = Qt::yellow;
             break;
         case 4:
             c = Qt::lightGray;
             break;
         case 5:
             c = Qt::cyan;
             break;
         }
         float color[] = { float(c.redF()), float(c.greenF()), float(c.blueF()) };
         d.initialUpdates->updateDynamicBuffer(d.oneface_ubuf, offset + 64, 12, color);
     }
 }

 // 6 render passes, 1 draw call each, targeting one cubemap face at a time
 void renderPerFace(QRhiCommandBuffer *cb)
 {
     for (int face = 0; face < 6; ++face) {
         cb->beginPass(d.oneface_rt[face], Qt::black, { 1.0f, 0 });
         cb->setGraphicsPipeline(d.oneface_ps);
         cb->setViewport({ 0, 0,
                           float(d.oneface_rt[face]->pixelSize().width()),
                           float(d.oneface_rt[face]->pixelSize().height()) });
         const QRhiCommandBuffer::DynamicOffset dynamicOffset(0, face * d.ubufSizePerFace);
         cb->setShaderResources(nullptr, 1, &dynamicOffset);
         QRhiCommandBuffer::VertexInput vbufBinding(d.half_quad_vbuf, 0);
         cb->setVertexInput(0, 1, &vbufBinding, d.half_quad_ibuf, 0, QRhiCommandBuffer::IndexUInt16);
         cb->drawIndexed(6);
         cb->endPass();
     }
 }

 void initializeMrtRendering(QRhi *rhi)
 {
     d.cubemap2 = rhi->newTexture(QRhiTexture::RGBA8, cubemapSize, 1, QRhiTexture::CubeMap | QRhiTexture::RenderTarget);
     d.cubemap2->build();
     d.releasePool << d.cubemap2;

     d.mrt_ubuf = rhi->newBuffer(QRhiBuffer::Dynamic, QRhiBuffer::UniformBuffer, 64 + 6 * 16); // note that vec3 is aligned to 16 bytes
     d.mrt_ubuf->build();
     d.releasePool << d.mrt_ubuf;

     QVarLengthArray<QRhiColorAttachment, 6> attachments;
     for (int face = 0; face < 6; ++face) {
         QRhiColorAttachment att(d.cubemap2);
         att.setLayer(face);
         attachments.append(att);
     }
     QRhiTextureRenderTargetDescription rtDesc;
     rtDesc.setColorAttachments(attachments.cbegin(), attachments.cend());
     d.mrt_rt = rhi->newTextureRenderTarget(rtDesc);
     d.mrt_rp = d.mrt_rt->newCompatibleRenderPassDescriptor();
     d.releasePool << d.mrt_rp;
     d.mrt_rt->setRenderPassDescriptor(d.mrt_rp);
     d.mrt_rt->build();
     d.releasePool << d.mrt_rt;

     d.mrt_srb = rhi->newShaderResourceBindings();
     const QRhiShaderResourceBinding::StageFlags visibility =
             QRhiShaderResourceBinding::VertexStage | QRhiShaderResourceBinding::FragmentStage;
     d.mrt_srb->setBindings({
         QRhiShaderResourceBinding::uniformBuffer(0, visibility, d.mrt_ubuf)
     });
     d.mrt_srb->build();
     d.releasePool << d.mrt_srb;

     d.mrt_ps = rhi->newGraphicsPipeline();
     d.mrt_ps->setShaderStages({
         { QRhiShaderStage::Vertex, getShader(QLatin1String(":/cubemap_mrt.vert.qsb")) },
         { QRhiShaderStage::Fragment, getShader(QLatin1String(":/cubemap_mrt.frag.qsb")) }
     });
     QVarLengthArray<QRhiGraphicsPipeline::TargetBlend, 6> targetBlends;
     for (int face = 0; face < 6; ++face)
         targetBlends.append({}); // default to blend = false, color write = all, which is good
     d.mrt_ps->setTargetBlends(targetBlends.cbegin(), targetBlends.cend());
     QRhiVertexInputLayout inputLayout;
     inputLayout.setBindings({
         { 2 * sizeof(float) }
     });
     inputLayout.setAttributes({
         { 0, 0, QRhiVertexInputAttribute::Float2, 0 },
     });
     d.mrt_ps->setVertexInputLayout(inputLayout);
     d.mrt_ps->setShaderResourceBindings(d.mrt_srb);
     d.mrt_ps->setRenderPassDescriptor(d.mrt_rp);
     d.mrt_ps->build();
     d.releasePool << d.mrt_ps;

     QMatrix4x4 identity;
     d.initialUpdates->updateDynamicBuffer(d.mrt_ubuf, 0, 64, identity.constData());
     for (int face = 0; face < 6; ++face) {
         const int offset = 64 + face * 16;
         // will use a different color for each face
         QColor c;
         switch (face) {
         case 0:
             c = Qt::red;
             break;
         case 1:
             c = Qt::green;
             break;
         case 2:
             c = Qt::blue;
             break;
         case 3:
             c = Qt::yellow;
             break;
         case 4:
             c = Qt::lightGray;
             break;
         case 5:
             c = Qt::cyan;
             break;
         }
         float color[] = { float(c.redF()), float(c.greenF()), float(c.blueF()) };
         d.initialUpdates->updateDynamicBuffer(d.mrt_ubuf, offset, 12, color);
     }
 }

 // 1 render pass, 1 draw call, with all 6 faces attached and written to
 void renderWithMrt(QRhiCommandBuffer *cb)
 {
     // use a different clear color to differentiate from cubemap1 (because the
     // results are expected to be identical otherwise)
     cb->beginPass(d.mrt_rt, Qt::magenta, { 1.0f, 0 });
     cb->setGraphicsPipeline(d.mrt_ps);
     cb->setViewport({ 0, 0,
                       float(d.mrt_rt->pixelSize().width()),
                       float(d.mrt_rt->pixelSize().height()) });
     cb->setShaderResources();
     QRhiCommandBuffer::VertexInput vbufBinding(d.half_quad_vbuf, 0);
     cb->setVertexInput(0, 1, &vbufBinding, d.half_quad_ibuf, 0, QRhiCommandBuffer::IndexUInt16);
     cb->drawIndexed(6);
     cb->endPass();
 }

 void Window::customInit()
 {
     d.half_quad_vbuf = m_r->newBuffer(QRhiBuffer::Immutable, QRhiBuffer::VertexBuffer, sizeof(halfQuadVertexData));
     d.half_quad_vbuf->build();
     d.releasePool << d.half_quad_vbuf;

     d.half_quad_ibuf = m_r->newBuffer(QRhiBuffer::Immutable, QRhiBuffer::IndexBuffer, sizeof(halfQuadIndexData));
     d.half_quad_ibuf->build();
     d.releasePool << d.half_quad_ibuf;

     d.initialUpdates = m_r->nextResourceUpdateBatch();
     d.initialUpdates->uploadStaticBuffer(d.half_quad_vbuf, 0, sizeof(halfQuadVertexData), halfQuadVertexData);
     d.initialUpdates->uploadStaticBuffer(d.half_quad_ibuf, halfQuadIndexData);

     initializePerFaceRendering(m_r);

     d.canDoMrt = m_r->resourceLimit(QRhi::MaxColorAttachments) >= 6;
     if (d.canDoMrt)
         initializeMrtRendering(m_r);
     else
         qWarning("Not enough color attachments (need 6, supports %d)", m_r->resourceLimit(QRhi::MaxColorAttachments));


     // onscreen stuff
     d.vbuf = m_r->newBuffer(QRhiBuffer::Immutable, QRhiBuffer::VertexBuffer, sizeof(cube));
     d.vbuf->build();
     d.releasePool << d.vbuf;
     d.initialUpdates->uploadStaticBuffer(d.vbuf, cube);

     d.ubuf = m_r->newBuffer(QRhiBuffer::Dynamic, QRhiBuffer::UniformBuffer, 64);
     d.ubuf->build();
     d.releasePool << d.ubuf;

     d.sampler = m_r->newSampler(QRhiSampler::Linear, QRhiSampler::Linear, QRhiSampler::None,
                                 QRhiSampler::Repeat, QRhiSampler::Repeat);
     d.sampler->build();
     d.releasePool << d.sampler;

     d.srb = m_r->newShaderResourceBindings();
     d.srb->setBindings({
         QRhiShaderResourceBinding::uniformBuffer(0, QRhiShaderResourceBinding::VertexStage | QRhiShaderResourceBinding::FragmentStage, d.ubuf),
         QRhiShaderResourceBinding::sampledTexture(1, QRhiShaderResourceBinding::FragmentStage, d.cubemap1, d.sampler)
     });
     d.srb->build();
     d.releasePool << d.srb;

     d.ps = m_r->newGraphicsPipeline();
     d.ps->setDepthTest(true);
     d.ps->setDepthWrite(true);
     d.ps->setDepthOp(QRhiGraphicsPipeline::LessOrEqual);
     d.ps->setCullMode(QRhiGraphicsPipeline::Front); // we are inside the cube so cull front, not back
     d.ps->setFrontFace(QRhiGraphicsPipeline::CCW); // front is ccw in the cube data
     QShader vs = getShader(QLatin1String(":/cubemap_sample.vert.qsb"));
     Q_ASSERT(vs.isValid());
     QShader fs = getShader(QLatin1String(":/cubemap_sample.frag.qsb"));
     Q_ASSERT(fs.isValid());
     d.ps->setShaderStages({
         { QRhiShaderStage::Vertex, vs },
         { QRhiShaderStage::Fragment, fs }
     });
     QRhiVertexInputLayout inputLayout;
     inputLayout.setBindings({
         { 3 * sizeof(float) }
     });
     inputLayout.setAttributes({
         { 0, 0, QRhiVertexInputAttribute::Float3, 0 }
     });
     d.ps->setVertexInputLayout(inputLayout);
     d.ps->setShaderResourceBindings(d.srb);
     d.ps->setRenderPassDescriptor(m_rp);
     d.ps->build();
     d.releasePool << d.ps;

     if (d.canDoMrt)
         qDebug("Use the arrow keys to switch between the two generated cubemaps");
 }

 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;
     }

     QMatrix4x4 mvp = m_r->clipSpaceCorrMatrix();
     mvp.perspective(90.0f, outputSizeInPixels.width() / (float) outputSizeInPixels.height(), 0.01f, 1000.0f);
     mvp.scale(10);
     mvp.rotate(d.rx, 1, 0, 0);
     d.rx += 0.5f;
     u->updateDynamicBuffer(d.ubuf, 0, 64, mvp.constData());

     cb->resourceUpdate(u);

     renderPerFace(cb);

     if (d.canDoMrt)
         renderWithMrt(cb);

     cb->beginPass(m_sc->currentFrameRenderTarget(), m_clearColor, { 1.0f, 0 });
     cb->setGraphicsPipeline(d.ps);
     cb->setViewport(QRhiViewport(0, 0, outputSizeInPixels.width(), outputSizeInPixels.height()));
     cb->setShaderResources();
     const QRhiCommandBuffer::VertexInput vbufBinding(d.vbuf, 0);
     cb->setVertexInput(0, 1, &vbufBinding);
     cb->draw(36);
     cb->endPass();
 }

 void Window::keyPressEvent(QKeyEvent *e)
 {
     switch (e->key()) {
     case Qt::Key_Left:
     case Qt::Key_Up:
         qDebug("Showing first cubemap (generated by rendering to the faces one by one; black background)");
         d.srb->setBindings({
             QRhiShaderResourceBinding::uniformBuffer(0, QRhiShaderResourceBinding::VertexStage | QRhiShaderResourceBinding::FragmentStage, d.ubuf),
             QRhiShaderResourceBinding::sampledTexture(1, QRhiShaderResourceBinding::FragmentStage, d.cubemap1, d.sampler)
         });
         d.srb->build();
         break;
     case Qt::Key_Right:
     case Qt::Key_Down:
         if (d.canDoMrt) {
             qDebug("Showing second cubemap (generated with multiple render targets; magenta background)");
             d.srb->setBindings({
                 QRhiShaderResourceBinding::uniformBuffer(0, QRhiShaderResourceBinding::VertexStage | QRhiShaderResourceBinding::FragmentStage, d.ubuf),
                 QRhiShaderResourceBinding::sampledTexture(1, QRhiShaderResourceBinding::FragmentStage, d.cubemap2, d.sampler)
             });
             d.srb->build();
         }
         break;
     default:
         e->ignore();
         break;
     }
 }
	/****************************************************************************
	**
	** Copyright (C) 2020 The Qt Company Ltd.
	** Contact: https://www.qt.io/licensing/
	**
	** This file is part of the examples of the Qt Toolkit.
	**
	** $QT_BEGIN_LICENSE:BSD$
	** Commercial License Usage
	** Licensees holding valid commercial Qt licenses may use this file in
	** accordance with the commercial license agreement provided with the
	** Software or, alternatively, in accordance with the terms contained in
	** a written agreement between you and The Qt Company. For licensing terms
	** and conditions see https://www.qt.io/terms-conditions. For further
	** information use the contact form at https://www.qt.io/contact-us.
	**
	** BSD License Usage
	** Alternatively, you may use this file under the terms of the BSD license
	** as follows:
	**
	** "Redistribution and use in source and binary forms, with or without
	** modification, are permitted provided that the following conditions are
	** met:
	** * Redistributions of source code must retain the above copyright
	** notice, this list of conditions and the following disclaimer.
	** * Redistributions in binary form must reproduce the above copyright
	** notice, this list of conditions and the following disclaimer in
	** the documentation and/or other materials provided with the
	** distribution.
	** * Neither the name of The Qt Company Ltd nor the names of its
	** contributors may be used to endorse or promote products derived
	** from this software without specific prior written permission.
	**
	**
	** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
	** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
	** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
	** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
	** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
	** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
	** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
	** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
	** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
	** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
	** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
	**
	** $QT_END_LICENSE$
	**
	****************************************************************************/

	// Demonstrates rendering to two cubemaps in two different ways:
	// - one by one, to each face,
	// - if the supported max number of color attachments is greater than 4: in
	// one go with all 6 faces attached as render targets.
	//
	// Finally, show what we got in a skybox-ish thing. Press the arrow keys to
	// switch between the two cubemaps. (the only difference should be their
	// background clear color)

	#define EXAMPLEFW_KEYPRESS_EVENTS
	#include "../shared/examplefw.h"
	#include "../shared/cube.h"

	// each face is 512x512
	static const QSize cubemapSize(512, 512);

	// each cubemap face gets a 256x256 quad in the center
	static float halfQuadVertexData[] =
	{ // Y up, CCW
	-0.5f, 0.5f,
	-0.5f, -0.5f,
	0.5f, -0.5f,
	0.5f, 0.5f,
	};

	static quint16 halfQuadIndexData[] =
	{
	0, 1, 2, 0, 2, 3
	};

	struct {
	QVector<QRhiResource *> releasePool;

	QRhiTexture *cubemap1 = nullptr;
	QRhiTexture *cubemap2 = nullptr;
	bool canDoMrt = false;

	QRhiBuffer *half_quad_vbuf = nullptr;
	QRhiBuffer *half_quad_ibuf = nullptr;

	QRhiBuffer *oneface_ubuf = nullptr;
	int ubufSizePerFace;
	QRhiTextureRenderTarget *oneface_rt[6];
	QRhiRenderPassDescriptor *oneface_rp = nullptr;
	QRhiShaderResourceBindings *oneface_srb = nullptr;
	QRhiGraphicsPipeline *oneface_ps = nullptr;

	QRhiBuffer *mrt_ubuf = nullptr;
	QRhiTextureRenderTarget *mrt_rt = nullptr;
	QRhiRenderPassDescriptor *mrt_rp = nullptr;
	QRhiShaderResourceBindings *mrt_srb = nullptr;
	QRhiGraphicsPipeline *mrt_ps = nullptr;

	QRhiBuffer *vbuf = nullptr;
	QRhiBuffer *ubuf = nullptr;
	QRhiSampler *sampler = nullptr;
	QRhiShaderResourceBindings *srb = nullptr;
	QRhiGraphicsPipeline *ps = nullptr;

	QRhiResourceUpdateBatch *initialUpdates = nullptr;
	QMatrix4x4 winProj;
	float rx = 0;
	} d;

	void initializePerFaceRendering(QRhi *rhi)
	{
	d.cubemap1 = rhi->newTexture(QRhiTexture::RGBA8, cubemapSize, 1, QRhiTexture::CubeMap \| QRhiTexture::RenderTarget);
	d.cubemap1->build();
	d.releasePool << d.cubemap1;

	d.ubufSizePerFace = rhi->ubufAligned(64 + 12);
	d.oneface_ubuf = rhi->newBuffer(QRhiBuffer::Dynamic, QRhiBuffer::UniformBuffer, d.ubufSizePerFace * 6);
	d.oneface_ubuf->build();
	d.releasePool << d.oneface_ubuf;

	for (int face = 0; face < 6; ++face) {
	QRhiColorAttachment att(d.cubemap1);
	att.setLayer(face);
	QRhiTextureRenderTargetDescription rtDesc(att);
	d.oneface_rt[face] = rhi->newTextureRenderTarget(rtDesc);
	if (face == 0) {
	d.oneface_rp = d.oneface_rt[0]->newCompatibleRenderPassDescriptor();
	d.releasePool << d.oneface_rp;
	}
	d.oneface_rt[face]->setRenderPassDescriptor(d.oneface_rp);
	d.oneface_rt[face]->build();
	d.releasePool << d.oneface_rt[face];
	}

	d.oneface_srb = rhi->newShaderResourceBindings();
	const QRhiShaderResourceBinding::StageFlags visibility =
	QRhiShaderResourceBinding::VertexStage \| QRhiShaderResourceBinding::FragmentStage;
	d.oneface_srb->setBindings({
	QRhiShaderResourceBinding::uniformBufferWithDynamicOffset(0, visibility, d.oneface_ubuf, 64 + 12)
	});
	d.oneface_srb->build();
	d.releasePool << d.oneface_srb;

	d.oneface_ps = rhi->newGraphicsPipeline();
	d.oneface_ps->setShaderStages({
	{ QRhiShaderStage::Vertex, getShader(QLatin1String(":/cubemap_oneface.vert.qsb")) },
	{ QRhiShaderStage::Fragment, getShader(QLatin1String(":/cubemap_oneface.frag.qsb")) }
	});
	QRhiVertexInputLayout inputLayout;
	inputLayout.setBindings({
	{ 2 * sizeof(float) }
	});
	inputLayout.setAttributes({
	{ 0, 0, QRhiVertexInputAttribute::Float2, 0 },
	});
	d.oneface_ps->setVertexInputLayout(inputLayout);
	d.oneface_ps->setShaderResourceBindings(d.oneface_srb);
	d.oneface_ps->setRenderPassDescriptor(d.oneface_rp);
	d.oneface_ps->build();
	d.releasePool << d.oneface_ps;

	// wasteful to duplicate the mvp as well but will do for now
	for (int face = 0; face < 6; ++face) {
	const int offset = d.ubufSizePerFace * face;
	QMatrix4x4 identity;
	d.initialUpdates->updateDynamicBuffer(d.oneface_ubuf, offset, 64, identity.constData());
	// will use a different color for each face
	QColor c;
	switch (face) {
	case 0:
	c = Qt::red;
	break;
	case 1:
	c = Qt::green;
	break;
	case 2:
	c = Qt::blue;
	break;
	case 3:
	c = Qt::yellow;
	break;
	case 4:
	c = Qt::lightGray;
	break;
	case 5:
	c = Qt::cyan;
	break;
	}
	float color[] = { float(c.redF()), float(c.greenF()), float(c.blueF()) };
	d.initialUpdates->updateDynamicBuffer(d.oneface_ubuf, offset + 64, 12, color);
	}
	}

	// 6 render passes, 1 draw call each, targeting one cubemap face at a time
	void renderPerFace(QRhiCommandBuffer *cb)
	{
	for (int face = 0; face < 6; ++face) {
	cb->beginPass(d.oneface_rt[face], Qt::black, { 1.0f, 0 });
	cb->setGraphicsPipeline(d.oneface_ps);
	cb->setViewport({ 0, 0,
	float(d.oneface_rt[face]->pixelSize().width()),
	float(d.oneface_rt[face]->pixelSize().height()) });
	const QRhiCommandBuffer::DynamicOffset dynamicOffset(0, face * d.ubufSizePerFace);
	cb->setShaderResources(nullptr, 1, &dynamicOffset);
	QRhiCommandBuffer::VertexInput vbufBinding(d.half_quad_vbuf, 0);
	cb->setVertexInput(0, 1, &vbufBinding, d.half_quad_ibuf, 0, QRhiCommandBuffer::IndexUInt16);
	cb->drawIndexed(6);
	cb->endPass();
	}
	}

	void initializeMrtRendering(QRhi *rhi)
	{
	d.cubemap2 = rhi->newTexture(QRhiTexture::RGBA8, cubemapSize, 1, QRhiTexture::CubeMap \| QRhiTexture::RenderTarget);
	d.cubemap2->build();
	d.releasePool << d.cubemap2;

	d.mrt_ubuf = rhi->newBuffer(QRhiBuffer::Dynamic, QRhiBuffer::UniformBuffer, 64 + 6 * 16); // note that vec3 is aligned to 16 bytes
	d.mrt_ubuf->build();
	d.releasePool << d.mrt_ubuf;

	QVarLengthArray<QRhiColorAttachment, 6> attachments;
	for (int face = 0; face < 6; ++face) {
	QRhiColorAttachment att(d.cubemap2);
	att.setLayer(face);
	attachments.append(att);
	}
	QRhiTextureRenderTargetDescription rtDesc;
	rtDesc.setColorAttachments(attachments.cbegin(), attachments.cend());
	d.mrt_rt = rhi->newTextureRenderTarget(rtDesc);
	d.mrt_rp = d.mrt_rt->newCompatibleRenderPassDescriptor();
	d.releasePool << d.mrt_rp;
	d.mrt_rt->setRenderPassDescriptor(d.mrt_rp);
	d.mrt_rt->build();
	d.releasePool << d.mrt_rt;

	d.mrt_srb = rhi->newShaderResourceBindings();
	const QRhiShaderResourceBinding::StageFlags visibility =
	QRhiShaderResourceBinding::VertexStage \| QRhiShaderResourceBinding::FragmentStage;
	d.mrt_srb->setBindings({
	QRhiShaderResourceBinding::uniformBuffer(0, visibility, d.mrt_ubuf)
	});
	d.mrt_srb->build();
	d.releasePool << d.mrt_srb;

	d.mrt_ps = rhi->newGraphicsPipeline();
	d.mrt_ps->setShaderStages({
	{ QRhiShaderStage::Vertex, getShader(QLatin1String(":/cubemap_mrt.vert.qsb")) },
	{ QRhiShaderStage::Fragment, getShader(QLatin1String(":/cubemap_mrt.frag.qsb")) }
	});
	QVarLengthArray<QRhiGraphicsPipeline::TargetBlend, 6> targetBlends;
	for (int face = 0; face < 6; ++face)
	targetBlends.append({}); // default to blend = false, color write = all, which is good
	d.mrt_ps->setTargetBlends(targetBlends.cbegin(), targetBlends.cend());
	QRhiVertexInputLayout inputLayout;
	inputLayout.setBindings({
	{ 2 * sizeof(float) }
	});
	inputLayout.setAttributes({
	{ 0, 0, QRhiVertexInputAttribute::Float2, 0 },
	});
	d.mrt_ps->setVertexInputLayout(inputLayout);
	d.mrt_ps->setShaderResourceBindings(d.mrt_srb);
	d.mrt_ps->setRenderPassDescriptor(d.mrt_rp);
	d.mrt_ps->build();
	d.releasePool << d.mrt_ps;

	QMatrix4x4 identity;
	d.initialUpdates->updateDynamicBuffer(d.mrt_ubuf, 0, 64, identity.constData());
	for (int face = 0; face < 6; ++face) {
	const int offset = 64 + face * 16;
	// will use a different color for each face
	QColor c;
	switch (face) {
	case 0:
	c = Qt::red;
	break;
	case 1:
	c = Qt::green;
	break;
	case 2:
	c = Qt::blue;
	break;
	case 3:
	c = Qt::yellow;
	break;
	case 4:
	c = Qt::lightGray;
	break;
	case 5:
	c = Qt::cyan;
	break;
	}
	float color[] = { float(c.redF()), float(c.greenF()), float(c.blueF()) };
	d.initialUpdates->updateDynamicBuffer(d.mrt_ubuf, offset, 12, color);
	}
	}

	// 1 render pass, 1 draw call, with all 6 faces attached and written to
	void renderWithMrt(QRhiCommandBuffer *cb)
	{
	// use a different clear color to differentiate from cubemap1 (because the
	// results are expected to be identical otherwise)
	cb->beginPass(d.mrt_rt, Qt::magenta, { 1.0f, 0 });
	cb->setGraphicsPipeline(d.mrt_ps);
	cb->setViewport({ 0, 0,
	float(d.mrt_rt->pixelSize().width()),
	float(d.mrt_rt->pixelSize().height()) });
	cb->setShaderResources();
	QRhiCommandBuffer::VertexInput vbufBinding(d.half_quad_vbuf, 0);
	cb->setVertexInput(0, 1, &vbufBinding, d.half_quad_ibuf, 0, QRhiCommandBuffer::IndexUInt16);
	cb->drawIndexed(6);
	cb->endPass();
	}

	void Window::customInit()
	{
	d.half_quad_vbuf = m_r->newBuffer(QRhiBuffer::Immutable, QRhiBuffer::VertexBuffer, sizeof(halfQuadVertexData));
	d.half_quad_vbuf->build();
	d.releasePool << d.half_quad_vbuf;

	d.half_quad_ibuf = m_r->newBuffer(QRhiBuffer::Immutable, QRhiBuffer::IndexBuffer, sizeof(halfQuadIndexData));
	d.half_quad_ibuf->build();
	d.releasePool << d.half_quad_ibuf;

	d.initialUpdates = m_r->nextResourceUpdateBatch();
	d.initialUpdates->uploadStaticBuffer(d.half_quad_vbuf, 0, sizeof(halfQuadVertexData), halfQuadVertexData);
	d.initialUpdates->uploadStaticBuffer(d.half_quad_ibuf, halfQuadIndexData);

	initializePerFaceRendering(m_r);

	d.canDoMrt = m_r->resourceLimit(QRhi::MaxColorAttachments) >= 6;
	if (d.canDoMrt)
	initializeMrtRendering(m_r);
	else
	qWarning("Not enough color attachments (need 6, supports %d)", m_r->resourceLimit(QRhi::MaxColorAttachments));


	// onscreen stuff
	d.vbuf = m_r->newBuffer(QRhiBuffer::Immutable, QRhiBuffer::VertexBuffer, sizeof(cube));
	d.vbuf->build();
	d.releasePool << d.vbuf;
	d.initialUpdates->uploadStaticBuffer(d.vbuf, cube);

	d.ubuf = m_r->newBuffer(QRhiBuffer::Dynamic, QRhiBuffer::UniformBuffer, 64);
	d.ubuf->build();
	d.releasePool << d.ubuf;

	d.sampler = m_r->newSampler(QRhiSampler::Linear, QRhiSampler::Linear, QRhiSampler::None,
	QRhiSampler::Repeat, QRhiSampler::Repeat);
	d.sampler->build();
	d.releasePool << d.sampler;

	d.srb = m_r->newShaderResourceBindings();
	d.srb->setBindings({
	QRhiShaderResourceBinding::uniformBuffer(0, QRhiShaderResourceBinding::VertexStage \| QRhiShaderResourceBinding::FragmentStage, d.ubuf),
	QRhiShaderResourceBinding::sampledTexture(1, QRhiShaderResourceBinding::FragmentStage, d.cubemap1, d.sampler)
	});
	d.srb->build();
	d.releasePool << d.srb;

	d.ps = m_r->newGraphicsPipeline();
	d.ps->setDepthTest(true);
	d.ps->setDepthWrite(true);
	d.ps->setDepthOp(QRhiGraphicsPipeline::LessOrEqual);
	d.ps->setCullMode(QRhiGraphicsPipeline::Front); // we are inside the cube so cull front, not back
	d.ps->setFrontFace(QRhiGraphicsPipeline::CCW); // front is ccw in the cube data
	QShader vs = getShader(QLatin1String(":/cubemap_sample.vert.qsb"));
	Q_ASSERT(vs.isValid());
	QShader fs = getShader(QLatin1String(":/cubemap_sample.frag.qsb"));
	Q_ASSERT(fs.isValid());
	d.ps->setShaderStages({
	{ QRhiShaderStage::Vertex, vs },
	{ QRhiShaderStage::Fragment, fs }
	});
	QRhiVertexInputLayout inputLayout;
	inputLayout.setBindings({
	{ 3 * sizeof(float) }
	});
	inputLayout.setAttributes({
	{ 0, 0, QRhiVertexInputAttribute::Float3, 0 }
	});
	d.ps->setVertexInputLayout(inputLayout);
	d.ps->setShaderResourceBindings(d.srb);
	d.ps->setRenderPassDescriptor(m_rp);
	d.ps->build();
	d.releasePool << d.ps;

	if (d.canDoMrt)
	qDebug("Use the arrow keys to switch between the two generated cubemaps");
	}

	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;
	}

	QMatrix4x4 mvp = m_r->clipSpaceCorrMatrix();
	mvp.perspective(90.0f, outputSizeInPixels.width() / (float) outputSizeInPixels.height(), 0.01f, 1000.0f);
	mvp.scale(10);
	mvp.rotate(d.rx, 1, 0, 0);
	d.rx += 0.5f;
	u->updateDynamicBuffer(d.ubuf, 0, 64, mvp.constData());

	cb->resourceUpdate(u);

	renderPerFace(cb);

	if (d.canDoMrt)
	renderWithMrt(cb);

	cb->beginPass(m_sc->currentFrameRenderTarget(), m_clearColor, { 1.0f, 0 });
	cb->setGraphicsPipeline(d.ps);
	cb->setViewport(QRhiViewport(0, 0, outputSizeInPixels.width(), outputSizeInPixels.height()));
	cb->setShaderResources();
	const QRhiCommandBuffer::VertexInput vbufBinding(d.vbuf, 0);
	cb->setVertexInput(0, 1, &vbufBinding);
	cb->draw(36);
	cb->endPass();
	}

	void Window::keyPressEvent(QKeyEvent *e)
	{
	switch (e->key()) {
	case Qt::Key_Left:
	case Qt::Key_Up:
	qDebug("Showing first cubemap (generated by rendering to the faces one by one; black background)");
	d.srb->setBindings({
	QRhiShaderResourceBinding::uniformBuffer(0, QRhiShaderResourceBinding::VertexStage \| QRhiShaderResourceBinding::FragmentStage, d.ubuf),
	QRhiShaderResourceBinding::sampledTexture(1, QRhiShaderResourceBinding::FragmentStage, d.cubemap1, d.sampler)
	});
	d.srb->build();
	break;
	case Qt::Key_Right:
	case Qt::Key_Down:
	if (d.canDoMrt) {
	qDebug("Showing second cubemap (generated with multiple render targets; magenta background)");
	d.srb->setBindings({
	QRhiShaderResourceBinding::uniformBuffer(0, QRhiShaderResourceBinding::VertexStage \| QRhiShaderResourceBinding::FragmentStage, d.ubuf),
	QRhiShaderResourceBinding::sampledTexture(1, QRhiShaderResourceBinding::FragmentStage, d.cubemap2, d.sampler)
	});
	d.srb->build();
	}
	break;
	default:
	e->ignore();
	break;
	}
	}