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// Copyright (C) 2021 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause
#include "../shared/examplefw.h"
#include <QImage>
#include <QPainter>
// Create a 3D texture of 256x256x3, where we will render to one of the slices
// in a render pass, while providing data to two other slices in texture
// uploads. Finally we use the texture to in the on-screen rendering: texture 3
// quads with the same volume texture, in each draw the shader will sample with
// a w that selects slice 0, 1, or 2, respectively.
const int TEXTURE_DEPTH = 3;
// Tests mipmap generation and linear-mipmap filtering when true. Note: Be
// aware what a mipmap chain for a 3D texture is and isn't, do not confuse with
// 2D (array) textures. The expected result on-screen is the black-red (slice
// 1) content mixed in to slice 0 and 2 on lower mip levels (resize the window
// to a smaller size -> the effect becomes more apparent, with totally taking
// over at small sizes)
// See https://docs.microsoft.com/en-us/windows/win32/direct3d11/overviews-direct3d-11-resources-textures-intro
//
const bool MIPMAP = true;
static float quadVertexData[] =
{ // Y up, CCW
-0.5f, 0.5f, 0.0f, 0.0f,
-0.5f, -0.5f, 0.0f, 1.0f,
0.5f, -0.5f, 1.0f, 1.0f,
0.5f, 0.5f, 1.0f, 0.0f
};
static quint16 quadIndexData[] =
{
0, 1, 2, 0, 2, 3
};
struct {
QList<QRhiResource *> releasePool;
QRhiResourceUpdateBatch *initialUpdates = nullptr;
QRhiTexture *tex = nullptr;
QRhiTextureRenderTarget *rt = nullptr;
QRhiRenderPassDescriptor *rtRp = nullptr;
QRhiBuffer *vbuf = nullptr;
QRhiBuffer *ibuf = nullptr;
QRhiBuffer *ubuf = nullptr;
QRhiSampler *sampler = nullptr;
QRhiGraphicsPipeline *ps = nullptr;
QRhiShaderResourceBindings *srb = nullptr;
QMatrix4x4 winProj;
QVector3D slice1ClearColor;
} d;
void Window::customInit()
{
if (!m_r->isFeatureSupported(QRhi::ThreeDimensionalTextures))
qWarning("3D textures are not supported");
QRhiTexture::Flags texFlags = QRhiTexture::RenderTarget;
if (MIPMAP)
texFlags |= QRhiTexture::MipMapped | QRhiTexture::UsedWithGenerateMips;
d.tex = m_r->newTexture(QRhiTexture::RGBA8,
256, 256, TEXTURE_DEPTH,
1, texFlags);
d.releasePool << d.tex;
d.tex->create();
d.initialUpdates = m_r->nextResourceUpdateBatch();
QImage imgWhiteText(256, 256, QImage::Format_RGBA8888);
imgWhiteText.fill(Qt::blue);
QPainter p(&imgWhiteText);
p.setPen(Qt::white);
p.drawText(10, 10, "Slice 2:\nWhite text on blue background");
p.end();
// imgWhiteText -> slice 2 of the 3D texture
QRhiTextureUploadEntry uploadSlice2(2, 0, QRhiTextureSubresourceUploadDescription(imgWhiteText));
d.initialUpdates->uploadTexture(d.tex, uploadSlice2);
QImage imgYellowText(256, 256, QImage::Format_RGBA8888);
imgYellowText.fill(Qt::green);
p.begin(&imgYellowText);
p.setPen(Qt::yellow);
p.drawText(10, 10, "Slice 0: Yellow text on green background");
p.end();
// imgYellowText -> slice 0 of the 3D texture
QRhiTextureUploadEntry uploadSlice0(0, 0, QRhiTextureSubresourceUploadDescription(imgYellowText));
d.initialUpdates->uploadTexture(d.tex, uploadSlice0);
// slice 1 -> clear to some color in a render pass
QRhiColorAttachment att(d.tex);
att.setLayer(1);
QRhiTextureRenderTargetDescription rtDesc(att);
d.rt = m_r->newTextureRenderTarget(rtDesc);
d.releasePool << d.rt;
d.rtRp = d.rt->newCompatibleRenderPassDescriptor();
d.releasePool << d.rtRp;
d.rt->setRenderPassDescriptor(d.rtRp);
d.rt->create();
// set up resources needed to render a quad
d.vbuf = m_r->newBuffer(QRhiBuffer::Immutable, QRhiBuffer::VertexBuffer, sizeof(quadVertexData));
d.vbuf->create();
d.releasePool << d.vbuf;
d.ibuf = m_r->newBuffer(QRhiBuffer::Immutable, QRhiBuffer::IndexBuffer, sizeof(quadIndexData));
d.ibuf->create();
d.releasePool << d.ibuf;
d.initialUpdates->uploadStaticBuffer(d.vbuf, 0, sizeof(quadVertexData), quadVertexData);
d.initialUpdates->uploadStaticBuffer(d.ibuf, quadIndexData);
d.ubuf = m_r->newBuffer(QRhiBuffer::Dynamic, QRhiBuffer::UniformBuffer, m_r->ubufAligned(72) * TEXTURE_DEPTH);
d.ubuf->create();
d.releasePool << d.ubuf;
for (int i = 0; i < TEXTURE_DEPTH; ++i) {
qint32 flip = 0;
if (i == 1) // this slice will be rendered to in a render pass so needs flipping with OpenGL when on screen
flip = m_r->isYUpInFramebuffer() ? 1 : 0;
d.initialUpdates->updateDynamicBuffer(d.ubuf, m_r->ubufAligned(72) * i + 64, 4, &flip);
qint32 idx = i;
d.initialUpdates->updateDynamicBuffer(d.ubuf, m_r->ubufAligned(72) * i + 68, 4, &idx);
}
d.sampler = m_r->newSampler(QRhiSampler::Linear, QRhiSampler::Linear, MIPMAP ? QRhiSampler::Linear : QRhiSampler::None,
QRhiSampler::ClampToEdge, QRhiSampler::ClampToEdge, QRhiSampler::ClampToEdge);
d.releasePool << d.sampler;
d.sampler->create();
d.srb = m_r->newShaderResourceBindings();
d.releasePool << d.srb;
d.srb->setBindings({
QRhiShaderResourceBinding::uniformBufferWithDynamicOffset(0, QRhiShaderResourceBinding::VertexStage | QRhiShaderResourceBinding::FragmentStage, d.ubuf, 72),
QRhiShaderResourceBinding::sampledTexture(1, QRhiShaderResourceBinding::FragmentStage, d.tex, d.sampler)
});
d.srb->create();
d.ps = m_r->newGraphicsPipeline();
d.releasePool << d.ps;
d.ps->setShaderStages({
{ QRhiShaderStage::Vertex, getShader(QLatin1String(":/texture3d.vert.qsb")) },
{ QRhiShaderStage::Fragment, getShader(QLatin1String(":/texture3d.frag.qsb")) }
});
QRhiVertexInputLayout inputLayout;
inputLayout.setBindings({
{ 4 * sizeof(float) }
});
inputLayout.setAttributes({
{ 0, 0, QRhiVertexInputAttribute::Float2, 0 },
{ 0, 1, QRhiVertexInputAttribute::Float2, quint32(2 * sizeof(float)) }
});
d.ps->setVertexInputLayout(inputLayout);
d.ps->setShaderResourceBindings(d.srb);
d.ps->setRenderPassDescriptor(m_rp);
d.ps->create();
}
void Window::customRelease()
{
qDeleteAll(d.releasePool);
d.releasePool.clear();
}
void Window::customRender()
{
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;
for (int i = 0; i < TEXTURE_DEPTH; ++i) {
QMatrix4x4 mvp = m_proj;
switch (i) {
case 0:
mvp.translate(-2.0f, 0.0f, 0.0f);
break;
case 2:
mvp.translate(2.0f, 0.0f, 0.0f);
break;
default:
break;
}
u->updateDynamicBuffer(d.ubuf, m_r->ubufAligned(72) * i, 64, mvp.constData());
}
}
const QColor slice1ClearColor = QColor::fromRgbF(d.slice1ClearColor.x(), d.slice1ClearColor.y(), d.slice1ClearColor.z());
d.slice1ClearColor.setX(d.slice1ClearColor.x() + 0.01f);
if (d.slice1ClearColor.x() > 1.0f)
d.slice1ClearColor.setX(0.0f);
cb->beginPass(d.rt, slice1ClearColor, { 1.0f, 0 }, u);
cb->endPass();
// now all 3 slices have something, regenerate the mipmaps
u = m_r->nextResourceUpdateBatch();
if (MIPMAP)
u->generateMips(d.tex);
const QSize outputSizeInPixels = m_sc->currentPixelSize();
cb->beginPass(m_sc->currentFrameRenderTarget(), m_clearColor, { 1.0f, 0 }, u);
cb->setGraphicsPipeline(d.ps);
QRhiCommandBuffer::DynamicOffset dynOfs = { 0, 0 };
cb->setShaderResources(d.srb, 1, &dynOfs);
cb->setViewport({ 0, 0, float(outputSizeInPixels.width()), float(outputSizeInPixels.height()) });
QRhiCommandBuffer::VertexInput vbufBinding(d.vbuf, 0);
cb->setVertexInput(0, 1, &vbufBinding, d.ibuf, 0, QRhiCommandBuffer::IndexUInt16);
cb->drawIndexed(6);
dynOfs.second = m_r->ubufAligned(72);
cb->setShaderResources(d.srb, 1, &dynOfs);
cb->drawIndexed(6);
dynOfs.second = m_r->ubufAligned(72) * 2;
cb->setShaderResources(d.srb, 1, &dynOfs);
cb->drawIndexed(6);
cb->endPass();
}
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