rhi: Add a test for instancing

Draws 1024 cubes at random x,y positions with varying color with
a single instanced draw call.

Change-Id: I8737503acf23866ad4734b1d88753415a3b93445
Reviewed-by: Lars Knoll <lars.knoll@qt.io>

tests/manual/rhi/instancing/buildshaders.bat

@@ -0,0 +1,2 @@
+qsb --glsl "330,300 es" --hlsl 50 --msl 12 inst.vert -o inst.vert.qsb
+qsb --glsl "330,300 es" --hlsl 50 --msl 12 inst.frag -o inst.frag.qsb

tests/manual/rhi/instancing/inst.frag

@@ -0,0 +1,9 @@
+#version 440
+
+layout(location = 0) in vec3 vColor;
+layout(location = 0) out vec4 fragColor;
+
+void main()
+{
+    fragColor = vec4(vColor, 1.0);
+}

tests/manual/rhi/instancing/inst.vert

@@ -0,0 +1,25 @@
+#version 440
+
+layout(location = 0) in vec4 position;
+
+// Instanced attributes to variate the translation and color of the cube
+layout(location = 1) in vec3 instTranslate;
+layout(location = 2) in vec3 instColor;
+
+layout(location = 0) out vec3 vColor;
+
+out gl_PerVertex { vec4 gl_Position; };
+
+layout(std140, binding = 0) uniform buf {
+    mat4 mvp;
+} ubuf;
+
+void main()
+{
+    vColor = instColor;
+    mat4 t = mat4(1, 0, 0, 0,
+                  0, 1, 0, 0,
+                  0, 0, 1, 0,
+                  instTranslate.x, instTranslate.y, instTranslate.z, 1);
+    gl_Position = ubuf.mvp * t * position;
+}

tests/manual/rhi/instancing/instancing.cpp

@@ -0,0 +1,175 @@
+/****************************************************************************
+**
+** Copyright (C) 2019 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."
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#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 {
+    QVector<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->build();
+    d.releasePool << d.vbuf;
+
+    d.initialUpdates->uploadStaticBuffer(d.vbuf, cube);
+
+    // translation + color (vec3 + vec3), interleaved, for each instance
+    d.instBuf = m_r->newBuffer(QRhiBuffer::Immutable, QRhiBuffer::VertexBuffer, INSTANCE_COUNT * 6 * sizeof(float));
+    d.instBuf->build();
+    d.releasePool << d.instBuf;
+
+    d.ubuf = m_r->newBuffer(QRhiBuffer::Dynamic, QRhiBuffer::UniformBuffer, 64 + 12);
+    d.ubuf->build();
+    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->build();
+
+    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
+        { 6 * sizeof(float), QRhiVertexInputBinding::PerInstance }    // per-instance translation and color
+    });
+    inputLayout.setAttributes({
+        { 0, 0, QRhiVertexInputAttribute::Float3, 0 },                // position
+        { 1, 1, QRhiVertexInputAttribute::Float3, 0 },                // instTranslate
+        { 1, 2, QRhiVertexInputAttribute::Float3, 3 * sizeof(float) } // instColor
+    });
+    d.ps->setVertexInputLayout(inputLayout);
+    d.ps->setShaderResourceBindings(d.srb);
+    d.ps->setRenderPassDescriptor(m_rp);
+    d.ps->build();
+
+    QByteArray instData;
+    instData.resize(INSTANCE_COUNT * 6 * sizeof(float));
+    float *p = reinterpret_cast<float *>(instData.data());
+    QRandomGenerator *rgen = QRandomGenerator::global();
+    for (int i = 0; i < INSTANCE_COUNT; ++i) {
+        // translation
+        *p++ = rgen->bounded(8000) / 100.0f - 40.0f;
+        *p++ = rgen->bounded(8000) / 100.0f - 40.0f;
+        *p++ = 0.0f;
+        // 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(), QColor::fromRgbF(0.4f, 0.7f, 0.0f, 1.0f), { 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();
+}

tests/manual/rhi/instancing/instancing.pro

@@ -0,0 +1,8 @@
+TEMPLATE = app
+
+QT += gui-private
+
+SOURCES = \
+    instancing.cpp
+
+RESOURCES = instancing.qrc

tests/manual/rhi/instancing/instancing.qrc

@@ -0,0 +1,6 @@
+<!DOCTYPE RCC><RCC version="1.0">
+  <qresource>
+    <file>inst.vert.qsb</file>
+    <file>inst.frag.qsb</file>
+</qresource>
+</RCC>

tests/manual/rhi/rhi.pro

@@ -16,7 +16,8 @@ SUBDIRS += \
     mrt \
     shadowmap \
     computebuffer \
-    computeimage
+    computeimage \
+    instancing
 
 qtConfig(widgets) {
     SUBDIRS += \