rhi: Add support for arrays of combined image samplers

Introduces a new QRhiShaderResourceBinding function that takes an array
of texture-sampler pairs. The existing function is also available and is
equivalent to calling the array-based version with array size 1.

It is important to note that for Metal one needs MSL 2.0 for array of
textures, so qsb needs --msl 20 instead of --msl 12 for such shaders.

Comes with an autotest, and also updates all .qsb files for said test
with the latest shadertools.

Task-number: QTBUG-82624
Change-Id: Ibc1973aae826836f16d842c41d6c8403fd7ff876
Reviewed-by: Christian Strømme <christian.stromme@qt.io>

src/gui/rhi/qrhi.cpp

@@ -2885,16 +2885,57 @@ QRhiShaderResourceBinding QRhiShaderResourceBinding::uniformBufferWithDynamicOff
     \return a shader resource binding for the given binding number, pipeline
     stages, texture, and sampler specified by \a binding, \a stage, \a tex,
     \a sampler.
+
+    \note This function is equivalent to calling sampledTextures() with a
+    \c count of 1.
+
+    \sa sampledTextures()
  */
 QRhiShaderResourceBinding QRhiShaderResourceBinding::sampledTexture(
         int binding, StageFlags stage, QRhiTexture *tex, QRhiSampler *sampler)
 {
+    const TextureAndSampler texSampler = { tex, sampler };
+    return sampledTextures(binding, stage, 1, &texSampler);
+}
+
+/*!
+    \return a shader resource binding for the given binding number, pipeline
+    stages, and the array of texture-sampler pairs specified by \a binding, \a
+    stage, \a count, and \a texSamplers.
+
+    \note \a count must be at least 1, and not larger than 16.
+
+    \note When \a count is 1, this function is equivalent to sampledTexture().
+
+    This function is relevant when arrays of combined image samplers are
+    involved. For example, in GLSL \c{layout(binding = 5) uniform sampler2D
+    shadowMaps[8];} declares an array of combined image samplers. The
+    application is then expected provide a QRhiShaderResourceBinding for
+    binding point 5, set up by calling this function with \a count set to 8 and
+    a valid texture and sampler for each element of the array.
+
+    \warning All elements of the array must be specified. With the above
+    example, the only valid, portable approach is calling this function with a
+    \a count of 8. Additionally, all QRhiTexture and QRhiSampler instances must
+    be valid, meaning nullptr is not an accepted value. This is due to some of
+    the underlying APIs, such as, Vulkan, that require a valid image and
+    sampler object for each element in descriptor arrays. Applications are
+    advised to provide "dummy" samplers and textures if some array elements are
+    not relevant (due to not being accessed in the shader).
+
+    \sa sampledTexture()
+ */
+QRhiShaderResourceBinding QRhiShaderResourceBinding::sampledTextures(
+        int binding, StageFlags stage, int count, const TextureAndSampler *texSamplers)
+{
+    Q_ASSERT(count >= 1 && count <= Data::MAX_TEX_SAMPLER_ARRAY_SIZE);
     QRhiShaderResourceBinding b;
     b.d.binding = binding;
     b.d.stage = stage;
     b.d.type = SampledTexture;
-    b.d.u.stex.tex = tex;
-    b.d.u.stex.sampler = sampler;
+    b.d.u.stex.count = count;
+    for (int i = 0; i < count; ++i)
+        b.d.u.stex.texSamplers[i] = texSamplers[i];
     return b;
 }
 
@@ -3084,11 +3125,15 @@ bool operator==(const QRhiShaderResourceBinding &a, const QRhiShaderResourceBind
         }
         break;
     case QRhiShaderResourceBinding::SampledTexture:
-        if (da->u.stex.tex != db->u.stex.tex
-                || da->u.stex.sampler != db->u.stex.sampler)
+        if (da->u.stex.count != db->u.stex.count)
+            return false;
+        for (int i = 0; i < da->u.stex.count; ++i) {
+            if (da->u.stex.texSamplers[i].tex != db->u.stex.texSamplers[i].tex
+                    || da->u.stex.texSamplers[i].sampler != db->u.stex.texSamplers[i].sampler)
             {
                 return false;
             }
+        }
         break;
     case QRhiShaderResourceBinding::ImageLoad:
         Q_FALLTHROUGH();
@@ -3162,10 +3207,13 @@ QDebug operator<<(QDebug dbg, const QRhiShaderResourceBinding &b)
                       << ')';
         break;
     case QRhiShaderResourceBinding::SampledTexture:
-        dbg.nospace() << " SampledTexture("
-                      << "texture=" << d->u.stex.tex
-                      << " sampler=" << d->u.stex.sampler
-                      << ')';
+        dbg.nospace() << " SampledTextures("
+                      << "count=" << d->u.stex.count;
+        for (int i = 0; i < d->u.stex.count; ++i) {
+            dbg.nospace() << " texture=" << d->u.stex.texSamplers[i].tex
+                          << " sampler=" << d->u.stex.texSamplers[i].sampler;
+        }
+        dbg.nospace() << ')';
         break;
     case QRhiShaderResourceBinding::ImageLoad:
         dbg.nospace() << " ImageLoad("

src/gui/rhi/qrhi_p.h

@@ -348,6 +348,12 @@ public:
 
     static QRhiShaderResourceBinding sampledTexture(int binding, StageFlags stage, QRhiTexture *tex, QRhiSampler *sampler);
 
+    struct TextureAndSampler {
+        QRhiTexture *tex;
+        QRhiSampler *sampler;
+    };
+    static QRhiShaderResourceBinding sampledTextures(int binding, StageFlags stage, int count, const TextureAndSampler *texSamplers);
+
     static QRhiShaderResourceBinding imageLoad(int binding, StageFlags stage, QRhiTexture *tex, int level);
     static QRhiShaderResourceBinding imageStore(int binding, StageFlags stage, QRhiTexture *tex, int level);
     static QRhiShaderResourceBinding imageLoadStore(int binding, StageFlags stage, QRhiTexture *tex, int level);
@@ -370,9 +376,10 @@ public:
             int maybeSize;
             bool hasDynamicOffset;
         };
+        static const int MAX_TEX_SAMPLER_ARRAY_SIZE = 16;
         struct SampledTextureData {
-            QRhiTexture *tex;
-            QRhiSampler *sampler;
+            int count;
+            TextureAndSampler texSamplers[MAX_TEX_SAMPLER_ARRAY_SIZE];
         };
         struct StorageImageData {
             QRhiTexture *tex;

src/gui/rhi/qrhid3d11.cpp

@@ -627,18 +627,25 @@ void QRhiD3D11::setShaderResources(QRhiCommandBuffer *cb, QRhiShaderResourceBind
             break;
         case QRhiShaderResourceBinding::SampledTexture:
         {
-            QD3D11Texture *texD = QRHI_RES(QD3D11Texture, b->u.stex.tex);
-            QD3D11Sampler *samplerD = QRHI_RES(QD3D11Sampler, b->u.stex.sampler);
-            if (texD->generation != bd.stex.texGeneration
-                    || texD->m_id != bd.stex.texId
-                    || samplerD->generation != bd.stex.samplerGeneration
-                    || samplerD->m_id != bd.stex.samplerId)
+            const QRhiShaderResourceBinding::Data::SampledTextureData *data = &b->u.stex;
+            if (bd.stex.count != data->count) {
+                bd.stex.count = data->count;
+                srbUpdate = true;
+            }
+            for (int elem = 0; elem < data->count; ++elem) {
+                QD3D11Texture *texD = QRHI_RES(QD3D11Texture, data->texSamplers[elem].tex);
+                QD3D11Sampler *samplerD = QRHI_RES(QD3D11Sampler, data->texSamplers[elem].sampler);
+                if (texD->generation != bd.stex.d[elem].texGeneration
+                        || texD->m_id != bd.stex.d[elem].texId
+                        || samplerD->generation != bd.stex.d[elem].samplerGeneration
+                        || samplerD->m_id != bd.stex.d[elem].samplerId)
                 {
                     srbUpdate = true;
-                bd.stex.texId = texD->m_id;
-                bd.stex.texGeneration = texD->generation;
-                bd.stex.samplerId = samplerD->m_id;
-                bd.stex.samplerGeneration = samplerD->generation;
+                    bd.stex.d[elem].texId = texD->m_id;
+                    bd.stex.d[elem].texGeneration = texD->generation;
+                    bd.stex.d[elem].samplerId = samplerD->m_id;
+                    bd.stex.d[elem].samplerGeneration = samplerD->generation;
+                }
             }
         }
             break;
@@ -1894,31 +1901,38 @@ void QRhiD3D11::updateShaderResourceBindings(QD3D11ShaderResourceBindings *srbD,
             break;
         case QRhiShaderResourceBinding::SampledTexture:
         {
-            QD3D11Texture *texD = QRHI_RES(QD3D11Texture, b->u.stex.tex);
-            QD3D11Sampler *samplerD = QRHI_RES(QD3D11Sampler, b->u.stex.sampler);
-            bd.stex.texId = texD->m_id;
-            bd.stex.texGeneration = texD->generation;
-            bd.stex.samplerId = samplerD->m_id;
-            bd.stex.samplerGeneration = samplerD->generation;
+            const QRhiShaderResourceBinding::Data::SampledTextureData *data = &b->u.stex;
+            bd.stex.count = data->count;
+            const QPair<int, int> nativeBindingVert = mapBinding(b->binding, RBM_VERTEX, nativeResourceBindingMaps);
+            const QPair<int, int> nativeBindingFrag = mapBinding(b->binding, RBM_FRAGMENT, nativeResourceBindingMaps);
+            const QPair<int, int> nativeBindingComp = mapBinding(b->binding, RBM_COMPUTE, nativeResourceBindingMaps);
+            // if SPIR-V binding b is mapped to tN and sN in HLSL, and it
+            // is an array, then it will use tN, tN+1, tN+2, ..., and sN,
+            // sN+1, sN+2, ...
+            for (int elem = 0; elem < data->count; ++elem) {
+                QD3D11Texture *texD = QRHI_RES(QD3D11Texture, data->texSamplers[elem].tex);
+                QD3D11Sampler *samplerD = QRHI_RES(QD3D11Sampler, data->texSamplers[elem].sampler);
+                bd.stex.d[elem].texId = texD->m_id;
+                bd.stex.d[elem].texGeneration = texD->generation;
+                bd.stex.d[elem].samplerId = samplerD->m_id;
+                bd.stex.d[elem].samplerGeneration = samplerD->generation;
                 if (b->stage.testFlag(QRhiShaderResourceBinding::VertexStage)) {
-                QPair<int, int> nativeBinding = mapBinding(b->binding, RBM_VERTEX, nativeResourceBindingMaps);
-                if (nativeBinding.first >= 0 && nativeBinding.second >= 0) {
-                    res[RBM_VERTEX].textures.append({ nativeBinding.first, texD->srv });
-                    res[RBM_VERTEX].samplers.append({ nativeBinding.second, samplerD->samplerState });
+                    if (nativeBindingVert.first >= 0 && nativeBindingVert.second >= 0) {
+                        res[RBM_VERTEX].textures.append({ nativeBindingVert.first + elem, texD->srv });
+                        res[RBM_VERTEX].samplers.append({ nativeBindingVert.second + elem, samplerD->samplerState });
                     }
                 }
                 if (b->stage.testFlag(QRhiShaderResourceBinding::FragmentStage)) {
-                QPair<int, int> nativeBinding = mapBinding(b->binding, RBM_FRAGMENT, nativeResourceBindingMaps);
-                if (nativeBinding.first >= 0 && nativeBinding.second >= 0) {
-                    res[RBM_FRAGMENT].textures.append({ nativeBinding.first, texD->srv });
-                    res[RBM_FRAGMENT].samplers.append({ nativeBinding.second, samplerD->samplerState });
+                    if (nativeBindingFrag.first >= 0 && nativeBindingFrag.second >= 0) {
+                        res[RBM_FRAGMENT].textures.append({ nativeBindingFrag.first + elem, texD->srv });
+                        res[RBM_FRAGMENT].samplers.append({ nativeBindingFrag.second + elem, samplerD->samplerState });
                     }
                 }
                 if (b->stage.testFlag(QRhiShaderResourceBinding::ComputeStage)) {
-                QPair<int, int> nativeBinding = mapBinding(b->binding, RBM_COMPUTE, nativeResourceBindingMaps);
-                if (nativeBinding.first >= 0 && nativeBinding.second >= 0) {
-                    res[RBM_COMPUTE].textures.append({ nativeBinding.first, texD->srv });
-                    res[RBM_COMPUTE].samplers.append({ nativeBinding.second, samplerD->samplerState });
+                    if (nativeBindingComp.first >= 0 && nativeBindingComp.second >= 0) {
+                        res[RBM_COMPUTE].textures.append({ nativeBindingComp.first + elem, texD->srv });
+                        res[RBM_COMPUTE].samplers.append({ nativeBindingComp.second + elem, samplerD->samplerState });
+                    }
                 }
             }
         }
@@ -3529,11 +3543,15 @@ static pD3DCompile resolveD3DCompile()
 
 static QByteArray compileHlslShaderSource(const QShader &shader, QShader::Variant shaderVariant, QString *error, QShaderKey *usedShaderKey)
 {
-    QShaderCode dxbc = shader.shader({ QShader::DxbcShader, 50, shaderVariant });
-    if (!dxbc.shader().isEmpty())
+    QShaderKey key = { QShader::DxbcShader, 50, shaderVariant };
+    QShaderCode dxbc = shader.shader(key);
+    if (!dxbc.shader().isEmpty()) {
+        if (usedShaderKey)
+            *usedShaderKey = key;
         return dxbc.shader();
+    }
 
-    const QShaderKey key = { QShader::HlslShader, 50, shaderVariant };
+    key = { QShader::HlslShader, 50, shaderVariant };
     QShaderCode hlslSource = shader.shader(key);
     if (hlslSource.shader().isEmpty()) {
         qWarning() << "No HLSL (shader model 5.0) code found in baked shader" << shader;

src/gui/rhi/qrhid3d11_p_p.h

@@ -210,10 +210,13 @@ struct QD3D11ShaderResourceBindings : public QRhiShaderResourceBindings
         uint generation;
     };
     struct BoundSampledTextureData {
+        int count;
+        struct {
             quint64 texId;
             uint texGeneration;
             quint64 samplerId;
             uint samplerGeneration;
+        } d[QRhiShaderResourceBinding::Data::MAX_TEX_SAMPLER_ARRAY_SIZE];
     };
     struct BoundStorageImageData {
         quint64 id;

src/gui/rhi/qrhigles2.cpp

@@ -919,10 +919,12 @@ void QRhiGles2::setShaderResources(QRhiCommandBuffer *cb, QRhiShaderResourceBind
                 hasDynamicOffsetInSrb = true;
             break;
         case QRhiShaderResourceBinding::SampledTexture:
+            for (int elem = 0; elem < b->u.stex.count; ++elem) {
                 trackedRegisterTexture(&passResTracker,
-                                   QRHI_RES(QGles2Texture, b->u.stex.tex),
+                                       QRHI_RES(QGles2Texture, b->u.stex.texSamplers[elem].tex),
                                        QRhiPassResourceTracker::TexSample,
                                        QRhiPassResourceTracker::toPassTrackerTextureStage(b->stage));
+            }
             break;
         case QRhiShaderResourceBinding::ImageLoad:
         case QRhiShaderResourceBinding::ImageStore:
@@ -2574,11 +2576,11 @@ void QRhiGles2::bindShaderResources(QRhiGraphicsPipeline *maybeGraphicsPs, QRhiC
             break;
         case QRhiShaderResourceBinding::SampledTexture:
         {
-            QGles2Texture *texD = QRHI_RES(QGles2Texture, b->u.stex.tex);
-            QGles2Sampler *samplerD = QRHI_RES(QGles2Sampler, b->u.stex.sampler);
             QVector<QGles2SamplerDescription> &samplers(maybeGraphicsPs ? QRHI_RES(QGles2GraphicsPipeline, maybeGraphicsPs)->samplers
                                                                         : QRHI_RES(QGles2ComputePipeline, maybeComputePs)->samplers);
-
+            for (int elem = 0; elem < b->u.stex.count; ++elem) {
+                QGles2Texture *texD = QRHI_RES(QGles2Texture, b->u.stex.texSamplers[elem].tex);
+                QGles2Sampler *samplerD = QRHI_RES(QGles2Sampler, b->u.stex.texSamplers[elem].sampler);
                 for (QGles2SamplerDescription &sampler : samplers) {
                     if (sampler.binding == b->binding) {
                         f->glActiveTexture(GL_TEXTURE0 + uint(texUnit));
@@ -2602,11 +2604,12 @@ void QRhiGles2::bindShaderResources(QRhiGraphicsPipeline *maybeGraphicsPs, QRhiC
                             texD->samplerState = samplerD->d;
                         }
 
-                    f->glUniform1i(sampler.glslLocation, texUnit);
+                        f->glUniform1i(sampler.glslLocation + elem, texUnit);
                         ++texUnit;
                     }
                 }
             }
+        }
             break;
         case QRhiShaderResourceBinding::ImageLoad:
         case QRhiShaderResourceBinding::ImageStore:

src/gui/rhi/qrhimetal.mm

@@ -748,30 +748,33 @@ void QRhiMetal::enqueueShaderResourceBindings(QMetalShaderResourceBindings *srbD
             break;
         case QRhiShaderResourceBinding::SampledTexture:
         {
-            QMetalTexture *texD = QRHI_RES(QMetalTexture, b->u.stex.tex);
-            QMetalSampler *samplerD = QRHI_RES(QMetalSampler, b->u.stex.sampler);
+            const QRhiShaderResourceBinding::Data::SampledTextureData *data = &b->u.stex;
+            for (int elem = 0; elem < data->count; ++elem) {
+                QMetalTexture *texD = QRHI_RES(QMetalTexture, b->u.stex.texSamplers[elem].tex);
+                QMetalSampler *samplerD = QRHI_RES(QMetalSampler, b->u.stex.texSamplers[elem].sampler);
                 if (b->stage.testFlag(QRhiShaderResourceBinding::VertexStage)) {
                     const int nativeBindingTexture = mapBinding(b->binding, VERTEX, nativeResourceBindingMaps, BindingType::Texture);
                     const int nativeBindingSampler = mapBinding(b->binding, VERTEX, nativeResourceBindingMaps, BindingType::Sampler);
                     if (nativeBindingTexture >= 0 && nativeBindingSampler >= 0) {
-                    res[VERTEX].textures.append({ nativeBindingTexture, texD->d->tex });
-                    res[VERTEX].samplers.append({ nativeBindingSampler, samplerD->d->samplerState });
+                        res[VERTEX].textures.append({ nativeBindingTexture + elem, texD->d->tex });
+                        res[VERTEX].samplers.append({ nativeBindingSampler + elem, samplerD->d->samplerState });
                     }
                 }
                 if (b->stage.testFlag(QRhiShaderResourceBinding::FragmentStage)) {
                     const int nativeBindingTexture = mapBinding(b->binding, FRAGMENT, nativeResourceBindingMaps, BindingType::Texture);
                     const int nativeBindingSampler = mapBinding(b->binding, FRAGMENT, nativeResourceBindingMaps, BindingType::Sampler);
                     if (nativeBindingTexture >= 0 && nativeBindingSampler >= 0) {
-                    res[FRAGMENT].textures.append({ nativeBindingTexture, texD->d->tex });
-                    res[FRAGMENT].samplers.append({ nativeBindingSampler, samplerD->d->samplerState });
+                        res[FRAGMENT].textures.append({ nativeBindingTexture + elem, texD->d->tex });
+                        res[FRAGMENT].samplers.append({ nativeBindingSampler + elem, samplerD->d->samplerState });
                     }
                 }
                 if (b->stage.testFlag(QRhiShaderResourceBinding::ComputeStage)) {
                     const int nativeBindingTexture = mapBinding(b->binding, COMPUTE, nativeResourceBindingMaps, BindingType::Texture);
                     const int nativeBindingSampler = mapBinding(b->binding, COMPUTE, nativeResourceBindingMaps, BindingType::Sampler);
                     if (nativeBindingTexture >= 0 && nativeBindingSampler >= 0) {
-                    res[COMPUTE].textures.append({ nativeBindingTexture, texD->d->tex });
-                    res[COMPUTE].samplers.append({ nativeBindingSampler, samplerD->d->samplerState });
+                        res[COMPUTE].textures.append({ nativeBindingTexture + elem, texD->d->tex });
+                        res[COMPUTE].samplers.append({ nativeBindingSampler + elem, samplerD->d->samplerState });
+                    }
                 }
             }
         }
@@ -1020,22 +1023,29 @@ void QRhiMetal::setShaderResources(QRhiCommandBuffer *cb, QRhiShaderResourceBind
             break;
         case QRhiShaderResourceBinding::SampledTexture:
         {
-            QMetalTexture *texD = QRHI_RES(QMetalTexture, b->u.stex.tex);
-            QMetalSampler *samplerD = QRHI_RES(QMetalSampler, b->u.stex.sampler);
-            if (texD->generation != bd.stex.texGeneration
-                    || texD->m_id != bd.stex.texId
-                    || samplerD->generation != bd.stex.samplerGeneration
-                    || samplerD->m_id != bd.stex.samplerId)
+            const QRhiShaderResourceBinding::Data::SampledTextureData *data = &b->u.stex;
+            if (bd.stex.count != data->count) {
+                bd.stex.count = data->count;
+                resNeedsRebind = true;
+            }
+            for (int elem = 0; elem < data->count; ++elem) {
+                QMetalTexture *texD = QRHI_RES(QMetalTexture, data->texSamplers[elem].tex);
+                QMetalSampler *samplerD = QRHI_RES(QMetalSampler, data->texSamplers[elem].sampler);
+                if (texD->generation != bd.stex.d[elem].texGeneration
+                        || texD->m_id != bd.stex.d[elem].texId
+                        || samplerD->generation != bd.stex.d[elem].samplerGeneration
+                        || samplerD->m_id != bd.stex.d[elem].samplerId)
                 {
                     resNeedsRebind = true;
-                bd.stex.texId = texD->m_id;
-                bd.stex.texGeneration = texD->generation;
-                bd.stex.samplerId = samplerD->m_id;
-                bd.stex.samplerGeneration = samplerD->generation;
+                    bd.stex.d[elem].texId = texD->m_id;
+                    bd.stex.d[elem].texGeneration = texD->generation;
+                    bd.stex.d[elem].samplerId = samplerD->m_id;
+                    bd.stex.d[elem].samplerGeneration = samplerD->generation;
                 }
                 texD->lastActiveFrameSlot = currentFrameSlot;
                 samplerD->lastActiveFrameSlot = currentFrameSlot;
             }
+        }
             break;
         case QRhiShaderResourceBinding::ImageLoad:
         case QRhiShaderResourceBinding::ImageStore:
@@ -2981,12 +2991,16 @@ bool QMetalShaderResourceBindings::build()
             break;
         case QRhiShaderResourceBinding::SampledTexture:
         {
-            QMetalTexture *texD = QRHI_RES(QMetalTexture, b->u.stex.tex);
-            QMetalSampler *samplerD = QRHI_RES(QMetalSampler, b->u.stex.sampler);
-            bd.stex.texId = texD->m_id;
-            bd.stex.texGeneration = texD->generation;
-            bd.stex.samplerId = samplerD->m_id;
-            bd.stex.samplerGeneration = samplerD->generation;
+            const QRhiShaderResourceBinding::Data::SampledTextureData *data = &b->u.stex;
+            bd.stex.count = data->count;
+            for (int elem = 0; elem < data->count; ++elem) {
+                QMetalTexture *texD = QRHI_RES(QMetalTexture, data->texSamplers[elem].tex);
+                QMetalSampler *samplerD = QRHI_RES(QMetalSampler, data->texSamplers[elem].sampler);
+                bd.stex.d[elem].texId = texD->m_id;
+                bd.stex.d[elem].texGeneration = texD->generation;
+                bd.stex.d[elem].samplerId = samplerD->m_id;
+                bd.stex.d[elem].samplerGeneration = samplerD->generation;
+            }
         }
             break;
         case QRhiShaderResourceBinding::ImageLoad:
@@ -3241,8 +3255,12 @@ static inline MTLCullMode toMetalCullMode(QRhiGraphicsPipeline::CullMode c)
 id<MTLLibrary> QRhiMetalData::createMetalLib(const QShader &shader, QShader::Variant shaderVariant,
                                              QString *error, QByteArray *entryPoint, QShaderKey *activeKey)
 {
-    QShaderKey key = { QShader::MetalLibShader, 12, shaderVariant };
+    QShaderKey key = { QShader::MetalLibShader, 20, shaderVariant };
     QShaderCode mtllib = shader.shader(key);
+    if (mtllib.shader().isEmpty()) {
+        key.setSourceVersion(12);
+        mtllib = shader.shader(key);
+    }
     if (!mtllib.shader().isEmpty()) {
         dispatch_data_t data = dispatch_data_create(mtllib.shader().constData(),
                                                     size_t(mtllib.shader().size()),
@@ -3261,16 +3279,20 @@ id<MTLLibrary> QRhiMetalData::createMetalLib(const QShader &shader, QShader::Var
         }
     }
 
-    key = { QShader::MslShader, 12, shaderVariant };
+    key = { QShader::MslShader, 20, shaderVariant };
     QShaderCode mslSource = shader.shader(key);
     if (mslSource.shader().isEmpty()) {
-        qWarning() << "No MSL 1.2 code found in baked shader" << shader;
+        key.setSourceVersion(12);
+        mslSource = shader.shader(key);
+    }
+    if (mslSource.shader().isEmpty()) {
+        qWarning() << "No MSL 2.0 or 1.2 code found in baked shader" << shader;
         return nil;
     }
 
     NSString *src = [NSString stringWithUTF8String: mslSource.shader().constData()];
     MTLCompileOptions *opts = [[MTLCompileOptions alloc] init];
-    opts.languageVersion = MTLLanguageVersion1_2;
+    opts.languageVersion = key.sourceVersion() == 20 ? MTLLanguageVersion2_0 : MTLLanguageVersion1_2;
     NSError *err = nil;
     id<MTLLibrary> lib = [dev newLibraryWithSource: src options: opts error: &err];
     [opts release];

src/gui/rhi/qrhimetal_p_p.h

@@ -197,10 +197,13 @@ struct QMetalShaderResourceBindings : public QRhiShaderResourceBindings
         uint generation;
     };
     struct BoundSampledTextureData {
+        int count;
+        struct {
             quint64 texId;
             uint texGeneration;
             quint64 samplerId;
             uint samplerGeneration;
+        } d[QRhiShaderResourceBinding::Data::MAX_TEX_SAMPLER_ARRAY_SIZE];
     };
     struct BoundStorageImageData {
         quint64 id;

src/gui/rhi/qrhivulkan.cpp

@@ -2487,7 +2487,8 @@ void QRhiVulkan::updateShaderResourceBindings(QRhiShaderResourceBindings *srb, i
     QVkShaderResourceBindings *srbD = QRHI_RES(QVkShaderResourceBindings, srb);
 
     QVarLengthArray<VkDescriptorBufferInfo, 8> bufferInfos;
-    QVarLengthArray<VkDescriptorImageInfo, 8> imageInfos;
+    using ArrayOfImageDesc = QVarLengthArray<VkDescriptorImageInfo, 8>;
+    QVarLengthArray<ArrayOfImageDesc, 8> imageInfos;
     QVarLengthArray<VkWriteDescriptorSet, 12> writeInfos;
     QVarLengthArray<QPair<int, int>, 12> infoIndices;
 
@@ -2530,17 +2531,22 @@ void QRhiVulkan::updateShaderResourceBindings(QRhiShaderResourceBindings *srb, i
                 break;
             case QRhiShaderResourceBinding::SampledTexture:
             {
-                QVkTexture *texD = QRHI_RES(QVkTexture, b->u.stex.tex);
-                QVkSampler *samplerD = QRHI_RES(QVkSampler, b->u.stex.sampler);
+                const QRhiShaderResourceBinding::Data::SampledTextureData *data = &b->u.stex;
+                writeInfo.descriptorCount = data->count; // arrays of combined image samplers are supported
                 writeInfo.descriptorType = VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER;
-                bd.stex.texId = texD->m_id;
-                bd.stex.texGeneration = texD->generation;
-                bd.stex.samplerId = samplerD->m_id;
-                bd.stex.samplerGeneration = samplerD->generation;
-                VkDescriptorImageInfo imageInfo;
-                imageInfo.sampler = samplerD->sampler;
-                imageInfo.imageView = texD->imageView;
-                imageInfo.imageLayout = VK_IMAGE_LAYOUT_SHADER_READ_ONLY_OPTIMAL;
+                ArrayOfImageDesc imageInfo(data->count);
+                for (int elem = 0; elem < data->count; ++elem) {
+                    QVkTexture *texD = QRHI_RES(QVkTexture, data->texSamplers[elem].tex);
+                    QVkSampler *samplerD = QRHI_RES(QVkSampler, data->texSamplers[elem].sampler);
+                    bd.stex.d[elem].texId = texD->m_id;
+                    bd.stex.d[elem].texGeneration = texD->generation;
+                    bd.stex.d[elem].samplerId = samplerD->m_id;
+                    bd.stex.d[elem].samplerGeneration = samplerD->generation;
+                    imageInfo[elem].sampler = samplerD->sampler;
+                    imageInfo[elem].imageView = texD->imageView;
+                    imageInfo[elem].imageLayout = VK_IMAGE_LAYOUT_SHADER_READ_ONLY_OPTIMAL;
+                }
+                bd.stex.count = data->count;
                 imageInfoIndex = imageInfos.count();
                 imageInfos.append(imageInfo);
             }
@@ -2555,10 +2561,10 @@ void QRhiVulkan::updateShaderResourceBindings(QRhiShaderResourceBindings *srb, i
                     writeInfo.descriptorType = VK_DESCRIPTOR_TYPE_STORAGE_IMAGE;
                     bd.simage.id = texD->m_id;
                     bd.simage.generation = texD->generation;
-                    VkDescriptorImageInfo imageInfo;
-                    imageInfo.sampler = VK_NULL_HANDLE;
-                    imageInfo.imageView = view;
-                    imageInfo.imageLayout = VK_IMAGE_LAYOUT_GENERAL;
+                    ArrayOfImageDesc imageInfo(1);
+                    imageInfo[0].sampler = VK_NULL_HANDLE;
+                    imageInfo[0].imageView = view;
+                    imageInfo[0].imageLayout = VK_IMAGE_LAYOUT_GENERAL;
                     imageInfoIndex = imageInfos.count();
                     imageInfos.append(imageInfo);
                 }
@@ -2596,7 +2602,7 @@ void QRhiVulkan::updateShaderResourceBindings(QRhiShaderResourceBindings *srb, i
         if (bufferInfoIndex >= 0)
             writeInfos[i].pBufferInfo = &bufferInfos[bufferInfoIndex];
         else if (imageInfoIndex >= 0)
-            writeInfos[i].pImageInfo = &imageInfos[imageInfoIndex];
+            writeInfos[i].pImageInfo = imageInfos[imageInfoIndex].constData();
     }
 
     df->vkUpdateDescriptorSets(dev, uint32_t(writeInfos.count()), writeInfos.constData(), 0, nullptr);
@@ -4210,24 +4216,30 @@ void QRhiVulkan::setShaderResources(QRhiCommandBuffer *cb, QRhiShaderResourceBin
             break;
         case QRhiShaderResourceBinding::SampledTexture:
         {
-            QVkTexture *texD = QRHI_RES(QVkTexture, b->u.stex.tex);
-            QVkSampler *samplerD = QRHI_RES(QVkSampler, b->u.stex.sampler);
+            const QRhiShaderResourceBinding::Data::SampledTextureData *data = &b->u.stex;
+            if (bd.stex.count != data->count) {
+                bd.stex.count = data->count;
+                rewriteDescSet = true;
+            }
+            for (int elem = 0; elem < data->count; ++elem) {
+                QVkTexture *texD = QRHI_RES(QVkTexture, data->texSamplers[elem].tex);
+                QVkSampler *samplerD = QRHI_RES(QVkSampler, data->texSamplers[elem].sampler);
                 texD->lastActiveFrameSlot = currentFrameSlot;
                 samplerD->lastActiveFrameSlot = currentFrameSlot;
                 trackedRegisterTexture(&passResTracker, texD,
                                        QRhiPassResourceTracker::TexSample,
                                        QRhiPassResourceTracker::toPassTrackerTextureStage(b->stage));
-
-            if (texD->generation != bd.stex.texGeneration
-                    || texD->m_id != bd.stex.texId
-                    || samplerD->generation != bd.stex.samplerGeneration
-                    || samplerD->m_id != bd.stex.samplerId)
+                if (texD->generation != bd.stex.d[elem].texGeneration
+                        || texD->m_id != bd.stex.d[elem].texId
+                        || samplerD->generation != bd.stex.d[elem].samplerGeneration
+                        || samplerD->m_id != bd.stex.d[elem].samplerId)
                 {
                     rewriteDescSet = true;
-                bd.stex.texId = texD->m_id;
-                bd.stex.texGeneration = texD->generation;
-                bd.stex.samplerId = samplerD->m_id;
-                bd.stex.samplerGeneration = samplerD->generation;
+                    bd.stex.d[elem].texId = texD->m_id;
+                    bd.stex.d[elem].texGeneration = texD->generation;
+                    bd.stex.d[elem].samplerId = samplerD->m_id;
+                    bd.stex.d[elem].samplerGeneration = samplerD->generation;
+                }
             }
         }
             break;
@@ -6065,7 +6077,10 @@ bool QVkShaderResourceBindings::build()
         memset(&vkbinding, 0, sizeof(vkbinding));
         vkbinding.binding = uint32_t(b->binding);
         vkbinding.descriptorType = toVkDescriptorType(b);
-        vkbinding.descriptorCount = 1; // no array support yet
+        if (b->type == QRhiShaderResourceBinding::SampledTexture)
+            vkbinding.descriptorCount = b->u.stex.count;
+        else
+            vkbinding.descriptorCount = 1;
         vkbinding.stageFlags = toVkShaderStageFlags(b->stage);
         vkbindings.append(vkbinding);
     }

src/gui/rhi/qrhivulkan_p_p.h

@@ -254,10 +254,13 @@ struct QVkShaderResourceBindings : public QRhiShaderResourceBindings
         uint generation;
     };
     struct BoundSampledTextureData {
+        int count;
+        struct {
             quint64 texId;
             uint texGeneration;
             quint64 samplerId;
             uint samplerGeneration;
+        } d[QRhiShaderResourceBinding::Data::MAX_TEX_SAMPLER_ARRAY_SIZE];
     };
     struct BoundStorageImageData {
         quint64 id;

tests/auto/gui/rhi/qrhi/data/buildshaders.bat

@@ -44,5 +44,6 @@ qsb --glsl "150,120,100 es" --hlsl 50 -c --msl 12 -o simple.vert.qsb simple.vert
 qsb --glsl "150,120,100 es" --hlsl 50 -c --msl 12 -o simple.frag.qsb simple.frag
 qsb --glsl "150,120,100 es" --hlsl 50 -c --msl 12 -o simpletextured.vert.qsb simpletextured.vert
 qsb --glsl "150,120,100 es" --hlsl 50 -c --msl 12 -o simpletextured.frag.qsb simpletextured.frag
+qsb --glsl "150,120,100 es" --hlsl 50 -c --msl 20 -o simpletextured_array.frag.qsb simpletextured_array.frag
 qsb --glsl "150,120,100 es" --hlsl 50 -c --msl 12 -o textured.vert.qsb textured.vert
 qsb --glsl "150,120,100 es" --hlsl 50 -c --msl 12 -o textured.frag.qsb textured.frag

tests/auto/gui/rhi/qrhi/data/simpletextured_array.frag

@@ -0,0 +1,17 @@
+#version 440
+
+layout(location = 0) in vec2 uv;
+layout(location = 0) out vec4 fragColor;
+
+layout(binding = 0) uniform sampler2D tex[3];
+
+void main()
+{
+    vec4 c0 = texture(tex[0], uv);
+    vec4 c1 = texture(tex[1], uv);
+    vec4 c2 = texture(tex[2], uv);
+    vec4 cc = c0 + c1 + c2;
+    vec4 c = vec4(clamp(cc.r, 0.0, 1.0), clamp(cc.g, 0.0, 1.0), clamp(cc.b, 0.0, 1.0), clamp(cc.a, 0.0, 1.0));
+    c.rgb *= c.a;
+    fragColor = c;
+}

tests/auto/gui/rhi/qrhi/tst_qrhi.cpp

@@ -91,6 +91,8 @@ private slots:
     void renderToTextureSimple();
     void renderToTextureTexturedQuad_data();
     void renderToTextureTexturedQuad();
+    void renderToTextureArrayOfTexturedQuad_data();
+    void renderToTextureArrayOfTexturedQuad();
     void renderToTextureTexturedQuadAndUniformBuffer_data();
     void renderToTextureTexturedQuadAndUniformBuffer();
     void renderToWindowSimple_data();
@@ -1468,6 +1470,147 @@ void tst_QRhi::renderToTextureTexturedQuad()
     QVERIFY(qGreen(result.pixel(214, 191)) > 2 * qBlue(result.pixel(214, 191)));
 }
 
+void tst_QRhi::renderToTextureArrayOfTexturedQuad_data()
+{
+    rhiTestData();
+}
+
+void tst_QRhi::renderToTextureArrayOfTexturedQuad()
+{
+    QFETCH(QRhi::Implementation, impl);
+    QFETCH(QRhiInitParams *, initParams);
+
+    QScopedPointer<QRhi> rhi(QRhi::create(impl, initParams, QRhi::Flags(), nullptr));
+    if (!rhi)
+        QSKIP("QRhi could not be created, skipping testing rendering");
+
+    QImage inputImage;
+    inputImage.load(QLatin1String(":/data/qt256.png"));
+    QVERIFY(!inputImage.isNull());
+
+    QScopedPointer<QRhiTexture> texture(rhi->newTexture(QRhiTexture::RGBA8, inputImage.size(), 1,
+                                                        QRhiTexture::RenderTarget | QRhiTexture::UsedAsTransferSource));
+    QVERIFY(texture->build());
+
+    QScopedPointer<QRhiTextureRenderTarget> rt(rhi->newTextureRenderTarget({ texture.data() }));
+    QScopedPointer<QRhiRenderPassDescriptor> rpDesc(rt->newCompatibleRenderPassDescriptor());
+    rt->setRenderPassDescriptor(rpDesc.data());
+    QVERIFY(rt->build());
+
+    QRhiCommandBuffer *cb = nullptr;
+    QVERIFY(rhi->beginOffscreenFrame(&cb) == QRhi::FrameOpSuccess);
+    QVERIFY(cb);
+
+    QRhiResourceUpdateBatch *updates = rhi->nextResourceUpdateBatch();
+
+    static const float verticesUvs[] = {
+        -1.0f, -1.0f,   0.0f, 0.0f,
+        1.0f, -1.0f,    1.0f, 0.0f,
+        -1.0f, 1.0f,    0.0f, 1.0f,
+        1.0f, 1.0f,     1.0f, 1.0f
+    };
+    QScopedPointer<QRhiBuffer> vbuf(rhi->newBuffer(QRhiBuffer::Immutable, QRhiBuffer::VertexBuffer, sizeof(verticesUvs)));
+    QVERIFY(vbuf->build());
+    updates->uploadStaticBuffer(vbuf.data(), verticesUvs);
+
+    // In this test we pass 3 textures (and samplers) to the fragment shader in
+    // form of an array of combined image samplers.
+
+    QScopedPointer<QRhiTexture> inputTexture(rhi->newTexture(QRhiTexture::RGBA8, inputImage.size()));
+    QVERIFY(inputTexture->build());
+    updates->uploadTexture(inputTexture.data(), inputImage);
+
+    QImage redImage(inputImage.size(), QImage::Format_RGBA8888);
+    redImage.fill(Qt::red);
+
+    QScopedPointer<QRhiTexture> redTexture(rhi->newTexture(QRhiTexture::RGBA8, inputImage.size()));
+    QVERIFY(redTexture->build());
+    updates->uploadTexture(redTexture.data(), redImage);
+
+    QImage greenImage(inputImage.size(), QImage::Format_RGBA8888);
+    greenImage.fill(Qt::green);
+
+    QScopedPointer<QRhiTexture> greenTexture(rhi->newTexture(QRhiTexture::RGBA8, inputImage.size()));
+    QVERIFY(greenTexture->build());
+    updates->uploadTexture(greenTexture.data(), greenImage);
+
+    QScopedPointer<QRhiSampler> sampler(rhi->newSampler(QRhiSampler::Nearest, QRhiSampler::Nearest, QRhiSampler::None,
+                                                        QRhiSampler::ClampToEdge, QRhiSampler::ClampToEdge));
+    QVERIFY(sampler->build());
+
+    QScopedPointer<QRhiShaderResourceBindings> srb(rhi->newShaderResourceBindings());
+    QRhiShaderResourceBinding::TextureAndSampler texSamplers[3] = {
+        { inputTexture.data(), sampler.data() },
+        { redTexture.data(), sampler.data() },
+        { greenTexture.data(), sampler.data() }
+    };
+    srb->setBindings({
+                         QRhiShaderResourceBinding::sampledTextures(0, QRhiShaderResourceBinding::FragmentStage, 3, texSamplers)
+                     });
+    QVERIFY(srb->build());
+
+    QScopedPointer<QRhiGraphicsPipeline> pipeline(rhi->newGraphicsPipeline());
+    pipeline->setTopology(QRhiGraphicsPipeline::TriangleStrip);
+    QShader vs = loadShader(":/data/simpletextured.vert.qsb");
+    QVERIFY(vs.isValid());
+    QShader fs = loadShader(":/data/simpletextured_array.frag.qsb");
+    QVERIFY(fs.isValid());
+    pipeline->setShaderStages({ { QRhiShaderStage::Vertex, vs }, { QRhiShaderStage::Fragment, fs } });
+    QRhiVertexInputLayout inputLayout;
+    inputLayout.setBindings({ { 4 * sizeof(float) } });
+    inputLayout.setAttributes({
+                                  { 0, 0, QRhiVertexInputAttribute::Float2, 0 },
+                                  { 0, 1, QRhiVertexInputAttribute::Float2, 2 * sizeof(float) }
+                              });
+    pipeline->setVertexInputLayout(inputLayout);
+    pipeline->setShaderResourceBindings(srb.data());
+    pipeline->setRenderPassDescriptor(rpDesc.data());
+
+    QVERIFY(pipeline->build());
+
+    cb->beginPass(rt.data(), Qt::black, { 1.0f, 0 }, updates);
+    cb->setGraphicsPipeline(pipeline.data());
+    cb->setShaderResources();
+    cb->setViewport({ 0, 0, float(texture->pixelSize().width()), float(texture->pixelSize().height()) });
+    QRhiCommandBuffer::VertexInput vbindings(vbuf.data(), 0);
+    cb->setVertexInput(0, 1, &vbindings);
+    cb->draw(4);
+
+    QRhiReadbackResult readResult;
+    QImage result;
+    readResult.completed = [&readResult, &result] {
+        result = QImage(reinterpret_cast<const uchar *>(readResult.data.constData()),
+                        readResult.pixelSize.width(), readResult.pixelSize.height(),
+                        QImage::Format_RGBA8888_Premultiplied);
+    };
+    QRhiResourceUpdateBatch *readbackBatch = rhi->nextResourceUpdateBatch();
+    readbackBatch->readBackTexture({ texture.data() }, &readResult);
+    cb->endPass(readbackBatch);
+
+    rhi->endOffscreenFrame();
+
+    QVERIFY(!result.isNull());
+
+    if (impl == QRhi::Null)
+        return;
+
+    // Flip with D3D and Metal because these have Y down in images. Vulkan does
+    // not need this because there Y is down both in images and in NDC, which
+    // just happens to give correct results with our OpenGL-targeted vertex and
+    // UV data.
+    if (rhi->isYUpInFramebuffer() != rhi->isYUpInNDC())
+        result = std::move(result).mirrored();
+
+    // we added the input image + red + green together, so red and green must be all 1
+    for (int y = 0; y < result.height(); ++y) {
+        for (int x = 0; x < result.width(); ++x) {
+            const QRgb pixel = result.pixel(x, y);
+            QCOMPARE(qRed(pixel), 255);
+            QCOMPARE(qGreen(pixel), 255);
+        }
+    }
+}
+
 void tst_QRhi::renderToTextureTexturedQuadAndUniformBuffer_data()
 {
     rhiTestData();