rhi: Add support for 3D textures

Supported on OpenGL (and ES) 3.0+ and everywhere else.

Can also be a render target, targeting a single slice at a time.

Can be mipmapped, cannot be multisample.

Reading back a given slice from a 3D texture is left as a future
exercise, for now it is documented to be not supported.

Upload is going to be limited to one slice in one upload entry,
just like we specify one face or one miplevel for cubemap and
mipmapped textures.

This also involves some welcome hardening of how texture subresources
are described internally: as we no longer can count on a layer index
between 0..5 (as is the case with cubemaps), simply arrays with
MAX_LAYER==6 are no longer sufficient. Switch to sufficiently dynamic
data structures where applicable.

On Vulkan rendering to a slice needs Vulkan 1.1 (and 1.1 enabled on the
VkInstance).

Task-number: QTBUG-89703
Change-Id: Ide6c20124ec9201d94ffc339dd479cd1ece777b0
Reviewed-by: Andy Nichols <andy.nichols@qt.io>

1 files changed, 16 insertions, 5 deletions

diff --git a/src/gui/rhi/qrhi_p.h b/src/gui/rhi/qrhi_p.h
index c915f8df0d..c2a09b7edf 100644
--- a/src/gui/rhi/qrhi_p.h
+++ b/src/gui/rhi/qrhi_p.h
@@ -753,7 +753,8 @@ public:
         UsedWithGenerateMips = 1 << 6,
         UsedWithLoadStore = 1 << 7,
         UsedAsCompressedAtlas = 1 << 8,
-        ExternalOES = 1 << 9
+        ExternalOES = 1 << 9,
+        ThreeDimensional = 1 << 10
     };
     Q_DECLARE_FLAGS(Flags, Flag)
 
@@ -819,6 +820,9 @@ public:
     QSize pixelSize() const { return m_pixelSize; }
     void setPixelSize(const QSize &sz) { m_pixelSize = sz; }
 
+    int depth() const { return m_depth; }
+    void setDepth(int depth) { m_depth = depth; }
+
     Flags flags() const { return m_flags; }
     void setFlags(Flags f) { m_flags = f; }
 
@@ -831,10 +835,11 @@ public:
     virtual void setNativeLayout(int layout);
 
 protected:
-    QRhiTexture(QRhiImplementation *rhi, Format format_, const QSize &pixelSize_,
+    QRhiTexture(QRhiImplementation *rhi, Format format_, const QSize &pixelSize_, int depth_,
                 int sampleCount_, Flags flags_);
     Format m_format;
     QSize m_pixelSize;
+    int m_depth;
     int m_sampleCount;
     Flags m_flags;
 };
@@ -1540,7 +1545,9 @@ public:
         ReadBackAnyTextureFormat,
         PipelineCacheDataLoadSave,
         ImageDataStride,
-        RenderBufferImport
+        RenderBufferImport,
+        ThreeDimensionalTextures,
+        RenderTo3DTextureSlice
     };
 
     enum BeginFrameFlag {
@@ -1600,6 +1607,11 @@ public:
                             int sampleCount = 1,
                             QRhiTexture::Flags flags = {});
 
+    QRhiTexture *newTexture(QRhiTexture::Format format,
+                            int width, int height, int depth,
+                            int sampleCount = 1,
+                            QRhiTexture::Flags flags = {});
+
     QRhiSampler *newSampler(QRhiSampler::Filter magFilter,
                             QRhiSampler::Filter minFilter,
                             QRhiSampler::Filter mipmapMode,
@@ -1646,8 +1658,7 @@ public:
 
     QRhiProfiler *profiler();
 
-    static const int MAX_LAYERS = 6; // cubemaps only
-    static const int MAX_LEVELS = 16; // a width and/or height of 65536 should be enough for everyone
+    static const int MAX_MIP_LEVELS = 16; // a width and/or height of 65536 should be enough for everyone
 
     void releaseCachedResources();