gl: tex imp/exp

plus rework it a bit for metal

src/rhi/qrhi.h

@@ -69,8 +69,8 @@ struct QRhiResourceUpdateBatchPrivate;
 //   1. new*() does not create underlying graphics resources. build() does.
 //   2. Except: new*Descriptor() implicitly "builds". (no build() for QRhiRenderPassDescriptor f.ex.)
 //   3. release() schedules graphics resources for destruction. The C++ object is reusable immediately via build(), or can be destroyed.
-//   4. build() on an already built object calls release() implicitly. Except swapchains. (buildOrResize - special semantics)
-//   5. Ownership of resources imported via QRhi*InitParams is not taken.
+//   4. build() on an already built object calls release() implicitly. Except swapchains. (buildOrResize() - special semantics)
+//   5. Ownership of resources imported (QRhi*InitParams or buildFrom()) or exported (nativeHandles()) is never taken or given away.
 //
 // Other:
 //   1. QRhiResourceUpdateBatch manages no graphics resources underneath. beginPass() implicitly calls release() on the batch.

src/rhi/qrhigles2.cpp

@@ -1609,9 +1609,12 @@ void QGles2Texture::release()
 
     texture = 0;
     specified = false;
+    nativeHandlesStruct.texture = 0;
 
-    QRHI_RES_RHI(QRhiGles2);
-    rhiD->releaseQueue.append(e);
+    if (owns) {
+        QRHI_RES_RHI(QRhiGles2);
+        rhiD->releaseQueue.append(e);
+    }
 }
 
 static inline bool isPowerOfTwo(int x)
@@ -1620,7 +1623,7 @@ static inline bool isPowerOfTwo(int x)
     return x == (x & -x);
 }
 
-bool QGles2Texture::build()
+bool QGles2Texture::prepareBuild(QSize *adjustedSize)
 {
     QRHI_RES_RHI(QRhiGles2);
 
@@ -1639,7 +1642,6 @@ bool QGles2Texture::build()
 
     const bool isCube = m_flags.testFlag(CubeMap);
     const bool hasMipMaps = m_flags.testFlag(MipMapped);
-    const int mipLevelCount = hasMipMaps ? qCeil(log2(qMax(size.width(), size.height()))) + 1 : 1;
     const bool isCompressed = rhiD->isCompressedFormat(m_format);
 
     // ### more formats
@@ -1647,6 +1649,7 @@ bool QGles2Texture::build()
     glintformat = GL_RGBA;
     glformat = GL_RGBA;
     gltype = GL_UNSIGNED_BYTE;
+    mipLevelCount = hasMipMaps ? qCeil(log2(qMax(size.width(), size.height()))) + 1 : 1;
 
     if (isCompressed) {
         glintformat = toGlCompressedTextureFormat(m_format, m_flags);
@@ -1656,8 +1659,25 @@ bool QGles2Texture::build()
         }
     }
 
+    if (adjustedSize)
+        *adjustedSize = size;
+
+    return true;
+}
+
+bool QGles2Texture::build()
+{
+    QRHI_RES_RHI(QRhiGles2);
+
+    QSize size;
+    if (!prepareBuild(&size))
+        return false;
+
     rhiD->f->glGenTextures(1, &texture);
 
+    const bool isCube = m_flags.testFlag(CubeMap);
+    const bool hasMipMaps = m_flags.testFlag(MipMapped);
+    const bool isCompressed = rhiD->isCompressedFormat(m_format);
     if (!isCompressed) {
         rhiD->f->glBindTexture(target, texture);
         if (hasMipMaps || isCube) {
@@ -1682,10 +1702,37 @@ bool QGles2Texture::build()
         specified = false;
     }
 
+    owns = true;
+    nativeHandlesStruct.texture = texture;
+
+    generation += 1;
+    return true;
+}
+
+bool QGles2Texture::buildFrom(QRhiNativeHandles *src)
+{
+    QRhiGles2TextureNativeHandles *h = static_cast<QRhiGles2TextureNativeHandles *>(src);
+    if (!h || !h->texture)
+        return false;
+
+    if (!prepareBuild())
+        return false;
+
+    texture = h->texture;
+    specified = true;
+
+    owns = false;
+    nativeHandlesStruct.texture = texture;
+
     generation += 1;
     return true;
 }
 
+QRhiNativeHandles *QGles2Texture::nativeHandles()
+{
+    return &nativeHandlesStruct;
+}
+
 QGles2Sampler::QGles2Sampler(QRhiImplementation *rhi, Filter magFilter, Filter minFilter, Filter mipmapMode,
                              AddressMode u, AddressMode v, AddressMode w)
     : QRhiSampler(rhi, magFilter, minFilter, mipmapMode, u, v, w)

src/rhi/qrhigles2.h

@@ -67,6 +67,11 @@ struct Q_RHI_EXPORT QRhiGles2NativeHandles : public QRhiNativeHandles
     QOpenGLContext *context;
 };
 
+struct Q_RHI_EXPORT QRhiGles2TextureNativeHandles : public QRhiNativeHandles
+{
+    uint texture = 0;
+};
+
 QT_END_NAMESPACE
 
 #endif

src/rhi/qrhigles2_p.h

@@ -91,13 +91,20 @@ struct QGles2Texture : public QRhiTexture
                   int sampleCount, Flags flags);
     void release() override;
     bool build() override;
+    bool buildFrom(QRhiNativeHandles *src) override;
+    QRhiNativeHandles *nativeHandles() override;
+
+    bool prepareBuild(QSize *adjustedSize = nullptr);
 
     GLuint texture = 0;
+    bool owns = true;
     GLenum target;
     GLenum glintformat;
     GLenum glformat;
     GLenum gltype;
     bool specified = false;
+    int mipLevelCount = 0;
+    QRhiGles2TextureNativeHandles nativeHandlesStruct;
 
     uint generation = 0;
     friend class QRhiGles2;

src/rhi/qrhimetal.mm

@@ -1470,8 +1470,10 @@ static inline MTLPixelFormat toMetalTextureFormat(QRhiTexture::Format format, QR
     }
 }
 
-bool QMetalTexture::build()
+bool QMetalTexture::prepareBuild(QSize *adjustedSize)
 {
+    QRHI_RES_RHI(QRhiMetal);
+
     if (d->tex)
         release();
 
@@ -1479,7 +1481,6 @@ bool QMetalTexture::build()
     const bool isCube = m_flags.testFlag(CubeMap);
     const bool hasMipMaps = m_flags.testFlag(MipMapped);
 
-    QRHI_RES_RHI(QRhiMetal);
     d->format = toMetalTextureFormat(m_format, m_flags);
     mipLevelCount = hasMipMaps ? qCeil(log2(qMax(size.width(), size.height()))) + 1 : 1;
     samples = rhiD->effectiveSampleCount(m_sampleCount);
@@ -1494,8 +1495,23 @@ bool QMetalTexture::build()
         }
     }
 
+    if (adjustedSize)
+        *adjustedSize = size;
+
+    return true;
+}
+
+bool QMetalTexture::build()
+{
+    QRHI_RES_RHI(QRhiMetal);
+
+    QSize size;
+    if (!prepareBuild(&size))
+        return false;
+
     MTLTextureDescriptor *desc = [[MTLTextureDescriptor alloc] init];
-    if (isCube)
+
+    if (m_flags.testFlag(CubeMap))
         desc.textureType = MTLTextureTypeCube;
     else
         desc.textureType = samples > 1 ? MTLTextureType2DMultisample : MTLTextureType2D;
@@ -1522,26 +1538,14 @@ bool QMetalTexture::build()
     return true;
 }
 
-QRhiNativeHandles *QMetalTexture::nativeHandles()
-{
-    return &nativeHandlesStruct;
-}
-
 bool QMetalTexture::buildFrom(QRhiNativeHandles *src)
 {
     QRhiMetalTextureNativeHandles *h = static_cast<QRhiMetalTextureNativeHandles *>(src);
     if (!h || !h->texture)
         return false;
 
-    if (d->tex)
-        release();
-
-    QRHI_RES_RHI(QRhiMetal);
-    d->format = toMetalTextureFormat(m_format, m_flags);
-    const QSize size = m_pixelSize.isEmpty() ? QSize(16, 16) : m_pixelSize;
-    const bool hasMipMaps = m_flags.testFlag(MipMapped);
-    mipLevelCount = hasMipMaps ? qCeil(log2(qMax(size.width(), size.height()))) + 1 : 1;
-    samples = rhiD->effectiveSampleCount(m_sampleCount);
+    if (!prepareBuild())
+        return false;
 
     d->tex = (id<MTLTexture>) h->texture;
 
@@ -1553,6 +1557,11 @@ bool QMetalTexture::buildFrom(QRhiNativeHandles *src)
     return true;
 }
 
+QRhiNativeHandles *QMetalTexture::nativeHandles()
+{
+    return &nativeHandlesStruct;
+}
+
 QMetalSampler::QMetalSampler(QRhiImplementation *rhi, Filter magFilter, Filter minFilter, Filter mipmapMode,
                              AddressMode u, AddressMode v, AddressMode w)
     : QRhiSampler(rhi, magFilter, minFilter, mipmapMode, u, v, w),

src/rhi/qrhimetal_p.h

@@ -93,8 +93,10 @@ struct QMetalTexture : public QRhiTexture
     ~QMetalTexture();
     void release() override;
     bool build() override;
-    QRhiNativeHandles *nativeHandles() override;
     bool buildFrom(QRhiNativeHandles *src) override;
+    QRhiNativeHandles *nativeHandles() override;
+
+    bool prepareBuild(QSize *adjustedSize = nullptr);
 
     QMetalTextureData *d;
     QRhiMetalTextureNativeHandles nativeHandlesStruct;