core: Defer WebGPU dynamic texture wrapper creation (#4369)

include/mbgl/gfx/dynamic_texture.hpp

@@ -65,8 +65,11 @@ public:
     virtual bool removeTexture(const TextureHandle& texHandle);
 
 protected:
+    DynamicTexture(Size size, TexturePixelType pixelType);
+
     mapbox::ShelfPack shelfPack;
     Texture2DPtr texture;
+    TexturePixelType pixelFormat;
     int numTextures = 0;
     std::mutex mutex;
 };

include/mbgl/webgpu/dynamic_texture.hpp

@@ -19,6 +19,9 @@ public:
         std::unordered_map<gfx::TextureHandle, std::unique_ptr<uint8_t[]>, gfx::TextureHandle::Hasher>;
 
 private:
+    Context& context;
+    Size size;
+    gfx::TexturePixelType pixelType;
     bool deferredCreation = false;
     ImagesToUpload imagesToUpload;
 };

src/mbgl/gfx/dynamic_texture.cpp

@@ -5,11 +5,15 @@
 namespace mbgl {
 namespace gfx {
 
-DynamicTexture::DynamicTexture(Context& context, Size size, TexturePixelType pixelType) {
+DynamicTexture::DynamicTexture(Size size, TexturePixelType pixelType)
+    : pixelFormat(pixelType) {
     mapbox::ShelfPack::ShelfPackOptions options;
     options.autoResize = false;
     shelfPack = mapbox::ShelfPack(size.width, size.height, options);
+}
 
+DynamicTexture::DynamicTexture(Context& context, Size size, TexturePixelType pixelType)
+    : DynamicTexture(size, pixelType) {
     texture = context.createTexture2D();
     texture->setSize(size);
     texture->setFormat(pixelType, gfx::TextureChannelDataType::UnsignedByte);
@@ -24,7 +28,7 @@ const gfx::Texture2DPtr& DynamicTexture::getTexture() const {
 }
 
 TexturePixelType DynamicTexture::getPixelFormat() const {
-    return getTexture()->getFormat();
+    return pixelFormat;
 }
 
 bool DynamicTexture::isEmpty() const {

src/mbgl/webgpu/dynamic_texture.cpp

@@ -6,18 +6,37 @@ namespace mbgl {
 namespace webgpu {
 
 DynamicTexture::DynamicTexture(Context& context, Size size, gfx::TexturePixelType pixelType)
-    : gfx::DynamicTexture(context, size, pixelType) {
+    : gfx::DynamicTexture(size, pixelType),
+      context(context),
+      size(size),
+      pixelType(pixelType) {
     deferredCreation = true;
 }
 
+namespace {
+size_t pixelStride(gfx::TexturePixelType pixelType) {
+    switch (pixelType) {
+        case gfx::TexturePixelType::Alpha:
+        case gfx::TexturePixelType::Luminance:
+            return 1;
+        case gfx::TexturePixelType::RGBA:
+            return 4;
+        case gfx::TexturePixelType::Stencil:
+        case gfx::TexturePixelType::Depth:
+            return 4;
+    }
+    return 4;
+}
+} // namespace
+
 void DynamicTexture::uploadImage(const uint8_t* pixelData, gfx::TextureHandle& texHandle) {
     std::scoped_lock lock(mutex);
     const auto& rect = texHandle.getRectangle();
     const auto imageSize = Size(rect.w, rect.h);
 
-    auto size = imageSize.area() * texture->getPixelStride();
-    auto imageData = std::make_unique<uint8_t[]>(size);
-    std::copy(pixelData, pixelData + size, imageData.get());
+    auto byteSize = imageSize.area() * pixelStride(pixelType);
+    auto imageData = std::make_unique<uint8_t[]>(byteSize);
+    std::copy(pixelData, pixelData + byteSize, imageData.get());
     imagesToUpload.emplace(texHandle, std::move(imageData));
 
     gfx::DynamicTexture::uploadImage(pixelData, texHandle);
@@ -26,6 +45,12 @@ void DynamicTexture::uploadImage(const uint8_t* pixelData, gfx::TextureHandle& t
 void DynamicTexture::uploadDeferredImages(gfx::UploadPass&) {
     std::scoped_lock lock(mutex);
     if (deferredCreation) {
+        texture = context.createTexture2D();
+        texture->setSize(size);
+        texture->setFormat(pixelType, gfx::TextureChannelDataType::UnsignedByte);
+        texture->setSamplerConfiguration({.filter = gfx::TextureFilterType::Linear,
+                                          .wrapU = gfx::TextureWrapType::Clamp,
+                                          .wrapV = gfx::TextureWrapType::Clamp});
         texture->create();
         deferredCreation = false;
     }