[core] add onStyleImageMissing to allow dynamically loaded or generated images (#14253)

Also make `Style#updateImage(...)` much faster when the image doesn't change size. This can be useful for asynchronously generating images.

1 files changed, 18 insertions, 0 deletions

diff --git a/src/mbgl/gl/context.cpp b/src/mbgl/gl/context.cpp
index 5193381251..11fa9444b7 100644
--- a/src/mbgl/gl/context.cpp
+++ b/src/mbgl/gl/context.cpp
@@ -547,6 +547,24 @@ void Context::updateTextureResource(const gfx::TextureResource& resource,
                                   Enum<gfx::TextureChannelDataType>::to(type), data));
 }
 
+void Context::updateTextureResourceSub(const gfx::TextureResource& resource,
+                                    const uint16_t xOffset,
+                                    const uint16_t yOffset,
+                                    const Size size,
+                                    const void* data,
+                                    gfx::TexturePixelType format,
+                                    gfx::TextureChannelDataType type) {
+    // Always use texture unit 0 for manipulating it.
+    activeTextureUnit = 0;
+    texture[0] = static_cast<const gl::TextureResource&>(resource).texture;
+    MBGL_CHECK_ERROR(glTexSubImage2D(GL_TEXTURE_2D, 0,
+                                  xOffset, yOffset,
+                                  size.width, size.height,
+                                  Enum<gfx::TexturePixelType>::to(format),
+                                  Enum<gfx::TextureChannelDataType>::to(type), data));
+}
+
+
 std::unique_ptr<gfx::DrawScopeResource> Context::createDrawScopeResource() {
     return std::make_unique<gl::DrawScopeResource>(createVertexArray());
 }