sdl3 wsi: size the swapchain in pixels on HiDPI displays#1
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fbraz3 merged 1 commit intoJul 12, 2026
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getWindowSize returned logical points via SDL_GetWindowSize, but the CAMetalLayer backing the Vulkan surface is in physical pixels. With a high-density drawable (SDL_WINDOW_HIGH_PIXEL_DENSITY) the swapchain was sized in points while the layer was in pixels, so the frame rendered 1:1 in the top-left corner of the window with the rest black. Query SDL_GetWindowSizeInPixels instead, and register it in the SDL proc table. On non-HiDPI displays points equal pixels, so this is a no-op there. Tested with GeneralsX (Zero Hour) on a 14" M4 Pro (3024x1964): before, the game rendered in a quarter of the screen; after, it fills the screen at native resolution. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01Gpbm3zSo8ggFfLaRByKoaC
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On macOS Retina displays,
Sdl3WsiDriver::getWindowSizereturns logical points viaSDL_GetWindowSize, but the CAMetalLayer backing the Vulkan surface is in physical pixels. When the consumer requests a high-density drawable (SDL_WINDOW_HIGH_PIXEL_DENSITY), the swapchain gets sized in points while the layer is in pixels, so the rendered frame lands 1:1 in the top-left corner of the window and the rest stays black.This changes
getWindowSizeto useSDL_GetWindowSizeInPixels, which is the size the swapchain and present path actually need. It also registers that function in the SDL proc-loader table.On non-HiDPI displays points equal pixels, so this is a no-op there.
Tested with GeneralsX (Zero Hour) on a 14" M4 Pro (3024x1964): before, the game rendered in a quarter of the screen; after, it fills the screen at native resolution.
Changes:
src/wsi/sdl3/wsi_platform_sdl3_funcs.h: addSDL_GetWindowSizeInPixelsto the proc tablesrc/wsi/sdl3/wsi_window_sdl3.cpp:getWindowSizequeries pixels instead of pointsThis is the DXVK half of the macOS HiDPI fix; the GeneralsX side is fbraz3/GeneralsX#204, which currently vendors this same change as a patch until it lands here.
🤖 Generated with Claude Code
https://claude.ai/code/session_01Gpbm3zSo8ggFfLaRByKoaC