1 files changed, 161 insertions, 0 deletions

diff --git a/contrib/SDL-3.2.8/src/video/emscripten/SDL_emscriptenframebuffer.c b/contrib/SDL-3.2.8/src/video/emscripten/SDL_emscriptenframebuffer.c
new file mode 100644
index 0000000..503fac6
--- /dev/null
+++ b/contrib/SDL-3.2.8/src/video/emscripten/SDL_emscriptenframebuffer.c
@@ -0,0 +1,161 @@
+/*
+  Simple DirectMedia Layer
+  Copyright (C) 1997-2025 Sam Lantinga <slouken@libsdl.org>
+
+  This software is provided 'as-is', without any express or implied
+  warranty.  In no event will the authors be held liable for any damages
+  arising from the use of this software.
+
+  Permission is granted to anyone to use this software for any purpose,
+  including commercial applications, and to alter it and redistribute it
+  freely, subject to the following restrictions:
+
+  1. The origin of this software must not be misrepresented; you must not
+     claim that you wrote the original software. If you use this software
+     in a product, an acknowledgment in the product documentation would be
+     appreciated but is not required.
+  2. Altered source versions must be plainly marked as such, and must not be
+     misrepresented as being the original software.
+  3. This notice may not be removed or altered from any source distribution.
+*/
+#include "SDL_internal.h"
+
+#ifdef SDL_VIDEO_DRIVER_EMSCRIPTEN
+
+#include "SDL_emscriptenvideo.h"
+#include "SDL_emscriptenframebuffer.h"
+
+#include <emscripten/threading.h>
+
+bool Emscripten_CreateWindowFramebuffer(SDL_VideoDevice *_this, SDL_Window *window, SDL_PixelFormat *format, void **pixels, int *pitch)
+{
+    SDL_Surface *surface;
+    const SDL_PixelFormat surface_format = SDL_PIXELFORMAT_XBGR8888;
+    int w, h;
+
+    // Free the old framebuffer surface
+    SDL_WindowData *data = window->internal;
+    surface = data->surface;
+    SDL_DestroySurface(surface);
+
+    // Create a new one
+    SDL_GetWindowSizeInPixels(window, &w, &h);
+
+    surface = SDL_CreateSurface(w, h, surface_format);
+    if (!surface) {
+        return false;
+    }
+
+    // Save the info and return!
+    data->surface = surface;
+    *format = surface_format;
+    *pixels = surface->pixels;
+    *pitch = surface->pitch;
+    return true;
+}
+
+bool Emscripten_UpdateWindowFramebuffer(SDL_VideoDevice *_this, SDL_Window *window, const SDL_Rect *rects, int numrects)
+{
+    SDL_Surface *surface;
+
+    SDL_WindowData *data = window->internal;
+    surface = data->surface;
+    if (!surface) {
+        return SDL_SetError("Couldn't find framebuffer surface for window");
+    }
+
+    // Send the data to the display
+
+    /* *INDENT-OFF* */ // clang-format off
+    MAIN_THREAD_EM_ASM({
+        var w = $0;
+        var h = $1;
+        var pixels = $2;
+        var canvasId = UTF8ToString($3);
+        var canvas = document.querySelector(canvasId);
+
+        //TODO: this should store a context per canvas
+        if (!Module['SDL3']) Module['SDL3'] = {};
+        var SDL3 = Module['SDL3'];
+        if (SDL3.ctxCanvas !== canvas) {
+            SDL3.ctx = Module['createContext'](canvas, false, true);
+            SDL3.ctxCanvas = canvas;
+        }
+        if (SDL3.w !== w || SDL3.h !== h || SDL3.imageCtx !== SDL3.ctx) {
+            SDL3.image = SDL3.ctx.createImageData(w, h);
+            SDL3.w = w;
+            SDL3.h = h;
+            SDL3.imageCtx = SDL3.ctx;
+        }
+        var data = SDL3.image.data;
+        var src = pixels / 4;
+        var dst = 0;
+        var num;
+
+        if (SDL3.data32Data !== data) {
+            SDL3.data32 = new Int32Array(data.buffer);
+            SDL3.data8 = new Uint8Array(data.buffer);
+            SDL3.data32Data = data;
+        }
+        var data32 = SDL3.data32;
+        num = data32.length;
+        // logically we need to do
+        //      while (dst < num) {
+        //          data32[dst++] = HEAP32[src++] | 0xff000000
+        //      }
+        // the following code is faster though, because
+        // .set() is almost free - easily 10x faster due to
+        // native SDL_memcpy efficiencies, and the remaining loop
+        // just stores, not load + store, so it is faster
+        data32.set(HEAP32.subarray(src, src + num));
+        var data8 = SDL3.data8;
+        var i = 3;
+        var j = i + 4*num;
+        if (num % 8 == 0) {
+            // unrolling gives big speedups
+            while (i < j) {
+              data8[i] = 0xff;
+              i = i + 4 | 0;
+              data8[i] = 0xff;
+              i = i + 4 | 0;
+              data8[i] = 0xff;
+              i = i + 4 | 0;
+              data8[i] = 0xff;
+              i = i + 4 | 0;
+              data8[i] = 0xff;
+              i = i + 4 | 0;
+              data8[i] = 0xff;
+              i = i + 4 | 0;
+              data8[i] = 0xff;
+              i = i + 4 | 0;
+              data8[i] = 0xff;
+              i = i + 4 | 0;
+            }
+         } else {
+            while (i < j) {
+              data8[i] = 0xff;
+              i = i + 4 | 0;
+            }
+        }
+
+        SDL3.ctx.putImageData(SDL3.image, 0, 0);
+    }, surface->w, surface->h, surface->pixels, data->canvas_id);
+    /* *INDENT-ON* */ // clang-format on
+
+    if (emscripten_has_asyncify() && SDL_GetHintBoolean(SDL_HINT_EMSCRIPTEN_ASYNCIFY, true)) {
+        // give back control to browser for screen refresh
+        emscripten_sleep(0);
+    }
+
+    return true;
+}
+
+void Emscripten_DestroyWindowFramebuffer(SDL_VideoDevice *_this, SDL_Window *window)
+{
+    SDL_WindowData *data = window->internal;
+
+    SDL_DestroySurface(data->surface);
+    data->surface = NULL;
+}
+
+#endif // SDL_VIDEO_DRIVER_EMSCRIPTEN