From 2b367cb6b05b186be147f62dc1ac4f66ee61fad6 Mon Sep 17 00:00:00 2001 From: Alon Zakai Date: Tue, 13 Sep 2016 00:03:43 -0700 Subject: [PATCH] optimize Emscripten_UpdateWindowFramebuffer - avoid creating contexts and images all the time - use set and then fix alpha directly --- .../emscripten/SDL_emscriptenframebuffer.c | 76 ++++++++++++++----- 1 file changed, 59 insertions(+), 17 deletions(-) diff --git a/src/video/emscripten/SDL_emscriptenframebuffer.c b/src/video/emscripten/SDL_emscriptenframebuffer.c index a26e23ae6..da03497bb 100644 --- a/src/video/emscripten/SDL_emscriptenframebuffer.c +++ b/src/video/emscripten/SDL_emscriptenframebuffer.c @@ -69,15 +69,25 @@ int Emscripten_UpdateWindowFramebuffer(_THIS, SDL_Window * window, const SDL_Rec /* Send the data to the display */ EM_ASM_INT({ - //TODO: don't create context every update - var ctx = Module['canvas'].getContext('2d'); + var w = $0; + var h = $1; + var pixels = $2; - //library_sdl.js SDL_UnlockSurface - var image = ctx.createImageData($0, $1); - var data = image.data; - var src = $2 >> 2; + if (!Module['SDL2']) Module['SDL2'] = {}; + var SDL2 = Module['SDL2']; + if (SDL2.ctxCanvas !== Module['canvas']) { + SDL2.ctx = Module['canvas'].getContext('2d'); + SDL2.ctxCanvas = Module['canvas']; + } + if (SDL2.w !== w || SDL2.h !== h || SDL2.imageCtx !== SDL2.ctx) { + SDL2.image = SDL2.ctx.createImageData(w, h); + SDL2.w = w; + SDL2.h = h; + SDL2.imageCtx = SDL2.ctx; + } + var data = SDL2.image.data; + var src = pixels >> 2; var dst = 0; - var isScreen = true; var num; if (typeof CanvasPixelArray !== 'undefined' && data instanceof CanvasPixelArray) { // IE10/IE11: ImageData objects are backed by the deprecated CanvasPixelArray, @@ -90,26 +100,58 @@ int Emscripten_UpdateWindowFramebuffer(_THIS, SDL_Window * window, const SDL_Rec data[dst ] = val & 0xff; data[dst+1] = (val >> 8) & 0xff; data[dst+2] = (val >> 16) & 0xff; - data[dst+3] = isScreen ? 0xff : ((val >> 24) & 0xff); + data[dst+3] = 0xff; src++; dst += 4; } } else { - var data32 = new Uint32Array(data.buffer); + if (SDL2.data32Data !== data) { + SDL2.data32 = new Int32Array(data.buffer); + SDL2.data8 = new Uint8Array(data.buffer); + } + var data32 = SDL2.data32; num = data32.length; - if (isScreen) { - while (dst < num) { - // HEAP32[src++] is an optimization. Instead, we could do {{{ makeGetValue('buffer', 'dst', 'i32') }}}; - data32[dst++] = HEAP32[src++] | 0xff000000; + // 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 memcpy efficiencies, and the remaining loop + // just stores, not load + store, so it is faster + data32.set(HEAP32.subarray(src, src + num)); + var data8 = SDL2.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 (dst < num) { - data32[dst++] = HEAP32[src++]; + } else { + while (i < j) { + data8[i] = 0xff; + i = i + 4 | 0; } } } - ctx.putImageData(image, 0, 0); + SDL2.ctx.putImageData(SDL2.image, 0, 0); return 0; }, surface->w, surface->h, surface->pixels);