diff options
Diffstat (limited to 'src/library_sdl.js')
| -rw-r--r-- | src/library_sdl.js | 19 |
1 files changed, 15 insertions, 4 deletions
diff --git a/src/library_sdl.js b/src/library_sdl.js index 9fc979d2..42207f23 100644 --- a/src/library_sdl.js +++ b/src/library_sdl.js @@ -524,8 +524,18 @@ var LibrarySDL = { } else { // Otherwise, calculate the movement based on the changes // in the coordinates. - var x = event.pageX - Module["canvas"].offsetLeft; - var y = event.pageY - Module["canvas"].offsetTop; + var rect = Module["canvas"].getBoundingClientRect(); + var x = event.pageX - (window.scrollX + rect.left); + var y = event.pageY - (window.scrollY + rect.top); + + // the canvas might be CSS-scaled compared to its backbuffer; + // SDL-using content will want mouse coordinates in terms + // of backbuffer units. + var cw = Module["canvas"].width; + var ch = Module["canvas"].height; + x = x * (cw / rect.width); + y = y * (ch / rect.height); + var movementX = x - SDL.mouseX; var movementY = y - SDL.mouseY; } @@ -912,10 +922,11 @@ var LibrarySDL = { SDL_WarpMouse: function(x, y) { return; // TODO: implement this in a non-buggy way. Need to keep relative mouse movements correct after calling this + var rect = Module["canvas"].getBoundingClientRect(); SDL.events.push({ type: 'mousemove', - pageX: x + Module['canvas'].offsetLeft, - pageY: y + Module['canvas'].offsetTop + pageX: x + (window.scrollX + rect.left), + pageY: y + (window.scrollY + rect.top) }); }, |