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mergeInto(Library, {
SDL_Init: function(what) {
SDL_SURFACES = {};
return 1;
},
SDL_SetVideoMode: function(width, height, depth, flags, canvas) {
// ^^^^^^ a 'canvas' parameter is added here; supply a canvas from JS there
var surf = _malloc(14*QUANTUM_SIZE); // SDL_Surface has 14 fields of quantum size
SDL_SURFACES[surf] = {
width: width,
height: height,
canvas: canvas,
ctx: canvas.getContext('2d'),
surf: surf,
buffer: _malloc(width*height*4)
};
return surf;
},
SDL_Quit: function() {
return 1;
},
SDL_LockSurface: function(surf) {
var surfData = SDL_SURFACES[surf];
surfData.image = surfData.ctx.getImageData(0, 0, surfData.width, surfData.height);
// Copy pixel data to somewhere accessible to 'C/C++'
var num = surfData.image.data.length;
for (var i = 0; i < num; i++) {
IHEAP[surfData.buffer+i] = surfData.image.data[i];
}
// Mark in C/C++-accessible SDL structure
// SDL_Surface has the following fields: Uint32 flags, SDL_PixelFormat *format; int w, h; Uint16 pitch; void *pixels; ...
// So we have fields all of the same size, and 5 of them before us.
IHEAP[surf + 5*QUANTUM_SIZE] = surfData.buffer;
},
SDL_UnlockSurface: function(surf) {
var surfData = SDL_SURFACES[surf];
// Copy pixel data to image
var num = surfData.image.data.length;
for (var i = 0; i < num; i++) {
surfData.image.data[i] = IHEAP[surfData.buffer+i];
}
for (var i = 0; i < num/4; i++) {
surfData.image.data[i*4+3] = 255; // opacity, as canvases blend alpha
}
// Copy to canvas
surfData.ctx.putImageData(surfData.image, 0, 0);
// Cleanup
surfData.image = null;
},
SDL_Flip: function(surf) {
// We actually do this in Unlock...
},
SDL_Delay: function(delay) {
// No can do... unless you were a generator...
},
});
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