93 lines
2.8 KiB
JavaScript
93 lines
2.8 KiB
JavaScript
tessellate = (function() {
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Module.TOTAL_MEMORY = 1024 * 1024;
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var c_tessellate = Module.cwrap('tessellate', 'void', ['number', 'number', 'number',
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'number', 'number', 'number']);
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// special tessellator for extrusion layer
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var tessellate = function(vertices, v_start, v_end, boundaries, b_start, b_end) {
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var i;
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var v_len = (v_end - v_start);
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var b_len = (b_end - b_start);
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var p = Module._malloc(v_len * 8);
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for (i=0; i< v_len; ++i)
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Module.setValue(p+i*8, vertices[v_start + i], 'double');
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var contours = Module._malloc((b_len + 1) * 4);
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// pointer to first contour
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Module.setValue(contours + 0, p + 0, 'i32');
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var offset = p;
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// pointer to further contours + end
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for (i = 0; i<b_len; ++i) {
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offset += 8 * boundaries[b_start + i];
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Module.setValue(contours + 4 * (i + 1), offset, 'i32');
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}
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var ppcoordinates_out = Module._malloc(4);
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var pptris_out = Module._malloc(4);
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var pnverts = Module._malloc(4);
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var pntris = Module._malloc(4);
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c_tessellate(ppcoordinates_out, pnverts, pptris_out, pntris,
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contours, contours+4*(b_len + 1));
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var pcoordinates_out = Module.getValue(ppcoordinates_out, 'i32');
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var ptris_out = Module.getValue(pptris_out, 'i32');
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var nverts = Module.getValue(pnverts, 'i32');
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var ntris = Module.getValue(pntris, 'i32');
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var result_vertices = new Float32Array(nverts * 2);
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var result_triangles = new Int32Array(ntris * 3);
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for (i=0; i<2*nverts; ++i) {
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result_vertices[i] = Module.getValue(pcoordinates_out + i*8, 'double');
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if (result_vertices[i] != vertices[v_start + i])
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console.log("i:" + i + " " + result_vertices[i] + " " + vertices[v_start + i]);
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}
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for (i=0; i<3*ntris; ++i) {
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result_triangles[i] = Module.getValue(ptris_out + i*4, 'i32') * 2;
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}
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// when a ring has an odd number of points one (or rather two)
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// additional vertices will be added. so the following rings
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// needs extra offset...
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var start = 0;
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for (var j = 0, m = b_len - 1; j < m; j++) {
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start += boundaries[b_start + j];
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// even number of points?
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if (!((boundaries[b_start + j] >> 1) & 1))
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continue;
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console.log("shift " + boundaries[b_start + j]);
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for (var n = ntris * 3, tri = 0; tri < n; tri++)
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if (result_triangles[tri] >= start)
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result_triangles[tri] += 2;
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start += 2;
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}
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Module._free(pnverts);
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Module._free(pntris);
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Module._free(ppcoordinates_out);
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Module._free(pptris_out);
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Module._free(pcoordinates_out);
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Module._free(ptris_out);
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Module._free(p);
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Module._free(contours);
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return {
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vertices: result_vertices,
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triangles: result_triangles
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};
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};
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return tessellate;
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})();
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