108 lines
3.5 KiB
JavaScript
108 lines
3.5 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',
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'number', 'number', 'number', 'number' ]);
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// special tessellator for extrusion layer - only returns triangle indices
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var tessellate = function(vertices, v_start, v_end, boundaries, b_start,
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b_end, mode) {
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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, contours,
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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_triangles = null;
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var result_vertices = null;
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if (mode){
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result_triangles = new Int32Array(ntris * 3);
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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');
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result_vertices = new Float32Array(nverts * 2);
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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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} else {
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if (nverts * 2 == v_len) {
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result_triangles = new Int32Array(ntris * 3);
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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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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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}
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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(pcoordinates_out);
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Module._free(pptris_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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if (mode)
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return { vertices: result_vertices, triangles: result_triangles };
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else
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return result_triangles;
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};
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return tessellate;
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})();
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