26 lines
752 B
GLSL
26 lines
752 B
GLSL
#ifndef UTILS_COMP
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#define UTILS_COMP
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// mod and div are expensive and coordinates/dimensions are often power of 2 or equal to 1
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uint fastmod(uint a, uint b) {
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if ((b & (b-1)) == 0) {
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return a & (b-1);
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}
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return a % b;
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}
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uint fastdiv(uint a, uint b) {
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return (a < b) ? 0 : (a / b);
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}
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void get_indices(uint idx, out uint i00, out uint i01, out uint i02, out uint i03, uint ne00, uint ne01, uint ne02, uint ne03) {
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i03 = fastdiv(idx, (ne02*ne01*ne00));
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const uint i03_offset = i03 * ne02*ne01*ne00;
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i02 = fastdiv((idx - i03_offset), (ne01*ne00));
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const uint i02_offset = i02*ne01*ne00;
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i01 = (idx - i03_offset - i02_offset) / ne00;
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i00 = idx - i03_offset - i02_offset - i01*ne00;
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}
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#endif // UTILS_COMP
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