mirror of
https://github.com/mikolalysenko/glsl-read-float.git
synced 2025-12-08 21:26:01 +00:00
42 lines
962 B
GLSL
42 lines
962 B
GLSL
#define FLOAT_MAX 1.70141184e38
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#define FLOAT_MIN 1.17549435e-38
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lowp vec4 encode_float(highp float v) {
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highp float av = abs(v);
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//Handle special cases
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if(av < FLOAT_MIN) {
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return vec4(0.0, 0.0, 0.0, 0.0);
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} else if(v > FLOAT_MAX) {
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return vec4(127.0, 128.0, 0.0, 0.0) / 255.0;
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} else if(v < -FLOAT_MAX) {
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return vec4(255.0, 128.0, 0.0, 0.0) / 255.0;
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}
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highp vec4 c = vec4(0,0,0,0);
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//Compute exponent and mantissa
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highp float e = floor(log2(av));
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highp float m = av * pow(2.0, -e) - 1.0;
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//Unpack mantissa
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c[1] = floor(128.0 * m);
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m -= c[1] / 128.0;
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c[2] = floor(32768.0 * m);
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m -= c[2] / 32768.0;
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c[3] = floor(8388608.0 * m);
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//Unpack exponent
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highp float ebias = e + 127.0;
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c[0] = floor(ebias / 2.0);
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ebias -= c[0] * 2.0;
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c[1] += floor(ebias) * 128.0;
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//Unpack sign bit
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c[0] += 128.0 * step(0.0, -v);
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//Scale back to range
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return c / 255.0;
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}
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#pragma glslify: export(encode_float) |