Lubos Lenco
60 lines
2.2 KiB
GLSL
60 lines
2.2 KiB
GLSL
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vec2 octahedron_wrap(const vec2 v) {
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return (1.0 - abs(v.yx)) * (vec2(v.x >= 0.0 ? 1.0 : -1.0, v.y >= 0.0 ? 1.0 : -1.0));
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}
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vec3 get_nor(const vec2 enc) {
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vec3 n;
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n.z = 1.0 - abs(enc.x) - abs(enc.y);
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n.xy = n.z >= 0.0 ? enc.xy : octahedron_wrap(enc.xy);
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n = normalize(n);
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return n;
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}
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vec3 get_pos_view(const vec3 view_ray, const float depth, const vec2 camera_proj) {
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float linear_depth = camera_proj.y / (camera_proj.x - depth);
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// float linear_depth = camera_proj.y / ((depth * 0.5 + 0.5) - camera_proj.x);
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return view_ray * linear_depth;
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}
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vec3 get_pos(const vec3 eye, const vec3 eye_look, const vec3 view_ray, const float depth, const vec2 camera_proj) {
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// eye_look, view_ray should be normalized
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float linear_depth = camera_proj.y / ((depth * 0.5 + 0.5) - camera_proj.x);
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float view_z_dist = dot(eye_look, view_ray);
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vec3 wposition = eye + view_ray * (linear_depth / view_z_dist);
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return wposition;
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}
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// GBuffer helper - Sebastien Lagarde
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// https://seblagarde.wordpress.com/2018/09/02/gbuffer-helper-packing-integer-and-float-together/
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float pack_f32_i16(const float f, const uint i) {
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// Constant optimize by compiler
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const int num_bit_target = 16;
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const int num_bit_i = 4;
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const float prec = float(1 << num_bit_target);
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const float maxi = float(1 << num_bit_i);
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const float prec_minus_one = prec - 1.0;
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const float t1 = ((prec / maxi) - 1.0) / prec_minus_one;
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const float t2 = (prec / maxi) / prec_minus_one;
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// Code
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return t1 * f + t2 * float(i);
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}
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void unpack_f32_i16(const float val, OUT(float, f), OUT(uint, i)) {
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// Constant optimize by compiler
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const int num_bit_target = 16;
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const int num_bit_i = 4;
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const float prec = float(1 << num_bit_target);
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const float maxi = float(1 << num_bit_i);
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const float prec_minus_one = prec - 1.0;
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const float t1 = ((prec / maxi) - 1.0) / prec_minus_one;
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const float t2 = (prec / maxi) / prec_minus_one;
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// Code
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// extract integer part
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// + rcp(prec_minus_one) to deal with precision issue
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i = int((val / t2) + (1.0 / prec_minus_one));
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// Now that we have i, solve formula in pack_f32_i16 for f
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//f = (val - t2 * float(i)) / t1 => convert in mads form
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f = clamp((-t2 * float(i) + val) / t1, 0.0, 1.0); // Saturate in case of precision issue
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}
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