98 lines
2.5 KiB
GLSL
98 lines
2.5 KiB
GLSL
//------------------------------------------------------------------------------
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// Common math
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//------------------------------------------------------------------------------
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/** @public-api */
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#define PI 3.14159265359
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/** @public-api */
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#define HALF_PI 1.570796327
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#define MEDIUMP_FLT_MAX 65504.0
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#define MEDIUMP_FLT_MIN 0.00006103515625
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#ifdef TARGET_MOBILE
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#define FLT_EPS MEDIUMP_FLT_MIN
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#define saturateMediump(x) min(x, MEDIUMP_FLT_MAX)
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#else
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#define FLT_EPS 1e-5
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#define saturateMediump(x) x
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#endif
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#define saturate(x) clamp(x, 0.0, 1.0)
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//------------------------------------------------------------------------------
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// Scalar operations
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//------------------------------------------------------------------------------
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/**
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* Computes x^5 using only multiply operations.
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*
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* @public-api
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*/
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float pow5(float x) {
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float x2 = x * x;
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return x2 * x2 * x;
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}
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/**
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* Computes x^2 as a single multiplication.
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*
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* @public-api
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*/
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float sq(float x) {
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return x * x;
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}
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/**
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* Returns the maximum component of the specified vector.
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*
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* @public-api
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*/
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float max3(const vec3 v) {
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return max(v.x, max(v.y, v.z));
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}
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//------------------------------------------------------------------------------
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// Matrix and quaternion operations
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//------------------------------------------------------------------------------
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/**
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* Multiplies the specified 3-component vector by the 4x4 matrix (m * v) in
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* high precision.
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*
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* @public-api
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*/
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vec4 mulMat4x4Float3(const HIGHP mat4 m, const HIGHP vec3 v) {
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return v.x * m[0] + (v.y * m[1] + (v.z * m[2] + m[3]));
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}
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/**
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* Multiplies the specified 3-component vector by the 3x3 matrix (m * v) in
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* high precision.
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*
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* @public-api
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*/
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vec3 mulMat3x3Float3(const HIGHP mat4 m, const HIGHP vec3 v) {
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return v.x * m[0].xyz + (v.y * m[1].xyz + (v.z * m[2].xyz));
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}
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/**
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* Extracts the normal vector of the tangent frame encoded in the specified quaternion.
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*/
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void toTangentFrame(const HIGHP vec4 q, out HIGHP vec3 n) {
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n = vec3( 0.0, 0.0, 1.0) +
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vec3( 2.0, -2.0, -2.0) * q.x * q.zwx +
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vec3( 2.0, 2.0, -2.0) * q.y * q.wzy;
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}
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/**
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* Extracts the normal and tangent vectors of the tangent frame encoded in the
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* specified quaternion.
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*/
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void toTangentFrame(const HIGHP vec4 q, out HIGHP vec3 n, out HIGHP vec3 t) {
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toTangentFrame(q, n);
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t = vec3( 1.0, 0.0, 0.0) +
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vec3(-2.0, 2.0, -2.0) * q.y * q.yxw +
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vec3(-2.0, 2.0, 2.0) * q.z * q.zwx;
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}
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