Initial commit.

.gitignore

@@ -0,0 +1,26 @@
+/[Ll]ibrary/
+/[Tt]emp/
+/[Oo]bj/
+/[Bb]uild/
+/[Bb]uilds/
+/Assets/AssetStoreTools*
+
+ExportedObj/
+.consulo/
+*.csproj
+*.unityproj
+*.sln
+*.suo
+*.tmp
+*.user
+*.userprefs
+*.pidb
+*.booproj
+*.svd
+
+*.pidb.meta
+
+sysinfo.txt
+
+*.apk
+*.unitypackage

Assets/Colour/Adaptation/CAT.cginc

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+// CAT02 Chromatic Adaptation Transform.
+static const float3x3 CAT02_CAT = {
+ 0.7328, 0.4296, -0.1624,
+ -0.7036, 1.6975, 0.0061,
+ 0.0030, 0.0136, 0.9834
+};
+
+// CAT02 Inverse Chromatic Adaptation Transform.
+static const float3x3 CAT02_INVERSE_CAT = {
+ 1.096123820835514, -0.278869000218287, 0.182745179382773,
+ 0.454369041975359, 0.473533154307412, 0.072097803717229,
+ -0.009627608738429, -0.005698031216113, 1.015325639954543
+};

Assets/Colour/Appearance/CIECAM02.cginc

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+#include "../Adaptation/CAT.cginc"
+#include "../Utilities/Common.cginc"
+
+struct CIECAM02_InductionFactors
+{
+ float F;
+ float c;
+ float N_c;
+};
+
+static const CIECAM02_InductionFactors CIECAM02_VIEWING_CONDITIONS_AVERAGE = {
+ 1, 0.69, 1
+};
+
+static const CIECAM02_InductionFactors CIECAM02_VIEWING_CONDITIONS_DIM = {
+ 0.9, 0.59, 0.95
+};
+
+static const CIECAM02_InductionFactors CIECAM02_VIEWING_CONDITIONS_DARK = {
+ 0.8, 0.525, 0.8
+};
+
+struct CIECAM02_Specification
+{
+ float J;
+ float C;
+ float h;
+ float s;
+ float Q;
+ float M;
+ float H;
+ float HC;
+};
+
+// Hunt colour appearance model *CIE XYZ* tristimulus values to
+// *Hunt-Pointer-Estevez* :math:`\\rho\gamma\\beta` colourspace matrix.
+static const float3x3 XYZ_TO_HPE_MATRIX = {
+ 0.38971, 0.68898, -0.07868,
+ -0.22981, 1.18340, 0.04641,
+ 0.00000, 0.00000, 1.00000
+};
+
+static const float3x3 HPE_TO_XYZ_MATRIX = {
+ 1.910196834052035, -1.112123892787875, 0.201907956767499,
+ 0.370950088248689, 0.629054257392613, -0.000008055142184,
+ 0.000000000000000, 0.000000000000000, 1.000000000000000
+};
+
+float luminance_level_adaptation_factor(float L_A) {
+
+ float k = 1.0 / (5.0 * L_A + 1.0);
+ float k4 = pow(k, 4.0);
+
+ float F_L = (0.2 * k4 * (5.0 * L_A) + 0.1 * pow((1.0 - k4), 2.0) * 
+ pow((5.0 * L_A), (1.0 / 3.0)));
+
+ return F_L;
+}
+
+float chromatic_induction_factors(float n) {
+ float N_bbcb = 0.725 * pow((1.0 / n), 0.2);
+
+ return N_bbcb;
+}
+
+float base_exponential_non_linearity(float n) {
+ float z = 1.48 + sqrt(n);
+
+ return z;
+}
+
+float4 viewing_condition_dependent_parameters(float Y_b, float Y_w, float L_A) {
+
+ float n = Y_b / Y_w;
+ float F_L = luminance_level_adaptation_factor(L_A);
+ float N_bbcb = chromatic_induction_factors(n);
+ float z = base_exponential_non_linearity(n);
+
+ return float4(n, F_L, N_bbcb, z);
+}
+
+float degree_of_adaptation(float F, float L_A) {
+ float D = F * (1.0 - (1.0 / 3.6) * exp((-L_A - 42.0) / 92.0));
+
+ return D;
+}
+
+float3 full_chromatic_adaptation_forward(float3 RGB, float3 RGB_w, float Y_w, float D) {
+ float3 RGB_c = ((Y_w * D / RGB_w) + 1.0 - D) * RGB;
+
+ return RGB_c;
+}
+
+float3 RGB_to_rgb(float3 RGB) {
+ // TODO: Check operations order correctness.
+ return mul(mul(XYZ_TO_HPE_MATRIX, CAT02_INVERSE_CAT), RGB);
+}
+
+float3 post_adaptation_non_linear_response_compression_forward(float3 RGB, float F_L) {
+ float3 RGB_c = ((((400.0 * pow((F_L * RGB / 100.0), 0.42)) /
+ (27.13 + pow((F_L * RGB / 100.0), 0.42)))) + 0.1);
+
+ return RGB_c;
+}
+
+float2 opponent_colour_dimensions_forward(float3 RGB) {
+ float a_o = RGB.r - 12.0 * RGB.g / 11.0 + RGB.b / 11.0;
+ float b_o = (RGB.r + RGB.g - 2.0 * RGB.b) / 9.0;
+
+ return float2(a_o, b_o);
+}
+
+float hue_angle(float2 ab) {
+ float h = degrees(atan2(ab.g, ab.r)) % 360;
+ if (h < 0) h += 360;
+
+ return h;
+}
+
+float hue_quadrature(float h) {
+ float t = ((h - 237.53)/1.2) + ((360.0 - h + 20.14)/0.8);
+ float H = 300.0 + ((100 * ((h - 237.53) / 1.2)) / t);
+
+ if (h < 20.14) {
+ t = ((h + 122.47) / 1.2) + ((20.14 - h) / 0.8);
+ H = 300.0 + (100.0 * ((h + 122.47) / 1.2)) / t;
+ }
+
+ if (h < 90.0) {
+ t = ((h - 20.14) / 0.8) + ((90.00 - h) / 0.7);
+ H = (100.0 * ((h - 20.14) / 0.8)) / t;
+ }
+
+ if (h < 164.25) {
+ t = ((h - 90.00) / 0.7) + ((164.25 - h) / 1.0);
+ H = 100.0 + ((100.0 * ((h - 90.00) / 0.7)) / t);
+ }
+
+ if (h < 237.53) {
+ t = ((h - 164.25) / 1.0) + ((237.53 - h) / 1.2);
+ H = 200.0 + ((100.0 * ((h - 164.25) / 1.0)) / t);
+ }
+
+ return H;
+}
+
+float eccentricity_factor(float h) {
+ float e_t = 1.0 / 4.0 * (cos(2.0 + h * PI / 180.0) + 3.8);
+
+ return e_t;
+}
+
+float achromatic_response_forward(float3 RGB, float N_bb) {
+ float A = (2.0 * RGB.r + RGB.g + (1.0 / 20.0) * RGB.b - 0.305) * N_bb;
+
+ return A;
+}
+
+float lightness_correlate(float A, float A_w, float c, float z) {
+ float J = 100.0 * pow(A / A_w, c * z);
+
+ return J;
+}
+
+float brightness_correlate(float c, float J, float A_w, float F_L) {
+ float Q = (4.0 / c) * sqrt(J / 100.0) * (A_w + 4.0) * pow(F_L, 0.25);
+
+ return Q;
+}
+
+float temporary_magnitude_quantity_forward(float N_c, float N_cb, float e_t, float2 ab, float3 RGB_a) {
+ float t = (((50000.0 / 13.0) * N_c * N_cb) * (e_t * pow(pow(ab.r, 2.0) + pow(ab.g, 2.0), 0.5)) /
+ (RGB_a.r + RGB_a.g + 21.0 * RGB_a.b / 20.0));
+
+ return t;
+}
+
+float chroma_correlate(float J, float n, float N_c, float N_cb, float e_t, float2 ab, float3 RGB_a) {
+ float t = temporary_magnitude_quantity_forward(N_c, N_cb, e_t, ab, RGB_a);
+ float C = pow(t, 0.9) * pow(J / 100.0, 0.5) * pow(1.64 - pow(0.29, n), 0.73);
+
+ return C;
+}
+
+float colourfulness_correlate(float C, float F_L) {
+ float M = C * pow(F_L, 0.25);
+
+ return M;
+}
+
+float saturation_correlate(float M, float Q) {
+ float s = 100.0 * pow(M / Q, 0.5);
+
+ return s;
+}
+
+CIECAM02_Specification XYZ_to_CIECAM02(float3 XYZ,
+ float3 XYZ_w,
+ float L_A,
+ float Y_b,
+ CIECAM02_InductionFactors surround,
+ bool discount_illuminant) {
+
+ float Y_w = XYZ_w.g;
+
+ float4 vcdp = viewing_condition_dependent_parameters(Y_b, Y_w, L_A);
+ float n = vcdp.r;
+ float F_L = vcdp.g;
+ float N_bbcb = vcdp.b;
+ float z = vcdp.a;
+
+ // Converting *CIE XYZ* tristimulus values to CMCCAT2000 transform
+ // sharpened *RGB* values.
+ float3 RGB = mul(CAT02_CAT, XYZ);
+ float3 RGB_w = mul(CAT02_CAT, XYZ_w);
+
+ float D = 1.0;
+ if (discount_illuminant == false)
+ D = degree_of_adaptation(surround.F, L_A);
+
+ float3 RGB_c = full_chromatic_adaptation_forward(
+ RGB, RGB_w, Y_w, D);
+ float3 RGB_wc = full_chromatic_adaptation_forward(
+ RGB_w, RGB_w, Y_w, D);
+
+ // Converting to *Hunt-Pointer-Estevez* colourspace.
+ float3 RGB_p = RGB_to_rgb(RGB_c);
+ float3 RGB_pw = RGB_to_rgb(RGB_wc);
+
+ // Applying forward post-adaptation non linear response compression.
+ float3 RGB_a = post_adaptation_non_linear_response_compression_forward(
+ RGB_p, F_L);
+ float3 RGB_aw = post_adaptation_non_linear_response_compression_forward(
+ RGB_pw, F_L);
+
+ // Converting to preliminary cartesian coordinates.
+ float2 ab = opponent_colour_dimensions_forward(RGB_a);
+
+ // -------------------------------------------------------------------------
+ // Computing the *hue* angle :math:`h`.
+ float h = hue_angle(ab);
+
+ // -------------------------------------------------------------------------
+ // Computing hue :math:`h` quadrature :math:`H`.
+ float H = hue_quadrature(h);
+ // TODO: Compute hue composition.
+
+ // Computing eccentricity factor *e_t*.
+ float e_t = eccentricity_factor(h);
+
+ // Computing achromatic responses for the stimulus and the whitepoint.
+ float A = achromatic_response_forward(RGB_a, N_bbcb);
+ float A_w = achromatic_response_forward(RGB_aw, N_bbcb);
+
+ // -------------------------------------------------------------------------
+ // Computing the correlate of *Lightness* :math:`J`.
+ // -------------------------------------------------------------------------
+ float J = lightness_correlate(A, A_w, surround.c, z);
+
+ // -------------------------------------------------------------------------
+ // Computing the correlate of *brightness* :math:`Q`.
+ // -------------------------------------------------------------------------
+ float Q = brightness_correlate(surround.c, J, A_w, F_L);
+
+ // -------------------------------------------------------------------------
+ // Computing the correlate of *chroma* :math:`C`.
+ // -------------------------------------------------------------------------
+ float C = chroma_correlate(J, n, surround.N_c, N_bbcb, e_t, ab, RGB_a);
+
+ // -------------------------------------------------------------------------
+ // Computing the correlate of *colourfulness* :math:`M`.
+ // -------------------------------------------------------------------------
+ float M = colourfulness_correlate(C, F_L);
+
+ // -------------------------------------------------------------------------
+ // Computing the correlate of *saturation* :math:`s`.
+ // -------------------------------------------------------------------------
+ float s = saturation_correlate(M, Q);
+
+ CIECAM02_Specification specification = {J, C, h, s, Q, M, H, 0};
+
+ return specification;
+}