X-Git-Url: https://git.sesse.net/?p=movit;a=blobdiff_plain;f=colorspace_conversion_effect.cpp;h=2b8a0ca329fd34b3d535fca0cbdfb56584b8ff1d;hp=ca1661b7868b95c7a7765fe8712f164dade2db9e;hb=8e9f58fec54a4c879035b214fd7411f6ff7b3a32;hpb=1ca4785183b5af9a2a255bba0a28dfdae156470a diff --git a/colorspace_conversion_effect.cpp b/colorspace_conversion_effect.cpp index ca1661b..2b8a0ca 100644 --- a/colorspace_conversion_effect.cpp +++ b/colorspace_conversion_effect.cpp @@ -1,20 +1,29 @@ #include +#include +#include #include "colorspace_conversion_effect.h" +#include "d65.h" #include "util.h" +using namespace Eigen; +using namespace std; + +namespace movit { + // Color coordinates from Rec. 709; sRGB uses the same primaries. -double rec709_x_R = 0.640, rec709_x_G = 0.300, rec709_x_B = 0.150; -double rec709_y_R = 0.330, rec709_y_G = 0.600, rec709_y_B = 0.060; +static const double rec709_x_R = 0.640, rec709_x_G = 0.300, rec709_x_B = 0.150; +static const double rec709_y_R = 0.330, rec709_y_G = 0.600, rec709_y_B = 0.060; // Color coordinates from Rec. 601. (Separate for 525- and 625-line systems.) -double rec601_525_x_R = 0.630, rec601_525_x_G = 0.310, rec601_525_x_B = 0.155; -double rec601_525_y_R = 0.340, rec601_525_y_G = 0.595, rec601_525_y_B = 0.070; -double rec601_625_x_R = 0.640, rec601_625_x_G = 0.290, rec601_625_x_B = 0.150; -double rec601_625_y_R = 0.330, rec601_625_y_G = 0.600, rec601_625_y_B = 0.060; +static const double rec601_525_x_R = 0.630, rec601_525_x_G = 0.310, rec601_525_x_B = 0.155; +static const double rec601_525_y_R = 0.340, rec601_525_y_G = 0.595, rec601_525_y_B = 0.070; +static const double rec601_625_x_R = 0.640, rec601_625_x_G = 0.290, rec601_625_x_B = 0.150; +static const double rec601_625_y_R = 0.330, rec601_625_y_G = 0.600, rec601_625_y_B = 0.060; -// The D65 white point. Given in both Rec. 601 and 709. -double d65_x = 0.3127, d65_y = 0.3290; +// Color coordinates from Rec. 2020. +static const double rec2020_x_R = 0.708, rec2020_x_G = 0.170, rec2020_x_B = 0.131; +static const double rec2020_y_R = 0.292, rec2020_y_G = 0.797, rec2020_y_B = 0.046; ColorspaceConversionEffect::ColorspaceConversionEffect() : source_space(COLORSPACE_sRGB), @@ -24,13 +33,10 @@ ColorspaceConversionEffect::ColorspaceConversionEffect() register_int("destination_space", (int *)&destination_space); } -void get_xyz_matrix(Colorspace space, Matrix3x3 m) +Matrix3d ColorspaceConversionEffect::get_xyz_matrix(Colorspace space) { if (space == COLORSPACE_XYZ) { - m[0] = 1.0f; m[3] = 0.0f; m[6] = 0.0f; - m[1] = 0.0f; m[4] = 1.0f; m[7] = 0.0f; - m[2] = 0.0f; m[5] = 0.0f; m[8] = 1.0f; - return; + return Matrix3d::Identity(); } double x_R, x_G, x_B; @@ -49,6 +55,10 @@ void get_xyz_matrix(Colorspace space, Matrix3x3 m) x_R = rec601_625_x_R; x_G = rec601_625_x_G; x_B = rec601_625_x_B; y_R = rec601_625_y_R; y_G = rec601_625_y_G; y_B = rec601_625_y_B; break; + case COLORSPACE_REC_2020: + x_R = rec2020_x_R; x_G = rec2020_x_G; x_B = rec2020_x_B; + y_R = rec2020_y_R; y_G = rec2020_y_G; y_B = rec2020_y_B; + break; default: assert(false); } @@ -58,12 +68,6 @@ void get_xyz_matrix(Colorspace space, Matrix3x3 m) double z_G = 1.0 - x_G - y_G; double z_B = 1.0 - x_B - y_B; - // Find the XYZ coordinates of D65 (white point for both Rec. 601 and 709), - // normalized so that Y=1. - double d65_X = d65_x / d65_y; - double d65_Y = 1.0; - double d65_Z = (1.0 - d65_x - d65_y) / d65_y; - // We have, for each primary (example is with red): // // X_R / (X_R + Y_R + Z_R) = x_R @@ -72,8 +76,8 @@ void get_xyz_matrix(Colorspace space, Matrix3x3 m) // // Some algebraic fiddling yields (unsurprisingly): // - // X_R = (x_R / y_R) Y_R - // Z_R = (z_R / y_R) Y_R + // X_R = (x_R / y_R) Y_R (so define k1 = x_R / y_R) + // Z_R = (z_R / y_R) Y_R (so define k4 = z_R / y_R) // // We also know that since RGB=(1,1,1) should give us the // D65 illuminant, we must have @@ -82,8 +86,8 @@ void get_xyz_matrix(Colorspace space, Matrix3x3 m) // Y_R + Y_G + Y_B = D65_Y // Z_R + Z_G + Z_B = D65_Z // - // But since we already know how to express Y and Z by - // some constant multiple of X, this reduces to + // But since we already know how to express X and Z by + // some constant multiple of Y, this reduces to // // k1 Y_R + k2 Y_G + k3 Y_B = D65_X // Y_R + Y_G + Y_B = D65_Y @@ -91,37 +95,41 @@ void get_xyz_matrix(Colorspace space, Matrix3x3 m) // // Which we can solve for (Y_R, Y_G, Y_B) by inverting a 3x3 matrix. - Matrix3x3 temp, inverted; - temp[0] = x_R / y_R; - temp[3] = x_G / y_G; - temp[6] = x_B / y_B; + Matrix3d temp; + temp(0,0) = x_R / y_R; + temp(0,1) = x_G / y_G; + temp(0,2) = x_B / y_B; - temp[1] = 1.0; - temp[4] = 1.0; - temp[7] = 1.0; + temp(1,0) = 1.0; + temp(1,1) = 1.0; + temp(1,2) = 1.0; - temp[2] = z_R / y_R; - temp[5] = z_G / y_G; - temp[8] = z_B / y_B; + temp(2,0) = z_R / y_R; + temp(2,1) = z_G / y_G; + temp(2,2) = z_B / y_B; - invert_3x3_matrix(temp, inverted); - float Y_R, Y_G, Y_B; - multiply_3x3_matrix_float3(inverted, d65_X, d65_Y, d65_Z, &Y_R, &Y_G, &Y_B); + Vector3d d65_XYZ(d65_X, d65_Y, d65_Z); + Vector3d Y_RGB = temp.inverse() * d65_XYZ; // Now convert xyY -> XYZ. - double X_R = temp[0] * Y_R; - double Z_R = temp[2] * Y_R; - double X_G = temp[3] * Y_G; - double Z_G = temp[5] * Y_G; - double X_B = temp[6] * Y_B; - double Z_B = temp[8] * Y_B; - - m[0] = X_R; m[3] = X_G; m[6] = X_B; - m[1] = Y_R; m[4] = Y_G; m[7] = Y_B; - m[2] = Z_R; m[5] = Z_G; m[8] = Z_B; + double X_R = temp(0,0) * Y_RGB[0]; + double Z_R = temp(2,0) * Y_RGB[0]; + + double X_G = temp(0,1) * Y_RGB[1]; + double Z_G = temp(2,1) * Y_RGB[1]; + + double X_B = temp(0,2) * Y_RGB[2]; + double Z_B = temp(2,2) * Y_RGB[2]; + + Matrix3d m; + m(0,0) = X_R; m(0,1) = X_G; m(0,2) = X_B; + m(1,0) = Y_RGB[0]; m(1,1) = Y_RGB[1]; m(1,2) = Y_RGB[2]; + m(2,0) = Z_R; m(2,1) = Z_G; m(2,2) = Z_B; + + return m; } -std::string ColorspaceConversionEffect::output_fragment_shader() +string ColorspaceConversionEffect::output_fragment_shader() { // Create a matrix to convert from source space -> XYZ, // another matrix to convert from XYZ -> destination space, @@ -129,26 +137,12 @@ std::string ColorspaceConversionEffect::output_fragment_shader() // // Since we right-multiply the RGB column vector, the matrix // concatenation order needs to be the opposite of the operation order. - Matrix3x3 m; - - Matrix3x3 source_space_to_xyz; - Matrix3x3 destination_space_to_xyz; - Matrix3x3 xyz_to_destination_space; - - get_xyz_matrix(source_space, source_space_to_xyz); - get_xyz_matrix(destination_space, destination_space_to_xyz); - invert_3x3_matrix(destination_space_to_xyz, xyz_to_destination_space); - - multiply_3x3_matrices(xyz_to_destination_space, source_space_to_xyz, m); - - char buf[1024]; - sprintf(buf, - "const mat3 PREFIX(conversion_matrix) = mat3(\n" - " %.8f, %.8f, %.8f,\n" - " %.8f, %.8f, %.8f,\n" - " %.8f, %.8f, %.8f);\n\n", - m[0], m[1], m[2], - m[3], m[4], m[5], - m[6], m[7], m[8]); - return buf + read_file("colorspace_conversion_effect.frag"); + Matrix3d source_space_to_xyz = get_xyz_matrix(source_space); + Matrix3d xyz_to_destination_space = get_xyz_matrix(destination_space).inverse(); + Matrix3d m = xyz_to_destination_space * source_space_to_xyz; + + return output_glsl_mat3("PREFIX(conversion_matrix)", m) + + read_file("colorspace_conversion_effect.frag"); } + +} // namespace movit