3 #include "colorspace_conversion_effect.h"
6 // Color coordinates from Rec. 709; sRGB uses the same primaries.
7 double rec709_x_R = 0.640, rec709_x_G = 0.300, rec709_x_B = 0.150;
8 double rec709_y_R = 0.330, rec709_y_G = 0.600, rec709_y_B = 0.060;
9 double rec709_Y_R = 0.2126, rec709_Y_G = 0.7152, rec709_Y_B = 0.0722;
11 // Color coordinates from Rec. 601. (Separate for 525- and 625-line systems.)
12 double rec601_525_x_R = 0.630, rec601_525_x_G = 0.310, rec601_525_x_B = 0.155;
13 double rec601_525_y_R = 0.340, rec601_525_y_G = 0.595, rec601_525_y_B = 0.070;
14 double rec601_625_x_R = 0.640, rec601_625_x_G = 0.290, rec601_625_x_B = 0.150;
15 double rec601_625_y_R = 0.330, rec601_625_y_G = 0.600, rec601_625_y_B = 0.060;
16 double rec601_Y_R = 0.299, rec601_Y_G = 0.587, rec601_Y_B = 0.114;
18 ColorSpaceConversionEffect::ColorSpaceConversionEffect()
19 : source_space(COLORSPACE_sRGB),
20 destination_space(COLORSPACE_sRGB)
22 register_int("source_space", (int *)&source_space);
23 register_int("destination_space", (int *)&destination_space);
26 void get_xyz_matrix(ColorSpace space, Matrix3x3 m)
28 if (space == COLORSPACE_XYZ) {
29 m[0] = 1.0f; m[3] = 0.0f; m[6] = 0.0f;
30 m[1] = 0.0f; m[4] = 1.0f; m[7] = 0.0f;
31 m[2] = 0.0f; m[5] = 0.0f; m[8] = 1.0f;
40 case COLORSPACE_REC_709: // And sRGB.
41 x_R = rec709_x_R; x_G = rec709_x_G; x_B = rec709_x_B;
42 y_R = rec709_y_R; y_G = rec709_y_G; y_B = rec709_y_B;
43 Y_R = rec709_Y_R; Y_G = rec709_Y_G; Y_B = rec709_Y_B;
45 case COLORSPACE_REC_601_525:
46 x_R = rec601_525_x_R; x_G = rec601_525_x_G; x_B = rec601_525_x_B;
47 y_R = rec601_525_y_R; y_G = rec601_525_y_G; y_B = rec601_525_y_B;
48 Y_R = rec601_Y_R; Y_G = rec601_Y_G; Y_B = rec601_Y_B;
50 case COLORSPACE_REC_601_625:
51 x_R = rec601_625_x_R; x_G = rec601_625_x_G; x_B = rec601_625_x_B;
52 y_R = rec601_625_y_R; y_G = rec601_625_y_G; y_B = rec601_625_y_B;
53 Y_R = rec601_Y_R; Y_G = rec601_Y_G; Y_B = rec601_Y_B;
59 // Convert xyY -> XYZ.
61 X_R = Y_R * x_R / y_R;
62 X_G = Y_G * x_G / y_G;
63 X_B = Y_B * x_B / y_B;
66 Z_R = Y_R * (1.0f - x_R - y_R) / y_R;
67 Z_G = Y_G * (1.0f - x_G - y_G) / y_G;
68 Z_B = Y_B * (1.0f - x_B - y_B) / y_B;
70 m[0] = X_R; m[3] = X_G; m[6] = X_B;
71 m[1] = Y_R; m[4] = Y_G; m[7] = Y_B;
72 m[2] = Z_R; m[5] = Z_G; m[8] = Z_B;
75 std::string ColorSpaceConversionEffect::output_fragment_shader()
77 // Create a matrix to convert from source space -> XYZ,
78 // another matrix to convert from XYZ -> destination space,
79 // and then concatenate the two.
81 // Since we right-multiply the RGB column vector, the matrix
82 // concatenation order needs to be the opposite of the operation order.
85 Matrix3x3 source_space_to_xyz;
86 Matrix3x3 destination_space_to_xyz;
87 Matrix3x3 xyz_to_destination_space;
89 get_xyz_matrix(source_space, source_space_to_xyz);
90 get_xyz_matrix(destination_space, destination_space_to_xyz);
91 invert_3x3_matrix(destination_space_to_xyz, xyz_to_destination_space);
93 multiply_3x3_matrices(xyz_to_destination_space, source_space_to_xyz, m);
97 "const mat3 PREFIX(conversion_matrix) = mat3(\n"
98 " %.8f, %.8f, %.8f,\n"
99 " %.8f, %.8f, %.8f,\n"
100 " %.8f, %.8f, %.8f);\n\n",
104 return buf + read_file("colorspace_conversion_effect.frag");