+#include <assert.h>
+
#include "colorspace_conversion_effect.h"
#include "util.h"
+// 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;
+double rec709_Y_R = 0.2126, rec709_Y_G = 0.7152, rec709_Y_B = 0.0722;
+
+// 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;
+double rec601_Y_R = 0.299, rec601_Y_G = 0.587, rec601_Y_B = 0.114;
+
ColorSpaceConversionEffect::ColorSpaceConversionEffect()
: source_space(COLORSPACE_sRGB),
destination_space(COLORSPACE_sRGB)
register_int("destination_space", (int *)&destination_space);
}
+void get_xyz_matrix(ColorSpace space, Matrix3x3 m)
+{
+ double x_R, x_G, x_B;
+ double y_R, y_G, y_B;
+ double Y_R, Y_G, Y_B;
+
+ switch (space) {
+ case COLORSPACE_REC_709: // And sRGB.
+ x_R = rec709_x_R; x_G = rec709_x_G; x_B = rec709_x_B;
+ y_R = rec709_y_R; y_G = rec709_y_G; y_B = rec709_y_B;
+ Y_R = rec709_Y_R; Y_G = rec709_Y_G; Y_B = rec709_Y_B;
+ break;
+ case COLORSPACE_REC_601_525:
+ x_R = rec601_525_x_R; x_G = rec601_525_x_G; x_B = rec601_525_x_B;
+ y_R = rec601_525_y_R; y_G = rec601_525_y_G; y_B = rec601_525_y_B;
+ Y_R = rec601_Y_R; Y_G = rec601_Y_G; Y_B = rec601_Y_B;
+ break;
+ case COLORSPACE_REC_601_625:
+ 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;
+ Y_R = rec601_Y_R; Y_G = rec601_Y_G; Y_B = rec601_Y_B;
+ break;
+ default:
+ assert(false);
+ }
+
+ // Convert xyY -> XYZ.
+ double X_R, X_G, X_B;
+ X_R = Y_R * x_R / y_R;
+ X_G = Y_G * x_G / y_G;
+ X_B = Y_B * x_B / y_B;
+
+ double Z_R, Z_G, Z_B;
+ Z_R = Y_R * (1.0f - x_R - y_R) / y_R;
+ Z_G = Y_G * (1.0f - x_G - y_G) / y_G;
+ Z_B = Y_B * (1.0f - x_B - y_B) / 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;
+}
+
std::string ColorSpaceConversionEffect::output_glsl()
{
- return read_file("todo.glsl");
+ // Create a matrix to convert from source space -> XYZ,
+ // another matrix to convert from XYZ -> destination space,
+ // and then concatenate the two.
+ //
+ // 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[3], m[6],
+ m[1], m[4], m[7],
+ m[2], m[5], m[8]);
+ return buf + read_file("colorspace_conversion_effect.glsl");
}
return obj;
}
+void multiply_3x3_matrices(const Matrix3x3 a, const Matrix3x3 b, Matrix3x3 result)
+{
+ result[0] = a[0] * b[0] + a[3] * b[1] + a[6] * b[2];
+ result[1] = a[1] * b[0] + a[4] * b[1] + a[7] * b[2];
+ result[2] = a[2] * b[0] + a[5] * b[1] + a[8] * b[2];
+
+ result[3] = a[0] * b[3] + a[3] * b[4] + a[6] * b[5];
+ result[4] = a[1] * b[3] + a[4] * b[4] + a[7] * b[5];
+ result[5] = a[2] * b[3] + a[5] * b[4] + a[8] * b[5];
+
+ result[6] = a[0] * b[6] + a[3] * b[7] + a[6] * b[8];
+ result[7] = a[1] * b[6] + a[4] * b[7] + a[7] * b[8];
+ result[8] = a[2] * b[6] + a[5] * b[7] + a[8] * b[8];
+}
+
+void invert_3x3_matrix(const Matrix3x3 m, Matrix3x3 result)
+{
+ double inv_det = 1.0 / (
+ m[6] * m[1] * m[5] - m[6] * m[2] * m[4] -
+ m[3] * m[1] * m[8] + m[3] * m[2] * m[7] +
+ m[0] * m[4] * m[8] - m[0] * m[5] * m[7]);
+
+ result[0] = inv_det * (m[4] * m[8] - m[5] * m[7]);
+ result[1] = inv_det * (m[2] * m[7] - m[1] * m[8]);
+ result[2] = inv_det * (m[1] * m[5] - m[2] * m[4]);
+
+ result[3] = inv_det * (m[6] * m[5] - m[3] * m[8]);
+ result[4] = inv_det * (m[0] * m[8] - m[6] * m[2]);
+ result[5] = inv_det * (m[3] * m[2] - m[0] * m[5]);
+
+ result[6] = inv_det * (m[3] * m[7] - m[6] * m[4]);
+ result[7] = inv_det * (m[6] * m[1] - m[0] * m[7]);
+ result[8] = inv_det * (m[0] * m[4] - m[3] * m[1]);
+}
+
+void print_3x3_matrix(const Matrix3x3 m)
+{
+ printf("%6.4f %6.4f %6.4f\n", m[0], m[3], m[6]);
+ printf("%6.4f %6.4f %6.4f\n", m[1], m[4], m[7]);
+ printf("%6.4f %6.4f %6.4f\n", m[2], m[5], m[8]);
+ printf("\n");
+}
// assumes h in [0, 2pi> or [-pi, pi>
void hsv2rgb(float h, float s, float v, float *r, float *g, float *b);
+// Column major (same as OpenGL).
+typedef double Matrix3x3[9];
+
std::string read_file(const std::string &filename);
GLhandleARB compile_shader(const std::string &shader_src, GLenum type);
+void multiply_3x3_matrices(const Matrix3x3 a, const Matrix3x3 b, Matrix3x3 result);
+void invert_3x3_matrix(const Matrix3x3 m, Matrix3x3 result);
+void print_3x3_matrix(const Matrix3x3 m);
#ifdef NDEBUG
#define check_error()