From: Steinar H. Gunderson Date: Mon, 1 Oct 2012 21:44:26 +0000 (+0200) Subject: Add color space conversions on input and output. X-Git-Tag: 1.0~451 X-Git-Url: https://git.sesse.net/?p=movit;a=commitdiff_plain;h=758f632c42befae7f2b7af137554429fa544d4cb;ds=inline Add color space conversions on input and output. --- diff --git a/colorspace_conversion_effect.cpp b/colorspace_conversion_effect.cpp index 8a0199e..4cef413 100644 --- a/colorspace_conversion_effect.cpp +++ b/colorspace_conversion_effect.cpp @@ -1,6 +1,20 @@ +#include + #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) @@ -9,7 +23,76 @@ ColorSpaceConversionEffect::ColorSpaceConversionEffect() 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"); } diff --git a/colorspace_conversion_effect.glsl b/colorspace_conversion_effect.glsl new file mode 100644 index 0000000..ea858fb --- /dev/null +++ b/colorspace_conversion_effect.glsl @@ -0,0 +1,8 @@ +// Colorspace conversion (needs to be done in linear space). +// The matrix is computed on the host and baked into the shader at compile time. + +vec4 FUNCNAME(vec2 tc) { + vec4 x = LAST_INPUT(tc); + x.rgb = PREFIX(conversion_matrix) * x.rgb; + return x; +} diff --git a/effect_chain.cpp b/effect_chain.cpp index 3ccab44..5d9eaa3 100644 --- a/effect_chain.cpp +++ b/effect_chain.cpp @@ -132,7 +132,13 @@ std::string replace_prefix(const std::string &text, const std::string &prefix) void EffectChain::finalize() { - // TODO: If we want a non-sRGB output color space, convert. + if (current_color_space != output_format.color_space) { + ColorSpaceConversionEffect *colorspace_conversion = new ColorSpaceConversionEffect(); + colorspace_conversion->set_int("source_space", current_color_space); + colorspace_conversion->set_int("destination_space", output_format.color_space); + effects.push_back(colorspace_conversion); + current_color_space = output_format.color_space; + } if (current_gamma_curve != output_format.gamma_curve) { if (current_gamma_curve != GAMMA_LINEAR) { diff --git a/util.cpp b/util.cpp index c18f009..2176786 100644 --- a/util.cpp +++ b/util.cpp @@ -88,3 +88,45 @@ GLhandleARB compile_shader(const std::string &shader_src, GLenum type) 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"); +} diff --git a/util.h b/util.h index ab0ee5d..498e5f2 100644 --- a/util.h +++ b/util.h @@ -11,8 +11,14 @@ // 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()