Fix colour primaries when previewing Rec.2020 content with OpenGL.

diff --git a/src/wx/gl_video_view.cc b/src/wx/gl_video_view.cc
index 16b01d25c01ccfb69656bab68e9c202bdf1ba963..4fc620936d9eb837bc22cefe089d1fb1f678a384 100644 (file)
--- a/src/wx/gl_video_view.cc
+++ b/src/wx/gl_video_view.cc
@@ -198,12 +198,14 @@ static constexpr char fragment_source[] =
  * type = 1: draw crop guess rectangle
  * type = 2: draw XYZ image
  * type = 3: draw RGB image (with sRGB/Rec709 primaries)
+ * type = 4: draw RGB image (converting from Rec2020 primaries)
  * See FragmentType enum below.
  */
 "uniform int type = 0;\n"
 "uniform vec4 outline_content_colour;\n"
 "uniform vec4 crop_guess_colour;\n"
 "uniform mat4 xyz_rec709_colour_conversion;\n"
+"uniform mat4 rec2020_rec709_colour_conversion;\n"
 "\n"
 "out vec4 FragColor;\n"
 "\n"
@@ -278,6 +280,10 @@ static constexpr char fragment_source[] =
 "                      break;\n"
 "              case 3:\n"
 "                      FragColor = texture_bicubic(texture_sampler, TexCoord);\n"
+"                       break;\n"
+"              case 4:\n"
+"                      FragColor = texture_bicubic(texture_sampler, TexCoord);\n"
+"                      FragColor = rec2020_rec709_colour_conversion * FragColor;\n"
 "                      break;\n"
 "      }\n"
 "}\n";
@@ -289,6 +295,7 @@ enum class FragmentType
        CROP_GUESS = 1,
        XYZ_IMAGE = 2,
        REC709_IMAGE = 3,
+       REC2020_IMAGE = 4,
 };
 
 
@@ -483,6 +490,19 @@ GLVideoView::setup_shaders ()
                glUniformMatrix4fv(xyz_rec709_colour_conversion, 1, GL_TRUE, gl_matrix);
        }
 
+       {
+               auto xyz_rec709 = dcp::ColourConversion::rec709_to_xyz().xyz_to_rgb();
+               auto rec2020_xyz = dcp::ColourConversion::rec2020_to_xyz().rgb_to_xyz();
+               auto product = boost::numeric::ublas::prod(xyz_rec709, rec2020_xyz);
+
+               GLfloat gl_matrix[16];
+               ublas_to_gl(product, gl_matrix);
+
+               auto rec2020_rec709_colour_conversion = glGetUniformLocation(program, "rec2020_rec709_colour_conversion");
+               check_gl_error("glGetUniformLocation");
+               glUniformMatrix4fv(rec2020_rec709_colour_conversion, 1, GL_TRUE, gl_matrix);
+       }
+
        glLineWidth (1.0f);
        check_gl_error ("glLineWidth");
        glEnable (GL_BLEND);
@@ -539,7 +559,13 @@ GLVideoView::draw ()
 
        glBindVertexArray(_vao);
        check_gl_error ("glBindVertexArray");
-       glUniform1i(_fragment_type, static_cast<GLint>(_optimise_for_j2k ? FragmentType::XYZ_IMAGE : FragmentType::REC709_IMAGE));
+       if (_optimise_for_j2k) {
+               glUniform1i(_fragment_type, static_cast<GLint>(FragmentType::XYZ_IMAGE));
+       } else if (_rec2020) {
+               glUniform1i(_fragment_type, static_cast<GLint>(FragmentType::REC2020_IMAGE));
+       } else {
+               glUniform1i(_fragment_type, static_cast<GLint>(FragmentType::REC709_IMAGE));
+       }
        _video_texture->bind();
        glDrawElements (GL_TRIANGLES, indices_video_texture_number, GL_UNSIGNED_INT, reinterpret_cast<void*>(indices_video_texture_offset * sizeof(int)));
        if (_have_subtitle_to_render) {
@@ -709,6 +735,8 @@ GLVideoView::set_image (shared_ptr<const PlayerVideo> pv)
                check_gl_error ("glBufferSubData (subtitle)");
        }
 
+       _rec2020 = pv->colour_conversion() && pv->colour_conversion()->about_equal(dcp::ColourConversion::rec2020_to_xyz(), 1e-6);
+
        /* opt: where should these go? */
 
        glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);

diff --git a/src/wx/gl_video_view.h b/src/wx/gl_video_view.h
index fd9154a7338d946a8c1b31a619adde843f9f4324..964f6f1ab9db2db8469e1fce8a36bd2d93279fa3 100644 (file)
--- a/src/wx/gl_video_view.h
+++ b/src/wx/gl_video_view.h
@@ -134,6 +134,7 @@ private:
        Last<boost::optional<dcpomatic::Rect<float>>> _last_crop_guess;
 
        boost::atomic<wxSize> _canvas_size;
+       boost::atomic<bool> _rec2020;
        std::unique_ptr<Texture> _video_texture;
        std::unique_ptr<Texture> _subtitle_texture;
        bool _have_subtitle_to_render = false;