rendervulkan, drm: Apply 709 -> 2020 CTM for scRGB

Get this in the right space!
ValveSoftware · Oct 25, 2023 · d6f2ecd · d6f2ecd
1 parent 06532b0
commit d6f2ecd
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Showing 3 changed files with 32 additions and 0 deletions.
diff --git a/src/color_helpers.cpp b/src/color_helpers.cpp
@@ -891,3 +891,11 @@ bool approxEqual( const glm::vec3 & a, const glm::vec3 & b, float flTolerance =
     glm::vec3 v = glm::abs(a - b);
     return ( v.x < flTolerance && v.y < flTolerance && v.z < flTolerance );
 }
+
+const glm::mat3 k_xyz_from_709 = normalised_primary_matrix( displaycolorimetry_709.primaries, displaycolorimetry_709.white, 1.f );
+const glm::mat3 k_709_from_xyz = glm::inverse( k_xyz_from_709 );
+
+const glm::mat3 k_xyz_from_2020 = normalised_primary_matrix( displaycolorimetry_2020.primaries, displaycolorimetry_2020.white, 1.f );
+const glm::mat3 k_2020_from_xyz = glm::inverse( k_xyz_from_2020 );
+
+const glm::mat3 k_2020_from_709 = k_2020_from_xyz * k_xyz_from_709;
diff --git a/src/color_helpers.h b/src/color_helpers.h
@@ -472,3 +472,12 @@ static constexpr displaycolorimetry_t displaycolorimetry_2020
 	.primaries = { { 0.708f, 0.292f }, { 0.170f, 0.797f }, { 0.131f, 0.046f } },
 	.white = { 0.3127f, 0.3290f },  // D65
 };
+
+
+extern const glm::mat3 k_xyz_from_709;
+extern const glm::mat3 k_709_from_xyz;
+
+extern const glm::mat3 k_xyz_from_2020;
+extern const glm::mat3 k_2020_from_xyz;
+
+extern const glm::mat3 k_2020_from_709;
diff --git a/src/steamcompmgr.cpp b/src/steamcompmgr.cpp
@@ -130,6 +130,7 @@ extern float g_flHDRItmTargetNits;
 
 extern std::atomic<uint64_t> g_lastVblank;
 
+static std::shared_ptr<wlserver_ctm> s_scRGB709To2020Matrix;
 
 std::string clipboard;
 std::string primarySelection;
@@ -1944,6 +1945,7 @@ void MouseCursor::paint(steamcompmgr_win_t *window, steamcompmgr_win_t *fit, str
 
 	layer->filter = cursor_scale != 1.0f ? GamescopeUpscaleFilter::LINEAR : GamescopeUpscaleFilter::NEAREST;
 	layer->blackBorder = false;
+	layer->ctm = nullptr;
 	layer->colorspace = GAMESCOPE_APP_TEXTURE_COLORSPACE_SRGB;
 }
 
@@ -1991,6 +1993,9 @@ paint_cached_base_layer(const std::shared_ptr<commit_t>& commit, const BaseLayer
 	layer->opacity = base.opacity * flOpacityScale;
 
 	layer->colorspace = commit->colorspace();
+	layer->ctm = nullptr;
+	if (layer->colorspace == GAMESCOPE_APP_TEXTURE_COLORSPACE_SCRGB)
+		layer->ctm = s_scRGB709To2020Matrix;
 	layer->tex = commit->vulkanTex;
 	layer->fbid = commit->fb_id;
 
@@ -2195,6 +2200,9 @@ paint_window(steamcompmgr_win_t *w, steamcompmgr_win_t *scaleW, struct FrameInfo
 
 	layer->filter = (w->isOverlay || w->isExternalOverlay) ? GamescopeUpscaleFilter::LINEAR : g_upscaleFilter;
 	layer->colorspace = lastCommit->colorspace();
+	layer->ctm = nullptr;
+	if (layer->colorspace == GAMESCOPE_APP_TEXTURE_COLORSPACE_SCRGB)
+		layer->ctm = s_scRGB709To2020Matrix;
 
 	if (layer->filter == GamescopeUpscaleFilter::PIXEL)
 	{
@@ -2675,6 +2683,7 @@ paint_all(bool async)
 				baseLayer->applyColorMgmt = false;
 
 				baseLayer->filter = GamescopeUpscaleFilter::NEAREST;
+				baseLayer->ctm = nullptr;
 				baseLayer->colorspace = g_bOutputHDREnabled ? GAMESCOPE_APP_TEXTURE_COLORSPACE_HDR10_PQ : GAMESCOPE_APP_TEXTURE_COLORSPACE_SRGB;
 
 				g_bWasPartialComposite = false;
@@ -2702,6 +2711,7 @@ paint_all(bool async)
 					overlayLayer->filter = GamescopeUpscaleFilter::NEAREST;
 					// Partial composition stuff has the same colorspace.
 					// So read that from the composite frame info
+					overlayLayer->ctm = nullptr;
 					overlayLayer->colorspace = compositeFrameInfo.layers[0].colorspace;
 				}
 				else
@@ -7465,6 +7475,11 @@ steamcompmgr_main(int argc, char **argv)
 
 	update_screenshot_color_mgmt();
 
+	// Transpose to get this 3x3 matrix into the right state for applying as a 3x4
+	// on DRM + the Vulkan side.
+	// ie. color.rgb = color.rgba * u_ctm[offsetLayerIdx];
+	s_scRGB709To2020Matrix = drm_create_ctm(&g_DRM, glm::mat3x4(glm::transpose(k_2020_from_709)));
+
 	for (;;)
 	{
 		bool vblank = false;