Added support for multi-plane rendering (YUV)

- kmscap_ctx_t: Added texture_uv (UV plane), nv12_effect (compiled shader), and yuv_color_space (BT.709 / BT.601 setting).
- kmscap_build_color_matrix(): New helper that computes the correct limited-range YUV→RGB 4×4 matrix for either BT.709 or BT.601 at runtime.
- kmscap_destroy_texture(): Now destroys texture_uv alongside the Y texture in a single obs_enter_graphics() block.
- kmscap_import_fb(): NV12/NV21 now take a separate code path — Y is imported as GS_R8 (full res) and UV as GS_R8G8 (half res), each as a single-plane DMA-BUF call.
- kmscap_video_render(): When texture_uv is set, dispatches through the nv12_effect shader instead of OBS_EFFECT_DEFAULT; then overlays the cursor with the default effect on top.
- kmscap_create/destroy: Loads/destroys the NV12 effect file via obs_module_file().
- kmscap_update/get_defaults/get_properties: Adds the YUV Color Space dropdown (BT.709 default, BT.601 option).

Author: xnqs

CMakeLists.txt

@@ -55,6 +55,11 @@ if(OS_LINUX)
       src/kmscap-source.c
   )
 
+  # Install the NV12 conversion effect alongside the plugin data
+  set_target_properties(${CMAKE_PROJECT_NAME} PROPERTIES
+    OBS_MODULE_INSTALL_DATA "${CMAKE_CURRENT_SOURCE_DIR}/data"
+  )
+
   # Build the privileged helper daemon
   add_executable(obs-kmscap-helper src/kmscap-helper.c src/kms-utils.c src/kms-ipc.c)
   target_link_libraries(obs-kmscap-helper PRIVATE PkgConfig::Libdrm)

data/effects/kmscap-nv12.effect

@@ -0,0 +1,56 @@
+/*
+ * obs-kmscap - NV12 YUV-to-RGB conversion effect
+ *
+ * Converts a two-plane NV12 DMA-BUF into RGB for display.
+ *   image    – Y plane  (GS_R8,    width  x height)
+ *   image_uv – UV plane (GS_R8G8,  width/2 x height/2)
+ *
+ * The color_matrix uniform is a row-major 4x4 that maps [Y, Cb, Cr, 1] to
+ * [R, G, B, 1].  Pre-built matrices for BT.601 and BT.709 are set from C.
+ *
+ * OBS shader dialect: HLSL-like (compiled via libobs cross-compiler).
+ */
+
+uniform float4x4 color_matrix;
+
+uniform texture2d image;    /* Y  plane */
+uniform texture2d image_uv; /* UV plane */
+
+sampler_state texSampler {
+	Filter   = Linear;
+	AddressU = Clamp;
+	AddressV = Clamp;
+};
+
+struct VertData {
+	float4 pos : POSITION;
+	float2 uv  : TEXCOORD0;
+};
+
+VertData VSDefault(VertData v_in)
+{
+	VertData v_out;
+	v_out.pos = mul(float4(v_in.pos.xyz, 1.0), ViewProj);
+	v_out.uv  = v_in.uv;
+	return v_out;
+}
+
+float4 PSConvertNV12(VertData v_in) : TARGET
+{
+	float  y  = image.Sample(texSampler, v_in.uv).r;
+	float2 uv = image_uv.Sample(texSampler, v_in.uv).rg;
+
+	/* color_matrix maps [Y, Cb, Cr, 1] → [R, G, B, A] */
+	float4 yuv1 = float4(y, uv.x, uv.y, 1.0);
+	float4 rgba = mul(color_matrix, yuv1);
+	return float4(clamp(rgba.rgb, 0.0, 1.0), 1.0);
+}
+
+technique Draw
+{
+	pass
+	{
+		vertex_shader = VSDefault(v_in);
+		pixel_shader  = PSConvertNV12(v_in);
+	}
+}

data/locale/en-US.ini

@@ -3,3 +3,6 @@ KMSCapture.DRICard="DRI Card"
 KMSCapture.CRTC="Display Output (CRTC)"
 KMSCapture.NoCRTC="No active display found"
 KMSCapture.CaptureCursor="Capture Cursor"
+KMSCapture.ColorSpace="YUV Color Space (NV12)"
+KMSCapture.ColorSpace.BT709="BT.709 (HD, default)"
+KMSCapture.ColorSpace.BT601="BT.601 (SD/legacy)"