Bcp-Rendering-Engine-Usage-in-Windows-NT-Kernel-BSOD

Undocumented Non-Exported Functions :

In dxgkrnl.sys Module :

NTSTATUS DpiSystemDisplayWrite (
      _In_ PDPI_RECT_DESC pSrcInfo, // Source rectangle description (contains pixel data, dimensions, format)
      _Out_ PDPI_DST_INFO pDstInfo, // Destination position (X, Y coordinates on screen)
      _In_ UINT8 Flags              // Control flags (usually 0)
);  // Function for drawing a rectangle on the screen

In ntoskrnl.exe Module :

VOID BgpFwAcquireLock (
      VOID
);  // Function for obtaining the IRQL spin lock of the Bcp/Bgp control object

NTSTATUS BcpDisplayCriticalString (
      _In_ PNTUNICODE_STRING String, // Pointer to the wide string to be displayed
      _In_ ULONG TextSize,           // Text size
      _Inout_ ULONG64 Reserved,      // Reserved parameter
      _In_ ULONG DisplayType         // Display type (usually 2)
);  // Function for displaying a string

NTSTATUS BgpTxtDisplayCharacter(
      _Inout_ ULONG_PTR* Context,    // Pointer to BgpTxtDisplayCharacter_struct
      _In_ WCHAR DisplayChar,        // Wide character to render (skip if < 0x20)
      _In_ BOOLEAN Flags,            // Control flags (usually FALSE)
      _Out_ ULONG* pAdvanceWidth,    // Returns advance width in pixels
      _Out_ ULONG* pHeight,          // Returns character height in pixels (for line spacing)
);  // Function to display a single wide character

Undocumented Exported Functions :

In ntoskrnl.exe Module :

NTSTATUS InbvAcquireDisplayOwnership (
      VOID
);  // Function to acquire exclusive ownership of the screen

Undocumented structures :

In ntoskrnl.exe Module :

typedef struct {
    UINT32 Height;     // Rectangle height
    UINT32 Width;      // Rectangle width
    UINT32 Flags;      // Flags (usually 5)
    UINT32 Stride;     // Pitch (bytes per row), usually Width * 4
    UINT32* PixelData; // Pointer to pixel rectangle data in non-paged memory (ARGB format)
} DPI_RECT_DESC, *PDPI_RECT_DESC;

typedef struct {
    UINT32  DstX;      // Start X coordinate for rendering
    UINT32  DstY;      // Start Y coordinate for rendering
} DPI_DST_INFO, *PDPI_DST_INFO;

typedef struct {
    USHORT Length;
    USHORT MaximumLength;
    ULONG Padding;     // Exists solely to enforce 16-byte alignment of the structure
    PWSTR Buffer;
} NTUNICODE_STRING, *PNTUNICODE_STRING;  // Identical to the UNICODE_STRING structure, with added padding to enforce alignment

typedef struct {
    ULONG Unknown;     // Unknown structure member
    ULONG Y;           // Screen height in pixels
    ULONG X;           // Screen width in pixels
} BgInternal_struct, *PBgInternal_struct;

typedef struct {
    ULONG X;           // Start X coordinate for rendering
    ULONG Y;           // Start Y coordinate for rendering
    // ...
} BcpCursor_struct, *PBcpCursor_struct;

typedef struct {
    // ...
    ULONG TextColor; // +0x28
    ULONG BackColor; // +0x2C
} BgpTxtDisplayCharacter_struct, *PBgpTxtDisplayCharacter_struct;

For examples of calling and modifying, see the ExampleUsage.c file in the repository.