PMD (High-Speed Modeling Data): Difference between revisions

Revision as of 02:22, 23 October 2026 RemmyLee (Hardware and system software pages from the Sony manuals)	Revision as of 02:27, 23 October 2026 RemmyLee (File format pages from the Sony File Formats manual)
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	+	---
	+	title: PMD (High-Speed Modeling Data)
	+	type: format
	+	summary: Modeling data for libgs that holds ready drawing packets for fast processing.
	+	category: File formats
	+	info: Extension = .PMD
	+	info: ID = 0x00000042
	+	---
	+
	+	## Overview
	+
	+	The PMD format holds modeling data for the extended graphics library (libgs).[^ff235]
	+
	+	PMD has fewer functions than [TMD](/formats/tmd/). The smaller scope allows faster processing.[^ff235]
	+
	+	PMD handles the following kinds of objects:[^ff235]
	+
	+	- Triangular and rectangular polygons only
	+	- Packet creation areas contained in the data
	+	- Groups of polygons that have the same attributes
	+
	+	## File Structure
	+
	+	A PMD file holds a table of 3D objects with their PRIMITIVE and VERTEX data.[^ff235]
	+
	+	The file has the following fields:
	+
	+	Table: PMD file structure
	+
	+	\| Field \| Contents \|
	+	\| --- \| --- \|
	+	\| ID \| 32-bit word with the version of the PMD file. The current version is 0x00000042. \|
	+	\| PRIM POINT \| 32-bit offset of the PRIMITIVE Gp section from the start of the file \|
	+	\| VERT POINT \| 32-bit offset of the VERTEX Gp section from the start of the file. 0 for independent vertices. \|
	+	\| OBJ TABLE \| The array of objects \|
	+	\| PRIMITIVE Gp \| Groups of polygons that have the same attributes \|
	+	\| VERTEX Gp \| Array of vertex coordinates, present only for shared vertices \|
	+
	+	## Coordinate Values
	+
	+	PMD coordinates follow the 3D coordinate space of the 3D graphics library. Each coordinate is a signed 16-bit integer from -32768 to +32767.[^ff236]
	+
	+	The positive X axis points right. The positive Y axis points down, and the positive Z axis points into the depth.[^ff236]
	+
	+	Conversion from RSD to PMD scales the floating point vertex values as needed. The current version of libgs ignores the scale value.[^ff236]
	+
	+	## OBJ TABLE
	+
	+	The OBJ TABLE holds pointers to the primitive groups of each object. One object is made of primitive groups.[^ff236]
	+
	+	The table has the following fields:
	+
	+	Table: OBJ TABLE fields
	+
	+	\| Field \| Contents \|
	+	\| --- \| --- \|
	+	\| NOBJ \| Number of objects in the OBJ TABLE \|
	+	\| NPTR \| Number of pointers in one object \|
	+	\| POINTER \| Pointer to a primitive group \|
	+
	+	Each object has an NPTR field. Its pointers POINTER 0 to POINTER (nptr-1) follow.[^ff236]
	+
	+	## PRIMITIVE Group
	+
	+	A PRIMITIVE Gp is a group of graphics packets. One packet holds one primitive.[^ff236]
	+
	+	PMD primitives differ from the drawing primitives of libgpu. libgs functions convert them to drawing primitives by perspective transformation.[^ff236]
	+
	+	A primitive group opens with one word that holds TYPE and NPACKET.[^ff237]
	+
	+	The word is as follows:
	+
	+	Table: Packet Gp header
	+
	+	\| Bits \| Field \| Contents \|
	+	\| --- \| --- \| --- \|
	+	\| 0..15 \| NPACKET \| Number of packets \|
	+	\| 16..31 \| TYPE \| Packet type \|
	+
	+	The TYPE bits are as follows:[^ff237]
	+
	+	Table: TYPE bit layout
	+
	+	\| Bit no. \| When 0 \| When 1 \|
	+	\| --- \| --- \| --- \|
	+	\| 16 \| Triangle \| Quadrilateral \|
	+	\| 17 \| Flat \| Gouraud \|
	+	\| 18 \| Texture-On \| Texture-Off \|
	+	\| 19 \| Independent vertex \| Shared vertex \|
	+	\| 20 \| Light source calculation Off \| Light source calculation On \|
	+	\| 21 \| Back clip \| No back clip \|
	+	\| 22..31 \| Reserved for system \| Reserved for system \|
	+
	+	The structure of the packet data depends on TYPE. Bits 20 and 21 do not change the packet data structure.[^ff237]
	+
	+	Each packet holds two drawing primitives for a double buffer. Both must be initialized in advance.[^ff237]
	+
	+	## Packet Data
	+
	+	Each TYPE value has its own packet structure:[^ff238][^ff239]
	+
	+	Table: Packet data structures
	+
	+	\| TYPE \| Primitive \| Structure \| Members \|
	+	\| --- \| --- \| --- \| --- \|
	+	\| 00 \| Triangle, flat, texture on, independent vertex \| _poly_ft3 \| POLY_FT3 pkt[2]; SVECTOR v1, v2, v3 \|
	+	\| 01 \| Quadrangle, flat, texture on, independent vertex \| _poly_ft4 \| POLY_FT4 pkt[2]; SVECTOR v1, v2, v3, v4 \|
	+	\| 02 \| Triangle, Gouraud, texture on, independent vertex \| _poly_gt3 \| POLY_GT3 pkt[2]; SVECTOR v1, v2, v3 \|
	+	\| 03 \| Quadrangle, Gouraud, texture on, independent vertex \| _poly_gt4 \| POLY_GT4 pkt[2]; SVECTOR v1, v2, v3, v4 \|
	+	\| 04 \| Triangle, flat, texture off, independent vertex \| _poly_f3 \| POLY_F3 pkt[2]; SVECTOR v1, v2, v3 \|
	+	\| 05 \| Quadrangle, flat, texture off, independent vertex \| _poly_f4 \| POLY_F4 pkt[2]; SVECTOR v1, v2, v3, v4 \|
	+	\| 06 \| Triangle, Gouraud, texture off, independent vertex \| _poly_g3 \| POLY_G3 pkt[2]; SVECTOR v1, v2, v3 \|
	+	\| 07 \| Quadrangle, Gouraud, texture off, independent vertex \| _poly_g4 \| POLY_G4 pkt[2]; SVECTOR v1, v2, v3, v4 \|
	+	\| 08 \| Triangle, flat, texture on, shared vertex \| _poly_ft3c \| POLY_FT3 pkt[2]; long vp1, vp2, vp3 \|
	+	\| 09 \| Quadrangle, flat, texture on, shared vertex \| _poly_ft4c \| POLY_FT4 pkt[2]; long vp1, vp2, vp3, vp4 \|
	+	\| 0a \| Triangle, Gouraud, texture on, shared vertex \| _poly_gt3c \| POLY_GT3 pkt[2]; long vp1, vp2, vp3 \|
	+	\| 0b \| Quadrangle, Gouraud, texture on, shared vertex \| _poly_gt4c \| POLY_GT4 pkt[2]; long vp1, vp2, vp3, vp4 \|
	+	\| 0c \| Triangle, flat, texture off, shared vertex \| _poly_f3c \| POLY_F3 pkt[2]; long vp1, vp2, vp3 \|
	+	\| 0d \| Quadrangle, flat, texture off, shared vertex \| _poly_f4c \| POLY_F4 pkt[2]; long vp1, vp2, vp3, vp4 \|
	+	\| 0e \| Triangle, Gouraud, texture off, shared vertex \| _poly_g3c \| POLY_G3 pkt[2]; long vp1, vp2, vp3 \|
	+	\| 0f \| Quadrangle, Gouraud, texture off, shared vertex \| _poly_g4c \| POLY_G4 pkt[2]; long vp1, vp2, vp3, vp4 \|
	+
	+	pkt[] is the matching drawing primitive packet. v1 to v4 are the vertex coordinates.[^ff239]
	+
	+	vp1 to vp4 are offsets from the start of the row of shared vertices.[^ff239]
	+
	+	## VERTEX
	+
	+	The VERTEX group is an array of SVECTOR structures for shared vertices.[^ff239]
	+
	+	One structure is as follows:
	+
	+	Table: VERTEX structure
	+
	+	\| Word \| Upper 16 bits \| Lower 16 bits \|
	+	\| --- \| --- \| --- \|
	+	\| 0 \| VY \| VX \|
	+	\| 1 \| \| VZ \|
	+
	+	VX, VY and VZ are the X, Y and Z coordinates of the vertex as 16-bit integers.[^ff239]
	+
	+	## References
	+
	+	[^ff235]: Sony Computer Entertainment Inc. File Formats. November 1998. Page 2-35, Figure 77.
	+	[^ff236]: Sony Computer Entertainment Inc. File Formats. November 1998. Page 2-36, Figure 78.
	+	[^ff237]: Sony Computer Entertainment Inc. File Formats. November 1998. Page 2-37, Figure 79 and Table 2-2.
	+	[^ff238]: Sony Computer Entertainment Inc. File Formats. November 1998. Page 2-38.
	+	[^ff239]: Sony Computer Entertainment Inc. File Formats. November 1998. Page 2-39, Figure 80.

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