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--- rcpstructs [2018/04/19 20:51]
trenavix created
+++ rcpstructs [2018/10/01 05:58] (current)
David [Vertex Structure] Lowered some capitals in the description, also testing if this summary appears with the waluigi bot. Hi Hack64 discord!
@@ Line 1: / Line 1: @@
 ====== RCP Structures ======
 Every rendition of Fast3D shares a few common structures by the RCP, such as some bit-mapping used within certain opcodes. These are explained within this page.
+===== RSP Geometry Mode =====
+This 32-bit value configures how the RSP will process geometry. They are all 1-bit flags. All of these flags are disabled by default //except// for <color #00a2e8>G_CLIPPING</color>.\\
+<color #1df61d>1</color> is the affected bit, and <color #FF121b>1</color> is the affected bit for F3D and F3DEX (if different from EX2).
+^ Affects Bit ^ Name ^ Description ^
+| <color #206320>0000 0000 0000 0000 0000 0000 0000 000</color><color #1df61d>1</color> | <color #00a2e8>G_ZBUFFER</color> | Enables depth (Z buffer) calculations in the RSP |
+| <color #206320>0000 0000 0000 0000 0000 0000 0000 0</color><color #1df61d>1</color><color #206320>00</color> | <color #00a2e8>G_SHADE</color> | Enables calculating vertex color for triangle. Uses flat shading without <color #00a2e8>G_SHADING_SMOOTH.</color> |
+| <color #206320>0000 0000 0000 0000 000</color><color #FF121b>1</color> <color #206320>00</color><color #1df61d>1</color><color #206320>0 0000 0000</color> | <color #00a2e8>G_CULL_FRONT</color> | Front-face culling |
+| <color #206320>0000 0000 0000 0000 00</color><color #FF121b>1</color><color #206320>0 0</color><color #1df61d>1</color><color #206320>00 0000 0000</color> | <color #00a2e8>G_CULL_BACK</color> | Back-face culling |
+| <color #206320>0000 0000 0000 000</color><color #1df61d>1</color><color #206320> 0000 0000 0000 0000</color> | <color #00a2e8>G_FOG</color> | Calculates alpha value of primitives for fog effects |
+| <color #206320>0000 0000 0000 00</color><color #1df61d>1</color><color #206320>0 0000 0000 0000 0000</color> | <color #00a2e8>G_LIGHTING</color> | Enables lighting calculations to determine vertex color (determines how the color/normal part of loaded vertices are interpreted) |
+| <color #206320>0000 0000 0000 0</color><color #1df61d>1</color><color #206320>00 0000 0000 0000 0000</color> | <color #00a2e8>G_TEXTURE_GEN</color> | Generates spherical texture coordinates, based on X and Y components of the projected version of the normal |
+| <color #206320>0000 0000 0000 </color><color #1df61d>1</color><color #206320>000 0000 0000 0000 0000</color> | <color #00a2e8>G_TEXTURE_GEN_LINEAR</color> | Generates linear texture coordinates, based on acos() of X and Y components of the normal, after projection transformation |
+| <color #206320>0000 0000 00</color><color #1df61d>1</color><color #206320>0 0000 0000 00</color><color #FF121b>1</color><color #206320>0 0000 0000</color> | <color #00a2e8>G_SHADING_SMOOTH</color> | Enables smooth (Gouraud) shading of primitives. Needs <color #00a2e8>G_SHADE</color> enabled to work. |
+| <color #206320>0000 0000 </color><color #1df61d>1</color><color #206320>000 0000 0000 0000 0000 0000</color> | <color #00a2e8>G_CLIPPING</color> | In F3DLX2, can disable clipping calculations, and is on by default. Ignored by other F3D microcodes, clipping is always on. |
+^ Affects Bits ^ Other Meanings ^
+| <color #876407>0000 0000 0000 0000 0000 0000</color> <color #ffc90e>1111 1111</color> | The lowest byte of the geometry mode can be OR'd with <color #B755FF>G_TRI_FILL</color> (0xC8) to generate an appropriate internal triangle opcode, apparently. |
+| <color #ffc90e>1111 1111</color> <color #876407>0000 0000 0000 0000 0000 0000</color> | The highest byte of the geometry mode is OR'd with 0x703 to generate a "clip code mask". All that's known about this value is that when set to 0x04 (after ORing, 0x707), "near clipping will occur". |
+----
 ===== SetOtherMode =====
@@ Line 108: / Line 130: @@
   * <color #1df61d>__11:__</color> <color #00a2e8>G_BL_0:</color> Constant 0.0 value
+----
+===== Vertex Structure =====
+Vertices are points in 3D space that are used in drawing triangles. This structure is the same no matter which graphics microcode you use. Each vertex takes up 16 bytes.
+''[<color red>XX XX</color>] [<color green>YY YY</color>] [<color cyan>ZZ ZZ</color>] [<color lightgray>FF FF</color>] [<color orange>UU UU</color>] [<color #AA88DD>VV VV</color>] [<color pink>XR</color>] [<color lightgreen>YG</color>] [<color lightblue>ZB</color>] [<color lightgray>AA</color>]''
+| <color red>XXXX</color> |    short    | Position on X axis |
+| <color green>YYYY</color> |    short    | Position on Y axis |
+| <color cyan>ZZZZ</color> |    short    | Position on Z axis |
+| <color lightgray>FFFF</color> |    ushort   | Flag. Unknown usage, usually just 0000 |
+| <color orange>UUUU</color> |    short    | Texture coordinate on the U axis |
+| <color #AA88DD>VVVV</color> |    short    | Texture coordinate on the V axis |
+| <color pink>XR</color> | byte or ubyte | X unit vector of normal or red color* |
+| <color lightgreen>YG</color> | byte or ubyte | Y unit vector of normal or green color* |
+| <color lightblue>ZB</color> | byte or ubyte | Z unit vector of normal or blue color* |
+| <color lightgray>AA</color> |     ubyte     | Alpha (Transparency)<nowiki>**</nowiki> |
+* You cannot use vertex colors and vertex lighting at the same time. Normals are used if the geometry mode ''G_LIGHTING'' bit is enabled, otherwise the RGB colors will be used instead. (see: [[rcpstructs#rsp_geometry_mode|RSP Geometry Mode]])
+<nowiki>**</nowiki> Vertex alpha cannot be used when fog is enabled. The vertex will use the fog alpha value instead.
 ----

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