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This commit is contained in:
Edward R. Gonzalez
2026-06-16 00:30:21 -04:00
parent 288f92ff5b
commit b1982ba862
2 changed files with 135 additions and 9 deletions
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code/duffle/lottes_tape.h
+130 -1
View File
@@ -101,6 +101,8 @@ FI_ Slice_U4 tb_slice(TapeBuilder tb) { return (Sli
, gte_sw(C2_SXY1, R_PrimCur, 12) \
, gte_sw(C2_SXY2, R_PrimCur, 16)
/* Correctly inserts a primitive into the Ordering Table linked list */
#define mac_insert_ot_tag(r_otz, prim_length) \
shift_ll( R_T1, r_otz, 2) \
@@ -152,8 +154,135 @@ internal MipsAtom_(set_gte_world) {
mips_yield()
};
/* ============================================================================
* cube_tri — Draw one cube face (Gouraud-shaded quad) via the GTE tape pipeline
* ============================================================================
*
* Reads 4 indices from R_FaceCur (V4_S2 = 8 bytes), loads 4 vertices into
* the GTE, runs the PsyQ RotAverageNclip4 sequence, and renders a Poly_G4.
*
* PsyQ RotAverageNclip4 sequence:
* 1. Load V0=p0, V1=p1, V2=p2
* 2. RTPT → SXY0=p0, SXY1=p1, SXY2=p2, SZ1,SZ2,SZ3
* 3. NCLIP → MAC0 = cross(p0,p1,p2) ← BEFORE RTPS!
* 4. Store SXY0 (p0) to primitive buffer
* 5. Load V3 into V0
* 6. RTPS → SXY0=p3, SZ0
* 7. Store SXY0 (p3) to primitive buffer
* 8. AVSZ3 → OTZ from SZ1,SZ2,SZ3
*
* PRIMITIVE FORMAT (Poly_G4 = 9 words = 36 bytes)
* ------------------------------------------------
* Word 0 (offset 0): OT tag (set by mac_insert_ot_tag)
* Word 1 (offset 4): c0 + code = 0x38FF00FF (magenta, opcode 0x38)
* Word 2 (offset 8): p0 = SXY0 (stored BEFORE RTPS)
* Word 3 (offset 12): c1 + pad = 0x0000FFFF (yellow)
* Word 4 (offset 16): p1 = SXY1
* Word 5 (offset 20): c2 + pad = 0x00FFFF00 (cyan)
* Word 6 (offset 24): p2 = SXY2
* Word 7 (offset 28): c3 + pad = 0x0000FF00 (green)
* Word 8 (offset 32): p3 = SXY0 (stored AFTER RTPS)
*
* BRANCH OFFSETS
* ----------------------------------------------
* Outer branch (backface cull): branch_le_zero(R_T0, 49)
* → Skip 49 instructions from BD slot, land at add_ui(R_FaceCur,...)
* Inner branch (OTZ bounds): branch_equal(R_AT, R_0, 13)
* → Skip 13 instructions from BD slot, land at add_ui(R_FaceCur,...)
* ============================================================================ */
internal MipsAtom_(cube_tri) {
/* ── 1. Load 4 face indices from R_FaceCur ──────────────────────────── */
load_half_u(R_T0, R_FaceCur, 0), /* T0 = face->x (vertex 0 index) */
load_half_u(R_T1, R_FaceCur, 2), /* T1 = face->y (vertex 1 index) */
load_half_u(R_T2, R_FaceCur, 4), /* T2 = face->z (vertex 2 index) */
load_half_u(R_T3, R_FaceCur, 6), /* T3 = face->w (vertex 3 index) */
/* ── 2. Load V0, V1, V2 into GTE ────────────────────────────────────── */
/* V0 = verts[face->x] */
shift_ll(R_AT, R_T0, 3), add_u(R_AT, R_AT, R_VertBase),
load_word(R_V0, R_AT, 0), load_word(R_V1, R_AT, 4),
gte_mt(R_V0, C2_VXY0), gte_mt(R_V1, C2_VZ0),
/* V1 = verts[face->y] */
shift_ll(R_AT, R_T1, 3), add_u(R_AT, R_AT, R_VertBase),
load_word(R_V0, R_AT, 0), load_word(R_V1, R_AT, 4),
gte_mt(R_V0, C2_VXY1), gte_mt(R_V1, C2_VZ1),
/* V2 = verts[face->z] */
shift_ll(R_AT, R_T2, 3), add_u(R_AT, R_AT, R_VertBase),
load_word(R_V0, R_AT, 0), load_word(R_V1, R_AT, 4),
gte_mt(R_V0, C2_VXY2), gte_mt(R_V1, C2_VZ2),
/* ── 3. RTPT — transforms V0/V1/V2 → SXY0/SXY1/SXY2 + SZ1/SZ2/SZ3 ─── */
nop, nop, gte_cmdw_rtpt,
/* ── 4. NCLIP — backface culling on SXY0/SXY1/SXY2 (p0,p1,p2) ──────── */
/* MUST be done BEFORE RTPS overwrites SXY0 with p3! */
nop, nop, gte_cmdw_nclip,
nop, nop,
/* ── 5. Cull check: skip format/insert if MAC0 ≤ 0 (backface) ───────── */
gte_mf(R_T0, C2_MAC0),
nop,
branch_le_zero(R_T0, 49), /* Skip 49 if MAC0 ≤ 0 (backface) → cull */
nop, /* BD slot */
/* ── 6. Store p0,p1,p2 to primitive buffer (BEFORE RTPS overwrites) ─── */
store_word(R_0, R_PrimCur, 0),
/* Word 1: c0 (BGR) + code = 0x38FF00FF (magenta, opcode 0x38) */
load_ui(R_AT, 0x38FF), or_i(R_AT, R_AT, 0x00FF),
store_word(R_AT, R_PrimCur, 4),
/* Word 2: p0 = SXY0 (stored BEFORE RTPS overwrites it) */
gte_sw(C2_SXY0, R_PrimCur, 8),
/* Word 3: c1 (BGR) + pad = 0x0000FFFF (yellow) */
load_ui(R_AT, 0x0000), or_i(R_AT, R_AT, 0xFFFF),
store_word(R_AT, R_PrimCur, 12),
/* Word 4: p1 = SXY1 */
gte_sw(C2_SXY1, R_PrimCur, 16),
/* Word 5: c2 (BGR) + pad = 0x00FFFF00 (cyan) */
load_ui(R_AT, 0x00FF), or_i(R_AT, R_AT, 0xFF00),
store_word(R_AT, R_PrimCur, 20),
/* Word 6: p2 = SXY2 */
gte_sw(C2_SXY2, R_PrimCur, 24),
/* Word 7: c3 (BGR) + pad = 0x0000FF00 (green) */
load_ui(R_AT, 0x0000), or_i(R_AT, R_AT, 0xFF00),
store_word(R_AT, R_PrimCur, 28),
/* ── 7. Load V3 = verts[face->w] into V0 ─────────────────────────────── */
shift_ll(R_AT, R_T3, 3), add_u(R_AT, R_AT, R_VertBase),
load_word(R_V0, R_AT, 0), load_word(R_V1, R_AT, 4),
gte_mt(R_V0, C2_VXY0), gte_mt(R_V1, C2_VZ0),
/* ── 8. RTPS — transforms V0 (now V3) → SXY0 (p3) + SZ0 ─────────────── */
nop, nop, gte_cmdw_rtps,
/* Word 8: p3 = SXY0 (written AFTER RTPS with V3's screen coords) */
gte_sw(C2_SXY0, R_PrimCur, 32),
/* ── 9. AVSZ3 — average Z for OTZ (uses SZ1/SZ2/SZ3 from RTPT) ──────── */
nop, nop, gte_cmdw_avsz3,
nop, nop,
gte_mf(R_T1, C2_OTZ),
/* ── 10. Bounds check OTZ < 2048 ─────────────────────────────────────── */
add_ui( R_AT, R_0, 2048),
slt_u( R_AT, R_T1, R_AT),
branch_equal(R_AT, R_0, 13), /* Skip 13 → land at add_ui(R_FaceCur,...) */
nop, /* BD slot */
/* ── 11. Insert into Ordering Table (length = 8 for Poly_G4) ─────────── */
mac_insert_ot_tag(R_T1, 0x0800), /* 0x0800 = 8 << 8 = length 8 in tag */
/* ── 12. Advance cursors & yield ─────────────────────────────────────── */
add_ui(R_PrimCur, R_PrimCur, 36), /* 9 words × 4 bytes */
add_ui(R_FaceCur, R_FaceCur, 8), /* 4 × S2 = 8 bytes */
mips_yield()
};
code/gte_hello/hello_gte.c
+5 -8
View File
@@ -231,13 +231,13 @@ void update(PrimitiveArena* pa, U4* ordering_buf)
static_mem.cube.rot.y += 30;
}
// Draw cube (tape method)
if (0)
if (1)
{
m3s2_rotation (& static_mem.cube.rot, & static_mem.tform_world);
m3s2_translation(& static_mem.tform_world, & static_mem.cube.pos);
m3s2_scale (& static_mem.tform_world, & static_mem.cube.scale);
// gte_matrix_set_rotation (& static_mem.tform_world);
// gte_matrix_set_translation(& static_mem.tform_world);
gte_matrix_set_rotation (& static_mem.tform_world);
gte_matrix_set_translation(& static_mem.tform_world);
U4 prim_base = u4_(pa->buf[static_mem.active_buf_id]);
U4 prim_cursor = prim_base + pa->used;
@@ -250,9 +250,6 @@ void update(PrimitiveArena* pa, U4* ordering_buf)
tb_data(& tb, u4_(static_mem.cube.verts));
tb_data(& tb, u4_(ordering_buf));
tb_emit(& tb, code_set_gte_world);
tb_data(& tb, u4_(& static_mem.tform_world));
for (U4 i = 0; i < Cube_num_faces; i++) {
tb_emit(& tb, code_cube_tri);
}
@@ -326,8 +323,8 @@ void update(PrimitiveArena* pa, U4* ordering_buf)
m3s2_rotation (& static_mem.floor.rot, & static_mem.tform_world);
m3s2_translation(& static_mem.tform_world, & static_mem.floor.pos);
m3s2_scale (& static_mem.tform_world, & static_mem.floor.scale);
// gte_matrix_set_rotation (& static_mem.tform_world);
// gte_matrix_set_translation(& static_mem.tform_world);
gte_matrix_set_rotation (& static_mem.tform_world);
gte_matrix_set_translation(& static_mem.tform_world);
U4 prim_base = u4_(pa->buf[static_mem.active_buf_id]);
U4 prim_cursor = prim_base + pa->used;