abr-matrix.c

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/*
 
MIT License
 
Copyright (c) 2026 PCSX-Redux authors
 
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
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copies or substantial portions of the Software.
 
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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*/
 
// ABR mode matrix. The four PS1 semi-trans modes are:
//   ABR=0: B/2 + F/2 (average)
//   ABR=1: B + F     (additive, clamp at max)
//   ABR=2: B - F     (subtractive, clamp at 0)
//   ABR=3: B + F/4   (add quarter, clamp at max)
//
// where B is the existing VRAM pixel ("background") and F is the
// incoming foreground from the primitive. Per psx-spx the blend runs
// in 8-bit channel space: VRAM 5-bit B is conceptually shifted up by
// 3 to form B8, blended with the 8-bit F, then truncated back to 5
// bits for VRAM. We use 5-bit-boundary-aligned channel values (R5 *
// 8) so the round-trip is exact and the captured 5-bit output maps
// cleanly to the documented formulas.
 
CESTER_BODY(
 
// Convenience: build an R-only 24-bit command color from R5 (5-bit
// value 0..31). Foreground sent to the GPU as 8-bit; we put R8 = R5
// * 8 in the low byte. G and B are zero so the test focuses on R.
static inline uint32_t cmdR5(uint8_t r5) {
    return (uint32_t)(r5 & 0x1f) << 3;
}
 
// Pre-fill the test region with an R-only background. b5 is the
// 5-bit R channel; the rest is zero (which equals 0 in VRAM 5:5:5).
static inline void fillR(int16_t x, int16_t y, int16_t w, int16_t h,
                         uint8_t b5) {
    uint16_t pixel = rasterVram555((uint8_t)(b5 & 0x1f), 0, 0);
    rasterFillRect(x, y, w, h, pixel);
}
 
// Draw a 12x12 semi-trans triangle of color F at (0, 0). The
// triangle is wide enough that probing the deep interior at (4, 4)
// captures a pixel that's far from the top-left edge artifacts.
static void drawAbrTri(uint8_t b5, uint8_t f5, uint8_t abr) {
    rasterReset();
    fillR(0, 0, 32, 32, b5);
    rasterSetAbr(abr);
    rasterFlatTriSemi(cmdR5(f5),
                      0,  0,
                      11, 0,
                      0,  11);
    rasterFlushPrimitive();
    rasterSetAbr(0);  /* restore default for next test */
}
 
static void drawAbrQuad(uint8_t b5, uint8_t f5, uint8_t abr) {
    rasterReset();
    fillR(0, 0, 32, 32, b5);
    rasterSetAbr(abr);
    rasterFlatQuadSemi(cmdR5(f5),
                       0,  0,
                       11, 0,
                       0,  11,
                       11, 11);
    rasterFlushPrimitive();
    rasterSetAbr(0);
}
 
static void drawAbrRect(uint8_t b5, uint8_t f5, uint8_t abr) {
    rasterReset();
    fillR(0, 0, 32, 32, b5);
    rasterSetAbr(abr);
    rasterFlatRectSemi(cmdR5(f5), 0, 0, 12, 12);
    rasterFlushPrimitive();
    rasterSetAbr(0);
}
 
static void drawAbrLine(uint8_t b5, uint8_t f5, uint8_t abr) {
    rasterReset();
    fillR(0, 0, 32, 8, b5);
    rasterSetAbr(abr);
    rasterFlatLineSemi(cmdR5(f5), 0, 4, 11, 4);
    rasterFlushPrimitive();
    rasterSetAbr(0);
}
 
// GP0(0x26) semi-trans textured triangle. The texpage's ABR field
// would normally drive blend, but tests set E1 ABR explicitly via
// rasterSetAbr right before the draw - the soft renderer reads ABR
// from the cached texpage state set most recently via E1 or via the
// last textured primitive's embedded tpage word.
static inline void rasterTexTriSemi(uint32_t cmdColor,
                                    int16_t x0, int16_t y0, uint8_t u0, uint8_t v0,
                                    int16_t x1, int16_t y1, uint8_t u1, uint8_t v1,
                                    int16_t x2, int16_t y2, uint8_t u2, uint8_t v2,
                                    uint16_t clut_field, uint16_t tpage_field) {
    waitGPU();
    GPU_DATA = 0x26000000u | (cmdColor & 0x00ffffffu);
    GPU_DATA = ((uint32_t)(uint16_t)y0 << 16) | (uint32_t)(uint16_t)x0;
    GPU_DATA = ((uint32_t)clut_field << 16) |
               ((uint32_t)v0 << 8) | (uint32_t)u0;
    GPU_DATA = ((uint32_t)(uint16_t)y1 << 16) | (uint32_t)(uint16_t)x1;
    GPU_DATA = ((uint32_t)tpage_field << 16) |
               ((uint32_t)v1 << 8) | (uint32_t)u1;
    GPU_DATA = ((uint32_t)(uint16_t)y2 << 16) | (uint32_t)(uint16_t)x2;
    GPU_DATA = (0u << 16) | ((uint32_t)v2 << 8) | (uint32_t)u2;
}
 
// Draw a textured semi-trans triangle using the masked CLUT (every
// entry has bit-15 set). Probe pixel (4, 2) samples texel (4, 2) -
// 4-bit CLUT entry [4] = vram555(4, 27, 0) | 0x8000.
static void drawAbrTexTriMasked(uint8_t b5, uint8_t abr) {
    rasterReset();
    fillR(0, 0, 32, 16, b5);
    /* Build texpage with the requested ABR field embedded so the GPU
       sees the right blend mode even if E1 wasn't re-set. */
    uint16_t tpage = (uint16_t)((TEX4_TX & 0xf) | ((TEX4_TY & 1) << 4)
                                | ((abr & 3) << 5) | (0u << 7));
    setTexpage(TEX4_TX, TEX4_TY, 0);
    rasterSetAbr(abr);
    setTextureWindow(0, 0, 0, 0);
    rasterTexTriSemi(TEX_MOD_NEUTRAL,
                     0, 0,   0, 0,
                     11, 0,  11, 0,
                     0, 8,   0, 8,
                     CLUT4_FIELD, tpage);
    rasterFlushPrimitive();
    rasterSetAbr(0);
}
 
// Semi-trans triangle with E6 SET-MASK enabled. Output should be the
// blended value with bit-15 OR'd in.
static void drawAbrTriSetMask(uint8_t b5, uint8_t f5, uint8_t abr) {
    rasterReset();
    fillR(0, 0, 32, 32, b5);
    rasterSetAbr(abr);
    rasterSetMaskCtrl(1, 0);
    rasterFlatTriSemi(cmdR5(f5),
                      0, 0, 11, 0, 0, 11);
    rasterFlushPrimitive();
    rasterSetMaskCtrl(0, 0);
    rasterSetAbr(0);
}
 
// Semi-trans triangle with E6 CHECK-MASK enabled. Background pre-fill
// has bit-15 set so the check-mask SKIPS those pixels (no blend
// applied, sentinel-ish stays).
static void drawAbrTriCheckMask(uint8_t b5, uint8_t f5, uint8_t abr) {
    rasterReset();
    /* Pre-fill with bit-15 already set */
    uint16_t bg = (uint16_t)(rasterVram555((uint8_t)(b5 & 0x1f), 0, 0) | 0x8000u);
    rasterFillRect(0, 0, 32, 32, bg);
    rasterSetAbr(abr);
    rasterSetMaskCtrl(0, 1);
    rasterFlatTriSemi(cmdR5(f5),
                      0, 0, 11, 0, 0, 11);
    rasterFlushPrimitive();
    rasterSetMaskCtrl(0, 0);
    rasterSetAbr(0);
}
 
)  // CESTER_BODY
 
// ============================================================================
// ABR_TRI: math sweep across the 4 modes and 9 (B, F) pairs.
// All probes at (4, 4) - interior of the 12x12 semi-trans tri.
// B, F values chosen on 5-bit boundaries: 0, 16, 31 (8-bit: 0, 128,
// 248). 9 pairs cover (0,0), (0,16), (0,31), (16,0), (16,16),
// (16,31), (31,0), (31,16), (31,31). Each pair tested in all 4 modes
// = 36 tests.
// ============================================================================
 
CESTER_TEST(abr0_tri_b00_f00, gpu_raster_phase12, drawAbrTri(0,  0,  0); ASSERT_PIXEL_EQ(ABR0_B00_F00, 4, 4); )
CESTER_TEST(abr0_tri_b00_f16, gpu_raster_phase12, drawAbrTri(0,  16, 0); ASSERT_PIXEL_EQ(ABR0_B00_F16, 4, 4); )
CESTER_TEST(abr0_tri_b00_f31, gpu_raster_phase12, drawAbrTri(0,  31, 0); ASSERT_PIXEL_EQ(ABR0_B00_F31, 4, 4); )
CESTER_TEST(abr0_tri_b16_f00, gpu_raster_phase12, drawAbrTri(16, 0,  0); ASSERT_PIXEL_EQ(ABR0_B16_F00, 4, 4); )
CESTER_TEST(abr0_tri_b16_f16, gpu_raster_phase12, drawAbrTri(16, 16, 0); ASSERT_PIXEL_EQ(ABR0_B16_F16, 4, 4); )
CESTER_TEST(abr0_tri_b16_f31, gpu_raster_phase12, drawAbrTri(16, 31, 0); ASSERT_PIXEL_EQ(ABR0_B16_F31, 4, 4); )
CESTER_TEST(abr0_tri_b31_f00, gpu_raster_phase12, drawAbrTri(31, 0,  0); ASSERT_PIXEL_EQ(ABR0_B31_F00, 4, 4); )
CESTER_TEST(abr0_tri_b31_f16, gpu_raster_phase12, drawAbrTri(31, 16, 0); ASSERT_PIXEL_EQ(ABR0_B31_F16, 4, 4); )
CESTER_TEST(abr0_tri_b31_f31, gpu_raster_phase12, drawAbrTri(31, 31, 0); ASSERT_PIXEL_EQ(ABR0_B31_F31, 4, 4); )
 
CESTER_TEST(abr1_tri_b00_f00, gpu_raster_phase12, drawAbrTri(0,  0,  1); ASSERT_PIXEL_EQ(ABR1_B00_F00, 4, 4); )
CESTER_TEST(abr1_tri_b00_f16, gpu_raster_phase12, drawAbrTri(0,  16, 1); ASSERT_PIXEL_EQ(ABR1_B00_F16, 4, 4); )
CESTER_TEST(abr1_tri_b00_f31, gpu_raster_phase12, drawAbrTri(0,  31, 1); ASSERT_PIXEL_EQ(ABR1_B00_F31, 4, 4); )
CESTER_TEST(abr1_tri_b16_f00, gpu_raster_phase12, drawAbrTri(16, 0,  1); ASSERT_PIXEL_EQ(ABR1_B16_F00, 4, 4); )
CESTER_TEST(abr1_tri_b16_f16, gpu_raster_phase12, drawAbrTri(16, 16, 1); ASSERT_PIXEL_EQ(ABR1_B16_F16, 4, 4); )
CESTER_TEST(abr1_tri_b16_f31, gpu_raster_phase12, drawAbrTri(16, 31, 1); ASSERT_PIXEL_EQ(ABR1_B16_F31, 4, 4); )
CESTER_TEST(abr1_tri_b31_f00, gpu_raster_phase12, drawAbrTri(31, 0,  1); ASSERT_PIXEL_EQ(ABR1_B31_F00, 4, 4); )
CESTER_TEST(abr1_tri_b31_f16, gpu_raster_phase12, drawAbrTri(31, 16, 1); ASSERT_PIXEL_EQ(ABR1_B31_F16, 4, 4); )
CESTER_TEST(abr1_tri_b31_f31, gpu_raster_phase12, drawAbrTri(31, 31, 1); ASSERT_PIXEL_EQ(ABR1_B31_F31, 4, 4); )
 
CESTER_TEST(abr2_tri_b00_f00, gpu_raster_phase12, drawAbrTri(0,  0,  2); ASSERT_PIXEL_EQ(ABR2_B00_F00, 4, 4); )
CESTER_TEST(abr2_tri_b00_f16, gpu_raster_phase12, drawAbrTri(0,  16, 2); ASSERT_PIXEL_EQ(ABR2_B00_F16, 4, 4); )
CESTER_TEST(abr2_tri_b00_f31, gpu_raster_phase12, drawAbrTri(0,  31, 2); ASSERT_PIXEL_EQ(ABR2_B00_F31, 4, 4); )
CESTER_TEST(abr2_tri_b16_f00, gpu_raster_phase12, drawAbrTri(16, 0,  2); ASSERT_PIXEL_EQ(ABR2_B16_F00, 4, 4); )
CESTER_TEST(abr2_tri_b16_f16, gpu_raster_phase12, drawAbrTri(16, 16, 2); ASSERT_PIXEL_EQ(ABR2_B16_F16, 4, 4); )
CESTER_TEST(abr2_tri_b16_f31, gpu_raster_phase12, drawAbrTri(16, 31, 2); ASSERT_PIXEL_EQ(ABR2_B16_F31, 4, 4); )
CESTER_TEST(abr2_tri_b31_f00, gpu_raster_phase12, drawAbrTri(31, 0,  2); ASSERT_PIXEL_EQ(ABR2_B31_F00, 4, 4); )
CESTER_TEST(abr2_tri_b31_f16, gpu_raster_phase12, drawAbrTri(31, 16, 2); ASSERT_PIXEL_EQ(ABR2_B31_F16, 4, 4); )
CESTER_TEST(abr2_tri_b31_f31, gpu_raster_phase12, drawAbrTri(31, 31, 2); ASSERT_PIXEL_EQ(ABR2_B31_F31, 4, 4); )
 
CESTER_TEST(abr3_tri_b00_f00, gpu_raster_phase12, drawAbrTri(0,  0,  3); ASSERT_PIXEL_EQ(ABR3_B00_F00, 4, 4); )
CESTER_TEST(abr3_tri_b00_f16, gpu_raster_phase12, drawAbrTri(0,  16, 3); ASSERT_PIXEL_EQ(ABR3_B00_F16, 4, 4); )
CESTER_TEST(abr3_tri_b00_f31, gpu_raster_phase12, drawAbrTri(0,  31, 3); ASSERT_PIXEL_EQ(ABR3_B00_F31, 4, 4); )
CESTER_TEST(abr3_tri_b16_f00, gpu_raster_phase12, drawAbrTri(16, 0,  3); ASSERT_PIXEL_EQ(ABR3_B16_F00, 4, 4); )
CESTER_TEST(abr3_tri_b16_f16, gpu_raster_phase12, drawAbrTri(16, 16, 3); ASSERT_PIXEL_EQ(ABR3_B16_F16, 4, 4); )
CESTER_TEST(abr3_tri_b16_f31, gpu_raster_phase12, drawAbrTri(16, 31, 3); ASSERT_PIXEL_EQ(ABR3_B16_F31, 4, 4); )
CESTER_TEST(abr3_tri_b31_f00, gpu_raster_phase12, drawAbrTri(31, 0,  3); ASSERT_PIXEL_EQ(ABR3_B31_F00, 4, 4); )
CESTER_TEST(abr3_tri_b31_f16, gpu_raster_phase12, drawAbrTri(31, 16, 3); ASSERT_PIXEL_EQ(ABR3_B31_F16, 4, 4); )
CESTER_TEST(abr3_tri_b31_f31, gpu_raster_phase12, drawAbrTri(31, 31, 3); ASSERT_PIXEL_EQ(ABR3_B31_F31, 4, 4); )
 
// ============================================================================
// ABR_PRIM: same blend math across other untextured primitive types.
// Single representative (B=16, F=16) per ABR mode for each primitive.
// Confirms primitives share blend math.
// ============================================================================
 
CESTER_TEST(abr0_quad_b16_f16, gpu_raster_phase12, drawAbrQuad(16, 16, 0); ASSERT_PIXEL_EQ(ABR0_PRIM_QUAD, 4, 4); )
CESTER_TEST(abr1_quad_b16_f16, gpu_raster_phase12, drawAbrQuad(16, 16, 1); ASSERT_PIXEL_EQ(ABR1_PRIM_QUAD, 4, 4); )
CESTER_TEST(abr2_quad_b16_f16, gpu_raster_phase12, drawAbrQuad(16, 16, 2); ASSERT_PIXEL_EQ(ABR2_PRIM_QUAD, 4, 4); )
CESTER_TEST(abr3_quad_b16_f16, gpu_raster_phase12, drawAbrQuad(16, 16, 3); ASSERT_PIXEL_EQ(ABR3_PRIM_QUAD, 4, 4); )
 
CESTER_TEST(abr0_rect_b16_f16, gpu_raster_phase12, drawAbrRect(16, 16, 0); ASSERT_PIXEL_EQ(ABR0_PRIM_RECT, 4, 4); )
CESTER_TEST(abr1_rect_b16_f16, gpu_raster_phase12, drawAbrRect(16, 16, 1); ASSERT_PIXEL_EQ(ABR1_PRIM_RECT, 4, 4); )
CESTER_TEST(abr2_rect_b16_f16, gpu_raster_phase12, drawAbrRect(16, 16, 2); ASSERT_PIXEL_EQ(ABR2_PRIM_RECT, 4, 4); )
CESTER_TEST(abr3_rect_b16_f16, gpu_raster_phase12, drawAbrRect(16, 16, 3); ASSERT_PIXEL_EQ(ABR3_PRIM_RECT, 4, 4); )
 
CESTER_TEST(abr0_line_b16_f16, gpu_raster_phase12, drawAbrLine(16, 16, 0); ASSERT_PIXEL_EQ(ABR0_PRIM_LINE, 5, 4); )
CESTER_TEST(abr1_line_b16_f16, gpu_raster_phase12, drawAbrLine(16, 16, 1); ASSERT_PIXEL_EQ(ABR1_PRIM_LINE, 5, 4); )
CESTER_TEST(abr2_line_b16_f16, gpu_raster_phase12, drawAbrLine(16, 16, 2); ASSERT_PIXEL_EQ(ABR2_PRIM_LINE, 5, 4); )
CESTER_TEST(abr3_line_b16_f16, gpu_raster_phase12, drawAbrLine(16, 16, 3); ASSERT_PIXEL_EQ(ABR3_PRIM_LINE, 5, 4); )
 
// ============================================================================
// ABR_TEX_MASKED: textured semi-trans tri at 4-bit with masked CLUT.
// CLUT entry [4] has bit-15 set so the semi-trans gate fires. Probe
// (4, 2) which samples texel u=4, CLUT[4] = vram555(4, 27, 0)|0x8000.
// Then blend formula applies. Capture for all 4 ABR modes.
// ============================================================================
 
CESTER_TEST(abr0_tex_masked_b16, gpu_raster_phase12, drawAbrTexTriMasked(16, 0); ASSERT_PIXEL_EQ(ABR0_TEX_MASKED, 4, 2); )
CESTER_TEST(abr1_tex_masked_b16, gpu_raster_phase12, drawAbrTexTriMasked(16, 1); ASSERT_PIXEL_EQ(ABR1_TEX_MASKED, 4, 2); )
CESTER_TEST(abr2_tex_masked_b16, gpu_raster_phase12, drawAbrTexTriMasked(16, 2); ASSERT_PIXEL_EQ(ABR2_TEX_MASKED, 4, 2); )
CESTER_TEST(abr3_tex_masked_b16, gpu_raster_phase12, drawAbrTexTriMasked(16, 3); ASSERT_PIXEL_EQ(ABR3_TEX_MASKED, 4, 2); )
 
// ============================================================================
// ABR_MASKBIT: set-mask and check-mask interactions.
// Set-mask: output should be blended value with bit-15 forced to 1.
// Check-mask: pre-fill has bit-15 set, so writes are SKIPPED - read
// returns the pre-fill value unchanged.
// ============================================================================
 
CESTER_TEST(abr0_setmask_b16_f16, gpu_raster_phase12, drawAbrTriSetMask(16, 16, 0); ASSERT_PIXEL_EQ(ABR0_SETMASK, 4, 4); )
CESTER_TEST(abr1_setmask_b16_f16, gpu_raster_phase12, drawAbrTriSetMask(16, 16, 1); ASSERT_PIXEL_EQ(ABR1_SETMASK, 4, 4); )
CESTER_TEST(abr2_setmask_b16_f16, gpu_raster_phase12, drawAbrTriSetMask(16, 16, 2); ASSERT_PIXEL_EQ(ABR2_SETMASK, 4, 4); )
CESTER_TEST(abr3_setmask_b16_f16, gpu_raster_phase12, drawAbrTriSetMask(16, 16, 3); ASSERT_PIXEL_EQ(ABR3_SETMASK, 4, 4); )
 
CESTER_TEST(abr0_checkmask_b16_f16, gpu_raster_phase12, drawAbrTriCheckMask(16, 16, 0); ASSERT_PIXEL_EQ(ABR0_CHECKMASK, 4, 4); )
CESTER_TEST(abr1_checkmask_b16_f16, gpu_raster_phase12, drawAbrTriCheckMask(16, 16, 1); ASSERT_PIXEL_EQ(ABR1_CHECKMASK, 4, 4); )
CESTER_TEST(abr2_checkmask_b16_f16, gpu_raster_phase12, drawAbrTriCheckMask(16, 16, 2); ASSERT_PIXEL_EQ(ABR2_CHECKMASK, 4, 4); )
CESTER_TEST(abr3_checkmask_b16_f16, gpu_raster_phase12, drawAbrTriCheckMask(16, 16, 3); ASSERT_PIXEL_EQ(ABR3_CHECKMASK, 4, 4); )