uv-overflow.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
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*/
 
// Overflow probes. Each test draws one oversized 8-bit textured rect
// based at the test origin (0,0) with a chosen base UV, then reads
// back a column (U sweep, row v=0) or row (V sweep, col u=0). The
// fixture is texel(u,v) = (u+v)&0xff, so the texel sampled at
// primitive-offset k from base b is ((b + k) & 0xff) iff the texel
// coordinate wraps mod 256. Each expectation is therefore
// expectedClut8Color((base + offset) & 0xff).
 
CESTER_BODY(
 
// Draw an 8-bit textured rect at the origin with the given base UV and
// size. Clears the rect footprint to the sentinel first so any pixel
// that did NOT draw (e.g. a coordinate sampling transparent CLUT[0])
// is distinguishable from a wrapped fetch.
static void drawTex8Rect(uint8_t u0, uint8_t v0, int16_t w, int16_t h) {
    rasterReset();
    rasterClearTestRegion(0, 0, (int16_t)((w + 1) & ~1), h);
    setTexpage(TEX8_TX, TEX8_TY, 1);
    setTextureWindow(0, 0, 0, 0);
    rasterTexRect(TEX_MOD_NEUTRAL, 0, 0, u0, v0, w, h, CLUT8_FIELD);
    rasterFlushPrimitive();
}
 
)  // CESTER_BODY
 
// ============================================================================
// U overflow. Wide rect (264 px) based at u=0. Columns 0..255 map to
// u=0..255 (in range); columns 256..263 must wrap to u=0..7.
// ============================================================================
 
CESTER_TEST(ovf_u_base0_c5, gpu_raster_phase21,
    drawTex8Rect(0, 0, 264, 2);
    /* Control: in-range column, no overflow. u=5. */
    ASSERT_PIXEL_EQ(expectedClut8Color(5), 5, 0);
)
 
CESTER_TEST(ovf_u_base0_c200, gpu_raster_phase21,
    drawTex8Rect(0, 0, 264, 2);
    /* Control: deep in-range column. u=200. */
    ASSERT_PIXEL_EQ(expectedClut8Color(200), 200, 0);
)
 
CESTER_TEST(ovf_u_base0_c255, gpu_raster_phase21,
    drawTex8Rect(0, 0, 264, 2);
    /* Last in-range column. u=255. */
    ASSERT_PIXEL_EQ(expectedClut8Color(255), 255, 0);
)
 
CESTER_TEST(ovf_u_base0_c256, gpu_raster_phase21,
    drawTex8Rect(0, 0, 264, 2);
    /* First overflow column: u counter hits 256 -> wraps to 0. */
    ASSERT_PIXEL_EQ(expectedClut8Color(256 & 0xff), 256, 0);
)
 
CESTER_TEST(ovf_u_base0_c257, gpu_raster_phase21,
    drawTex8Rect(0, 0, 264, 2);
    /* Overflow -> u=1. */
    ASSERT_PIXEL_EQ(expectedClut8Color(257 & 0xff), 257, 0);
)
 
CESTER_TEST(ovf_u_base0_c263, gpu_raster_phase21,
    drawTex8Rect(0, 0, 264, 2);
    /* Overflow -> u=7. */
    ASSERT_PIXEL_EQ(expectedClut8Color(263 & 0xff), 263, 0);
)
 
// ============================================================================
// U overflow with a non-zero base. Base u=200, width 64 -> the wrap
// happens mid-rect at column 56 (200+56 = 256 -> 0).
// ============================================================================
 
CESTER_TEST(ovf_u_base200_c55, gpu_raster_phase21,
    drawTex8Rect(200, 0, 64, 2);
    /* u = 200+55 = 255, last before wrap. */
    ASSERT_PIXEL_EQ(expectedClut8Color((200 + 55) & 0xff), 55, 0);
)
 
CESTER_TEST(ovf_u_base200_c56, gpu_raster_phase21,
    drawTex8Rect(200, 0, 64, 2);
    /* u = 200+56 = 256 -> wraps to 0. */
    ASSERT_PIXEL_EQ(expectedClut8Color((200 + 56) & 0xff), 56, 0);
)
 
CESTER_TEST(ovf_u_base200_c57, gpu_raster_phase21,
    drawTex8Rect(200, 0, 64, 2);
    /* u -> 1. */
    ASSERT_PIXEL_EQ(expectedClut8Color((200 + 57) & 0xff), 57, 0);
)
 
// ============================================================================
// V overflow. Tall rect (264 px) based at v=0, sampled at col u=0.
// Rows 0..255 map to v=0..255 (in range); rows 256..263 must wrap.
// ============================================================================
 
CESTER_TEST(ovf_v_base0_r5, gpu_raster_phase21,
    drawTex8Rect(0, 0, 2, 264);
    /* Control: in-range row. v=5 -> texel(0,5)=5. */
    ASSERT_PIXEL_EQ(expectedClut8Color(5), 0, 5);
)
 
CESTER_TEST(ovf_v_base0_r255, gpu_raster_phase21,
    drawTex8Rect(0, 0, 2, 264);
    /* Last in-range row. v=255. */
    ASSERT_PIXEL_EQ(expectedClut8Color(255), 0, 255);
)
 
CESTER_TEST(ovf_v_base0_r256, gpu_raster_phase21,
    drawTex8Rect(0, 0, 2, 264);
    /* First overflow row: v counter hits 256 -> wraps to 0. */
    ASSERT_PIXEL_EQ(expectedClut8Color(256 & 0xff), 0, 256);
)
 
CESTER_TEST(ovf_v_base0_r257, gpu_raster_phase21,
    drawTex8Rect(0, 0, 2, 264);
    /* Overflow -> v=1. */
    ASSERT_PIXEL_EQ(expectedClut8Color(257 & 0xff), 0, 257);
)