Incorrect texture wrapping in Super Mario 64

[hulkholden]

The textures themselves are being decoded ok

The tiles are configured with G_TX_WRAP at 16 pixels:

tile #	format	size	line	tmem	palette	cmS	maskS	shiftS	cmT	maskT	shiftT	left	top	right	bottom	width	height	unmasked w	unmasked h
G_TX_RENDERTILE	G_IM_FMT_RGBA	G_IM_SIZ_16b	4	0	0	G_TX_WRAP	4	0	G_TX_WRAP	4	0	0	0	15	15	16	16	16	16
G_TX_LOADTILE	G_IM_FMT_RGBA	G_IM_SIZ_16b	0	0	0	G_TX_WRAP	4	0	G_TX_WRAP	4	0	0	0	0	0	1	1	1	1

RDP is set up with bilinear filtering:

setting	value
textureConvert	G_TC_FILT
textureFilter	G_TF_BILERP

In the case of the star it's being rendered with texrect:

02636 e4404078003c803c gsSPTextureRectangle(242,15,258,31,G_TX_RENDERTILE,0,0,1,1);
cmd2 = 0x00000000, cmd3 = 0x10000400
st0 = (0, 0) st1 = (16, 16)

Some possibilities:

• texture lookup in the fragment shader using float UVs is too imprecise
• texrect coords are slightly off (it's generating st1 of (16,16) but maybe this should be (15,15)?

[hulkholden]

Also worth mentioning this is G_CYC_COPY. In this mode we're adding 1 to the width and height:

    // In Fill/Copy mode the coordinates are inclusive (i.e. add 1.0f to the w/h)
    if (cycleType === gbi.CycleType.G_CYC_COPY ||
      cycleType === gbi.CycleType.G_CYC_FILL) {
      xh += 1.0;
      yh += 1.0;
    }