Transparency (alpha blend/clip)

[Dragorn421]

Thanks @turpaan64

[Dragorn421]

good alpha blend settings maybe @turpaan64

cvg_x_alpha cleared matters

[Dragorn421]

note: D_80116280 may be worth looking into for alpha blend transparency
looks like it's commonly used to make stuff fade away?

[Dragorn421]

Current Alpha Clip prevents fog, not ideal. Should take that into account when eventually batch testing

[Dragorn421]

Poe, used for Alpha Clip & Alpha Blend I think

@turpaan64

{
    gsDPPipeSync(),
    gsDPSetTextureLUT(G_TT_NONE),
    gsSPTexture(qu016(0.999985), qu016(0.999985), 0, G_TX_RENDERTILE, G_ON),
    gsDPLoadTextureBlock(0x06003910, G_IM_FMT_RGBA, G_IM_SIZ_16b, 32, 16, 0, G_TX_MIRROR | G_TX_CLAMP, G_TX_MIRROR | G_TX_CLAMP, 5, 4, G_TX_NOLOD, G_TX_NOLOD),
    gsDPSetCombineLERP(TEXEL0, 0, SHADE, 0, 0, 0, 0, TEXEL0, COMBINED, 0, PRIMITIVE, 0, COMBINED, 0, ENVIRONMENT, 0),
    gsDPSetRenderMode(AA_EN | Z_CMP | Z_UPD | IM_RD | CVG_DST_CLAMP | ZMODE_OPA | CVG_X_ALPHA | ALPHA_CVG_SEL | GBL_c1(G_BL_CLR_FOG, G_BL_A_SHADE, G_BL_CLR_IN, G_BL_1MA), G_RM_AA_ZB_TEX_EDGE2),
    gsSPClearGeometryMode(G_G_CULL_BACK | G_TEXTURE_GEN | G_TEXTURE_GEN_LINEAR),
    gsSPSetGeometryMode(G_LIGHTING),
    gsDPSetPrimColor(0, 0, 0xFF, 0xFF, 0xFF, 0xFF),
    gsSPDisplayList(0x08000000),
    gsSPVertex(0x060016B8, 3, 0),
    gsSP1Triangle(0, 1, 2, 0),
    gsDPSetCombineLERP(TEXEL0, 0, PRIMITIVE, 0, TEXEL0, 0, ENVIRONMENT, 0, 0, 0, 0, COMBINED, 0, 0, 0, COMBINED),
    gsDPPipeSync(),
    gsSPClearGeometryMode(G_LIGHTING),
    gsSPDisplayList(0x08000000),
    gsSPVertex(0x060016E8, 3, 0),
    gsSP1Triangle(0, 1, 2, 0),
    gsDPPipeSync(),
    gsSPTexture(0, 0, 0, G_TX_RENDERTILE, G_OFF),
    gsDPSetCombineLERP(SHADE, 0, PRIMITIVE, 0, SHADE, 0, ENVIRONMENT, 0, 0, 0, 0, COMBINED, 0, 0, 0, COMBINED),
    gsDPSetRenderMode(AA_EN | Z_CMP | Z_UPD | IM_RD | CVG_DST_CLAMP | ZMODE_OPA | ALPHA_CVG_SEL | GBL_c1(G_BL_CLR_FOG, G_BL_A_SHADE, G_BL_CLR_IN, G_BL_1MA), G_RM_AA_ZB_OPA_SURF2),
    gsSPSetGeometryMode(G_G_CULL_BACK | G_LIGHTING),
    gsDPSetPrimColor(0, 0, 0x00, 0x00, 0x00, 0xFF),
    gsSPDisplayList(0x08000000),
    gsSPVertex(0x06001718, 15, 0),
    gsSP2Triangles(0, 1, 2, 0, 3, 4, 5, 0),
    gsSP2Triangles(6, 7, 8, 0, 9, 10, 11, 0),
    gsSP1Triangle(12, 13, 14, 0),
    gsDPSetCombineLERP(0, 0, 0, PRIMITIVE, 0, 0, 0, ENVIRONMENT, 0, 0, 0, COMBINED, 0, 0, 0, COMBINED),
    gsDPPipeSync(),
    gsSPClearGeometryMode(G_LIGHTING),
    gsSPDisplayList(0x08000000),
    gsSPVertex(0x06001808, 3, 0),
    gsSP1Triangle(0, 1, 2, 0),
    gsDPSetCombineLERP(SHADE, 0, PRIMITIVE, 0, SHADE, 0, ENVIRONMENT, 0, 0, 0, 0, COMBINED, 0, 0, 0, COMBINED),
    gsDPPipeSync(),
    gsSPSetGeometryMode(G_LIGHTING),
    gsSPDisplayList(0x08000000),
    gsSPVertex(0x06001838, 6, 0),
    gsSP2Triangles(0, 1, 2, 0, 3, 4, 5, 0),
    gsSPEndDisplayList(),
}

[Dragorn421]

Alpha Clip, Cucco:

@turpaan64

{
    gsSPTexture(qu016(0.999985), qu016(0.999985), 0, G_TX_RENDERTILE, G_ON),
    gsDPPipeSync(),
    gsDPSetRenderMode(AA_EN | Z_CMP | Z_UPD | IM_RD | CVG_DST_CLAMP | ZMODE_OPA | CVG_X_ALPHA | ALPHA_CVG_SEL | GBL_c1(G
_BL_CLR_FOG, G_BL_A_SHADE, G_BL_CLR_IN, G_BL_1MA), G_RM_AA_ZB_TEX_EDGE2),
    gsDPSetCombineLERP(TEXEL0, 0, SHADE, 0, 0, 0, 0, TEXEL0, PRIMITIVE, 0, COMBINED, 0, 0, 0, 0, COMBINED),
    gsDPSetTextureLUT(G_TT_NONE),
    gsDPLoadTextureBlock(0x06002080, G_IM_FMT_RGBA, G_IM_SIZ_16b, 8, 16, 0, G_TX_MIRROR | G_TX_WRAP, G_TX_NOMIRROR | G_T
X_CLAMP, 3, 4, G_TX_NOLOD, G_TX_NOLOD),
    gsDPSetTileSize(G_TX_RENDERTILE, 0, 0, qu102(7), qu102(15)),
    gsDPSetPrimColor(0, qu08(0.5), 0xFF, 0xFF, 0xFF, 0xFF),
    gsSPSetGeometryMode(G_LIGHTING),
    gsSPClearGeometryMode(G_G_CULL_BACK),
    gsSPClearGeometryMode(G_TEXTURE_GEN | G_TEXTURE_GEN_LINEAR),
    gsSPVertex(0x060006D0, 3, 0),
    gsSP1Triangle(0, 1, 2, 0),
    gsSPEndDisplayList(),
}

[Dragorn421]

Alpha Blend, water plane

@turpaan64

{
    gsDPPipeSync(),
    gsDPSetTextureLUT(G_TT_NONE),
    gsSPTexture(qu016(0.999985), qu016(0.999985), 0, G_TX_RENDERTILE, G_ON),
    gsDPLoadTextureBlock(0x06007D20, G_IM_FMT_RGBA, G_IM_SIZ_16b, 32, 32, 0, G_TX_NOMIRROR | G_TX_WRAP, G_TX_NOMIRROR |
G_TX_WRAP, 5, 5, 14, 15),
    gsDPLoadMultiBlock(0x06007520, 0x0100, 1, G_IM_FMT_IA, G_IM_SIZ_16b, 32, 32, 0, G_TX_NOMIRROR | G_TX_WRAP, G_TX_NOMI
RROR | G_TX_WRAP, 5, 5, 15, 14),
    gsDPSetCombineLERP(TEXEL1, TEXEL0, ENV_ALPHA, TEXEL0, 0, 0, 0, 1, COMBINED, 0, SHADE, 0, COMBINED, 0, PRIMITIVE, 0),
    gsDPSetRenderMode(AA_EN | Z_CMP | IM_RD | CLR_ON_CVG | CVG_DST_WRAP | ZMODE_XLU | FORCE_BL | GBL_c1(G_BL_CLR_FOG, G_
BL_A_SHADE, G_BL_CLR_IN, G_BL_1MA), G_RM_AA_ZB_XLU_SURF2),
    gsSPClearGeometryMode(G_G_CULL_BACK | G_LIGHTING | G_TEXTURE_GEN | G_TEXTURE_GEN_LINEAR),
    gsSPSetGeometryMode(G_FOG),
    gsDPSetPrimColor(0, 0, 0xFF, 0xFF, 0xFF, 0x66),
    gsSPDisplayList(0x0C000000),
    gsSPVertex(0x06004AD0, 5, 0),
    gsSP2Triangles(0, 1, 2, 0, 0, 3, 1, 0),
    gsSP2Triangles(3, 4, 1, 0, 4, 2, 1, 0),
    gsSPEndDisplayList(),
}

[Dragorn421]

Alpha Blend, bushes and trees:

@turpaan64

{
    gsDPPipeSync(),
    gsDPSetTextureLUT(G_TT_NONE),
    gsSPTexture(qu016(0.999985), qu016(0.999985), 0, G_TX_RENDERTILE, G_ON),
    gsDPLoadTextureBlock(0x06003790, G_IM_FMT_IA, G_IM_SIZ_8b, 32, 128, 0, G_TX_MIRROR | G_TX_WRAP, G_TX_NOMIRROR | G_TX
_CLAMP, 5, 7, G_TX_NOLOD, G_TX_NOLOD),
    gsDPSetCombineLERP(TEXEL0, 0, SHADE, 0, 0, 0, 0, TEXEL0, COMBINED, 0, ENVIRONMENT, 0, 0, 0, 0, COMBINED),
    gsDPSetRenderMode(Z_CMP | IM_RD | CVG_DST_FULL | ZMODE_XLU | FORCE_BL | GBL_c1(G_BL_CLR_FOG, G_BL_A_SHADE, G_BL_CLR_
IN, G_BL_1MA), G_RM_ZB_XLU_SURF2),
    gsSPClearGeometryMode(G_G_CULL_BACK | G_TEXTURE_GEN | G_TEXTURE_GEN_LINEAR),
    gsSPSetGeometryMode(G_FOG | G_LIGHTING),
    gsDPSetPrimColor(0, 0, 0x23, 0x4C, 0x19, 0xFF),
    gsSPVertex(0x06007DF0, 3, 0),
    gsSP1Triangle(0, 1, 2, 0),
    gsSPEndDisplayList(),
}

[Dragorn421]

Alpha Clip @turpaan64

[Dragorn421]

Alpha combiner cycles shouldn't use shade because apparently that makes stuff transparent from far away, for unexplained reasons

More test for batch testing

[Dragorn421]

May be relevant for alpha clip (or any kind of alpha really)?

Manual 15.5.4 Alpha Compare Calculation http://n64devkit.square7.ch/pro-man/pro15/15-05.htm#04
gDPSetAlphaCompare http://n64devkit.square7.ch/n64man/gdp/gDPSetAlphaCompare.htm
gDPSetBlendColor http://n64devkit.square7.ch/n64man/gdp/gDPSetBlendColor.htm

gDPSetAlphaCompare(G_AC_THRESHOLD) makes a primitive draw only where its alpha is > the blender color register alpha

[Dragorn421]

Manual 15.7.2 Transparent Surfaces, XLU_SURF http://n64devkit.square7.ch/pro-man/pro15/15-07.htm#02
Table 15-5 Antialiased Z-Buffered Rendering Modes, G_RM_AA_ZB http://n64devkit.square7.ch/pro-man/pro15/15-07.htm#t15-05

CLR_ON_CVG is meant for alpha blend. In that case the coverage value should be used unaltered (clear alpha_cvg_sel and cvg_x_alpha)

the zbuffer should (indeed) not be written to for alpha blend (see last note in 15.7.2 and table)

see also http://n64devkit.square7.ch/pro-man/pro15/15-07.htm#09 for description of g*DPSetRenderMode() flags