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nv2a: Fix blend tests #1901

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1f305f5
Fix blend tests
polymetal0 Feb 8, 2025
e96385b
Swap blend equations from gl/vk map
polymetal0 Feb 9, 2025
0e1f4b0
Merge branch 'master' into fix/blend-tests
polymetal0 Feb 16, 2025
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25 changes: 17 additions & 8 deletions hw/xbox/nv2a/pgraph/gl/draw.c
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Original file line number Diff line number Diff line change
Expand Up @@ -168,14 +168,6 @@ void pgraph_gl_draw_begin(NV2AState *d)

if (pgraph_reg_r(pg, NV_PGRAPH_BLEND) & NV_PGRAPH_BLEND_EN) {
glEnable(GL_BLEND);
uint32_t sfactor = GET_MASK(pgraph_reg_r(pg, NV_PGRAPH_BLEND),
NV_PGRAPH_BLEND_SFACTOR);
uint32_t dfactor = GET_MASK(pgraph_reg_r(pg, NV_PGRAPH_BLEND),
NV_PGRAPH_BLEND_DFACTOR);
assert(sfactor < ARRAY_SIZE(pgraph_blend_factor_gl_map));
assert(dfactor < ARRAY_SIZE(pgraph_blend_factor_gl_map));
glBlendFunc(pgraph_blend_factor_gl_map[sfactor],
pgraph_blend_factor_gl_map[dfactor]);

uint32_t equation = GET_MASK(pgraph_reg_r(pg, NV_PGRAPH_BLEND),
NV_PGRAPH_BLEND_EQN);
Expand All @@ -187,6 +179,23 @@ void pgraph_gl_draw_begin(NV2AState *d)
pgraph_argb_pack32_to_rgba_float(blend_color, gl_blend_color);
glBlendColor(gl_blend_color[0], gl_blend_color[1], gl_blend_color[2],
gl_blend_color[3]);
uint32_t sfactor = GET_MASK(pgraph_reg_r(pg, NV_PGRAPH_BLEND),
NV_PGRAPH_BLEND_SFACTOR);
uint32_t dfactor = GET_MASK(pgraph_reg_r(pg, NV_PGRAPH_BLEND),
NV_PGRAPH_BLEND_DFACTOR);
assert(sfactor < ARRAY_SIZE(pgraph_blend_factor_gl_map));
assert(dfactor < ARRAY_SIZE(pgraph_blend_factor_gl_map));

if (equation < 5) {
glBlendFunc(pgraph_blend_factor_gl_map[sfactor],
pgraph_blend_factor_gl_map[dfactor]);
} else {
glBlendFuncSeparate(pgraph_blend_factor_gl_map[3],
pgraph_blend_factor_gl_map[1],
pgraph_blend_factor_gl_map[sfactor],
pgraph_blend_factor_gl_map[dfactor]);
}

} else {
glDisable(GL_BLEND);
}
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4 changes: 2 additions & 2 deletions hw/xbox/nv2a/pgraph/pgraph.c
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Expand Up @@ -1384,9 +1384,9 @@ DEF_METHOD(NV097, SET_BLEND_EQUATION)
equation = 3; break;
case NV097_SET_BLEND_EQUATION_V_MAX:
equation = 4; break;
case NV097_SET_BLEND_EQUATION_V_FUNC_REVERSE_SUBTRACT_SIGNED:
equation = 5; break;
case NV097_SET_BLEND_EQUATION_V_FUNC_ADD_SIGNED:
equation = 5; break;
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Have you checked this against the register value in hardware?

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You mean original hardware? unfortunately I can't since I don't own one, I actually made the calculations on paper and got that when using that src scaling factor, a sum turns into a reverse subtract and vice versa, +/- an offset equal to src squared. Does that make sense?

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Yes, Xbox hardware.

If you can't test the HW behavior I suggest you find someone who can check before changing register values.

I don't entirely follow your explanation; it looks like this change is made without any regard to the source factor (which it should be, I don't believe that SET_BLEND_EQUATION triggers a draw, so the order of setting the equation versus source/destination factors is not guaranteed).

I also share your concern that the test suite itself isn't broad enough. I don't recall whether the textures in #996 were signed or unsigned but it looks like the test is just checking for use of the signed blends with an unsigned texture. It would be good to expand the test and verify that this change matches HW for a variety of inputs. If it does, a better fix might be to swap the relevant entries in pgraph_blend_equation_gl_map with an explanation as to why they should be mismatched versus the nv2a/pgraph values (and a note explaining that signed channels would be handled separately in the shader).

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Yes, I'd better change the entries in pgraph_blend_equation_gl_map and pgraph_blend_equation_vk_map instead of here.

Sorry, I mean changing ONE for ONE_MINUS_SRC_COLOR in src factor in addition to this change. Without this swap, the tests are inverted.

case NV097_SET_BLEND_EQUATION_V_FUNC_REVERSE_SUBTRACT_SIGNED:
equation = 6; break;
default:
NV2A_DPRINTF("Unknown blend equation: 0x%08x\n", parameter);
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42 changes: 27 additions & 15 deletions hw/xbox/nv2a/pgraph/vk/draw.c
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Expand Up @@ -909,21 +909,6 @@ static void create_pipeline(PGRAPHState *pg)
if (pgraph_reg_r(pg, NV_PGRAPH_BLEND) & NV_PGRAPH_BLEND_EN) {
color_blend_attachment.blendEnable = VK_TRUE;

uint32_t sfactor =
GET_MASK(pgraph_reg_r(pg, NV_PGRAPH_BLEND), NV_PGRAPH_BLEND_SFACTOR);
uint32_t dfactor =
GET_MASK(pgraph_reg_r(pg, NV_PGRAPH_BLEND), NV_PGRAPH_BLEND_DFACTOR);
assert(sfactor < ARRAY_SIZE(pgraph_blend_factor_vk_map));
assert(dfactor < ARRAY_SIZE(pgraph_blend_factor_vk_map));
color_blend_attachment.srcColorBlendFactor =
pgraph_blend_factor_vk_map[sfactor];
color_blend_attachment.dstColorBlendFactor =
pgraph_blend_factor_vk_map[dfactor];
color_blend_attachment.srcAlphaBlendFactor =
pgraph_blend_factor_vk_map[sfactor];
color_blend_attachment.dstAlphaBlendFactor =
pgraph_blend_factor_vk_map[dfactor];

uint32_t equation =
GET_MASK(pgraph_reg_r(pg, NV_PGRAPH_BLEND), NV_PGRAPH_BLEND_EQN);
assert(equation < ARRAY_SIZE(pgraph_blend_equation_vk_map));
Expand All @@ -935,6 +920,33 @@ static void create_pipeline(PGRAPHState *pg)

uint32_t blend_color = pgraph_reg_r(pg, NV_PGRAPH_BLENDCOLOR);
pgraph_argb_pack32_to_rgba_float(blend_color, blend_constant);

uint32_t sfactor = GET_MASK(pgraph_reg_r(pg, NV_PGRAPH_BLEND),
NV_PGRAPH_BLEND_SFACTOR);
uint32_t dfactor = GET_MASK(pgraph_reg_r(pg, NV_PGRAPH_BLEND),
NV_PGRAPH_BLEND_DFACTOR);
assert(sfactor < ARRAY_SIZE(pgraph_blend_factor_vk_map));
assert(dfactor < ARRAY_SIZE(pgraph_blend_factor_vk_map));

if (equation < 5) {
color_blend_attachment.srcColorBlendFactor =
pgraph_blend_factor_vk_map[sfactor];
color_blend_attachment.dstColorBlendFactor =
pgraph_blend_factor_vk_map[dfactor];
color_blend_attachment.srcAlphaBlendFactor =
pgraph_blend_factor_vk_map[sfactor];
color_blend_attachment.dstAlphaBlendFactor =
pgraph_blend_factor_vk_map[dfactor];
} else {
color_blend_attachment.srcColorBlendFactor =
pgraph_blend_factor_vk_map[3];
color_blend_attachment.dstColorBlendFactor =
pgraph_blend_factor_vk_map[1];
color_blend_attachment.srcAlphaBlendFactor =
pgraph_blend_factor_vk_map[sfactor];
color_blend_attachment.dstAlphaBlendFactor =
pgraph_blend_factor_vk_map[dfactor];
}
}

VkPipelineColorBlendStateCreateInfo color_blending = {
Expand Down