From 186873420f9f10c65814db8d3a3388cbd21f8444 Mon Sep 17 00:00:00 2001
From: Subv <subv2112@gmail.com>
Date: Thu, 20 Aug 2015 10:10:35 -0500
Subject: [PATCH] GPU/Rasterizer: Corrected the stencil implementation.
Verified the behavior with hardware tests.
---
src/video_core/pica.h | 20 ++++++++++++++-----
src/video_core/rasterizer.cpp | 37 +++++++++++++++++++++++------------
2 files changed, 39 insertions(+), 18 deletions(-)
diff --git a/src/video_core/pica.h b/src/video_core/pica.h
index 58b924f9e..6383e5d56 100644
--- a/src/video_core/pica.h
+++ b/src/video_core/pica.h
@@ -441,8 +441,12 @@ struct Regs {
};
enum class StencilAction : u32 {
- Keep = 0,
- Xor = 5,
+ Keep = 0,
+
+ Replace = 2,
+ Increment = 3,
+ Decrement = 4,
+ Invert = 5
};
struct {
@@ -481,23 +485,29 @@ struct Regs {
struct {
union {
+ // Raw value of this register
+ u32 raw_func;
+
// If true, enable stencil testing
BitField< 0, 1, u32> enable;
// Comparison operation for stencil testing
BitField< 4, 3, CompareFunc> func;
- // Value to calculate the new stencil value from
- BitField< 8, 8, u32> replacement_value;
+ // Mask used to control writing to the stencil buffer
+ BitField< 8, 8, u32> write_mask;
// Value to compare against for stencil testing
BitField<16, 8, u32> reference_value;
// Mask to apply on stencil test inputs
- BitField<24, 8, u32> mask;
+ BitField<24, 8, u32> input_mask;
};
union {
+ // Raw value of this register
+ u32 raw_op;
+
// Action to perform when the stencil test fails
BitField< 0, 3, StencilAction> action_stencil_fail;
diff --git a/src/video_core/rasterizer.cpp b/src/video_core/rasterizer.cpp
index b83798b0f..000b4542b 100644
--- a/src/video_core/rasterizer.cpp
+++ b/src/video_core/rasterizer.cpp
@@ -215,14 +215,25 @@ static void SetStencil(int x, int y, u8 value) {
}
}
-// TODO: Should the stencil mask be applied to the "dest" or "ref" operands? Most likely not!
-static u8 PerformStencilAction(Regs::StencilAction action, u8 dest, u8 ref) {
+// TODO: Should the stencil mask be applied to the "old_stencil" or "ref" operands? Most likely not!
+static u8 PerformStencilAction(Regs::StencilAction action, u8 old_stencil, u8 ref) {
switch (action) {
case Regs::StencilAction::Keep:
- return dest;
+ return old_stencil;
- case Regs::StencilAction::Xor:
- return dest ^ ref;
+ case Regs::StencilAction::Replace:
+ return ref;
+
+ case Regs::StencilAction::Increment:
+ // Saturated increment
+ return std::min<u8>(old_stencil, 254) + 1;
+
+ case Regs::StencilAction::Decrement:
+ // Saturated decrement
+ return std::max<u8>(old_stencil, 1) - 1;
+
+ case Regs::StencilAction::Invert:
+ return ~old_stencil;
default:
LOG_CRITICAL(HW_GPU, "Unknown stencil action %x", (int)action);
@@ -782,8 +793,8 @@ static void ProcessTriangleInternal(const Shader::OutputVertex& v0,
u8 old_stencil = 0;
if (stencil_action_enable) {
old_stencil = GetStencil(x >> 4, y >> 4);
- u8 dest = old_stencil & stencil_test.mask;
- u8 ref = stencil_test.reference_value & stencil_test.mask;
+ u8 dest = old_stencil & stencil_test.input_mask;
+ u8 ref = stencil_test.reference_value & stencil_test.input_mask;
bool pass = false;
switch (stencil_test.func) {
@@ -821,8 +832,8 @@ static void ProcessTriangleInternal(const Shader::OutputVertex& v0,
}
if (!pass) {
- u8 new_stencil = PerformStencilAction(stencil_test.action_stencil_fail, old_stencil, stencil_test.replacement_value);
- SetStencil(x >> 4, y >> 4, new_stencil);
+ u8 new_stencil = PerformStencilAction(stencil_test.action_stencil_fail, old_stencil, stencil_test.reference_value);
+ SetStencil(x >> 4, y >> 4, (new_stencil & stencil_test.write_mask) | (old_stencil & ~stencil_test.write_mask));
continue;
}
}
@@ -873,8 +884,8 @@ static void ProcessTriangleInternal(const Shader::OutputVertex& v0,
if (!pass) {
if (stencil_action_enable) {
- u8 new_stencil = PerformStencilAction(stencil_test.action_depth_fail, old_stencil, stencil_test.replacement_value);
- SetStencil(x >> 4, y >> 4, new_stencil);
+ u8 new_stencil = PerformStencilAction(stencil_test.action_depth_fail, old_stencil, stencil_test.reference_value);
+ SetStencil(x >> 4, y >> 4, (new_stencil & stencil_test.write_mask) | (old_stencil & ~stencil_test.write_mask));
}
continue;
}
@@ -884,8 +895,8 @@ static void ProcessTriangleInternal(const Shader::OutputVertex& v0,
if (stencil_action_enable) {
// TODO: What happens if stencil testing is enabled, but depth testing is not? Will stencil get updated anyway?
- u8 new_stencil = PerformStencilAction(stencil_test.action_depth_pass, old_stencil, stencil_test.replacement_value);
- SetStencil(x >> 4, y >> 4, new_stencil);
+ u8 new_stencil = PerformStencilAction(stencil_test.action_depth_pass, old_stencil, stencil_test.reference_value);
+ SetStencil(x >> 4, y >> 4, (new_stencil & stencil_test.write_mask) | (old_stencil & ~stencil_test.write_mask));
}
}