1 files changed, 99 insertions, 0 deletions
diff --git a/src/video_core/swrasterizer/framebuffer.cpp b/src/video_core/swrasterizer/framebuffer.cpp
index 4b31eda89c..7de3aac751 100644
--- a/src/video_core/swrasterizer/framebuffer.cpp
+++ b/src/video_core/swrasterizer/framebuffer.cpp
@@ -8,6 +8,7 @@
 #include "common/color.h"
 #include "common/common_types.h"
 #include "common/logging/log.h"
+#include "common/math_util.h"
 #include "common/vector_math.h"
 #include "core/hw/gpu.h"
 #include "core/memory.h"
@@ -255,5 +256,103 @@ u8 PerformStencilAction(FramebufferRegs::StencilAction action, u8 old_stencil, u
     }
 }
 
+Math::Vec4<u8> EvaluateBlendEquation(const Math::Vec4<u8>& src, const Math::Vec4<u8>& srcfactor,
+                                     const Math::Vec4<u8>& dest, const Math::Vec4<u8>& destfactor,
+                                     FramebufferRegs::BlendEquation equation) {
+    Math::Vec4<int> result;
+
+    auto src_result = (src * srcfactor).Cast<int>();
+    auto dst_result = (dest * destfactor).Cast<int>();
+
+    switch (equation) {
+    case FramebufferRegs::BlendEquation::Add:
+        result = (src_result + dst_result) / 255;
+        break;
+
+    case FramebufferRegs::BlendEquation::Subtract:
+        result = (src_result - dst_result) / 255;
+        break;
+
+    case FramebufferRegs::BlendEquation::ReverseSubtract:
+        result = (dst_result - src_result) / 255;
+        break;
+
+    // TODO: How do these two actually work?  OpenGL doesn't include the blend factors in the
+    //       min/max computations, but is this what the 3DS actually does?
+    case FramebufferRegs::BlendEquation::Min:
+        result.r() = std::min(src.r(), dest.r());
+        result.g() = std::min(src.g(), dest.g());
+        result.b() = std::min(src.b(), dest.b());
+        result.a() = std::min(src.a(), dest.a());
+        break;
+
+    case FramebufferRegs::BlendEquation::Max:
+        result.r() = std::max(src.r(), dest.r());
+        result.g() = std::max(src.g(), dest.g());
+        result.b() = std::max(src.b(), dest.b());
+        result.a() = std::max(src.a(), dest.a());
+        break;
+
+    default:
+        LOG_CRITICAL(HW_GPU, "Unknown RGB blend equation %x", equation);
+        UNIMPLEMENTED();
+    }
+
+    return Math::Vec4<u8>(MathUtil::Clamp(result.r(), 0, 255), MathUtil::Clamp(result.g(), 0, 255),
+                          MathUtil::Clamp(result.b(), 0, 255), MathUtil::Clamp(result.a(), 0, 255));
+};
+
+u8 LogicOp(u8 src, u8 dest, FramebufferRegs::LogicOp op) {
+    switch (op) {
+    case FramebufferRegs::LogicOp::Clear:
+        return 0;
+
+    case FramebufferRegs::LogicOp::And:
+        return src & dest;
+
+    case FramebufferRegs::LogicOp::AndReverse:
+        return src & ~dest;
+
+    case FramebufferRegs::LogicOp::Copy:
+        return src;
+
+    case FramebufferRegs::LogicOp::Set:
+        return 255;
+
+    case FramebufferRegs::LogicOp::CopyInverted:
+        return ~src;
+
+    case FramebufferRegs::LogicOp::NoOp:
+        return dest;
+
+    case FramebufferRegs::LogicOp::Invert:
+        return ~dest;
+
+    case FramebufferRegs::LogicOp::Nand:
+        return ~(src & dest);
+
+    case FramebufferRegs::LogicOp::Or:
+        return src | dest;
+
+    case FramebufferRegs::LogicOp::Nor:
+        return ~(src | dest);
+
+    case FramebufferRegs::LogicOp::Xor:
+        return src ^ dest;
+
+    case FramebufferRegs::LogicOp::Equiv:
+        return ~(src ^ dest);
+
+    case FramebufferRegs::LogicOp::AndInverted:
+        return ~src & dest;
+
+    case FramebufferRegs::LogicOp::OrReverse:
+        return src | ~dest;
+
+    case FramebufferRegs::LogicOp::OrInverted:
+        return ~src | dest;
+    }
+};
+
 } // namespace Rasterizer
 } // namespace Pica