From b011d756ee60987deb84808c390a392271042c1e Mon Sep 17 00:00:00 2001
From: Samuliak <samuliak77@gmail.com>
Date: Thu, 29 Aug 2024 08:47:22 +0200
Subject: [PATCH] adjust texture swizzle

---
 .../Renderer/Metal/LatteTextureViewMtl.cpp    | 55 ++++++++++++++++++-
 1 file changed, 54 insertions(+), 1 deletion(-)

diff --git a/src/Cafe/HW/Latte/Renderer/Metal/LatteTextureViewMtl.cpp b/src/Cafe/HW/Latte/Renderer/Metal/LatteTextureViewMtl.cpp
index 0607370b..950cadc1 100644
--- a/src/Cafe/HW/Latte/Renderer/Metal/LatteTextureViewMtl.cpp
+++ b/src/Cafe/HW/Latte/Renderer/Metal/LatteTextureViewMtl.cpp
@@ -3,6 +3,56 @@
 #include "Cafe/HW/Latte/Renderer/Metal/MetalRenderer.h"
 #include "Cafe/HW/Latte/Renderer/Metal/LatteToMtl.h"
 
+uint32 LatteTextureMtl_AdjustTextureCompSel(Latte::E_GX2SURFFMT format, uint32 compSel)
+{
+	switch (format)
+	{
+	case Latte::E_GX2SURFFMT::R8_UNORM: // R8 is replicated on all channels (while OpenGL would return 1.0 for BGA instead)
+	case Latte::E_GX2SURFFMT::R8_SNORM: // probably the same as _UNORM, but needs testing
+		if (compSel >= 1 && compSel <= 3)
+			compSel = 0;
+		break;
+	case Latte::E_GX2SURFFMT::A1_B5_G5_R5_UNORM: // order of components is reversed (RGBA -> ABGR)
+		if (compSel >= 0 && compSel <= 3)
+			compSel = 3 - compSel;
+		break;
+	case Latte::E_GX2SURFFMT::BC4_UNORM:
+	case Latte::E_GX2SURFFMT::BC4_SNORM:
+		if (compSel >= 1 && compSel <= 3)
+			compSel = 0;
+		break;
+	case Latte::E_GX2SURFFMT::BC5_UNORM:
+	case Latte::E_GX2SURFFMT::BC5_SNORM:
+		// RG maps to RG
+		// B maps to ?
+		// A maps to G (guessed)
+		if (compSel == 3)
+			compSel = 1; // read Alpha as Green
+		break;
+	case Latte::E_GX2SURFFMT::A2_B10_G10_R10_UNORM:
+		// reverse components (Wii U: ABGR, OpenGL: RGBA)
+		// used in Resident Evil Revelations
+		if (compSel >= 0 && compSel <= 3)
+			compSel = 3 - compSel;
+		break;
+	case Latte::E_GX2SURFFMT::X24_G8_UINT:
+		// map everything to alpha?
+		if (compSel >= 0 && compSel <= 3)
+			compSel = 3;
+		break;
+	case Latte::E_GX2SURFFMT::R4_G4_UNORM:
+		// red and green swapped
+		if (compSel == 0)
+			compSel = 1;
+		else if (compSel == 1)
+			compSel = 0;
+		break;
+	default:
+		break;
+	}
+	return compSel;
+}
+
 LatteTextureViewMtl::LatteTextureViewMtl(MetalRenderer* mtlRenderer, LatteTextureMtl* texture, Latte::E_DIM dim, Latte::E_GX2SURFFMT format, sint32 firstMip, sint32 mipCount, sint32 firstSlice, sint32 sliceCount)
 	: LatteTextureView(texture, firstMip, mipCount, firstSlice, sliceCount, dim, format), m_mtlr(mtlRenderer), m_baseTexture(texture)
 {
@@ -74,7 +124,10 @@ MTL::Texture* LatteTextureViewMtl::CreateSwizzledView(uint32 gpuSamplerSwizzle)
 	uint32 compSelG = (gpuSamplerSwizzle >> 19) & 0x7;
 	uint32 compSelB = (gpuSamplerSwizzle >> 22) & 0x7;
 	uint32 compSelA = (gpuSamplerSwizzle >> 25) & 0x7;
-	// TODO: adjust
+	compSelR = LatteTextureMtl_AdjustTextureCompSel(format, compSelR);
+	compSelG = LatteTextureMtl_AdjustTextureCompSel(format, compSelG);
+	compSelB = LatteTextureMtl_AdjustTextureCompSel(format, compSelB);
+	compSelA = LatteTextureMtl_AdjustTextureCompSel(format, compSelA);
 
 	MTL::TextureType textureType;
     switch (dim)