From 3e478ca13110639a67ad95880aae5d7d13e096b7 Mon Sep 17 00:00:00 2001
From: wwylele <wwylele@gmail.com>
Date: Fri, 18 Aug 2017 15:04:56 +0300
Subject: SwRasterizer/Lighting: implement bump mapping

---
 src/video_core/swrasterizer/lighting.cpp | 28 +++++++++++++++++++++++-----
 1 file changed, 23 insertions(+), 5 deletions(-)

(limited to 'src/video_core/swrasterizer/lighting.cpp')

diff --git a/src/video_core/swrasterizer/lighting.cpp b/src/video_core/swrasterizer/lighting.cpp
index 39a3e396d..4f16bac07 100644
--- a/src/video_core/swrasterizer/lighting.cpp
+++ b/src/video_core/swrasterizer/lighting.cpp
@@ -22,14 +22,32 @@ static float LookupLightingLut(const Pica::State::Lighting& lighting, size_t lut
 
 std::tuple<Math::Vec4<u8>, Math::Vec4<u8>> ComputeFragmentsColors(
     const Pica::LightingRegs& lighting, const Pica::State::Lighting& lighting_state,
-    const Math::Quaternion<float>& normquat, const Math::Vec3<float>& view) {
+    const Math::Quaternion<float>& normquat, const Math::Vec3<float>& view,
+    const Math::Vec4<u8> (&texture_color)[4]) {
 
-    // TODO(Subv): Bump mapping
-    Math::Vec3<float> surface_normal = {0.0f, 0.0f, 1.0f};
+    Math::Vec3<float> surface_normal;
+    Math::Vec3<float> surface_tangent;
 
     if (lighting.config0.bump_mode != LightingRegs::LightingBumpMode::None) {
-        LOG_CRITICAL(HW_GPU, "unimplemented bump mapping");
-        UNIMPLEMENTED();
+        Math::Vec3<float> perturbation =
+            texture_color[lighting.config0.bump_selector].xyz().Cast<float>() / 127.5f -
+            Math::MakeVec(1.0f, 1.0f, 1.0f);
+        if (lighting.config0.bump_mode == LightingRegs::LightingBumpMode::NormalMap) {
+            if (!lighting.config0.disable_bump_renorm) {
+                const float z_square = 1 - perturbation.xy().Length2();
+                perturbation.z = std::sqrt(std::max(z_square, 0.0f));
+            }
+            surface_normal = perturbation;
+            surface_tangent = Math::MakeVec(1.0f, 0.0f, 0.0f);
+        } else if (lighting.config0.bump_mode == LightingRegs::LightingBumpMode::TangentMap) {
+            surface_normal = Math::MakeVec(0.0f, 0.0f, 1.0f);
+            surface_tangent = perturbation;
+        } else {
+            LOG_ERROR(HW_GPU, "Unknown bump mode %u", lighting.config0.bump_mode.Value());
+        }
+    } else {
+        surface_normal = Math::MakeVec(0.0f, 0.0f, 1.0f);
+        surface_tangent = Math::MakeVec(1.0f, 0.0f, 0.0f);
     }
 
     // Use the normalized the quaternion when performing the rotation
-- 
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