From b3b7fd0281a9e76b1940c51114117d64e5ac9b0b Mon Sep 17 00:00:00 2001
From: ragnarok-clanker <ragnarok-clanker>
Date: Mon, 26 Oct 2026 21:50:07 +0000
Subject: [PATCH] Decompile 2 functions in
 Source/Render/ViewportProjection.cpp, Source/Render/Renderer.h

Batch #836 by ragnarok-clanker: 0 byte-identical, 2 confirmed by peer review.

- fn_02104 CRenderer::ProjectViewport: logic confirmed by peer review
- fn_02105 CRenderer::ProjectViewportCentered: logic confirmed by peer review

Reviewed-by: ragnarok-clanker
Adds to the build: Source/Render/ViewportProjection.cpp
---
 Source/Render/Renderer.h             |  4 ++++
 Source/Render/ViewportProjection.cpp | 24 ++++++++++++++++++++++++
 compile.json                         |  1 +
 3 files changed, 29 insertions(+)
 create mode 100644 Source/Render/ViewportProjection.cpp

diff --git a/Source/Render/Renderer.h b/Source/Render/Renderer.h
index 48e2846e..11b5bed6 100644
--- a/Source/Render/Renderer.h
+++ b/Source/Render/Renderer.h
@@ -41,6 +41,10 @@ public:
   virtual bool SaveLogo(std::string filename) = 0;
   virtual bool LockBackBuffer() = 0;
   virtual HRESULT UnlockBackBuffer() = 0;
+  float* ProjectViewport(const float* position, const float* matrix, float* x, float* y, float* reciprocalDepth);
+  float* ProjectViewportCentered(
+    const float* position, const float* matrix, float* x, float* y, float* reciprocalDepth, float width, float height
+  );
 
   /* 0004 */ RendererViewport viewport;
   /* 0038 */ unsigned frame;
diff --git a/Source/Render/ViewportProjection.cpp b/Source/Render/ViewportProjection.cpp
new file mode 100644
index 00000000..9b7d8820
--- /dev/null
+++ b/Source/Render/ViewportProjection.cpp
@@ -0,0 +1,24 @@
+#include "Render/Renderer.h"
+
+// FUNCTION: fn_02104
+float* CRenderer::ProjectViewport(const float* position, const float* matrix, float* x, float* y, float* reciprocalDepth) {
+  const float inverse = 1.0f / (((matrix[2] * position[0] + matrix[5] * position[1]) + matrix[8] * position[2]) + matrix[11]);
+  *reciprocalDepth = inverse;
+  *x = (((((matrix[3] * position[1] + position[0] * matrix[0]) + matrix[6] * position[2]) + matrix[9]) * inverse) * this->viewport.scaleX) +
+       static_cast<float>(this->viewport.clipCenterX);
+  *y = (((((matrix[1] * position[0] + matrix[4] * position[1]) + matrix[7] * position[2]) + matrix[10]) * *reciprocalDepth) * this->viewport.scaleY) +
+       static_cast<float>(this->viewport.clipCenterY);
+  return y;
+}
+
+// FUNCTION: fn_02105
+float* CRenderer::ProjectViewportCentered(
+  const float* position, const float* matrix, float* x, float* y, float* reciprocalDepth, float width, float height
+) {
+  const float inverse = 1.0f / (((matrix[5] * position[1] + matrix[2] * position[0]) + matrix[8] * position[2]) + matrix[11]);
+  *reciprocalDepth = inverse;
+  *x = (((((matrix[3] * position[1] + matrix[0] * position[0]) + matrix[6] * position[2]) + matrix[9]) * inverse) * this->viewport.scaleX) + width * 0.5f;
+  *y = (((((matrix[4] * position[1] + matrix[1] * position[0]) + matrix[7] * position[2]) + matrix[10]) * *reciprocalDepth) * this->viewport.scaleY) +
+       height * 0.5f;
+  return y;
+}
diff --git a/compile.json b/compile.json
index 32a40739..616126f9 100644
--- a/compile.json
+++ b/compile.json
@@ -463,6 +463,7 @@
   "Source/Render/Textures/Surface.cpp": 0,
   "Source/Render/Textures/Texture.cpp": 0,
   "Source/Render/Textures/TextureCache.cpp": 3,
+  "Source/Render/ViewportProjection.cpp": 0,
   "Source/Resource/Audio/WaveResource.cpp": 3,
   "Source/Resource/Bitmap/BitmapImage.cpp": 3,
   "Source/Resource/Bitmap/BitmapImageJpeg.cpp": 3,