From 28ef69ca5a082ae15235ddf885e224dbdac26632 Mon Sep 17 00:00:00 2001
From: Magnus Norddahl <dpjudas@users.noreply.github.com>
Date: Wed, 28 Dec 2022 15:56:39 +0100
Subject: [PATCH] Add the most basic implementation of a Mesh drawer as
 technically possible :)

---
 .../rendering/hwrenderer/data/hw_mesh.cpp     | 50 +++++++++++++++++++
 .../rendering/hwrenderer/data/hw_mesh.h       | 11 ++++
 .../hwrenderer/data/hw_meshbuilder.cpp        |  4 +-
 .../hwrenderer/data/hw_renderstate.h          |  1 +
 4 files changed, 65 insertions(+), 1 deletion(-)

diff --git a/src/common/rendering/hwrenderer/data/hw_mesh.cpp b/src/common/rendering/hwrenderer/data/hw_mesh.cpp
index cdb653343..b9343b737 100644
--- a/src/common/rendering/hwrenderer/data/hw_mesh.cpp
+++ b/src/common/rendering/hwrenderer/data/hw_mesh.cpp
@@ -1,2 +1,52 @@
 
 #include "hw_mesh.h"
+
+void Mesh::Draw(FRenderState& renderstate)
+{
+	auto pair = renderstate.AllocVertices(mVertices.Size());
+	memcpy(pair.first, mVertices.Data(), mVertices.Size() * sizeof(FFlatVertex));
+
+	int applyIndex = -1;
+	int depthFunc = -1;
+	for (const MeshDrawCommand& cmd : mDraws)
+	{
+		bool apply = applyIndex != cmd.ApplyIndex;
+		if (apply)
+		{
+			int newDepthFunc = mApplys[cmd.ApplyIndex].DepthFunc;
+			if (depthFunc != newDepthFunc)
+			{
+				depthFunc = newDepthFunc;
+				renderstate.SetDepthFunc(depthFunc);
+			}
+
+			applyIndex = cmd.ApplyIndex;
+			Apply(renderstate, mApplys[cmd.ApplyIndex]);
+		}
+		renderstate.Draw(cmd.DrawType, pair.second + cmd.Start, cmd.Count, apply);
+	}
+}
+
+void Mesh::Apply(FRenderState& renderstate, const MeshApplyState& state)
+{
+	renderstate.mRenderStyle = state.RenderStyle;
+	renderstate.mSpecialEffect = state.SpecialEffect;
+	renderstate.mTextureEnabled = state.TextureEnabled;
+	renderstate.mAlphaThreshold = state.AlphaThreshold;
+
+	renderstate.mStreamData = state.streamData;
+	renderstate.mMaterial = state.material;
+
+	renderstate.mClipSplit[0] = state.uClipSplit[0];
+	renderstate.mClipSplit[1] = state.uClipSplit[1];
+
+	renderstate.mFogEnabled = state.FogEnabled;
+	renderstate.mBrightmapEnabled = state.BrightmapEnabled;
+	renderstate.mTextureClamp = state.TextureClamp;
+	renderstate.mTextureMode = state.TextureMode;
+
+	renderstate.mLightParms[0] = state.uLightDist;
+	renderstate.mLightParms[1] = state.uLightFactor;
+	renderstate.mLightParms[2] = state.uFogDensity;
+	renderstate.mLightParms[3] = state.uLightLevel;
+}
diff --git a/src/common/rendering/hwrenderer/data/hw_mesh.h b/src/common/rendering/hwrenderer/data/hw_mesh.h
index 8e66e6e7d..0e3ddc765 100644
--- a/src/common/rendering/hwrenderer/data/hw_mesh.h
+++ b/src/common/rendering/hwrenderer/data/hw_mesh.h
@@ -1,7 +1,18 @@
 #pragma once
 
+#include "hw_meshbuilder.h"
+
 class Mesh
 {
 public:
+	void Draw(FRenderState& renderstate);
 
+private:
+	void Apply(FRenderState& renderstate, const MeshApplyState& apply);
+
+	TArray<MeshApplyState> mApplys;
+	TArray<MeshDrawCommand> mDraws;
+	TArray<FFlatVertex> mVertices;
+
+	friend class MeshBuilder;
 };
diff --git a/src/common/rendering/hwrenderer/data/hw_meshbuilder.cpp b/src/common/rendering/hwrenderer/data/hw_meshbuilder.cpp
index c5912688a..a6edee800 100644
--- a/src/common/rendering/hwrenderer/data/hw_meshbuilder.cpp
+++ b/src/common/rendering/hwrenderer/data/hw_meshbuilder.cpp
@@ -51,7 +51,9 @@ void MeshBuilder::Apply()
 std::unique_ptr<Mesh> MeshBuilder::Create()
 {
 	auto mesh = std::make_unique<Mesh>();
-
+	mesh->mApplys = std::move(mApplys);
+	mesh->mDraws = std::move(mDraws);
+	mesh->mVertices = std::move(mVertices);
 	return mesh;
 }
 
diff --git a/src/common/rendering/hwrenderer/data/hw_renderstate.h b/src/common/rendering/hwrenderer/data/hw_renderstate.h
index 99b1030f7..fc5632932 100644
--- a/src/common/rendering/hwrenderer/data/hw_renderstate.h
+++ b/src/common/rendering/hwrenderer/data/hw_renderstate.h
@@ -765,5 +765,6 @@ public:
 		SetColorMask(on, on, on, on);
 	}
 
+	friend class Mesh;
 };