From 126f670239676b80e40fa270cea052bdd39d9088 Mon Sep 17 00:00:00 2001
From: Christoph Oelckers <coelckers@users.noreply.github.com>
Date: Sun, 6 Oct 2019 09:31:36 +0200
Subject: [PATCH] - draft class for in-game textures.

These will abstract away all the gory details so that the using code only sees a single entity to use.
---
 source/glbackend/gl_hwtexture.h | 41 +++++++++++++++++++++++++++++++++
 source/glbackend/glbackend.h    |  2 ++
 2 files changed, 43 insertions(+)

diff --git a/source/glbackend/gl_hwtexture.h b/source/glbackend/gl_hwtexture.h
index 1797c7639..56edb6ea6 100644
--- a/source/glbackend/gl_hwtexture.h
+++ b/source/glbackend/gl_hwtexture.h
@@ -3,6 +3,7 @@
 #define __GLTEXTURE_H
 
 class FBitmap;
+class FTexture;
 
 class FHardwareTexture //: public IHardwareTexture
 {
@@ -15,6 +16,7 @@ private:
 	int glTextureBytes = 4;
 	bool mipmapped = true;
 	int mWidth = 0, mHeight = 0;
+	int colorId = 0;
 
 public:
 
@@ -28,6 +30,45 @@ public:
 	unsigned int GetTextureHandle();
 	int GetSampler() { return mSampler; }
 	void SetSampler(int sampler) { mSampler = sampler;  }
+
+	friend class FGameTexture;
+};
+
+class FGameTexture
+{
+	int Width, Height;
+	bool isHightile;
+
+	FTexture* sourceData = nullptr;
+	// either indexed or the sole image for hightiles.
+	FHardwareTexture* hwBase = nullptr;	
+	// If the number was large a TMap would be better - 
+	// but in most cases the maximum number of palettes for a single tile is less than 10 where a linear search is much faster than a TMap.
+	TArray<FHardwareTexture*> hwTextures;	
+public:
+	FGameTexture(bool hightile, int width, int height);
+	virtual ~FGameTexture();
+
+	// For dynamic subtypes.
+	virtual void SizeChanged(int width, int height);
+	static constexpr int MakeId(int palette, int palswap)
+	{
+		return palette + 256 * palswap;
+	}
+
+	FHardwareTexture* GetBaseTexture();
+	FHardwareTexture* CreateHardwareTexture(int palette, int palswap);
+
+	FHardwareTexture* GetHardwareTexture(int palette, int palswap)
+	{
+		if (isHightile) return GetBaseTexture();
+		auto id = MakeId(palette, palswap);
+		auto found = hwTextures.FindEx([=](FHardwareTexture* tex)
+			{
+				return tex->colorId == id;
+			});
+		if (!found) return CreateHardwareTexture(palette, palswap);
+	}
 };
 
 #endif
diff --git a/source/glbackend/glbackend.h b/source/glbackend/glbackend.h
index 04bc4c664..41b38bdb8 100644
--- a/source/glbackend/glbackend.h
+++ b/source/glbackend/glbackend.h
@@ -159,7 +159,9 @@ public:
 	
 	int GetTextureID();
 	FHardwareTexture* NewTexture();
+	FGameTexture* NewTexture(const char *name, bool hightile);
 	void BindTexture(int texunit, FHardwareTexture *texid, int sampler = NoSampler);
+	void BindTexture(int texunit, FGameTexture* texid, int sampler = NoSampler);
 	void UnbindTexture(int texunit);
 	void UnbindAllTextures();
 	void EnableBlend(bool on);