From 054d2b58224deeb374c062c4940123741fbf7218 Mon Sep 17 00:00:00 2001
From: Nathan Mills <38995150+Quipyowert2@users.noreply.github.com>
Date: Mon, 20 May 2024 14:49:26 -0700
Subject: [PATCH 01/13] Generate sprite sheet on the fly.

Buildings are drawn in three places now for some odd reason.

Fix building showing up three times bug.
---
 libgag/include/SDLGraphicContext.h | 14 +++++++--
 libgag/src/GraphicContext.cpp      | 22 +++++++++-----
 libgag/src/Sprite.cpp              | 49 ++++++++++++++++++++++++++++++
 3 files changed, 75 insertions(+), 10 deletions(-)

diff --git a/libgag/include/SDLGraphicContext.h b/libgag/include/SDLGraphicContext.h
index fc364c5ce..e78f34d34 100644
--- a/libgag/include/SDLGraphicContext.h
+++ b/libgag/include/SDLGraphicContext.h
@@ -158,6 +158,7 @@ namespace GAGCore
 	protected:
 		friend struct Color;
 		friend class GraphicContext;
+		friend class Sprite;
 		//! the underlying software SDL surface
 		SDL_Surface *sdlsurface;
 		//! The clipping rect, we do not draw outside it
@@ -166,6 +167,13 @@ namespace GAGCore
 		bool dirty;
 		//! texture index if GPU (GL) is used
 		unsigned int texture;
+		//! sprite sheet coordinates
+		int texX = 0;
+		int texY = 0;
+		//! width and height if using atlas
+		int w;
+		int h;
+		bool usingAtlas = false;
 		//! texture divisor
 		float texMultX, texMultY;
 		
@@ -209,8 +217,8 @@ namespace GAGCore
 		virtual void shiftHSV(float hue, float sat, float lum);
 		
 		// accessors
-		virtual int getW(void) { return sdlsurface->w; } 
-		virtual int getH(void) { return sdlsurface->h; }
+		virtual int getW(void) { if (usingAtlas && w) return w; return sdlsurface->w; }
+		virtual int getH(void) { if (usingAtlas && h) return h; return sdlsurface->h; }
 		
 		// capability querying
 		virtual bool canDrawStretchedSprite(void) { return false; }
@@ -420,6 +428,7 @@ namespace GAGCore
 		std::string fileName;
 		std::vector <DrawableSurface *> images;
 		std::vector <RotatedImage *> rotated;
+		DrawableSurface *atlas = nullptr;
 		Color actColor;
 	
 		friend class DrawableSurface;
@@ -428,6 +437,7 @@ namespace GAGCore
 		void loadFrame(SDL_RWops *frameStream, SDL_RWops *rotatedStream);
 		//! Check if index is within bound and return true, assert false and return false otherwise
 		bool checkBound(int index);
+		void createTextureAtlas();
 		//! Return a rotated drawable surface for actColor, create it if necessary
 		virtual DrawableSurface *getRotatedSurface(int index);
 	
diff --git a/libgag/src/GraphicContext.cpp b/libgag/src/GraphicContext.cpp
index 1033c0735..fdce55b15 100644
--- a/libgag/src/GraphicContext.cpp
+++ b/libgag/src/GraphicContext.cpp
@@ -303,6 +303,8 @@ namespace GAGCore
 	void DrawableSurface::allocateTexture(void)
 	{
 		#ifdef HAVE_OPENGL
+		if (usingAtlas)
+			return;
 		if (_gc->optionFlags & GraphicContext::USEGPU)
 		{
 			glGenTextures(1, reinterpret_cast<GLuint*>(&texture));
@@ -345,6 +347,10 @@ namespace GAGCore
 	void DrawableSurface::uploadToTexture(void)
 	{
 		#ifdef HAVE_OPENGL
+		if (usingAtlas)
+		{
+			return;
+		}
 		if (_gc->optionFlags & GraphicContext::USEGPU)
 		{
 			glState.setTexture(texture);
@@ -1049,22 +1055,22 @@ namespace GAGCore
 
 	void DrawableSurface::drawSurface(int x, int y, DrawableSurface *surface, Uint8 alpha)
 	{
-		drawSurface(x, y, surface, 0, 0, surface->getW(), surface->getH(), alpha);
+		drawSurface(x, y, surface, surface->texX, surface->texY, surface->getW(), surface->getH(), alpha);
 	}
 
 	void DrawableSurface::drawSurface(float x, float y, DrawableSurface *surface, Uint8 alpha)
 	{
-		drawSurface(x, y, surface, 0, 0, surface->getW(), surface->getH(), alpha);
+		drawSurface(x, y, surface, surface->texX, surface->texY, surface->getW(), surface->getH(), alpha);
 	}
 
 	void DrawableSurface::drawSurface(int x, int y, int w, int h, DrawableSurface *surface, Uint8 alpha)
 	{
-		drawSurface(x, y, w, h, surface, 0, 0, surface->getW(), surface->getH(), alpha);
+		drawSurface(x, y, w, h, surface, surface->texX, surface->texY, surface->getW(), surface->getH(), alpha);
 	}
 
 	void DrawableSurface::drawSurface(float x, float y, float w, float h, DrawableSurface *surface, Uint8 alpha)
 	{
-		drawSurface(x, y, w, h, surface, 0, 0, surface->getW(), surface->getH(), alpha);
+		drawSurface(x, y, w, h, surface, surface->texX, surface->texY, surface->getW(), surface->getH(), alpha);
 	}
 
 	void DrawableSurface::drawSurface(int x, int y, DrawableSurface *surface, int sx, int sy, int sw, int sh, Uint8 alpha)
@@ -1617,22 +1623,22 @@ namespace GAGCore
 
 	void GraphicContext::drawSurface(int x, int y, DrawableSurface *surface, Uint8 alpha)
 	{
-		drawSurface(x, y, surface, 0, 0, surface->getW(), surface->getH(), alpha);
+		drawSurface(x, y, surface, surface->texX, surface->texY, surface->getW(), surface->getH(), alpha);
 	}
 
 	void GraphicContext::drawSurface(float x, float y, DrawableSurface *surface, Uint8 alpha)
 	{
-		drawSurface(x, y, surface, 0, 0, surface->getW(), surface->getH(), alpha);
+		drawSurface(x, y, surface, surface->texX, surface->texY, surface->getW(), surface->getH(), alpha);
 	}
 
 	void GraphicContext::drawSurface(int x, int y, int w, int h, DrawableSurface *surface, Uint8 alpha)
 	{
-		drawSurface(x, y, w, h, surface, 0, 0, surface->getW(), surface->getH(), alpha);
+		drawSurface(x, y, w, h, surface, surface->texX, surface->texY, surface->getW(), surface->getH(), alpha);
 	}
 
 	void GraphicContext::drawSurface(float x, float y, float w, float h, DrawableSurface *surface, Uint8 alpha)
 	{
-		drawSurface(x, y, w, h, surface, 0, 0, surface->getW(), surface->getH(), alpha);
+		drawSurface(x, y, w, h, surface, surface->texX, surface->texY, surface->getW(), surface->getH(), alpha);
 	}
 
 	void GraphicContext::drawSurface(int x, int y, DrawableSurface *surface, int sx, int sy, int sw, int sh, Uint8 alpha)
diff --git a/libgag/src/Sprite.cpp b/libgag/src/Sprite.cpp
index 5293e3f35..b7aca3b8c 100644
--- a/libgag/src/Sprite.cpp
+++ b/libgag/src/Sprite.cpp
@@ -67,9 +67,58 @@ namespace GAGCore
 				SDL_RWclose(rotatedStream);
 			i++;
 		}
+		if (!images.empty())
+			createTextureAtlas();
 		
 		return getFrameCount() > 0;
 	}
+
+	// Create texture atlas for images array
+	void Sprite::createTextureAtlas()
+	{
+		size_t numImages = images.size();
+		int w = 0, h = 0;
+		for (auto image : images)
+		{
+			if (!image)
+				return;
+			if (!w || !h)
+			{
+				w = image->getW();
+				h = image->getH();
+			}
+			if (image->getW() != w || image->getH() != h)
+				return;
+		}
+		int tileWidth = images[0]->getW();
+		int tileHeight = images[0]->getH();
+		int sheetWidth = tileWidth * (sqrt(numImages) + 1);
+		int sheetHeight = tileHeight * (sqrt(numImages) + 1);
+		atlas = new DrawableSurface(sheetWidth, sheetHeight);
+		int x = 0, y = 0;
+		for (auto image: images)
+		{
+			atlas->drawSurface(x, y, image);
+			image->texX = x;
+			image->texY = y;
+			image->texMultX = 1.f;
+			image->texMultY = 1.f;
+			image->w = tileWidth;
+			image->h = tileHeight;
+			x += tileWidth;
+			if (sheetWidth - x < tileWidth) {
+				x = 0;
+				y += tileHeight;
+			}
+		}
+		atlas->uploadToTexture();
+		for (auto image : images)
+		{
+			image->texture = atlas->texture;
+			image->usingAtlas = true;
+			image->setRes(sheetWidth, sheetHeight);
+		}
+	}
 	
 	DrawableSurface *Sprite::getRotatedSurface(int index)
 	{

From 1d92a769e265ab37ab7d34c0a323a51f5c382fbf Mon Sep 17 00:00:00 2001
From: Nathan Mills <38995150+Quipyowert2@users.noreply.github.com>
Date: Mon, 20 May 2024 21:57:43 -0700
Subject: [PATCH 02/13] Prepare for a potential speedup with glDrawArrays.

---
 libgag/src/GraphicContext.cpp | 20 ++++++++++++++++++--
 1 file changed, 18 insertions(+), 2 deletions(-)

diff --git a/libgag/src/GraphicContext.cpp b/libgag/src/GraphicContext.cpp
index fdce55b15..c5e567e8d 100644
--- a/libgag/src/GraphicContext.cpp
+++ b/libgag/src/GraphicContext.cpp
@@ -1684,11 +1684,24 @@ namespace GAGCore
 			glState.blendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
 			glState.doBlend(true);
 			glState.doTexture(true);
+			glEnableClientState(GL_VERTEX_ARRAY);
+			glEnableClientState(GL_TEXTURE_COORD_ARRAY);
 			glColor4ub(255, 255, 255, alpha);
 
 			// draw
 			glState.setTexture(surface->texture);
-			glBegin(GL_QUADS);
+			float vertices[8] = { x, y, x + w, y, x + w, y + h, x, y + h };
+			float texCoords[8] = { static_cast<float>(sx) * surface->texMultX, static_cast<float>(sy) * surface->texMultY,
+				static_cast<float>(sx + sw) * surface->texMultX, static_cast<float>(sy) * surface->texMultY,
+				static_cast<float>(sx + sw) * surface->texMultX, static_cast<float>(sy + sh) * surface->texMultY,
+				static_cast<float>(sx) * surface->texMultX, static_cast<float>(sy + sh) * surface->texMultY
+			};
+			glVertexPointer(2, GL_FLOAT, 0, vertices);
+			glTexCoordPointer(2, GL_FLOAT, 0, texCoords);
+			glDrawArrays(GL_QUADS, 0, 4);
+			assert(!glGetError());
+		    //glDrawElements(GL_QUADS, 4, GL_FLOAT, );
+			/*glBegin(GL_QUADS);
 			glTexCoord2f(static_cast<float>(sx) * surface->texMultX, static_cast<float>(sy) * surface->texMultY);
 			glVertex2f(x, y);
 			glTexCoord2f(static_cast<float>(sx + sw) * surface->texMultX, static_cast<float>(sy) * surface->texMultY);
@@ -1697,7 +1710,10 @@ namespace GAGCore
 			glVertex2f(x+w, y+h);
 			glTexCoord2f(static_cast<float>(sx) * surface->texMultX, static_cast<float>(sy + sh) * surface->texMultY);
 			glVertex2f(x, y+h);
-			glEnd();
+			glEnd();*/
+
+			glDisableClientState(GL_VERTEX_ARRAY);
+			glDisableClientState(GL_TEXTURE_COORD_ARRAY);
 		}
 		else
 		#endif

From 9b01b1dfad0f483081e93a13447dba2320940be9 Mon Sep 17 00:00:00 2001
From: Nathan Mills <38995150+Quipyowert2@users.noreply.github.com>
Date: Thu, 10 Oct 2024 20:47:33 -0700
Subject: [PATCH 03/13] More efficient sprite drawing.

Doesn't compile yet because of a purportedly missing > when compiling native.h.
---
 libgag/include/SDLGraphicContext.h | 14 ++++++++++
 libgag/src/GraphicContext.cpp      | 44 ++++++++++++++++++++++++++----
 libgag/src/Sprite.cpp              | 26 ++++++++++++++++++
 src/Game.cpp                       |  4 ++-
 4 files changed, 81 insertions(+), 7 deletions(-)

diff --git a/libgag/include/SDLGraphicContext.h b/libgag/include/SDLGraphicContext.h
index e78f34d34..bcec7e4a8 100644
--- a/libgag/include/SDLGraphicContext.h
+++ b/libgag/include/SDLGraphicContext.h
@@ -161,6 +161,8 @@ namespace GAGCore
 		friend class Sprite;
 		//! the underlying software SDL surface
 		SDL_Surface *sdlsurface;
+		//! which animation or texture atlas this surface is part of.
+		Sprite* sprite = nullptr;
 		//! The clipping rect, we do not draw outside it
 		SDL_Rect clipRect;
 		//! this surface has been modified since latest blit
@@ -383,6 +385,8 @@ namespace GAGCore
 		
 		virtual void drawSurface(int x, int y, int w, int h, DrawableSurface *surface, int sx, int sy, int sw, int sh,  Uint8 alpha = Color::ALPHA_OPAQUE);
 		virtual void drawSurface(float x, float y, float w, float h, DrawableSurface *surface, int sx, int sy, int sw, int sh, Uint8 alpha = Color::ALPHA_OPAQUE);
+
+		void finishDrawingSprite(Sprite* sprite, Uint8 alpha);
 		
 		virtual void drawAlphaMap(const std::valarray<float> &map, int mapW, int mapH, int x, int y, int cellW, int cellH, const Color &color);
 		virtual void drawAlphaMap(const std::valarray<unsigned char> &map, int mapW, int mapH, int x, int y, int cellW, int cellH, const Color &color);
@@ -424,11 +428,21 @@ namespace GAGCore
 			RotatedImage(DrawableSurface *s) { orig = s; }
 			~RotatedImage();
 		};
+
+		friend class GraphicContext;
 	
 		std::string fileName;
 		std::vector <DrawableSurface *> images;
 		std::vector <RotatedImage *> rotated;
+
+		// Sprite sheet stuff to efficiently draw terrain/water/units.
+#ifdef HAVE_OPENGL
+		std::vector <float> vertices;
+		std::vector <float> texCoords;
+		unsigned int vbo;
+		unsigned int texCoordBuffer;
 		DrawableSurface *atlas = nullptr;
+#endif
 		Color actColor;
 	
 		friend class DrawableSurface;
diff --git a/libgag/src/GraphicContext.cpp b/libgag/src/GraphicContext.cpp
index c5e567e8d..46eb7ddea 100644
--- a/libgag/src/GraphicContext.cpp
+++ b/libgag/src/GraphicContext.cpp
@@ -37,6 +37,7 @@
 #include <config.h>
 #endif
 
+#define GL_GLEXT_PROTOTYPES
 #ifdef HAVE_OPENGL
 	#if defined(__APPLE__) || defined(OPENGL_HEADER_DIRECTORY_OPENGL)
 		#include <OpenGL/gl.h>
@@ -1690,16 +1691,14 @@ namespace GAGCore
 
 			// draw
 			glState.setTexture(surface->texture);
-			float vertices[8] = { x, y, x + w, y, x + w, y + h, x, y + h };
-			float texCoords[8] = { static_cast<float>(sx) * surface->texMultX, static_cast<float>(sy) * surface->texMultY,
+			std::vector<float> vertices = { x, y, x + w, y, x + w, y + h, x, y + h };
+			std::vector<float> texCoords = { static_cast<float>(sx) * surface->texMultX, static_cast<float>(sy) * surface->texMultY,
 				static_cast<float>(sx + sw) * surface->texMultX, static_cast<float>(sy) * surface->texMultY,
 				static_cast<float>(sx + sw) * surface->texMultX, static_cast<float>(sy + sh) * surface->texMultY,
 				static_cast<float>(sx) * surface->texMultX, static_cast<float>(sy + sh) * surface->texMultY
 			};
-			glVertexPointer(2, GL_FLOAT, 0, vertices);
-			glTexCoordPointer(2, GL_FLOAT, 0, texCoords);
-			glDrawArrays(GL_QUADS, 0, 4);
-			assert(!glGetError());
+			surface->sprite->vertices.insert(surface->sprite->vertices.end(), vertices.begin(), vertices.end());
+			surface->sprite->texCoords.insert(surface->sprite->texCoords.end(), texCoords.begin(), texCoords.end());
 		    //glDrawElements(GL_QUADS, 4, GL_FLOAT, );
 			/*glBegin(GL_QUADS);
 			glTexCoord2f(static_cast<float>(sx) * surface->texMultX, static_cast<float>(sy) * surface->texMultY);
@@ -1720,6 +1719,39 @@ namespace GAGCore
 			DrawableSurface::drawSurface(static_cast<int>(x), static_cast<int>(y), static_cast<int>(w), static_cast<int>(h), surface, sx, sy, sw, sh, alpha);
 	}
 
+	// Lets us efficiently draw terrain and water.
+	void GraphicContext::finishDrawingSprite(Sprite* sprite, Uint8 alpha)
+	{
+#ifdef HAVE_OPENGL
+		if (_gc->optionFlags & GraphicContext::USEGPU)
+		{
+			// state change
+			glState.blendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
+			glState.doBlend(true);
+			glState.doTexture(true);
+			glEnableClientState(GL_VERTEX_ARRAY);
+			glEnableClientState(GL_TEXTURE_COORD_ARRAY);
+			glColor4ub(255, 255, 255, alpha);
+			glState.setTexture(sprite->atlas->texture);
+			glBindBuffer(GL_ARRAY_BUFFER, sprite->vbo);
+			glBufferData(GL_ARRAY_BUFFER, sprite->vertices.size() * sizeof(float), &sprite->vertices[0], GL_STREAM_DRAW);
+			glBindBuffer(GL_ARRAY_BUFFER, sprite->texCoordBuffer);
+			glBufferData(GL_ARRAY_BUFFER, sprite->texCoords.size() * sizeof(float), &sprite->texCoords[0], GL_STREAM_DRAW);
+
+			glVertexPointer(2, GL_FLOAT, 0, &sprite->vertices[0]);
+			glTexCoordPointer(2, GL_FLOAT, 0, &sprite->texCoords[0]);
+			glDrawArrays(GL_QUADS, 0, sprite->vertices.size() / 4);
+
+			sprite->vertices.clear();
+			sprite->texCoords.clear();
+
+			glBindBuffer(GL_ARRAY_BUFFER, 0);
+			glDisableClientState(GL_VERTEX_ARRAY);
+			glDisableClientState(GL_TEXTURE_COORD_ARRAY);
+		}
+#endif
+	}
+
 	void GraphicContext::drawAlphaMap(const std::valarray<float> &map, int mapW, int mapH, int x, int y, int cellW, int cellH, const Color &color)
 	{
 	#ifdef HAVE_OPENGL
diff --git a/libgag/src/Sprite.cpp b/libgag/src/Sprite.cpp
index b7aca3b8c..d15d2ae33 100644
--- a/libgag/src/Sprite.cpp
+++ b/libgag/src/Sprite.cpp
@@ -27,6 +27,24 @@
 #include <iostream>
 #include <sstream>
 
+#define GL_GLEXT_PROTOTYPES
+#ifdef HAVE_OPENGL
+#if defined(__APPLE__) || defined(OPENGL_HEADER_DIRECTORY_OPENGL)
+#include <OpenGL/gl.h>
+#include <OpenGL/glext.h>
+#include <OpenGL/glu.h>
+#define GL_TEXTURE_RECTANGLE_NV GL_TEXTURE_RECTANGLE_EXT
+#else
+#include <GL/gl.h>
+#include <GL/glu.h>
+#endif
+#endif
+
+#ifdef WIN32
+#include <GL/glext.h>
+#endif
+
+
 namespace GAGCore
 {
 	Sprite::RotatedImage::~RotatedImage()
@@ -74,8 +92,11 @@ namespace GAGCore
 	}
 
 	// Create texture atlas for images array
+	// Using a sprite sheet lets us efficiently drawn terrain and water with a few calls
+	// to glDrawArrays, rather than 272 individual calls to glBegin...glEnd.
 	void Sprite::createTextureAtlas()
 	{
+#ifdef HAVE_OPENGL
 		size_t numImages = images.size();
 		int w = 0, h = 0;
 		for (auto image : images)
@@ -116,8 +137,12 @@ namespace GAGCore
 		{
 			image->texture = atlas->texture;
 			image->usingAtlas = true;
+			image->sprite = this;
 			image->setRes(sheetWidth, sheetHeight);
 		}
+		glGenBuffers(1, &vbo);
+		glGenBuffers(1, &texCoordBuffer);
+#endif
 	}
 	
 	DrawableSurface *Sprite::getRotatedSurface(int index)
@@ -159,6 +184,7 @@ namespace GAGCore
 			if (*rotatedIt)
 				delete (*rotatedIt);
 		}
+		delete atlas;
 	}
 	
 	void Sprite::loadFrame(SDL_RWops *frameStream, SDL_RWops *rotatedStream)
diff --git a/src/Game.cpp b/src/Game.cpp
index df3dab5ae..5904dc2bf 100644
--- a/src/Game.cpp
+++ b/src/Game.cpp
@@ -1971,6 +1971,8 @@ inline void Game::drawMapTerrain(int left, int top, int right, int bot, int view
 	Uint32 visibleTeams = teams[localTeam]->me;
 	if (globalContainer->replaying) visibleTeams = globalContainer->replayVisibleTeams;
 
+	Sprite* sprite;
+
 	// we draw the terrains, eventually with debug rects:
 	for (int y=top; y<=bot; y++)
 		for (int x=left; x<=right; x++)
@@ -1985,7 +1987,6 @@ inline void Game::drawMapTerrain(int left, int top, int right, int bot, int view
 			{
 				// draw terrain
 				int id=map.getTerrain(x+viewportX, y+viewportY);
-				Sprite *sprite;
 				if (id<272)
 				{
 					sprite=globalContainer->terrain;
@@ -1999,6 +2000,7 @@ inline void Game::drawMapTerrain(int left, int top, int right, int bot, int view
 				if ((id < 256) || (id >= 256+16))
 					globalContainer->gfx->drawSprite(x<<5, y<<5, sprite, id);
 			}
+	globalContainer->gfx->finishDrawingSprite(globalContainer->terrain, 255);
 }
 
 inline void Game::drawMapRessources(int left, int top, int right, int bot, int viewportX, int viewportY, int localTeam, Uint32 drawOptions)

From e7b66a1d158c16ac0c1208c6e7e8b9565d119a41 Mon Sep 17 00:00:00 2001
From: Nathan Mills <38995150+Quipyowert2@users.noreply.github.com>
Date: Thu, 10 Oct 2024 20:54:37 -0700
Subject: [PATCH 04/13] Inline the initializer lists into vector::insert.

Creating and deleting two std::vectors for every sprite draw during
every frame took a total of 7s over a profiling run of about 3 minutes.

Fix null pointer deref if no sprite or atlas.

Fix terrain drawing in-game.

Fix nothing to draw causing crash in finishDrawingSprite.
---
 libgag/src/GraphicContext.cpp | 66 ++++++++++++++++++++---------------
 src/Game.cpp                  |  1 +
 src/Glob2Screen.cpp           |  1 +
 3 files changed, 40 insertions(+), 28 deletions(-)

diff --git a/libgag/src/GraphicContext.cpp b/libgag/src/GraphicContext.cpp
index 46eb7ddea..2f96b27f7 100644
--- a/libgag/src/GraphicContext.cpp
+++ b/libgag/src/GraphicContext.cpp
@@ -1685,34 +1685,33 @@ namespace GAGCore
 			glState.blendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
 			glState.doBlend(true);
 			glState.doTexture(true);
-			glEnableClientState(GL_VERTEX_ARRAY);
-			glEnableClientState(GL_TEXTURE_COORD_ARRAY);
 			glColor4ub(255, 255, 255, alpha);
 
 			// draw
 			glState.setTexture(surface->texture);
-			std::vector<float> vertices = { x, y, x + w, y, x + w, y + h, x, y + h };
-			std::vector<float> texCoords = { static_cast<float>(sx) * surface->texMultX, static_cast<float>(sy) * surface->texMultY,
-				static_cast<float>(sx + sw) * surface->texMultX, static_cast<float>(sy) * surface->texMultY,
-				static_cast<float>(sx + sw) * surface->texMultX, static_cast<float>(sy + sh) * surface->texMultY,
-				static_cast<float>(sx) * surface->texMultX, static_cast<float>(sy + sh) * surface->texMultY
-			};
-			surface->sprite->vertices.insert(surface->sprite->vertices.end(), vertices.begin(), vertices.end());
-			surface->sprite->texCoords.insert(surface->sprite->texCoords.end(), texCoords.begin(), texCoords.end());
-		    //glDrawElements(GL_QUADS, 4, GL_FLOAT, );
-			/*glBegin(GL_QUADS);
-			glTexCoord2f(static_cast<float>(sx) * surface->texMultX, static_cast<float>(sy) * surface->texMultY);
-			glVertex2f(x, y);
-			glTexCoord2f(static_cast<float>(sx + sw) * surface->texMultX, static_cast<float>(sy) * surface->texMultY);
-			glVertex2f(x+w, y);
-			glTexCoord2f(static_cast<float>(sx + sw) * surface->texMultX, static_cast<float>(sy + sh) * surface->texMultY);
-			glVertex2f(x+w, y+h);
-			glTexCoord2f(static_cast<float>(sx) * surface->texMultX, static_cast<float>(sy + sh) * surface->texMultY);
-			glVertex2f(x, y+h);
-			glEnd();*/
-
-			glDisableClientState(GL_VERTEX_ARRAY);
-			glDisableClientState(GL_TEXTURE_COORD_ARRAY);
+			if (surface->sprite && alpha == Color::ALPHA_OPAQUE)
+			{
+				surface->sprite->vertices.insert(surface->sprite->vertices.end(), { x, y, x + w, y, x + w, y + h, x, y + h });
+				surface->sprite->texCoords.insert(surface->sprite->texCoords.end(), {
+					static_cast<float>(sx) * surface->texMultX, static_cast<float>(sy) * surface->texMultY,
+					static_cast<float>(sx + sw) * surface->texMultX, static_cast<float>(sy) * surface->texMultY,
+					static_cast<float>(sx + sw) * surface->texMultX, static_cast<float>(sy + sh) * surface->texMultY,
+					static_cast<float>(sx) * surface->texMultX, static_cast<float>(sy + sh) * surface->texMultY
+				});
+			}
+			else
+			{
+				glBegin(GL_QUADS);
+				glTexCoord2f(static_cast<float>(sx) * surface->texMultX, static_cast<float>(sy) * surface->texMultY);
+				glVertex2f(x, y);
+				glTexCoord2f(static_cast<float>(sx + sw) * surface->texMultX, static_cast<float>(sy) * surface->texMultY);
+				glVertex2f(x + w, y);
+				glTexCoord2f(static_cast<float>(sx + sw) * surface->texMultX, static_cast<float>(sy + sh) * surface->texMultY);
+				glVertex2f(x + w, y + h);
+				glTexCoord2f(static_cast<float>(sx) * surface->texMultX, static_cast<float>(sy + sh) * surface->texMultY);
+				glVertex2f(x, y + h);
+				glEnd();
+			}
 		}
 		else
 		#endif
@@ -1725,6 +1724,18 @@ namespace GAGCore
 #ifdef HAVE_OPENGL
 		if (_gc->optionFlags & GraphicContext::USEGPU)
 		{
+			if (!sprite->atlas)
+			{
+				// No sprite sheet, so we have nothing to draw.
+				assert(!sprite->vertices.size());
+				assert(!sprite->texCoords.size());
+				return;
+			}
+			if (sprite->vertices.empty() || sprite->texCoords.empty())
+			{
+				// No data.
+				return;
+			}
 			// state change
 			glState.blendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
 			glState.doBlend(true);
@@ -1735,12 +1746,11 @@ namespace GAGCore
 			glState.setTexture(sprite->atlas->texture);
 			glBindBuffer(GL_ARRAY_BUFFER, sprite->vbo);
 			glBufferData(GL_ARRAY_BUFFER, sprite->vertices.size() * sizeof(float), &sprite->vertices[0], GL_STREAM_DRAW);
+			glVertexPointer(2, GL_FLOAT, 0, 0);
 			glBindBuffer(GL_ARRAY_BUFFER, sprite->texCoordBuffer);
 			glBufferData(GL_ARRAY_BUFFER, sprite->texCoords.size() * sizeof(float), &sprite->texCoords[0], GL_STREAM_DRAW);
-
-			glVertexPointer(2, GL_FLOAT, 0, &sprite->vertices[0]);
-			glTexCoordPointer(2, GL_FLOAT, 0, &sprite->texCoords[0]);
-			glDrawArrays(GL_QUADS, 0, sprite->vertices.size() / 4);
+			glTexCoordPointer(2, GL_FLOAT, 0, 0);
+			glDrawArrays(GL_QUADS, 0, sprite->vertices.size() / 2);
 
 			sprite->vertices.clear();
 			sprite->texCoords.clear();
diff --git a/src/Game.cpp b/src/Game.cpp
index 5904dc2bf..d0cd630a7 100644
--- a/src/Game.cpp
+++ b/src/Game.cpp
@@ -2041,6 +2041,7 @@ inline void Game::drawMapRessources(int left, int top, int right, int bot, int v
 					globalContainer->gfx->drawSprite((x<<5)-dx, (y<<5)-dy, sprite, imgid);
 				}
 			}
+	globalContainer->gfx->finishDrawingSprite(globalContainer->ressources, 255);
 }
 
 inline void Game::drawMapGroundUnits(int left, int top, int right, int bot, int sw, int sh, int viewportX, int viewportY, int localTeam, Uint32 drawOptions)
diff --git a/src/Glob2Screen.cpp b/src/Glob2Screen.cpp
index 790ed8f01..18df84270 100644
--- a/src/Glob2Screen.cpp
+++ b/src/Glob2Screen.cpp
@@ -41,6 +41,7 @@ void Glob2Screen::paint(void)
 	for (int y = 0; y < getH(); y += 32)
 		for (int x = 0; x < getW(); x += 32)
 			gfx->drawSprite(x, y, globalContainer->terrain, getNextTerrain());
+	dynamic_cast<GraphicContext*>(gfx)->finishDrawingSprite(globalContainer->terrain, 255);
 
 	if ((globalContainer->settings.optionFlags & GlobalContainer::OPTION_LOW_SPEED_GFX) == 0)
 	{

From bde87da12b91a28659dfdc645edecfdf24c8d0f5 Mon Sep 17 00:00:00 2001
From: Nathan Mills <38995150+Quipyowert2@users.noreply.github.com>
Date: Sat, 25 May 2024 19:25:24 -0700
Subject: [PATCH 05/13] Fixed Boost error I was stuck on for two days.

---
 libusl/src/native.h | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/libusl/src/native.h b/libusl/src/native.h
index 3af05fbfc..876cbf4a3 100644
--- a/libusl/src/native.h
+++ b/libusl/src/native.h
@@ -8,6 +8,7 @@
 
 #include <sstream>
 #include <boost/function.hpp>
+#include <boost/type_traits/function_traits.hpp>
 #include <boost/lambda/lambda.hpp>
 #include <boost/mpl/assert.hpp>
 
@@ -42,7 +43,7 @@ struct NativeValuePrototype: Prototype
 	template<typename Function>
 	void addMethod(const std::string& name, const boost::function<Function>& function)
 	{
-		BOOST_MPL_ASSERT(( boost::is_same<This, typename boost::function<Function>::arg1_type> ));
+		BOOST_MPL_ASSERT(( boost::is_same<This, typename boost::function_traits<Function>::arg1_type> ));
 		NativeCode* native = new NativeFunction<Function>(name, function, true);
 		Prototype::addMethod(native);
 	}

From 4685eaad2d4fb0f7ce076ef77b86a10dbeac0900 Mon Sep 17 00:00:00 2001
From: Nathan Mills <38995150+Quipyowert2@users.noreply.github.com>
Date: Mon, 27 May 2024 11:03:21 -0700
Subject: [PATCH 06/13] Fix loading screen and Settings menu.

Fix water not being drawn.

Fix flags, zones, and building rendering.

Fix fog of war; missing icons when placing building.

Fix brush selection not showing up in flag view.

Draw zone animations.

Fix bullets not showing up.
---
 libgag/src/Sprite.cpp      | 3 ++-
 src/Brush.cpp              | 2 ++
 src/Game.cpp               | 8 ++++++++
 src/GameGUI.cpp            | 2 ++
 src/GameGUIToolManager.cpp | 1 +
 src/Glob2Screen.cpp        | 1 +
 src/GlobalContainer.cpp    | 1 +
 7 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/libgag/src/Sprite.cpp b/libgag/src/Sprite.cpp
index d15d2ae33..4a83bd520 100644
--- a/libgag/src/Sprite.cpp
+++ b/libgag/src/Sprite.cpp
@@ -85,7 +85,8 @@ namespace GAGCore
 				SDL_RWclose(rotatedStream);
 			i++;
 		}
-		if (!images.empty())
+		// TODO: How to cache rotated images?
+		if (!images.empty() && rotated.empty())
 			createTextureAtlas();
 		
 		return getFrameCount() > 0;
diff --git a/src/Brush.cpp b/src/Brush.cpp
index 757994fea..03ded5e9f 100644
--- a/src/Brush.cpp
+++ b/src/Brush.cpp
@@ -47,6 +47,8 @@ void BrushTool::draw(int x, int y)
 		if ((mode != MODE_NONE) && (figure == i))
 			globalContainer->gfx->drawSprite(x+decX, y+decY, globalContainer->gamegui, 22);
 	}
+	globalContainer->gfx->finishDrawingSprite(globalContainer->brush, 255);
+	globalContainer->gfx->finishDrawingSprite(globalContainer->gamegui, 255);
 }
 
 void BrushTool::handleClick(int x, int y)
diff --git a/src/Game.cpp b/src/Game.cpp
index d0cd630a7..7a8fbdad0 100644
--- a/src/Game.cpp
+++ b/src/Game.cpp
@@ -1964,6 +1964,7 @@ inline void Game::drawMapWater(int sw, int sh, int viewportX, int viewportY, int
 	for (int y=waterStartY; y<sh; y += 512)
 		for (int x=waterStartX; x<sw; x += 512)
 			globalContainer->gfx->drawSprite(x, y, globalContainer->terrainWater, 0);
+	globalContainer->gfx->finishDrawingSprite(globalContainer->terrainWater, 255);
 }
 
 inline void Game::drawMapTerrain(int left, int top, int right, int bot, int viewportX, int viewportY, int localTeam, Uint32 drawOptions)
@@ -2226,6 +2227,7 @@ inline void Game::drawMapBuilding(int x, int y, int gid, int viewportX, int view
 
 	// draw building
 	globalContainer->gfx->drawSprite(x+dx, y+dy, buildingSprite, imgid);
+	globalContainer->gfx->finishDrawingSprite(buildingSprite, 255);
 
 	if ((drawOptions & DRAW_BUILDING_RECT) != 0)
 	{
@@ -2459,6 +2461,7 @@ inline void Game::drawMapArea(int left, int top, int right, int bot, int sw,
 			}
 		}
 	}
+	globalContainer->gfx->finishDrawingSprite(sprite, 255);
 }
 
 inline void Game::drawMapAirUnits(int left, int top, int right, int bot, int sw, int sh, int viewportX, int viewportY, int localTeam, Uint32 drawOptions)
@@ -2541,6 +2544,7 @@ inline void Game::drawMapBulletsExplosionsDeathAnimations(int left, int top, int
 				globalContainer->gfx->drawSprite(x+(balisticShift>>1), y, bulletSprite, BULLET_IMGID+1);
 			}
 		}
+		globalContainer->gfx->finishDrawingSprite(bulletSprite, 255);
 		// explosions
 		for (std::list<BulletExplosion *>::iterator it=s->explosions.begin();it!=s->explosions.end();it++)
 		{
@@ -2554,6 +2558,7 @@ inline void Game::drawMapBulletsExplosionsDeathAnimations(int left, int top, int
 				globalContainer->gfx->drawSprite(x+16-decX, y+16-decY, globalContainer->bulletExplosion, frame);
 			}
 		}
+		globalContainer->gfx->finishDrawingSprite(globalContainer->bulletExplosion, 255);
 		// death animations
 		for (std::list<UnitDeathAnimation *>::iterator it=s->deathAnimations.begin();it!=s->deathAnimations.end();++it)
 		{
@@ -2570,6 +2575,7 @@ inline void Game::drawMapBulletsExplosionsDeathAnimations(int left, int top, int
 				globalContainer->gfx->drawSprite(x+16-decX, y+16-decY-frame, globalContainer->deathAnimation, frame);
 			}
 		}
+		globalContainer->gfx->finishDrawingSprite(globalContainer->deathAnimation, 255);
 	}
 }
 
@@ -2621,6 +2627,8 @@ inline void Game::drawMapFogOfWar(int left, int top, int right, int bot, int sw,
 						globalContainer->gfx->drawSprite((x<<5)+16, (y<<5)+16, globalContainer->terrainShader, shadeValue);
 				}
 			}
+		globalContainer->gfx->finishDrawingSprite(globalContainer->terrainBlack, 255);
+		globalContainer->gfx->finishDrawingSprite(globalContainer->terrainShader, 255);
 	}
 }
 
diff --git a/src/GameGUI.cpp b/src/GameGUI.cpp
index 55dfd7e52..cfca77c44 100644
--- a/src/GameGUI.cpp
+++ b/src/GameGUI.cpp
@@ -2744,6 +2744,7 @@ void GameGUI::drawChoice(int pos, std::vector<std::string> &types, std::vector<b
 
 			buildingSprite->setBaseColor(localTeam->color);
 			globalContainer->gfx->drawSprite(x+decX, y+decY, buildingSprite, imgid);
+			globalContainer->gfx->finishDrawingSprite(buildingSprite, 255);
 			
 			globalContainer->gfx->setClipRect();
 			if(hilights.find(HilightBuildingOnPanel+IntBuildingType::shortNumberFromType(type)) != hilights.end())
@@ -3953,6 +3954,7 @@ void GameGUI::drawFlagView(void)
 		int decX = 8 + ((int)toolManager.getZoneType()) * 40 + dec;
 		globalContainer->gfx->drawSprite(globalContainer->gfx->getW()-RIGHT_MENU_WIDTH+decX, YPOS_BASE_FLAG+YOFFSET_BRUSH, globalContainer->gamegui, 22);
 	}
+	globalContainer->gfx->finishDrawingSprite(globalContainer->gamegui, 255);
 	if(hilights.find(HilightForbiddenZoneOnPanel) != hilights.end())
 	{
 		arrowPositions.push_back(HilightArrowPosition(globalContainer->gfx->getW()-RIGHT_MENU_WIDTH-36+8+dec, YPOS_BASE_FLAG+YOFFSET_BRUSH, 38));
diff --git a/src/GameGUIToolManager.cpp b/src/GameGUIToolManager.cpp
index 4074a709d..cef8e3e5e 100644
--- a/src/GameGUIToolManager.cpp
+++ b/src/GameGUIToolManager.cpp
@@ -442,6 +442,7 @@ void GameGUIToolManager::drawBuildingAt(int mapX, int mapY, int localteam, int v
 	sprite->setBaseColor(game.teams[localteam]->color);
 	int spriteIntensity = 127+static_cast<int>(128.0f*splineInterpolation(1.f, 0.f, 1.f, hilightStrength));
 	globalContainer->gfx->drawSprite(batX, batY, sprite, bt->gameSpriteImage, spriteIntensity);
+	globalContainer->gfx->finishDrawingSprite(sprite, spriteIntensity);
 
 	if (!bt->isVirtual)
 	{
diff --git a/src/Glob2Screen.cpp b/src/Glob2Screen.cpp
index 18df84270..7be7afc70 100644
--- a/src/Glob2Screen.cpp
+++ b/src/Glob2Screen.cpp
@@ -82,6 +82,7 @@ void Glob2TabScreen::paint(void)
 	for (int y = 0; y < getH(); y += 32)
 		for (int x = 0; x < getW(); x += 32)
 			gfx->drawSprite(x, y, globalContainer->terrain, getNextTerrain());
+	dynamic_cast<GraphicContext*>(gfx)->finishDrawingSprite(globalContainer->terrain, 255);
 
 	if ((globalContainer->settings.optionFlags & GlobalContainer::OPTION_LOW_SPEED_GFX) == 0)
 	{
diff --git a/src/GlobalContainer.cpp b/src/GlobalContainer.cpp
index a44e2cd52..7ae9d1337 100644
--- a/src/GlobalContainer.cpp
+++ b/src/GlobalContainer.cpp
@@ -500,6 +500,7 @@ void GlobalContainer::updateLoadProgressScreen(int value)
 				index = ((randomSeed >> 16) & 0xF) + 128;
 			gfx->drawSprite(x, y, terrain, index);
 		}
+	gfx->finishDrawingSprite(terrain, 255);
 	//gfx->drawFilledRect(0, 0, gfx->getW(), gfx->getH(), Color::black);
 	gfx->drawSurface((gfx->getW()-title->getW())>>1, (gfx->getH()-title->getH())>>1, title);
 	//gfx->drawFilledRect(((gfx->getW()-400)>>1), (gfx->getH()>>1)+11+180, (value)<<2, 20, 10, 50, 255, 80);

From f6c0f8875339c3ca1ebfa32dd8ca2a05f15f0d0d Mon Sep 17 00:00:00 2001
From: Nathan Mills <38995150+Quipyowert2@users.noreply.github.com>
Date: Fri, 7 Jun 2024 09:44:14 -0700
Subject: [PATCH 07/13] Use Epoxy so that we can access OpenGL 2 functions.

---
 libgag/src/GraphicContext.cpp |  6 ++++++
 libgag/src/Sprite.cpp         | 16 +++++++-------
 vcpkg.json                    | 39 ++++++++++++++++++-----------------
 3 files changed, 34 insertions(+), 27 deletions(-)

diff --git a/libgag/src/GraphicContext.cpp b/libgag/src/GraphicContext.cpp
index 2f96b27f7..cd10d897a 100644
--- a/libgag/src/GraphicContext.cpp
+++ b/libgag/src/GraphicContext.cpp
@@ -25,6 +25,12 @@
 #include <string>
 #include <sstream>
 #include <iostream>
+#include <epoxy/gl.h>
+#ifdef _MSC_VER
+#include <epoxy/wgl.h>
+#else
+#include <epoxy/glx.h>
+#endif
 #include "SDL_ttf.h"
 #include <SDL_image.h>
 #include <math.h>
diff --git a/libgag/src/Sprite.cpp b/libgag/src/Sprite.cpp
index 4a83bd520..a37a7bb7e 100644
--- a/libgag/src/Sprite.cpp
+++ b/libgag/src/Sprite.cpp
@@ -35,14 +35,14 @@
 #include <OpenGL/glu.h>
 #define GL_TEXTURE_RECTANGLE_NV GL_TEXTURE_RECTANGLE_EXT
 #else
-#include <GL/gl.h>
-#include <GL/glu.h>
-#endif
-#endif
-
-#ifdef WIN32
-#include <GL/glext.h>
-#endif
+#include <epoxy/gl.h>
+#ifdef _MSC_VER
+#include <epoxy/wgl.h>
+#else
+#include <epoxy/glx.h>
+#endif // _MSC_VER
+#endif // defined(__APPLE__)
+#endif // ifdef HAVE_OPENGL
 
 
 namespace GAGCore
diff --git a/vcpkg.json b/vcpkg.json
index 46727ce93..b9b38ff00 100644
--- a/vcpkg.json
+++ b/vcpkg.json
@@ -3,23 +3,24 @@
   "name": "globulation2",
   "license": "GPL-3.0",
   "version": "0.9.5.0",
-    "dependencies": [
-      "sdl2",
-      "sdl2-net",
-      "sdl2-ttf",
-      "sdl2-image",
-      "zlib",
-      "fribidi",
-      "libogg",
-      "libvorbis",
-      "boost-math",
-      "boost-thread",
-      "boost-date-time",
-      "boost-random",
-      "boost-logic",
-      "boost-lambda",
-      "speex",
-      "opengl",
-      "pcre"
-    ]
+  "dependencies": [
+    "sdl2",
+    "sdl2-net",
+    "sdl2-ttf",
+    "sdl2-image",
+    "zlib",
+    "fribidi",
+    "libogg",
+    "libvorbis",
+    "boost-math",
+    "boost-thread",
+    "boost-date-time",
+    "boost-random",
+    "boost-logic",
+    "boost-lambda",
+    "speex",
+    "opengl",
+    "libepoxy",
+    "pcre"
+  ]
 }

From 0dbb307ae82da5fb5dce7224f5310106a888da5c Mon Sep 17 00:00:00 2001
From: Nathan Mills <38995150+Quipyowert2@users.noreply.github.com>
Date: Fri, 7 Jun 2024 15:50:27 -0700
Subject: [PATCH 08/13] Add Epoxy to Debian build dependencies.

---
 debian/control | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/debian/control b/debian/control
index 8d254ee57..77571b1ff 100644
--- a/debian/control
+++ b/debian/control
@@ -2,7 +2,7 @@ Source: glob2
 Section: games
 Priority: optional
 Maintainer: Stephane Magnenat <stephane at magnenat dot net>
-Build-Depends: debhelper (>> 6.0.0), quilt (>= 0.40), scons, libsdl2-dev (>=2.0.0), libsdl2-image-dev (>=2.0.0), libsdl2-net-dev (>=2.0.0), libsdl2-ttf-dev, libglu1-mesa-dev | libglu-dev, libvorbis-dev, libspeex-dev, libfreetype6-dev, libboost-dev, libboost-thread-dev, libboost-date-time-dev, libfribidi-dev, portaudio19-dev, libboost-math-dev
+Build-Depends: debhelper (>> 6.0.0), quilt (>= 0.40), scons, libsdl2-dev (>=2.0.0), libsdl2-image-dev (>=2.0.0), libsdl2-net-dev (>=2.0.0), libsdl2-ttf-dev, libglu1-mesa-dev | libglu-dev, libvorbis-dev, libspeex-dev, libfreetype6-dev, libboost-dev, libboost-thread-dev, libboost-date-time-dev, libfribidi-dev, portaudio19-dev, libboost-math-dev, libepoxy-dev
 Standards-Version: 3.8.1
 Homepage: http://globulation2.org
 

From 3cb04f46e9e4204dc2606639954ca6129d94ed80 Mon Sep 17 00:00:00 2001
From: Nathan Mills <38995150+Quipyowert2@users.noreply.github.com>
Date: Sat, 8 Jun 2024 13:39:35 -0700
Subject: [PATCH 09/13] Look for epoxy in SConstruct.

Link against Epoxy.
---
 SConstruct | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/SConstruct b/SConstruct
index 8476b3a46..e6ac52ec0 100644
--- a/SConstruct
+++ b/SConstruct
@@ -193,6 +193,13 @@ def configure(env, server_only):
         configfile.add("HAVE_OPENGL ", "Defined when OpenGL support is present and compiled")
         env.Append(LIBS=gl_libraries)
     
+    if not server_only:
+        if conf.CheckLib('epoxy') and conf.CheckCXXHeader('epoxy/gl.h'):
+            env.Append(LIBS=["epoxy"])
+        else:
+            print("Could not find epoxy/gl.h")
+            missing.append("epoxy")
+
     #Do checks for fribidi
     if not server_only and conf.CheckLib('fribidi') and conf.CheckCXXHeader('fribidi/fribidi.h'):
         configfile.add("HAVE_FRIBIDI ", "Defined when FRIBIDI support is present and compiled")

From ba5177a5b192b9fd2ca74ce066e0ef4522f58d07 Mon Sep 17 00:00:00 2001
From: Nathan Mills <38995150+Quipyowert2@users.noreply.github.com>
Date: Thu, 27 Jun 2024 20:12:03 -0700
Subject: [PATCH 10/13] Check that we have at least one non-NULL image.

If all the images in the array are NULL, we don't need to create a
texture atlas/sprite sheet.
---
 libgag/src/Sprite.cpp | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/libgag/src/Sprite.cpp b/libgag/src/Sprite.cpp
index a37a7bb7e..2b7b8f5e6 100644
--- a/libgag/src/Sprite.cpp
+++ b/libgag/src/Sprite.cpp
@@ -86,8 +86,10 @@ namespace GAGCore
 			i++;
 		}
 		// TODO: How to cache rotated images?
-		if (!images.empty() && rotated.empty())
+		if (std::any_of(images.begin(), images.end(), [](DrawableSurface *s) {return s != nullptr; }))
+		{
 			createTextureAtlas();
+		}
 		
 		return getFrameCount() > 0;
 	}
@@ -114,8 +116,8 @@ namespace GAGCore
 		}
 		int tileWidth = images[0]->getW();
 		int tileHeight = images[0]->getH();
-		int sheetWidth = tileWidth * (sqrt(numImages) + 1);
-		int sheetHeight = tileHeight * (sqrt(numImages) + 1);
+		int sheetWidth = tileWidth * (static_cast<int>(sqrt(numImages)) + 1);
+		int sheetHeight = tileHeight * (static_cast<int>(sqrt(numImages)) + 1);
 		atlas = new DrawableSurface(sheetWidth, sheetHeight);
 		int x = 0, y = 0;
 		for (auto image: images)

From 01151a83347af3f84430221008e62389b53a5c1a Mon Sep 17 00:00:00 2001
From: Nathan Mills <38995150+Quipyowert2@users.noreply.github.com>
Date: Mon, 29 Jul 2024 21:05:12 -0700
Subject: [PATCH 11/13] Make createTextureAtlas more exception-safe.

Changes Sprite::atlas variable to be a unique_ptr and adds a bunch of
preprocessor macros to find the right make_unique for the C++ and Boost
version.
---
 libgag/include/SDLGraphicContext.h |  2 +-
 libgag/src/Sprite.cpp              | 19 +++++++++++++++++--
 2 files changed, 18 insertions(+), 3 deletions(-)

diff --git a/libgag/include/SDLGraphicContext.h b/libgag/include/SDLGraphicContext.h
index bcec7e4a8..5b8dedbd7 100644
--- a/libgag/include/SDLGraphicContext.h
+++ b/libgag/include/SDLGraphicContext.h
@@ -441,7 +441,7 @@ namespace GAGCore
 		std::vector <float> texCoords;
 		unsigned int vbo;
 		unsigned int texCoordBuffer;
-		DrawableSurface *atlas = nullptr;
+		std::unique_ptr<DrawableSurface> atlas = nullptr;
 #endif
 		Color actColor;
 	
diff --git a/libgag/src/Sprite.cpp b/libgag/src/Sprite.cpp
index 2b7b8f5e6..efb8529c5 100644
--- a/libgag/src/Sprite.cpp
+++ b/libgag/src/Sprite.cpp
@@ -27,6 +27,22 @@
 #include <iostream>
 #include <sstream>
 
+#if __cplusplus >= 201402L
+#include <memory>
+using std::make_unique;
+#else
+#if BOOST_VERSION >= 107500
+#include <boost/smart_ptr/make_unique.hpp>
+#elif BOOST_VERSION >= 106300
+#include <boost/make_unique.hpp>
+#elif BOOST_VERSION >= 105700
+#include <boost/move/make_unique.hpp>
+#else
+#error "Can't make_unique when there's no Boost and C++ standard is earlier than C++14"
+#endif
+using boost::make_unique;
+#endif // __cplusplus
+
 #define GL_GLEXT_PROTOTYPES
 #ifdef HAVE_OPENGL
 #if defined(__APPLE__) || defined(OPENGL_HEADER_DIRECTORY_OPENGL)
@@ -118,7 +134,7 @@ namespace GAGCore
 		int tileHeight = images[0]->getH();
 		int sheetWidth = tileWidth * (static_cast<int>(sqrt(numImages)) + 1);
 		int sheetHeight = tileHeight * (static_cast<int>(sqrt(numImages)) + 1);
-		atlas = new DrawableSurface(sheetWidth, sheetHeight);
+		atlas = make_unique<DrawableSurface>(sheetWidth, sheetHeight);
 		int x = 0, y = 0;
 		for (auto image: images)
 		{
@@ -187,7 +203,6 @@ namespace GAGCore
 			if (*rotatedIt)
 				delete (*rotatedIt);
 		}
-		delete atlas;
 	}
 	
 	void Sprite::loadFrame(SDL_RWops *frameStream, SDL_RWops *rotatedStream)

From 5a340b2bcfe0510523c4ea364da6bbe2d586c2e4 Mon Sep 17 00:00:00 2001
From: Nathan Mills <38995150+Quipyowert2@users.noreply.github.com>
Date: Wed, 9 Oct 2024 20:15:21 -0700
Subject: [PATCH 12/13] Remove unnecessary usingAtlas boolean.

---
 libgag/include/SDLGraphicContext.h | 11 +++++------
 libgag/src/GraphicContext.cpp      |  4 ++--
 libgag/src/Sprite.cpp              |  1 -
 3 files changed, 7 insertions(+), 9 deletions(-)

diff --git a/libgag/include/SDLGraphicContext.h b/libgag/include/SDLGraphicContext.h
index 5b8dedbd7..cc6ad107d 100644
--- a/libgag/include/SDLGraphicContext.h
+++ b/libgag/include/SDLGraphicContext.h
@@ -172,10 +172,9 @@ namespace GAGCore
 		//! sprite sheet coordinates
 		int texX = 0;
 		int texY = 0;
-		//! width and height if using atlas
-		int w;
-		int h;
-		bool usingAtlas = false;
+		//! width and height of this tile if using atlas
+		int w = 0;
+		int h = 0;
 		//! texture divisor
 		float texMultX, texMultY;
 		
@@ -219,8 +218,8 @@ namespace GAGCore
 		virtual void shiftHSV(float hue, float sat, float lum);
 		
 		// accessors
-		virtual int getW(void) { if (usingAtlas && w) return w; return sdlsurface->w; }
-		virtual int getH(void) { if (usingAtlas && h) return h; return sdlsurface->h; }
+		virtual int getW(void) { if (sprite) return w; return sdlsurface->w; }
+		virtual int getH(void) { if (sprite) return h; return sdlsurface->h; }
 		
 		// capability querying
 		virtual bool canDrawStretchedSprite(void) { return false; }
diff --git a/libgag/src/GraphicContext.cpp b/libgag/src/GraphicContext.cpp
index cd10d897a..221ef2e0b 100644
--- a/libgag/src/GraphicContext.cpp
+++ b/libgag/src/GraphicContext.cpp
@@ -310,7 +310,7 @@ namespace GAGCore
 	void DrawableSurface::allocateTexture(void)
 	{
 		#ifdef HAVE_OPENGL
-		if (usingAtlas)
+		if (sprite)
 			return;
 		if (_gc->optionFlags & GraphicContext::USEGPU)
 		{
@@ -354,7 +354,7 @@ namespace GAGCore
 	void DrawableSurface::uploadToTexture(void)
 	{
 		#ifdef HAVE_OPENGL
-		if (usingAtlas)
+		if (sprite)
 		{
 			return;
 		}
diff --git a/libgag/src/Sprite.cpp b/libgag/src/Sprite.cpp
index efb8529c5..ffbec675d 100644
--- a/libgag/src/Sprite.cpp
+++ b/libgag/src/Sprite.cpp
@@ -155,7 +155,6 @@ namespace GAGCore
 		for (auto image : images)
 		{
 			image->texture = atlas->texture;
-			image->usingAtlas = true;
 			image->sprite = this;
 			image->setRes(sheetWidth, sheetHeight);
 		}

From 0dfc8bdc47e621cb67b84df6214bce8e930564e6 Mon Sep 17 00:00:00 2001
From: Nathan Mills <38995150+Quipyowert2@users.noreply.github.com>
Date: Thu, 10 Oct 2024 19:55:33 -0700
Subject: [PATCH 13/13] Prevent drawing on atlas once generated by making it
 readonly.

---
 libgag/include/SDLGraphicContext.h | 2 +-
 libgag/src/Sprite.cpp              | 3 ++-
 2 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/libgag/include/SDLGraphicContext.h b/libgag/include/SDLGraphicContext.h
index cc6ad107d..2c42a2fb8 100644
--- a/libgag/include/SDLGraphicContext.h
+++ b/libgag/include/SDLGraphicContext.h
@@ -440,7 +440,7 @@ namespace GAGCore
 		std::vector <float> texCoords;
 		unsigned int vbo;
 		unsigned int texCoordBuffer;
-		std::unique_ptr<DrawableSurface> atlas = nullptr;
+		std::unique_ptr<const DrawableSurface> atlas = nullptr;
 #endif
 		Color actColor;
 	
diff --git a/libgag/src/Sprite.cpp b/libgag/src/Sprite.cpp
index ffbec675d..6cdef83a7 100644
--- a/libgag/src/Sprite.cpp
+++ b/libgag/src/Sprite.cpp
@@ -134,7 +134,7 @@ namespace GAGCore
 		int tileHeight = images[0]->getH();
 		int sheetWidth = tileWidth * (static_cast<int>(sqrt(numImages)) + 1);
 		int sheetHeight = tileHeight * (static_cast<int>(sqrt(numImages)) + 1);
-		atlas = make_unique<DrawableSurface>(sheetWidth, sheetHeight);
+		std::unique_ptr<DrawableSurface> atlas = make_unique<DrawableSurface>(sheetWidth, sheetHeight);
 		int x = 0, y = 0;
 		for (auto image: images)
 		{
@@ -158,6 +158,7 @@ namespace GAGCore
 			image->sprite = this;
 			image->setRes(sheetWidth, sheetHeight);
 		}
+		this->atlas = std::move(atlas);
 		glGenBuffers(1, &vbo);
 		glGenBuffers(1, &texCoordBuffer);
 #endif