Load sprite sheet into new atlas structure

src/AssetManager.c

@@ -117,7 +117,7 @@ const i32 asset_loadTextureImage(AssetManager *assetManager,
 	if (imgWidth != imgHeight)
 	{
 		printf(
-		    "worldTraveller_gameInit() warning: Sprite sheet is not square: "
+		    "asset_loadTextureImage() warning: Sprite sheet is not square: "
 		    "%dx%dpx\n", imgWidth, imgHeight);
 	}
 #endif

src/Common.c

@@ -21,6 +21,16 @@ i32 common_strcmp(const char *a, const char *b)
 	return ((*a < *b) ? -1 : 1);
 }
 
+void common_strncat(char *dest, const char *src, i32 numChars)
+{
+	char *stringPtr = dest;
+	while (*stringPtr)
+		stringPtr++;
+
+	for (i32 i = 0; i < numChars; i++)
+		*(stringPtr++) = src[i];
+}
+
 char *common_strncpy(char *dest, const char *src, i32 numChars)
 {
 	for (i32 i = 0; i < numChars; i++)
@@ -112,3 +122,54 @@ i32 common_atoi(const char *string, const i32 len)
 
 	return result;
 }
+
+u32 common_murmurHash2(const void *key, i32 len, u32 seed)
+{
+	// 'm' and 'r' are mixing constants generated offline.
+	// They're not really 'magic', they just happen to work well.
+
+	const u32 m = 0x5bd1e995;
+	const i32 r = 24;
+
+	// Initialize the hash to a 'random' value
+
+	u32 h = seed ^ len;
+
+	// Mix 4 bytes at a time into the hash
+
+	const unsigned char * data = (const unsigned char *)key;
+
+	while(len >= 4)
+	{
+		u32 k = *(u32 *)data;
+
+		k *= m;
+		k ^= k >> r;
+		k *= m;
+		
+		h *= m;
+		h ^= k;
+
+		data += 4;
+		len -= 4;
+	}
+	
+	// Handle the last few bytes of the input array
+
+	switch(len)
+	{
+	case 3: h ^= data[2] << 16;
+	case 2: h ^= data[1] << 8;
+	case 1: h ^= data[0];
+	        h *= m;
+	};
+
+	// Do a few final mixes of the hash to ensure the last few
+	// bytes are well-incorporated.
+
+	h ^= h >> 13;
+	h *= m;
+	h ^= h >> 15;
+
+	return h;
+} 

src/WorldTraveller.c

@@ -289,9 +289,17 @@ INTERNAL void assetInit(GameState *state)
 	XmlNode root = {0};
 	XmlNode *node = &root;
 	node->parent  = node;
+
+	// NOTE(doyle): Used for when closing a node with many children. We
+	// automatically assign the next child after each child close within
+	// a group. Hence on the last child, we open another node but the next
+	// token indicates the group is closing- we need to set the last child's
+	// next reference to NULL
+	XmlNode *prevNode = NULL;
 	for (i32 i = 0; i < tokenIndex; i++)
 	{
 		XmlToken *token = &xmlTokens[i];
+
 		switch (token->type)
 		{
 
@@ -305,7 +313,16 @@ INTERNAL void assetInit(GameState *state)
 				if (common_strcmp(nextToken->string, node->parent->name) == 0)
 				{
 					node->parent->isClosed = TRUE;
-					node                   = node->parent;
+
+					if (prevNode)
+					{
+						prevNode->next = NULL;
+					}
+
+					XmlNode *parent = node->parent;
+					PLATFORM_MEM_FREE(arena, node, sizeof(XmlNode));
+
+					node            = node->parent;
 				}
 				else
 				{
@@ -360,6 +377,7 @@ INTERNAL void assetInit(GameState *state)
 		case xmltokentype_closeArrow:
 		{
 			XmlToken prevToken = xmlTokens[i - 1];
+			prevNode = node;
 
 			/* Closed node means we can return to parent */
 			if (prevToken.type == xmltokentype_backslash)
@@ -402,6 +420,9 @@ INTERNAL void assetInit(GameState *state)
 		}
 	}
 
+// TODO(doyle): Use a proper random seed
+#define RANDOM_SEED 0xDEADBEEF
+
 #if 1
 	DEBUG_RECURSIVE_PRINT_XML_TREE(&root);
 #endif
@@ -411,73 +432,164 @@ INTERNAL void assetInit(GameState *state)
 	{
 		if(common_strcmp(node->name, "TextureAtlas") == 0)
 		{
-			XmlNode *atlasXmlNode   = node;
-			XmlNode *atlasChildNode = atlasXmlNode->child;
-			while (atlasChildNode)
+			XmlNode *atlasXmlNode     = node;
+			TexAtlasEntry *atlasEntry = NULL;
+			if (common_strcmp(node->attribute.name, "imagePath") == 0)
 			{
-				if (common_strcmp(atlasChildNode->name, "SubTexture") == 0)
+				char *imageName = atlasXmlNode->attribute.value;
+				u32 atlasHashIndex = common_murmurHash2(
+				    imageName, common_strlen(imageName), RANDOM_SEED);
+				atlasHashIndex =
+				    atlasHashIndex % ARRAY_COUNT(assetManager->texAtlas_);
+
+				atlasEntry = &assetManager->texAtlas_[atlasHashIndex];
+				if (atlasEntry->name)
 				{
-					XmlAttribute *subTextureAttrib = &atlasChildNode->attribute;
-					while (subTextureAttrib)
+#ifdef DENGINE_DEBUG
+
+					// NOTE(doyle): Two atlas textures have the same access name
+					ASSERT(common_strcmp(atlasEntry->name, imageName) != 0);
+#endif
+
+					while (atlasEntry->next)
+						atlasEntry = atlasEntry->next;
+
+					atlasEntry->next =
+					    PLATFORM_MEM_ALLOC(arena, 1, TexAtlasEntry);
+					atlasEntry       = atlasEntry->next;
+				}
+
+				char *dataDir = "data/textures/WorldTraveller/";
+				char imagePath[512] = {0};
+				common_strncat(imagePath, dataDir, common_strlen(dataDir));
+				common_strncat(imagePath, imageName, common_strlen(imageName));
+
+				asset_loadTextureImage(assetManager, imagePath, texlist_claude);
+
+				atlasEntry->name =
+				    PLATFORM_MEM_ALLOC(arena, common_strlen(imageName), char);
+				common_strncpy(atlasEntry->name, imageName,
+				               common_strlen(imageName));
+
+				atlasEntry->tex =
+				    asset_getTexture(assetManager, texlist_claude);
+
+				XmlNode *atlasChildNode = atlasXmlNode->child;
+				while (atlasChildNode)
+				{
+					if (common_strcmp(atlasChildNode->name, "SubTexture") == 0)
 					{
-						// TODO(doyle): Fill in details properly
-						Rect rect = {0};
+						XmlAttribute *subTextureAttrib =
+						    &atlasChildNode->attribute;
 
-						// TODO(doyle): Work around for now in xml reading,
-						// reading the last node closing node not being merged
-						// to the parent
-						if (!subTextureAttrib->name) continue;
+						AtlasSubTexture newSubTexEntry = {0};
+						while (subTextureAttrib)
+						{
 
-						if (common_strcmp(subTextureAttrib->name, "name") == 0)
-						{
+							// TODO(doyle): Work around for now in xml reading,
+							// reading the last node closing node not being
+							// merged to the parent
+							if (!subTextureAttrib->name) continue;
+
+							if (common_strcmp(subTextureAttrib->name, "name") ==
+							    0)
+							{
+								char *value   = subTextureAttrib->value;
+								newSubTexEntry.name = value;
+							}
+							else if (common_strcmp(subTextureAttrib->name,
+							                       "x") == 0)
+							{
+								char *value  = subTextureAttrib->value;
+								i32 valueLen = common_strlen(value);
+								newSubTexEntry.rect.pos.x =
+								    CAST(f32) common_atoi(value, valueLen);
+							}
+							else if (common_strcmp(subTextureAttrib->name,
+							                       "y") == 0)
+							{
+								char *value  = subTextureAttrib->value;
+								i32 valueLen = common_strlen(value);
+								newSubTexEntry.rect.pos.y =
+								    CAST(f32) common_atoi(value, valueLen);
+							}
+							else if (common_strcmp(subTextureAttrib->name,
+							                       "width") == 0)
+							{
+								char *value  = subTextureAttrib->value;
+								i32 valueLen = common_strlen(value);
+								newSubTexEntry.rect.size.w =
+								    CAST(f32) common_atoi(value, valueLen);
+							}
+							else if (common_strcmp(subTextureAttrib->name,
+							                       "height") == 0)
+							{
+								char *value  = subTextureAttrib->value;
+								i32 valueLen = common_strlen(value);
+								newSubTexEntry.rect.size.h =
+								    CAST(f32) common_atoi(value, valueLen);
+							}
+							else
+							{
+#ifdef DENGINE_DEBUG
+								DEBUG_LOG(
+								    "Unsupported xml attribute in SubTexture");
+#endif
+							}
+
+							subTextureAttrib = subTextureAttrib->next;
 						}
-						else if (common_strcmp(subTextureAttrib->name, "x") ==
-						         0)
-						{
-							char *name  = subTextureAttrib->name;
-							i32 nameLen = common_strlen(name);
-							rect.pos.x  = CAST(f32) common_atoi(name, nameLen);
-						}
-						else if (common_strcmp(subTextureAttrib->name, "y") ==
-						         0)
-						{
-							char *name  = subTextureAttrib->name;
-							i32 nameLen = common_strlen(name);
-							rect.pos.y  = CAST(f32) common_atoi(name, nameLen);
-						}
-						else if (common_strcmp(subTextureAttrib->name,
-						                       "width") == 0)
-						{
-							char *name  = subTextureAttrib->name;
-							i32 nameLen = common_strlen(name);
-							rect.size.w = CAST(f32) common_atoi(name, nameLen);
-						}
-						else if (common_strcmp(subTextureAttrib->name,
-						                       "height") == 0)
-						{
-							char *name  = subTextureAttrib->name;
-							i32 nameLen = common_strlen(name);
-							rect.size.h = CAST(f32) common_atoi(name, nameLen);
-						}
-						else
+
+#ifdef DENGINE_DEBUG
+						ASSERT(newSubTexEntry.name)
+#endif
+
+
+						u32 subTexHashIndex = common_murmurHash2(
+						    newSubTexEntry.name, common_strlen(newSubTexEntry.name),
+						    RANDOM_SEED);
+						subTexHashIndex =
+						    subTexHashIndex % ARRAY_COUNT(atlasEntry->subTex);
+
+						// NOTE(doyle): Hash collision
+						AtlasSubTexture *subTexEntry =
+						    &atlasEntry->subTex[subTexHashIndex];
+						if (subTexEntry->name)
 						{
 #ifdef DENGINE_DEBUG
-							DEBUG_LOG(
-							    "Unsupported xml attribute in SubTexture");
+
+							// NOTE(doyle): Two textures have the same access
+							// name
+							ASSERT(common_strcmp(subTexEntry->name,
+							                     newSubTexEntry.name) != 0);
 #endif
+							while (subTexEntry->next)
+								subTexEntry = subTexEntry->next;
+
+							subTexEntry->next =
+							    PLATFORM_MEM_ALLOC(arena, 1, AtlasSubTexture);
+							subTexEntry = subTexEntry->next;
 						}
 
-						subTextureAttrib = subTextureAttrib->next;
+						*subTexEntry = newSubTexEntry;
+						common_strncpy(subTexEntry->name, newSubTexEntry.name,
+						               common_strlen(newSubTexEntry.name));
 					}
-				}
-				else
-				{
+					else
+					{
 #ifdef DENGINE_DEBUG
-					DEBUG_LOG("Unsupported xml node name not parsed");
+						DEBUG_LOG("Unsupported xml node name not parsed");
 #endif
-				}
+					}
 
-				atlasChildNode = atlasChildNode->next;
+					atlasChildNode = atlasChildNode->next;
+				}
+			}
+			else
+			{
+#ifdef DENGINE_DEBUG
+				DEBUG_LOG("Unsupported xml node");
+#endif
 			}
 		}
 		else
@@ -486,7 +598,6 @@ INTERNAL void assetInit(GameState *state)
 			DEBUG_LOG("Unsupported xml node name not parsed");
 #endif
 		}
-
 		node = node->next;
 	}
 

src/include/Dengine/AssetManager.h

@@ -16,6 +16,8 @@ typedef struct AssetManager
 	Animation anims[32];
 	AudioVorbis audio[32];
 	Font font;
+
+	TexAtlasEntry texAtlas_[8];
 } AssetManager;
 
 #define MAX_TEXTURE_SIZE 1024

src/include/Dengine/Assets.h

@@ -81,6 +81,25 @@ typedef struct AudioVorbis
 	i32 size;
 } AudioVorbis;
 
+typedef struct AtlasSubTexture
+{
+	char *name;
+	Rect rect;
+	
+	// NOTE(doyle): For hashing collisions
+	struct AtlasSubTexture *next;
+} AtlasSubTexture;
+
+typedef struct TexAtlasEntry
+{
+	char *name;
+	Texture *tex;
+	AtlasSubTexture subTex[1024];
+
+	// NOTE(doyle): For hashing collisions
+	struct TexAtlasEntry *next;
+} TexAtlasEntry;
+
 typedef struct TexAtlas
 {
 	// TODO(doyle): String hash based lookup

src/include/Dengine/Common.h

@@ -30,6 +30,7 @@ typedef double f64;
 
 i32 common_strlen(const char *const string);
 i32 common_strcmp(const char *a, const char *b);
+void common_strncat(char *dest, const char *src, i32 numChars);
 char *common_strncpy(char *dest, const char *src, i32 numChars);
 char *common_memset(char *const ptr, const i32 value, const i32 numBytes);
 
@@ -37,4 +38,20 @@ char *common_memset(char *const ptr, const i32 value, const i32 numBytes);
 void common_itoa(i32 value, char *buf, i32 bufSize);
 i32 common_atoi(const char *string, const i32 len);
 
+
+//-----------------------------------------------------------------------------
+// MurmurHash2, by Austin Appleby
+
+// Note - This code makes a few assumptions about how your machine behaves -
+
+// 1. We can read a 4-byte value from any address without crashing
+// 2. sizeof(int) == 4
+
+// And it has a few limitations -
+
+// 1. It will not work incrementally.
+// 2. It will not produce the same results on little-endian and big-endian
+//    machines.
+u32 common_murmurHash2(const void *key, i32 len, u32 seed);
+
 #endif