Working on UI part

src/render/TextureManager.cpp

@@ -8,9 +8,68 @@
 namespace ZL
 {
 
+	bool IsPowerOf2(size_t n) {
+		return n > 0 && (n & (n - 1)) == 0;
+	}
+
+	size_t NextPowerOf2(size_t n) {
+		if (n == 0) return 1;
+		--n;
+		n |= n >> 1; n |= n >> 2; n |= n >> 4; n |= n >> 8; n |= n >> 16;
+#if SIZE_MAX > 0xFFFFFFFF
+		n |= n >> 32;
+#endif
+		return n + 1;
+	}
+
+	TextureDataStruct ResizeTextureDataToPOT(const TextureDataStruct& src) {
+		size_t newW = IsPowerOf2(src.width)  ? src.width  : NextPowerOf2(src.width);
+		size_t newH = IsPowerOf2(src.height) ? src.height : NextPowerOf2(src.height);
+		if (newW == src.width && newH == src.height) return src;
+
+		int channels = (src.format == TextureDataStruct::R8)  ? 1
+		             : (src.format == TextureDataStruct::RGB) ? 3 : 4;
+
+		TextureDataStruct dst = src;
+		dst.width  = newW;
+		dst.height = newH;
+		dst.data.resize(newW * newH * channels);
+
+		for (size_t y = 0; y < newH; ++y) {
+			for (size_t x = 0; x < newW; ++x) {
+				float fx = (newW > 1) ? (float)x * (float)(src.width  - 1) / (float)(newW  - 1) : 0.f;
+				float fy = (newH > 1) ? (float)y * (float)(src.height - 1) / (float)(newH - 1) : 0.f;
+				size_t x0 = (size_t)fx, y0 = (size_t)fy;
+				size_t x1 = min(x0 + 1, src.width  - 1);
+				size_t y1 = min(y0 + 1, src.height - 1);
+				float tx = fx - (float)x0, ty = fy - (float)y0;
+				for (int c = 0; c < channels; ++c) {
+					float v00 = (float)(unsigned char)src.data[(y0 * src.width + x0) * channels + c];
+					float v10 = (float)(unsigned char)src.data[(y0 * src.width + x1) * channels + c];
+					float v01 = (float)(unsigned char)src.data[(y1 * src.width + x0) * channels + c];
+					float v11 = (float)(unsigned char)src.data[(y1 * src.width + x1) * channels + c];
+					float val = v00 * (1.f - tx) * (1.f - ty) + v10 * tx * (1.f - ty)
+					          + v01 * (1.f - tx) * ty          + v11 * tx * ty;
+					dst.data[(y * newW + x) * channels + c] = (char)(unsigned char)(val + 0.5f);
+				}
+			}
+		}
+		std::cout << "TextureManager: resized texture from "
+		          << src.width << "x" << src.height
+		          << " to " << newW << "x" << newH << " (POT)" << std::endl;
+		return dst;
+	}
+
 	Texture::Texture(const TextureDataStruct& texData) {
 		width = texData.width;
 		height = texData.height;
+
+		if (!IsPowerOf2(width) || !IsPowerOf2(height)) {
+			std::cerr << "TextureManager WARNING: non-POT texture "
+			          << width << "x" << height
+			          << " — upload may fail on some platforms." << std::endl;
+		}
+
 		glGenTextures(1, &texID);
 		glBindTexture(GL_TEXTURE_2D, texID);
 
@@ -422,36 +481,42 @@ namespace ZL
 		return zipFile.empty() ? fileName : fileName + "|" + zipFile;
 	}
 
-	std::shared_ptr<Texture> TextureManager::LoadFromBmp24(const std::string& fileName, const std::string& zipFile)
+	std::shared_ptr<Texture> TextureManager::LoadFromBmp24(const std::string& fileName, const std::string& zipFile, bool resizeToPOT)
 	{
 		std::string key = MakeKey(fileName, zipFile);
 		auto it = textureMap.find(key);
 		if (it != textureMap.end())
 			return it->second;
-		auto tex = std::make_shared<Texture>(CreateTextureDataFromBmp24(fileName, zipFile));
+		auto data = CreateTextureDataFromBmp24(fileName, zipFile);
+		if (resizeToPOT) data = ResizeTextureDataToPOT(data);
+		auto tex = std::make_shared<Texture>(data);
 		textureMap[key] = tex;
 		return tex;
 	}
 
-	std::shared_ptr<Texture> TextureManager::LoadFromBmp32(const std::string& fileName, const std::string& zipFile)
+	std::shared_ptr<Texture> TextureManager::LoadFromBmp32(const std::string& fileName, const std::string& zipFile, bool resizeToPOT)
 	{
 		std::string key = MakeKey(fileName, zipFile);
 		auto it = textureMap.find(key);
 		if (it != textureMap.end())
 			return it->second;
-		auto tex = std::make_shared<Texture>(CreateTextureDataFromBmp32(fileName, zipFile));
+		auto data = CreateTextureDataFromBmp32(fileName, zipFile);
+		if (resizeToPOT) data = ResizeTextureDataToPOT(data);
+		auto tex = std::make_shared<Texture>(data);
 		textureMap[key] = tex;
 		return tex;
 	}
 
 #ifdef PNG_ENABLED
-	std::shared_ptr<Texture> TextureManager::LoadFromPng(const std::string& fileName, const std::string& zipFile)
+	std::shared_ptr<Texture> TextureManager::LoadFromPng(const std::string& fileName, const std::string& zipFile, bool resizeToPOT)
 	{
 		std::string key = MakeKey(fileName, zipFile);
 		auto it = textureMap.find(key);
 		if (it != textureMap.end())
 			return it->second;
-		auto tex = std::make_shared<Texture>(CreateTextureDataFromPng(fileName, zipFile));
+		auto data = CreateTextureDataFromPng(fileName, zipFile);
+		if (resizeToPOT) data = ResizeTextureDataToPOT(data);
+		auto tex = std::make_shared<Texture>(data);
 		textureMap[key] = tex;
 		return tex;
 	}