From 8644e03586ac9c39741f62cbcbce87b18805538c Mon Sep 17 00:00:00 2001
From: chai <chaifix@163.com>
Date: Thu, 14 Mar 2019 23:12:54 +0800
Subject: =?UTF-8?q?*=E5=A4=A7=E5=B0=8F=E5=86=99?=
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---
 Source/Asura.Engine/graphics/stb_decoder.cpp | 65 ++++++++++++++++++++++++++++
 1 file changed, 65 insertions(+)
 create mode 100644 Source/Asura.Engine/graphics/stb_decoder.cpp

(limited to 'Source/Asura.Engine/graphics/stb_decoder.cpp')

diff --git a/Source/Asura.Engine/graphics/stb_decoder.cpp b/Source/Asura.Engine/graphics/stb_decoder.cpp
new file mode 100644
index 0000000..b14d0f3
--- /dev/null
+++ b/Source/Asura.Engine/graphics/stb_decoder.cpp
@@ -0,0 +1,65 @@
+#include "STBDecoder.h"
+
+#include "Exceptions/Exception.h"
+#include "stb/stb_image.h"
+
+namespace AsuraEngine
+{
+	namespace Graphics
+	{
+
+		bool STBDecoder::CanDecode(const Filesystem::DataBuffer& buffer)
+		{
+			int w = 0;
+			int h = 0;
+			int comp = 0;
+
+			int status = stbi_info_from_memory((const stbi_uc*)buffer.data, buffer.size, &w, &h, &comp);
+
+			return status == 1 && w > 0 && h > 0;
+		}
+
+		void STBDecoder::Decode(const Filesystem::DataBuffer& db, ImageData& imageData)
+		{
+			const stbi_uc *buffer = (const stbi_uc *)db.data;
+			int bufferlen = db.size;
+			int width, height;
+			int comp = 0;
+			byte* data = nullptr;
+			PixelFormat format = PIXELFORMAT_UNKNOWN;
+			std::size_t size = 0;
+
+			if (stbi_is_hdr_from_memory(buffer, bufferlen))
+			{
+				// 4个channel都是float
+				data = (byte*)stbi_loadf_from_memory(buffer, bufferlen, &width, &height, &comp, STBI_rgb_alpha);
+				format = PIXELFORMAT_RGBA32F;
+				size = width * height * 4 * sizeof(float);
+			}
+			else
+			{
+				data = (byte*)stbi_load_from_memory(buffer, bufferlen, &width, &height, &comp, STBI_rgb_alpha);
+				format = PIXELFORMAT_ASTC_8x5;
+				size = width * height * 4;
+			}
+			if (data)
+			{
+				// 保证内存被释放，做一个防护，理论上不会出现没有释放的情况，因为image data是一次性的，image才是多次的。
+				if (imageData.pixels)
+					delete[] imageData.pixels;
+				imageData.pixels = (byte*)data;
+				imageData.format = format;
+				imageData.width = width;
+				imageData.height = height;
+			}
+			else
+			{
+				const char *err = stbi_failure_reason();
+				if (err == nullptr)
+					err = "unknown error";
+				throw Exception("Could not decode image with stb_image (%s).", err);
+			}
+		}
+
+	}
+}
\ No newline at end of file
-- 
cgit v1.1-26-g67d0