From 4ce0e0e10d0cb02173c246f56f5b751e8f85d070 Mon Sep 17 00:00:00 2001
From: Epicalert <epicalert@protonmail.com>
Date: Sat, 6 Feb 2021 21:19:33 +0800
Subject: [PATCH] Add support for webp textures

This allows for models to use lossy textures with an alpha channel,
none of the formats supported by stb_image.h could do this.
---
 CMakeLists.txt       |  4 +++-
 cmake/FindWebP.cmake |  9 +++++++++
 src/graphics.cpp     | 23 ++++++++++++++++++++++-
 3 files changed, 34 insertions(+), 2 deletions(-)
 create mode 100644 cmake/FindWebP.cmake

diff --git a/CMakeLists.txt b/CMakeLists.txt
index e6159de..48c5c32 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1,6 +1,8 @@
 cmake_minimum_required( VERSION 3.0 )
 project( Facecam2D VERSION 0.1.0 )
+set( CMAKE_MODULE_PATH ${PROJECT_SOURCE_DIR}/cmake )
 find_package( libzip REQUIRED )
+find_package( WebP REQUIRED )
 find_package( OpenCV REQUIRED )
 message (STATUS "Found OpenCV at: " ${OpenCV_INCLUDE_DIRS} )
 find_package( OpenGL REQUIRED )
@@ -43,4 +45,4 @@ add_executable( fc2d
 	src/toml.c
 	src/tomlcpp.cpp
 )
-target_link_libraries( fc2d ${OpenCV_LIBS} ${OPENGL_LIBRARIES} FreeGLUT::freeglut GLEW::glew zip )
+target_link_libraries( fc2d ${OpenCV_LIBS} ${OPENGL_LIBRARIES} ${WEBP_LIBRARIES} FreeGLUT::freeglut GLEW::glew zip )
diff --git a/cmake/FindWebP.cmake b/cmake/FindWebP.cmake
new file mode 100644
index 0000000..7923d51
--- /dev/null
+++ b/cmake/FindWebP.cmake
@@ -0,0 +1,9 @@
+find_path( WEBP_INCLUDE_DIR NAMES webp/decode.h )
+
+find_library( WEBP_LIBRARY NAMES webp PATHS /usr/lib /usr/lib64 /lib /lib64 /usr/local/lib )
+
+if (WEBP_INCLUDE_DIR AND WEBP_LIBRARY)
+	set(WEBP_INCLUDE_DIR ${WEBP_INCLUDE_DIR})
+	set(WEBP_LIBRARIES ${WEBP_LIBRARY})
+	set( WEBP_FOUND "TRUE" )
+endif (WEBP_INCLUDE_DIR AND WEBP_LIBRARY)
diff --git a/src/graphics.cpp b/src/graphics.cpp
index f955894..4597032 100644
--- a/src/graphics.cpp
+++ b/src/graphics.cpp
@@ -8,6 +8,8 @@
 #define STB_IMAGE_IMPLEMENTATION
 #include <stb_image.h>
 
+#include <webp/decode.h>
+
 #include <iostream>
 
 #include <graphics.hpp>
@@ -103,7 +105,26 @@ void initTexture (GLuint* texNum, unsigned char* buffer, size_t bufferLength) {
 	glBindTexture(GL_TEXTURE_2D, *texNum);
 
 	int x, y, channels;
-	GLubyte* pixels = stbi_load_from_memory(buffer, bufferLength, &x, &y, &channels, 4);
+	GLubyte* pixels;
+	int webp = WebPGetInfo(buffer, bufferLength, &x, &y);
+	if (webp) {
+		pixels = WebPDecodeRGBA(buffer, bufferLength, &x, &y);
+	} else {
+		//try stb_image (png, jpg, gif, etc)
+		pixels = stbi_load_from_memory(buffer, bufferLength, &x, &y, &channels, 4);
+		if (!pixels) {
+			std::cerr << "Corrupt or unsupported texture format!" << std::endl;
+
+			GLubyte defaultPixels[] =
+				{255,   0, 255, 255, 	  0,   0,   0, 255,
+				   0,   0,   0, 255, 	255,   0, 255, 255 };
+
+			pixels = defaultPixels;
+			x = 2;
+			y = 2;
+		}
+	}
+
 	glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, x, y, 0, GL_RGBA, GL_UNSIGNED_BYTE, pixels);
 
 	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);