openGL法线贴图原理以及实现方法

/* Fork by Martin Lucas Golini Original author Jonathan Dummer 2007-07-26-10.36 Simple OpenGL Image Library 2 Public Domain using Sean Barret's stb_image as a base Thanks to: * Sean Barret - for the awesome stb_image * Dan Venkitachalam - for finding some non-compliant DDS files, and patching some explicit casts * everybody at gamedev.net */ #define SOIL_CHECK_FOR_GL_ERRORS 0 #if defined( __APPLE_CC__ ) || defined ( __APPLE__ ) #include <TargetConditionals.h> #if defined( __IPHONE__ ) || ( defined( TARGET_OS_IPHONE ) && TARGET_OS_IPHONE ) || ( defined( TARGET_IPHONE_SIMULATOR ) && TARGET_IPHONE_SIMULATOR ) #define SOIL_PLATFORM_IOS #include <dlfcn.h> #else #define SOIL_PLATFORM_OSX #endif #elif defined( __ANDROID__ ) || defined( ANDROID ) #define SOIL_PLATFORM_ANDROID #elif ( defined ( linux ) || defined( __linux__ ) || defined( __FreeBSD__ ) || defined(__OpenBSD__) || defined( __NetBSD__ ) || defined( __DragonFly__ ) || defined( __SVR4 ) ) #define SOIL_X11_PLATFORM #endif #if ( defined( SOIL_PLATFORM_IOS ) || defined( SOIL_PLATFORM_ANDROID ) ) && ( !defined( SOIL_GLES1 ) && !defined( SOIL_GLES2 ) ) #define SOIL_GLES2 #endif #if ( defined( SOIL_GLES2 ) || defined( SOIL_GLES1 ) ) && !defined( SOIL_NO_EGL ) && !defined( SOIL_PLATFORM_IOS ) #include <EGL/egl.h> #endif #if defined( SOIL_GLES2 ) #ifdef SOIL_PLATFORM_IOS #include <OpenGLES/ES2/gl.h> #include <OpenGLES/ES2/glext.h> #else #include <GLES2/gl2.h> #include <GLES2/gl2ext.h> #endif #define APIENTRY GL_APIENTRY #elif defined( SOIL_GLES1 ) #ifndef GL_GLEXT_PROTOTYPES #define GL_GLEXT_PROTOTYPES #endif #ifdef SOIL_PLATFORM_IOS #include <OpenGLES/ES1/gl.h> #include <OpenGLES/ES1/glext.h> #else #include <GLES/gl.h> #include <GLES/glext.h> #endif #define APIENTRY GL_APIENTRY #else #if defined( __WIN32__ ) || defined( _WIN32 ) || defined( WIN32 ) #define SOIL_PLATFORM_WIN32 #define WIN32_LEAN_AND_MEAN #include <windows.h> #include <wingdi.h> #include <GL/gl.h> #elif defined(__APPLE__) || defined(__APPLE_CC__) /* I can't test this Apple stuff! */ #include <OpenGL/gl.h> #include <Carbon/Carbon.h> #define APIENTRY #elif defined( SOIL_X11_PLATFORM ) #include <GL/gl.h> #include <GL/glx.h> #else #include <GL/gl.h> #endif #endif #ifndef GL_BGRA #define GL_BGRA 0x80E1 #endif #ifndef GL_RG #define GL_RG 0x8227 #endif #ifndef GL_UNSIGNED_SHORT_4_4_4_4 #define GL_UNSIGNED_SHORT_4_4_4_4 0x8033 #endif #ifndef GL_UNSIGNED_SHORT_5_5_5_1 #define GL_UNSIGNED_SHORT_5_5_5_1 0x8034 #endif #ifndef GL_UNSIGNED_SHORT_5_6_5 #define GL_UNSIGNED_SHORT_5_6_5 0x8363 #endif #ifndef GL_UNSIGNED_BYTE_3_3_2 #define GL_UNSIGNED_BYTE_3_3_2 0x8032 #endif #include "SOIL2.h" #define STB_IMAGE_IMPLEMENTATION #include "stb_image.h" #define STB_IMAGE_WRITE_IMPLEMENTATION #include "stb_image_write.h" #include "image_helper.h" #include "image_DXT.h" #include "pvr_helper.h" #include "pkm_helper.h" #include "jo_jpeg.h" #include <stdlib.h> #include <string.h> /* error reporting */ const char *result_string_pointer = "SOIL initialized"; /* for loading cube maps */ enum{ SOIL_CAPABILITY_UNKNOWN = -1, SOIL_CAPABILITY_NONE = 0, SOIL_CAPABILITY_PRESENT = 1 }; static int has_cubemap_capability = SOIL_CAPABILITY_UNKNOWN; int query_cubemap_capability( void ); #define SOIL_TEXTURE_WRAP_R 0x8072 #define SOIL_CLAMP_TO_EDGE 0x812F #define SOIL_NORMAL_MAP 0x8511 #define SOIL_REFLECTION_MAP 0x8512 #define SOIL_TEXTURE_CUBE_MAP 0x8513 #define SOIL_TEXTURE_BINDING_CUBE_MAP 0x8514 #define SOIL_TEXTURE_CUBE_MAP_POSITIVE_X 0x8515 #define SOIL_TEXTURE_CUBE_MAP_NEGATIVE_X 0x8516 #define SOIL_TEXTURE_CUBE_MAP_POSITIVE_Y 0x8517 #define SOIL_TEXTURE_CUBE_MAP_NEGATIVE_Y 0x8518 #define SOIL_TEXTURE_CUBE_MAP_POSITIVE_Z 0x8519 #define SOIL_TEXTURE_CUBE_MAP_NEGATIVE_Z 0x851A #define SOIL_PROXY_TEXTURE_CUBE_MAP 0x851B #define SOIL_MAX_CUBE_MAP_TEXTURE_SIZE 0x851C /* for non-power-of-two texture */ #define SOIL_IS_POW2( v ) ( ( v & ( v - 1 ) ) == 0 ) static int has_NPOT_capability = SOIL_CAPABILITY_UNKNOWN; int query_NPOT_capability( void ); /* for texture rectangles */ static int has_tex_rectangle_capability = SOIL_CAPABILITY_UNKNOWN; int query_tex_rectangle_capability( void ); #define SOIL_TEXTURE_RECTANGLE_ARB 0x84F5 #define SOIL_MAX_RECTANGLE_TEXTURE_SIZE_ARB 0x84F8 /* for using DXT compression */ static int has_DXT_capability = SOIL_CAPABILITY_UNKNOWN; int query_DXT_capability( void ); static int has_3Dc_capability = SOIL_CAPABILITY_UNKNOWN; int query_3Dc_capability( void ); #define SOIL_GL_SRGB 0x8C40 #define SOIL_GL_SRGB_ALPHA 0x8C42 #define SOIL_RGB_S3TC_DXT1 0x83F0 #define SOIL_RGBA_S3TC_DXT1 0x83F1 #define SOIL_RGBA_S3TC_DXT3 0x83F2 #define SOIL_RGBA_S3TC_DXT5 0x83F3 #define SOIL_COMPRESSED_RG_RGTC2 0x8DBD #define SOIL_GL_COMPRESSED_SRGB_S3TC_DXT1_EXT 0x8C4C #define SOIL_GL_COMPRESSED_SRGB_ALPHA_S3TC_DXT5_EXT 0x8C4F static int has_sRGB_capability = SOIL_CAPABILITY_UNKNOWN; int query_sRGB_capability( void ); typedef void (APIENTRY * P_SOIL_GLCOMPRESSEDTEXIMAGE2DPROC) (GLenum target, GLint level, GLenum internalformat, GLsizei width, GLsizei height, GLint border, GLsizei imageSize, const GLvoid * data); static P_SOIL_GLCOMPRESSEDTEXIMAGE2DPROC soilGlCompressedTexImage2D = NULL; typedef void (APIENTRY *P_SOIL_GLGENERATEMIPMAPPROC)(GLenum target); static P_SOIL_GLGENERATEMIPMAPPROC soilGlGenerateMipmap = NULL; static int has_gen_mipmap_capability = SOIL_CAPABILITY_UNKNOWN; static int query_gen_mipmap_capability( void ); static int has_PVR_capability = SOIL_CAPABILITY_UNKNOWN; int query_PVR_capability( void ); static int has_BGRA8888_capability = SOIL_CAPABILITY_UNKNOWN; int query_BGRA8888_capability( void ); static int has_ETC1_capability = SOIL_CAPABILITY_UNKNOWN; int query_ETC1_capability( void ); /* GL_IMG_texture_compression_pvrtc */ #define SOIL_COMPRESSED_RGB_PVRTC_4BPPV1_IMG 0x8C00 #define SOIL_COMPRESSED_RGB_PVRTC_2BPPV1_IMG 0x8C01 #define SOIL_COMPRESSED_RGBA_PVRTC_4BPPV1_IMG 0x8C02 #define SOIL_COMPRESSED_RGBA_PVRTC_2BPPV1_IMG 0x8C03 #define SOIL_GL_ETC1_RGB8_OES 0x8D64 #if defined( SOIL_X11_PLATFORM ) || defined( SOIL_PLATFORM_WIN32 ) || defined( SOIL_PLATFORM_OSX ) || defined(__HAIKU__) typedef const GLubyte *(APIENTRY * P_SOIL_glGetStringiFunc) (GLenum, GLuint); static P_SOIL_glGetStringiFunc soilGlGetStringiFunc = NULL; static int isAtLeastGL3() { static int is_gl3 = SOIL_CAPABILITY_UNKNOWN; if ( SOIL_CAPABILITY_UNKNOWN == is_gl3 ) { const char * verstr = (const char *) glGetString( GL_VERSION ); is_gl3 = ( verstr && ( atoi(verstr) >= 3 ) && strstr( verstr, " ES " ) == NULL ); } return is_gl3; } #else static int isAtLeastGL3() { return SOIL_CAPABILITY_NONE; } #endif #ifdef SOIL_PLATFORM_WIN32 static HMODULE openglModule = NULL; static int soilTestWinProcPointer(const PROC pTest) { ptrdiff_t iTest; if(!pTest) return 0; iTest = (ptrdiff_t)pTest; if(iTest == 1 || iTest == 2 || iTest == 3 || iTest == -1) return 0; return 1; } #endif #if defined(__sgi) || defined (__sun) || defined(__HAIKU__) #include <dlfcn.h> void* dlGetProcAddress (const char* name) { static void* h = NULL; static void* gpa; if (h == NULL) { if ((h = dlopen(NULL, RTLD_LAZY | RTLD_LOCAL)) == NULL) return NULL; gpa = dlsym(h, "glXGetProcAddress"); } if (gpa != NULL) return ((void*(*)(const GLubyte*))gpa)((const GLubyte*)name); else return dlsym(h, (const char*)name); } #endif void * SOIL_GL_GetProcAddress(const char *proc) { void *func = NULL; #if defined( SOIL_PLATFORM_IOS ) func = dlsym( RTLD_DEFAULT, proc ); #elif defined( SOIL_GLES2