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stb single-file public domain libraries for C/C++
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stb/tests/caveview/stb_gl.h

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// stbgl - v0.04 - Sean Barrett 2008 - public domain
//
// Note that the gl extensions support requires glext.h. In fact, it works
// if you just concatenate glext.h onto the end of this file. In that case,
// this file is covered by the SGI FreeB license, and is not public domain.
//
// Extension usage:
//
// 1. Make a file called something like "extlist.txt" which contains stuff like:
// GLE(ShaderSourceARB,SHADERSOURCEARB)
// GLE(Uniform1iARB,UNIFORM1IARB)
// GLARB(ActiveTexture,ACTIVETEXTURE) // same as GLE(ActiveTextureARB,ACTIVETEXTUREARB)
// GLARB(ClientActiveTexture,CLIENTACTIVETEXTURE)
// GLE(MultiTexCoord2f,MULTITEXCOORD2F)
//
// 2. To declare functions (to make a header file), do this:
// #define STB_GLEXT_DECLARE "extlist.txt"
// #include "stb_gl.h"
//
// A good way to do this is to define STB_GLEXT_DECLARE project-wide.
//
// 3. To define functions (implement), do this in some C file:
// #define STB_GLEXT_DEFINE "extlist.txt"
// #include "stb_gl.h"
//
// If you've already defined STB_GLEXT_DECLARE, you can just do:
// #define STB_GLEXT_DEFINE_DECLARE
// #include "stb_gl.h"
//
// 4. Now you need to initialize:
//
// stbgl_initExtensions();
#ifndef INCLUDE_STB_GL_H
#define INCLUDE_STB_GL_H
#define STB_GL
#ifdef _WIN32
#ifndef WINGDIAPI
#define CALLBACK __stdcall
#define WINGDIAPI __declspec(dllimport)
#define APIENTRY __stdcall
#endif
#endif //_WIN32
#include <stddef.h>
#include <gl/gl.h>
#include <gl/glu.h>
#ifndef M_PI
#define M_PI 3.14159265358979323846f
#endif
#ifdef __cplusplus
extern "C" {
#endif
// like gluPerspective, but:
// fov is chosen to satisfy both hfov <= max_hfov & vfov <= max_vfov;
// set one to 179 or 0 to ignore it
// zoom is applied separately, so you can do linear zoom without
// mucking with trig with fov; 1 -> use exact fov
// 'aspect' is inferred from the current viewport, and ignores the
// possibility of non-square pixels
extern void stbgl_Perspective(float zoom, float max_hfov, float max_vfov, float znear, float zfar);
extern void stbgl_PerspectiveViewport(int x, int y, int w, int h, float zoom, float max_hfov, float max_vfov, float znear, float zfar);
extern void stbgl_initCamera_zup_facing_x(void);
extern void stbgl_initCamera_zup_facing_y(void);
extern void stbgl_positionCameraWithEulerAngles(float *loc, float *ang);
extern void stbgl_drawRect(float x0, float y0, float x1, float y1);
extern void stbgl_drawRectTC(float x0, float y0, float x1, float y1, float s0, float t0, float s1, float t1);
extern void stbgl_drawBox(float x, float y, float z, float sx, float sy, float sz, int cw);
extern int stbgl_hasExtension(char *ext);
extern void stbgl_SimpleLight(int index, float bright, float x, float y, float z);
extern void stbgl_GlobalAmbient(float r, float g, float b);
extern int stbgl_LoadTexture(char *filename, char *props); // only if stb_image is available
extern int stbgl_TestTexture(int w);
extern int stbgl_TestTextureEx(int w, char *scale_table, int checks_log2, int r1,int g1,int b1, int r2, int b2, int g2);
extern unsigned int stbgl_rand(void); // internal, but exposed just in case; LCG, so use middle bits
extern int stbgl_TexImage2D(int texid, int w, int h, void *data, char *props);
extern int stbgl_TexImage2D_Extra(int texid, int w, int h, void *data, int chan, char *props, int preserve_data);
// "props" is a series of characters (and blocks of characters), a la fopen()'s mode,
// e.g.:
// GLuint texid = stbgl_LoadTexture("myfile.jpg", "mbc")
// means: load the image "myfile.jpg", and do the following:
// generate mipmaps
// use bilinear filtering (not trilinear)
// use clamp-to-edge on both channels
//
// input descriptor: AT MOST ONE
// TEXT MEANING
// 1 1 channel of input (intensity/alpha)
// 2 2 channels of input (luminance, alpha)
// 3 3 channels of input (RGB)
// 4 4 channels of input (RGBA)
// l 1 channel of input (luminance)
// a 1 channel of input (alpha)
// la 2 channels of input (lum/alpha)
// rgb 3 channels of input (RGB)
// ycocg 3 channels of input (YCoCg - forces YCoCg output)
// ycocgj 4 channels of input (YCoCgJunk - forces YCoCg output)
// rgba 4 channels of input (RGBA)
//
// output descriptor: AT MOST ONE
// TEXT MEANING
// A 1 channel of output (alpha)
// I 1 channel of output (intensity)
// LA 2 channels of output (lum/alpha)
// RGB 3 channels of output (RGB)
// RGBA 4 channels of output (RGBA)
// DXT1 encode as a DXT1 texture (RGB unless input has RGBA)
// DXT3 encode as a DXT3 texture
// DXT5 encode as a DXT5 texture
// YCoCg encode as a DXT5 texture with Y in alpha, CoCg in RG
// D GL_DEPTH_COMPONENT
// NONE no input/output, don't call TexImage2D at all
//
// when reading from a file or using another interface with an explicit
// channel count, the input descriptor is ignored and instead the channel
// count is used as the input descriptor. if the file read is a DXT DDS,
// then it is passed directly to OpenGL in the file format.
//
// if an input descriptor is supplied but no output descriptor, the output
// is assumed to be the same as the input. if an output descriptor is supplied
// but no input descriptor, the input is assumed to be the same as the
// output. if neither is supplied, the input is assumed to be 4-channel.
// If DXT1 or YCoCG output is requested with no input, the input is assumed
// to be 4-channel but the alpha channel is ignored.
//
// filtering descriptor (default is no mipmaps)
// TEXT MEANING
// m generate mipmaps
// M mipmaps are provided, concatenated at end of data (from largest to smallest)
// t use trilinear filtering (default if mipmapped)
// b use bilinear filtering (default if not-mipmapped)
// n use nearest-neighbor sampling
//
// wrapping descriptor
// TEXT MEANING
// w wrap (default)
// c clamp-to-edge
// C GL_CLAMP (uses border color)
//
// If only one wrapping descriptor is supplied, it is applied to both channels.
//
// special:
// TEXT MEANING
// f input data is floats (default unsigned bytes)
// F input&output data is floats (default unsigned bytes)
// p explicitly pre-multiply the alpha
// P pad to power-of-two (default stretches)
// NP2 non-power-of-two
// + can overwrite the texture data with temp data
// ! free the texture data with "free"
//
// the properties string can also include spaces
#ifdef __cplusplus
}
#endif
#ifdef STB_GL_IMPLEMENTATION
#include <math.h>
#include <stdlib.h>
#include <assert.h>
#include <memory.h>
int stbgl_hasExtension(char *ext)
{
const char *s = glGetString(GL_EXTENSIONS);
for(;;) {
char *e = ext;
for (;;) {
if (*e == 0) {
if (*s == 0 || *s == ' ') return 1;
break;
}
if (*s != *e)
break;
++s, ++e;
}
while (*s && *s != ' ') ++s;
if (!*s) return 0;
++s; // skip space
}
}
void stbgl_drawRect(float x0, float y0, float x1, float y1)
{
glBegin(GL_POLYGON);
glTexCoord2f(0,0); glVertex2f(x0,y0);
glTexCoord2f(1,0); glVertex2f(x1,y0);
glTexCoord2f(1,1); glVertex2f(x1,y1);
glTexCoord2f(0,1); glVertex2f(x0,y1);
glEnd();
}
void stbgl_drawRectTC(float x0, float y0, float x1, float y1, float s0, float t0, float s1, float t1)
{
glBegin(GL_POLYGON);
glTexCoord2f(s0,t0); glVertex2f(x0,y0);
glTexCoord2f(s1,t0); glVertex2f(x1,y0);
glTexCoord2f(s1,t1); glVertex2f(x1,y1);
glTexCoord2f(s0,t1); glVertex2f(x0,y1);
glEnd();
}
void stbgl_drawBox(float x, float y, float z, float sx, float sy, float sz, int cw)
{
float x0,y0,z0,x1,y1,z1;
sx /=2, sy/=2, sz/=2;
x0 = x-sx; y0 = y-sy; z0 = z-sz;
x1 = x+sx; y1 = y+sy; z1 = z+sz;
glBegin(GL_QUADS);
if (cw) {
glNormal3f(0,0,-1);
glTexCoord2f(0,0); glVertex3f(x0,y0,z0);
glTexCoord2f(1,0); glVertex3f(x1,y0,z0);
glTexCoord2f(1,1); glVertex3f(x1,y1,z0);
glTexCoord2f(0,1); glVertex3f(x0,y1,z0);
glNormal3f(0,0,1);
glTexCoord2f(0,0); glVertex3f(x1,y0,z1);
glTexCoord2f(1,0); glVertex3f(x0,y0,z1);
glTexCoord2f(1,1); glVertex3f(x0,y1,z1);
glTexCoord2f(0,1); glVertex3f(x1,y1,z1);
glNormal3f(-1,0,0);
glTexCoord2f(0,0); glVertex3f(x0,y1,z1);
glTexCoord2f(1,0); glVertex3f(x0,y0,z1);
glTexCoord2f(1,1); glVertex3f(x0,y0,z0);
glTexCoord2f(0,1); glVertex3f(x0,y1,z0);
glNormal3f(1,0,0);
glTexCoord2f(0,0); glVertex3f(x1,y0,z1);
glTexCoord2f(1,0); glVertex3f(x1,y1,z1);
glTexCoord2f(1,1); glVertex3f(x1,y1,z0);
glTexCoord2f(0,1); glVertex3f(x1,y0,z0);
glNormal3f(0,-1,0);
glTexCoord2f(0,0); glVertex3f(x0,y0,z1);
glTexCoord2f(1,0); glVertex3f(x1,y0,z1);
glTexCoord2f(1,1); glVertex3f(x1,y0,z0);
glTexCoord2f(0,1); glVertex3f(x0,y0,z0);
glNormal3f(0,1,0);
glTexCoord2f(0,0); glVertex3f(x1,y1,z1);
glTexCoord2f(1,0); glVertex3f(x0,y1,z1);
glTexCoord2f(1,1); glVertex3f(x0,y1,z0);
glTexCoord2f(0,1); glVertex3f(x1,y1,z0);
} else {
glNormal3f(0,0,-1);
glTexCoord2f(0,0); glVertex3f(x0,y0,z0);
glTexCoord2f(0,1); glVertex3f(x0,y1,z0);
glTexCoord2f(1,1); glVertex3f(x1,y1,z0);
glTexCoord2f(1,0); glVertex3f(x1,y0,z0);
glNormal3f(0,0,1);
glTexCoord2f(0,0); glVertex3f(x1,y0,z1);
glTexCoord2f(0,1); glVertex3f(x1,y1,z1);
glTexCoord2f(1,1); glVertex3f(x0,y1,z1);
glTexCoord2f(1,0); glVertex3f(x0,y0,z1);
glNormal3f(-1,0,0);
glTexCoord2f(0,0); glVertex3f(x0,y1,z1);
glTexCoord2f(0,1); glVertex3f(x0,y1,z0);
glTexCoord2f(1,1); glVertex3f(x0,y0,z0);
glTexCoord2f(1,0); glVertex3f(x0,y0,z1);
glNormal3f(1,0,0);
glTexCoord2f(0,0); glVertex3f(x1,y0,z1);
glTexCoord2f(0,1); glVertex3f(x1,y0,z0);
glTexCoord2f(1,1); glVertex3f(x1,y1,z0);
glTexCoord2f(1,0); glVertex3f(x1,y1,z1);
glNormal3f(0,-1,0);
glTexCoord2f(0,0); glVertex3f(x0,y0,z1);
glTexCoord2f(0,1); glVertex3f(x0,y0,z0);
glTexCoord2f(1,1); glVertex3f(x1,y0,z0);
glTexCoord2f(1,0); glVertex3f(x1,y0,z1);
glNormal3f(0,1,0);
glTexCoord2f(0,0); glVertex3f(x1,y1,z1);
glTexCoord2f(0,1); glVertex3f(x1,y1,z0);
glTexCoord2f(1,1); glVertex3f(x0,y1,z0);
glTexCoord2f(1,0); glVertex3f(x0,y1,z1);
}
glEnd();
}
void stbgl_SimpleLight(int index, float bright, float x, float y, float z)
{
float d = (float) (1.0f/sqrt(x*x+y*y+z*z));
float dir[4] = { x*d,y*d,z*d,0 }, zero[4] = { 0,0,0,0 };
float c[4] = { bright,bright,bright,0 };
GLuint light = GL_LIGHT0 + index;
glLightfv(light, GL_POSITION, dir);
glLightfv(light, GL_DIFFUSE, c);
glLightfv(light, GL_AMBIENT, zero);
glLightfv(light, GL_SPECULAR, zero);
glEnable(light);
glColorMaterial(GL_FRONT, GL_AMBIENT_AND_DIFFUSE);
glEnable(GL_COLOR_MATERIAL);
}
void stbgl_GlobalAmbient(float r, float g, float b)
{
float v[4] = { r,g,b,0 };
glLightModelfv(GL_LIGHT_MODEL_AMBIENT, v);
}
#define stbgl_rad2deg(r) ((r)*180.0f / M_PI)
#define stbgl_deg2rad(r) ((r)/180.0f * M_PI)
void stbgl_Perspective(float zoom, float max_hfov, float max_vfov, float znear, float zfar)
{
float unit_width, unit_height, aspect, vfov;
int data[4],w,h;
glGetIntegerv(GL_VIEWPORT, data);
w = data[2];
h = data[3];
aspect = (float) w / h;
if (max_hfov <= 0) max_hfov = 179;
if (max_vfov <= 0) max_vfov = 179;
// convert max_hfov, max_vfov to worldspace width at depth=1
unit_width = (float) tan(stbgl_deg2rad(max_hfov/2)) * 2;
unit_height = (float) tan(stbgl_deg2rad(max_vfov/2)) * 2;
// check if hfov = max_hfov is enough to satisfy it
if (unit_width <= aspect * unit_height) {
float height = unit_width / aspect;
vfov = (float) atan(( height/2) / zoom);
} else {
vfov = (float) atan((unit_height/2) / zoom);
}
vfov = (float) stbgl_rad2deg(vfov * 2);
gluPerspective(vfov, aspect, znear, zfar);
}
void stbgl_PerspectiveViewport(int x, int y, int w, int h, float zoom, float min_hfov, float min_vfov, float znear, float zfar)
{
if (znear <= 0.0001f) znear = 0.0001f;
glViewport(x,y,w,h);
glScissor(x,y,w,h);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
stbgl_Perspective(zoom, min_hfov, min_vfov, znear, zfar);
glMatrixMode(GL_MODELVIEW);
}
// point the camera along the positive X axis, Z-up
void stbgl_initCamera_zup_facing_x(void)
{
glRotatef(-90, 1,0,0);
glRotatef( 90, 0,0,1);
}
// point the camera along the positive Y axis, Z-up
void stbgl_initCamera_zup_facing_y(void)
{
glRotatef(-90, 1,0,0);
}
// setup a camera using Euler angles
void stbgl_positionCameraWithEulerAngles(float *loc, float *ang)
{
glRotatef(-ang[1], 0,1,0);
glRotatef(-ang[0], 1,0,0);
glRotatef(-ang[2], 0,0,1);
glTranslatef(-loc[0], -loc[1], -loc[2]);
}
static int stbgl_m(char *a, char *b)
{
// skip first character
do { ++a,++b; } while (*b && *a == *b);
return *b == 0;
}
#ifdef STBI_VERSION
#ifndef STBI_NO_STDIO
int stbgl_LoadTexture(char *filename, char *props)
{
// @TODO: handle DDS files directly
int res;
void *data;
int w,h,c;
#ifndef STBI_NO_HDR
if (stbi_is_hdr(filename)) {
data = stbi_loadf(filename, &w, &h, &c, 0);
if (!data) return 0;
res = stbgl_TexImage2D_Extra(0, w,h,data, -c, props, 0);
free(data);
return res;
}
#endif
data = stbi_load(filename, &w, &h, &c, 0);
if (!data) return 0;
res = stbgl_TexImage2D_Extra(0, w,h,data, c, props, 0);
free(data);
return res;
}
#endif
#endif // STBI_VERSION
int stbgl_TexImage2D(int texid, int w, int h, void *data, char *props)
{
return stbgl_TexImage2D_Extra(texid, w, h, data, 0, props,1);
}
int stbgl_TestTexture(int w)
{
char scale_table[] = { 10,20,30,30,35,40,5,18,25,13,7,5,3,3,2,2,2,2,1,1,1,1,1,0,0,0,0,0,0,0,0,0,0 };
return stbgl_TestTextureEx(w, scale_table, 2, 140,130,200, 180,200,170);
}
unsigned int stbgl_rand(void)
{
static unsigned int stbgl__rand_seed = 3248980923; // random typing
return stbgl__rand_seed = stbgl__rand_seed * 2147001325 + 715136305; // BCPL generator
}
// wish this could be smaller, since it's so frivolous
int stbgl_TestTextureEx(int w, char *scale_table, int checks_log2, int r1,int g1,int b1, int r2, int b2, int g2)
{
int rt[2] = {r1,r2}, gt[2] = {g1,g2}, bt[2] = {b1,b2};
signed char modded[256];
int i,j, m = w-1, s,k,scale;
unsigned char *data = (unsigned char *) malloc(w*w*3);
assert((m & w) == 0);
data[0] = 128;
for (s=0; s < 16; ++s) if ((1 << s) == w) break;
assert(w == (1 << s));
// plasma fractal noise
for (k=s-1; k >= 0; --k) {
int step = 1 << k;
// interpolate from "parents"
for (j=0; j < w; j += step*2) {
for (i=0; i < w; i += step*2) {
int i1 = i+step, j1=j+step;
int i2 = (i+step*2)&m, j2 = (j+step*2)&m;
int p00 = data[(j*w+i )*3], p01 = data[(j2*w+i )*3];
int p10 = data[(j*w+i2)*3], p11 = data[(j2*w+i2)*3];
data[(j*w+i1)*3] = (p00+p10)>>1;
data[(j1*w+i)*3] = (p00+p01)>>1;
data[(j1*w+i1)*3]= (p00+p01+p10+p11)>>2;
}
}
scale = scale_table[s-k+1];
if (!scale) continue; // just interpolate down the remaining data
for (j=0,i=0; i < 256; i += 2, j == scale ? j=0 : ++j)
modded[i] = j, modded[i+1] = -j; // precompute i%scale (plus sign)
for (j=0; j < w; j += step)
for (i=0; i < w; i += step) {
int x = data[(j*w+i)*3] + modded[(stbgl_rand() >> 12) & 255];
data[(j*w+i)*3] = x < 0 ? 0 : x > 255 ? 255 : x;
}
}
for (j=0; j < w; ++j)
for (i=0; i < w; ++i) {
int check = ((i^j) & (1 << (s-checks_log2))) == 0;
int v = data[(j*w+i)*3] >> 2;
data[(j*w+i)*3+0] = rt[check]-v;
data[(j*w+i)*3+1] = gt[check]-v;
data[(j*w+i)*3+2] = bt[check]-v;
}
return stbgl_TexImage2D(0, w, w, data, "3m!"); // 3 channels, mipmap, free
}
#ifdef _WIN32
#ifndef WINGDIAPI
typedef int (__stdcall *stbgl__voidfunc)(void);
__declspec(dllimport) stbgl__voidfunc wglGetProcAddress(char *);
#endif
#define STB__HAS_WGLPROC
static void (__stdcall *stbgl__CompressedTexImage2DARB)(int target, int level,
int internalformat, int width,
int height, int border,
int imageSize, void *data);
static void stbgl__initCompTex(void)
{
*((void **) &stbgl__CompressedTexImage2DARB) = (void *) wglGetProcAddress("glCompressedTexImage2DARB");
}
#else
static void (*stbgl__CompressedTexImage2DARB)(int target, int level,
int internalformat, int width,
int height, int border,
int imageSize, void *data);
static void stbgl__initCompTex(void)
{
}
#endif // _WIN32
#define STBGL_COMPRESSED_RGB_S3TC_DXT1 0x83F0
#define STBGL_COMPRESSED_RGBA_S3TC_DXT1 0x83F1
#define STBGL_COMPRESSED_RGBA_S3TC_DXT3 0x83F2
#define STBGL_COMPRESSED_RGBA_S3TC_DXT5 0x83F3
#ifdef STB_COMPRESS_DXT_BLOCK
static void stbgl__convert(uint8 *p, uint8 *q, int n, int input_desc, uint8 *end)
{
int i;
switch (input_desc) {
case GL_RED:
case GL_LUMINANCE: for (i=0; i < n; ++i,p+=4) p[0] = p[1] = p[2] = q[0], p[3]=255, q+=1; break;
case GL_ALPHA: for (i=0; i < n; ++i,p+=4) p[0] = p[1] = p[2] = 0, p[3] = q[0], q+=1; break;
case GL_LUMINANCE_ALPHA: for (i=0; i < n; ++i,p+=4) p[0] = p[1] = p[2] = q[0], p[3]=q[1], q+=2; break;
case GL_RGB: for (i=0; i < n; ++i,p+=4) p[0]=q[0],p[1]=q[1],p[2]=q[2],p[3]=255,q+=3; break;
case GL_RGBA: memcpy(p, q, n*4); break;
case GL_INTENSITY: for (i=0; i < n; ++i,p+=4) p[0] = p[1] = p[2] = p[3] = q[0], q+=1; break;
}
assert(p <= end);
}
static void stbgl__compress(uint8 *p, uint8 *rgba, int w, int h, int output_desc, uint8 *end)
{
int i,j,y,y2;
int alpha = (output_desc == STBGL_COMPRESSED_RGBA_S3TC_DXT5);
for (j=0; j < w; j += 4) {
int x=4;
for (i=0; i < h; i += 4) {
uint8 block[16*4];
if (i+3 >= w) x = w-i;
for (y=0; y < 4; ++y) {
if (j+y >= h) break;
memcpy(block+y*16, rgba + w*4*(j+y) + i*4, x*4);
}
if (x < 4) {
switch (x) {
case 0: assert(0);
case 1:
for (y2=0; y2 < y; ++y2) {
memcpy(block+y2*16+1*4, block+y2*16+0*4, 4);
memcpy(block+y2*16+2*4, block+y2*16+0*4, 8);
}
break;
case 2:
for (y2=0; y2 < y; ++y2)
memcpy(block+y2*16+2*4, block+y2*16+0*4, 8);
break;
case 3:
for (y2=0; y2 < y; ++y2)
memcpy(block+y2*16+3*4, block+y2*16+1*4, 4);
break;
}
}
y2 = 0;
for(; y<4; ++y,++y2)
memcpy(block+y*16, block+y2*16, 4*4);
stb_compress_dxt_block(p, block, alpha, 10);
p += alpha ? 16 : 8;
}
}
assert(p <= end);
}
#endif // STB_COMPRESS_DXT_BLOCK
// use the reserved temporary-use enumerant range, since no
// OpenGL enumerants should fall in that range
enum
{
STBGL_UNDEFINED = 0x6000,
STBGL_YCOCG,
STBGL_YCOCGJ,
STBGL_GEN_MIPMAPS,
STBGL_MIPMAPS,
STBGL_NO_DOWNLOAD,
};
#define STBGL_CLAMP_TO_EDGE 0x812F
#define STBGL_CLAMP_TO_BORDER 0x812D
#define STBGL_DEPTH_COMPONENT16 0x81A5
#define STBGL_DEPTH_COMPONENT24 0x81A6
#define STBGL_DEPTH_COMPONENT32 0x81A7
int stbgl_TexImage2D_Extra(int texid, int w, int h, void *data, int chan, char *props, int preserve_data)
{
static int has_s3tc = -1; // haven't checked yet
int free_data = 0, is_compressed = 0;
int pad_to_power_of_two = 0, non_power_of_two = 0;
int premultiply_alpha = 0; // @TODO
int float_tex = 0; // @TODO
int input_type = GL_UNSIGNED_BYTE;
int input_desc = STBGL_UNDEFINED;
int output_desc = STBGL_UNDEFINED;
int mipmaps = STBGL_UNDEFINED;
int filter = STBGL_UNDEFINED, mag_filter;
int wrap_s = STBGL_UNDEFINED, wrap_t = STBGL_UNDEFINED;
// parse out the properties
if (props == NULL) props = "";
while (*props) {
switch (*props) {
case '1' : input_desc = GL_LUMINANCE; break;
case '2' : input_desc = GL_LUMINANCE_ALPHA; break;
case '3' : input_desc = GL_RGB; break;
case '4' : input_desc = GL_RGBA; break;
case 'l' : if (props[1] == 'a') { input_desc = GL_LUMINANCE_ALPHA; ++props; }
else input_desc = GL_LUMINANCE;
break;
case 'a' : input_desc = GL_ALPHA; break;
case 'r' : if (stbgl_m(props, "rgba")) { input_desc = GL_RGBA; props += 3; break; }
if (stbgl_m(props, "rgb")) { input_desc = GL_RGB; props += 2; break; }
input_desc = GL_RED;
break;
case 'y' : if (stbgl_m(props, "ycocg")) {
if (props[5] == 'j') { props += 5; input_desc = STBGL_YCOCGJ; }
else { props += 4; input_desc = STBGL_YCOCG; }
break;
}
return 0;
case 'L' : if (props[1] == 'A') { output_desc = GL_LUMINANCE_ALPHA; ++props; }
else output_desc = GL_LUMINANCE;
break;
case 'I' : output_desc = GL_INTENSITY; break;
case 'A' : output_desc = GL_ALPHA; break;
case 'R' : if (stbgl_m(props, "RGBA")) { output_desc = GL_RGBA; props += 3; break; }
if (stbgl_m(props, "RGB")) { output_desc = GL_RGB; props += 2; break; }
output_desc = GL_RED;
break;
case 'Y' : if (stbgl_m(props, "YCoCg") || stbgl_m(props, "YCOCG")) {
props += 4;
output_desc = STBGL_YCOCG;
break;
}
return 0;
case 'D' : if (stbgl_m(props, "DXT")) {
switch (props[3]) {
case '1': output_desc = STBGL_COMPRESSED_RGB_S3TC_DXT1; break;
case '3': output_desc = STBGL_COMPRESSED_RGBA_S3TC_DXT3; break;
case '5': output_desc = STBGL_COMPRESSED_RGBA_S3TC_DXT5; break;
default: return 0;
}
props += 3;
} else if (stbgl_m(props, "D16")) {
output_desc = STBGL_DEPTH_COMPONENT16;
input_desc = GL_DEPTH_COMPONENT;
props += 2;
} else if (stbgl_m(props, "D24")) {
output_desc = STBGL_DEPTH_COMPONENT24;
input_desc = GL_DEPTH_COMPONENT;
props += 2;
} else if (stbgl_m(props, "D32")) {
output_desc = STBGL_DEPTH_COMPONENT32;
input_desc = GL_DEPTH_COMPONENT;
props += 2;
} else {
output_desc = GL_DEPTH_COMPONENT;
input_desc = GL_DEPTH_COMPONENT;
}
break;
case 'N' : if (stbgl_m(props, "NONE")) {
props += 3;
input_desc = STBGL_NO_DOWNLOAD;
output_desc = STBGL_NO_DOWNLOAD;
break;
}
if (stbgl_m(props, "NP2")) {
non_power_of_two = 1;
props += 2;
break;
}
return 0;
case 'm' : mipmaps = STBGL_GEN_MIPMAPS; break;
case 'M' : mipmaps = STBGL_MIPMAPS; break;
case 't' : filter = GL_LINEAR_MIPMAP_LINEAR; break;
case 'b' : filter = GL_LINEAR; break;
case 'n' : filter = GL_NEAREST; break;
case 'w' : if (wrap_s == STBGL_UNDEFINED) wrap_s = GL_REPEAT; else wrap_t = GL_REPEAT; break;
case 'C' : if (wrap_s == STBGL_UNDEFINED) wrap_s = STBGL_CLAMP_TO_BORDER; else wrap_t = STBGL_CLAMP_TO_BORDER; break;
case 'c' : if (wrap_s == STBGL_UNDEFINED) wrap_s = STBGL_CLAMP_TO_EDGE; else wrap_t = STBGL_CLAMP_TO_EDGE; break;
case 'f' : input_type = GL_FLOAT; break;
case 'F' : input_type = GL_FLOAT; float_tex = 1; break;
case 'p' : premultiply_alpha = 1; break;
case 'P' : pad_to_power_of_two = 1; break;
case '+' : preserve_data = 0; break;
case '!' : preserve_data = 0; free_data = 1; break;
case ' ' : break;
case '-' : break;
default : if (free_data) free(data);
return 0;
}
++props;
}
// override input_desc based on channel count
if (output_desc != STBGL_NO_DOWNLOAD) {
switch (abs(chan)) {
case 1: input_desc = GL_LUMINANCE; break;
case 2: input_desc = GL_LUMINANCE_ALPHA; break;
case 3: input_desc = GL_RGB; break;
case 4: input_desc = GL_RGBA; break;
case 0: break;
default: return 0;
}
}
// override input_desc based on channel info
if (chan > 0) { input_type = GL_UNSIGNED_BYTE; }
if (chan < 0) { input_type = GL_FLOAT; }
if (output_desc == GL_ALPHA) {
if (input_desc == GL_LUMINANCE)
input_desc = GL_ALPHA;
if (input_desc == GL_RGB) {
// force a presumably-mono image to alpha
// @TODO handle 'preserve_data' case?
if (data && !preserve_data && input_type == GL_UNSIGNED_BYTE) {
int i;
unsigned char *p = (unsigned char *) data, *q = p;
for (i=0; i < w*h; ++i) {
*q = (p[0] + 2*p[1] + p[2]) >> 2;
p += 3;
q += 1;
}
input_desc = GL_ALPHA;
}
}
}
// set undefined input/output based on the other
if (input_desc == STBGL_UNDEFINED && output_desc == STBGL_UNDEFINED) {
input_desc = output_desc = GL_RGBA;
} else if (output_desc == STBGL_UNDEFINED) {
switch (input_desc) {
case GL_LUMINANCE:
case GL_ALPHA:
case GL_LUMINANCE_ALPHA:
case GL_RGB:
case GL_RGBA:
output_desc = input_desc;
break;
case GL_RED:
output_desc = GL_INTENSITY;
break;
case STBGL_YCOCG:
case STBGL_YCOCGJ:
output_desc = STBGL_YCOCG;
break;
default: assert(0); return 0;
}
} else if (input_desc == STBGL_UNDEFINED) {
switch (output_desc) {
case GL_LUMINANCE:
case GL_ALPHA:
case GL_LUMINANCE_ALPHA:
case GL_RGB:
case GL_RGBA:
input_desc = output_desc;
break;
case GL_INTENSITY:
input_desc = GL_RED;
break;
case STBGL_YCOCG:
case STBGL_COMPRESSED_RGB_S3TC_DXT1:
case STBGL_COMPRESSED_RGBA_S3TC_DXT3:
case STBGL_COMPRESSED_RGBA_S3TC_DXT5:
input_desc = GL_RGBA;
break;
}
} else {
if (output_desc == STBGL_COMPRESSED_RGB_S3TC_DXT1) {
// if input has alpha, force output alpha
switch (input_desc) {
case GL_ALPHA:
case GL_LUMINANCE_ALPHA:
case GL_RGBA:
output_desc = STBGL_COMPRESSED_RGBA_S3TC_DXT5;
break;
}
}
}
switch(input_desc) {
case GL_LUMINANCE:
case GL_RED:
case GL_ALPHA:
chan = 1;
break;
case GL_LUMINANCE_ALPHA:
chan = 2;
break;
case GL_RGB:
chan = 3;
break;
case GL_RGBA:
chan = 4;
break;
}
if (pad_to_power_of_two && ((w & (w-1)) || (h & (h-1)))) {
if (output_desc != STBGL_NO_DOWNLOAD && input_type == GL_UNSIGNED_BYTE && chan > 0) {
unsigned char *new_data;
int w2 = w, h2 = h, j;
while (w & (w-1))
w = (w | (w>>1))+1;
while (h & (h-1))
h = (h | (h>>1))+1;
new_data = malloc(w * h * chan);
for (j=0; j < h2; ++j) {
memcpy(new_data + j * w * chan, (char *) data+j*w2*chan, w2*chan);
memset(new_data + (j * w+w2) * chan, 0, (w-w2)*chan);
}
for (; j < h; ++j)
memset(new_data + j*w*chan, 0, w*chan);
if (free_data)
free(data);
data = new_data;
free_data = 1;
}
}
switch (output_desc) {
case STBGL_COMPRESSED_RGB_S3TC_DXT1:
case STBGL_COMPRESSED_RGBA_S3TC_DXT1:
case STBGL_COMPRESSED_RGBA_S3TC_DXT3:
case STBGL_COMPRESSED_RGBA_S3TC_DXT5:
is_compressed = 1;
if (has_s3tc == -1) {
has_s3tc = stbgl_hasExtension("GL_EXT_texture_compression_s3tc");
if (has_s3tc) stbgl__initCompTex();
}
if (!has_s3tc) {
is_compressed = 0;
if (output_desc == STBGL_COMPRESSED_RGB_S3TC_DXT1)
output_desc = GL_RGB;
else
output_desc = GL_RGBA;
}
}
if (output_desc == STBGL_YCOCG) {
assert(0);
output_desc = GL_RGB; // @TODO!
if (free_data) free(data);
return 0;
}
mag_filter = 0;
if (mipmaps != STBGL_UNDEFINED) {
switch (filter) {
case STBGL_UNDEFINED: filter = GL_LINEAR_MIPMAP_LINEAR; break;
case GL_NEAREST : mag_filter = GL_NEAREST; filter = GL_LINEAR_MIPMAP_LINEAR; break;
case GL_LINEAR : filter = GL_LINEAR_MIPMAP_NEAREST; break;
}
} else {
if (filter == STBGL_UNDEFINED)
filter = GL_LINEAR;
}
// update filtering
if (!mag_filter) {
if (filter == GL_NEAREST)
mag_filter = GL_NEAREST;
else
mag_filter = GL_LINEAR;
}
// update wrap/clamp
if (wrap_s == STBGL_UNDEFINED) wrap_s = GL_REPEAT;
if (wrap_t == STBGL_UNDEFINED) wrap_t = wrap_s;
// if no texture id, generate one
if (texid == 0) {
GLuint tex;
glGenTextures(1, &tex);
if (tex == 0) { if (free_data) free(data); return 0; }
texid = tex;
}
if (data == NULL && mipmaps == STBGL_GEN_MIPMAPS)
mipmaps = STBGL_MIPMAPS;
if (output_desc == STBGL_NO_DOWNLOAD)
mipmaps = STBGL_NO_DOWNLOAD;
glBindTexture(GL_TEXTURE_2D, texid);
#ifdef STB_COMPRESS_DXT_BLOCK
if (!is_compressed || !stbgl__CompressedTexImage2DARB || output_desc == STBGL_COMPRESSED_RGBA_S3TC_DXT3 || data == NULL)
#endif
{
switch (mipmaps) {
case STBGL_NO_DOWNLOAD:
break;
case STBGL_UNDEFINED:
// check if actually power-of-two
if (non_power_of_two || ((w & (w-1)) == 0 && (h & (h-1)) == 0))
glTexImage2D(GL_TEXTURE_2D, 0, output_desc, w, h, 0, input_desc, input_type, data);
else
gluBuild2DMipmaps(GL_TEXTURE_2D, output_desc, w, h, input_desc, input_type, data);
// not power of two, so use glu to resize (generates mipmaps needlessly)
break;
case STBGL_MIPMAPS: {
int level = 0;
int size = input_type == GL_FLOAT ? sizeof(float) : 1;
if (data == NULL) size = 0; // reuse same block of memory for all mipmaps
assert((w & (w-1)) == 0 && (h & (h-1)) == 0); // verify power-of-two
while (w > 1 && h > 1) {
glTexImage2D(GL_TEXTURE_2D, level, output_desc, w, h, 0, input_desc, input_type, data);
data = (void *) ((char *) data + w * h * size * chan);
if (w > 1) w >>= 1;
if (h > 1) h >>= 1;
++level;
}
break;
}
case STBGL_GEN_MIPMAPS:
gluBuild2DMipmaps(GL_TEXTURE_2D, output_desc, w, h, input_desc, input_type, data);
break;
default:
assert(0);
if (free_data) free(data);
return 0;
}
#ifdef STB_COMPRESS_DXT_BLOCK
} else {
uint8 *out, *rgba=0, *end_out, *end_rgba;
int level = 0, alpha = (output_desc != STBGL_COMPRESSED_RGB_S3TC_DXT1);
int size = input_type == GL_FLOAT ? sizeof(float) : 1;
int osize = alpha ? 16 : 8;
if (!free_data && mipmaps == STBGL_GEN_MIPMAPS) {
uint8 *temp = malloc(w*h*chan);
if (!temp) { if (free_data) free(data); return 0; }
memcpy(temp, data, w*h*chan);
if (free_data) free(data);
free_data = 1;
data = temp;
}
if (chan != 4 || size != 1) {
rgba = malloc(w*h*4);
if (!rgba) return 0;
end_rgba = rgba+w*h*4;
}
out = malloc((w+3)*(h+3)/16*osize); // enough storage for the s3tc data
if (!out) return 0;
end_out = out + ((w+3)*(h+3))/16*osize;
for(;;) {
if (chan != 4)
stbgl__convert(rgba, data, w*h, input_desc, end_rgba);
stbgl__compress(out, rgba ? rgba : data, w, h, output_desc, end_out);
stbgl__CompressedTexImage2DARB(GL_TEXTURE_2D, level, output_desc, w, h, 0, ((w+3)&~3)*((h+3)&~3)/16*osize, out);
//glTexImage2D(GL_TEXTURE_2D, level, alpha?GL_RGBA:GL_RGB, w, h, 0, GL_RGBA, GL_UNSIGNED_BYTE, rgba ? rgba : data);
if (mipmaps == STBGL_UNDEFINED) break;
if (w <= 1 && h <= 1) break;
if (mipmaps == STBGL_MIPMAPS) data = (void *) ((char *) data + w * h * size * chan);
if (mipmaps == STBGL_GEN_MIPMAPS) {
int w2 = w>>1, h2=h>>1, i,j,k, s=w*chan;
uint8 *p = data, *q=data;
if (w == 1) {
for (j=0; j < h2; ++j) {
for (k=0; k < chan; ++k)
*p++ = (q[k] + q[s+k] + 1) >> 1;
q += s*2;
}
} else if (h == 1) {
for (i=0; i < w2; ++i) {
for (k=0; k < chan; ++k)
*p++ = (q[k] + q[k+chan] + 1) >> 1;
q += chan*2;
}
} else {
for (j=0; j < h2; ++j) {
for (i=0; i < w2; ++i) {
for (k=0; k < chan; ++k)
*p++ = (q[k] + q[k+chan] + q[s+k] + q[s+k+chan] + 2) >> 2;
q += chan*2;
}
q += s;
}
}
}
if (w > 1) w >>= 1;
if (h > 1) h >>= 1;
++level;
}
if (out) free(out);
if (rgba) free(rgba);
#endif // STB_COMPRESS_DXT_BLOCK
}
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, wrap_s);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, wrap_t);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, mag_filter);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, filter);
if (free_data) free(data);
return texid;
}
#endif // STB_DEFINE
#undef STB_EXTERN
#endif //INCLUDE_STB_GL_H
// Extension handling... must be outside the INCLUDE_ brackets
#if defined(STB_GLEXT_DEFINE) || defined(STB_GLEXT_DECLARE)
#ifndef STB_GLEXT_SKIP_DURING_RECURSION
#ifndef GL_GLEXT_VERSION
// First check if glext.h is concatenated on the end of this file
// (if it's concatenated on the beginning, we'll have GL_GLEXT_VERSION)
#define STB_GLEXT_SKIP_DURING_RECURSION
#include __FILE__
#undef STB_GLEXT_SKIP_DURING_RECURSION
// now check if it's still undefined; if so, try going for it by name;
// if this errors, that's fine, since we can't compile without it
#ifndef GL_GLEXT_VERSION
#include "glext.h"
#endif
#endif
#define GLARB(a,b) GLE(a##ARB,b##ARB)
#define GLEXT(a,b) GLE(a##EXT,b##EXT)
#define GLNV(a,b) GLE(a##NV ,b##NV)
#define GLATI(a,b) GLE(a##ATI,b##ATI)
#define GLCORE(a,b) GLE(a,b)
#ifdef STB_GLEXT_DEFINE_DECLARE
#define STB_GLEXT_DEFINE STB_GLEXT_DECLARE
#endif
#if defined(STB_GLEXT_DECLARE) && defined(STB_GLEXT_DEFINE)
#undef STB_GLEXT_DECLARE
#endif
#if defined(STB_GLEXT_DECLARE) && !defined(STB_GLEXT_DEFINE)
#define GLE(a,b) extern PFNGL##b##PROC gl##a;
#ifdef __cplusplus
extern "C" {
#endif
extern void stbgl_initExtensions(void);
#include STB_GLEXT_DECLARE
#ifdef __cplusplus
};
#endif
#else
#ifndef STB_GLEXT_DEFINE
#error "Header file is screwed up somehow"
#endif
#ifdef _WIN32
#ifndef WINGDIAPI
#ifndef STB__HAS_WGLPROC
typedef int (__stdcall *stbgl__voidfunc)(void);
__declspec(dllimport) stbgl__voidfunc wglGetProcAddress(char *);
#endif
#endif
#define STBGL__GET_FUNC(x) wglGetProcAddress(x)
#endif
#ifdef GLE
#undef GLE
#endif
#define GLE(a,b) PFNGL##b##PROC gl##a;
#include STB_GLEXT_DEFINE
#undef GLE
#define GLE(a,b) gl##a = (PFNGL##b##PROC) STBGL__GET_FUNC("gl" #a );
void stbgl_initExtensions(void)
{
#include STB_GLEXT_DEFINE
}
#undef GLE
#endif // STB_GLEXT_DECLARE
#endif // STB_GLEXT_SKIP
#endif // STB_GLEXT_DEFINE || STB_GLEXT_DECLARE