85 lines
1.8 KiB
C
85 lines
1.8 KiB
C
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/*
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* This file can be build as a shared library and then used as an
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* LD_PRELOAD to fake a system where NPOTs is not supported. It simply
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* overrides glGetString and removes the extension strings.
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*/
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#include <GL/gl.h>
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#include <dlfcn.h>
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#include <stdio.h>
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#include <string.h>
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#include <errno.h>
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#include <ctype.h>
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typedef const GLubyte * (* GetStringFunc) (GLenum name);
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static const char * const bad_strings[]
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= { "GL_ARB_texture_non_power_of_two",
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"GL_ARB_texture_rectangle",
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"GL_EXT_texture_rectangle",
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NULL };
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const GLubyte *
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glGetString (GLenum name)
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{
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const GLubyte *ret = NULL;
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static void *gl_lib = NULL;
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static GetStringFunc func = NULL;
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static GLubyte *extensions = NULL;
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if (gl_lib == NULL
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&& (gl_lib = dlopen ("libGL.so", RTLD_LAZY)) == NULL)
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fprintf (stderr, "dlopen: %s\n", dlerror ());
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else if (func == NULL
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&& (func = (GetStringFunc) dlsym (gl_lib, "glGetString")) == NULL)
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fprintf (stderr, "dlsym: %s\n", dlerror ());
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else
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{
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ret = (* func) (name);
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if (name == GL_EXTENSIONS)
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{
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if (extensions == NULL)
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{
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if ((extensions = (GLubyte *) strdup ((char *) ret)) == NULL)
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fprintf (stderr, "strdup: %s\n", strerror (errno));
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else
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{
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GLubyte *dst = extensions, *src = extensions;
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while (1)
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{
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const char * const *str = bad_strings;
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GLubyte *end;
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while (isspace (*src))
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*(dst++) = *(src++);
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if (*src == 0)
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break;
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for (end = src + 1; *end && !isspace (*end); end++);
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while (*str && strncmp ((char *) src, *str, end - src))
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str++;
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if (*str == NULL)
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{
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memcpy (dst, src, end - src);
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dst += end - src;
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}
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src = end;
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}
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*dst = '\0';
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}
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}
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ret = extensions;
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}
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}
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return ret;
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}
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