8f1edcb6ed
Cogl now assumes non-power-of-two textures are supported if the GL version is >= 2.0 so the disable-npots utility should also change the GL version.
156 lines
3.9 KiB
C
156 lines
3.9 KiB
C
/*
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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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/* This is just included to get the right GL header */
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#include <cogl/cogl.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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#include <stdlib.h>
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/* If RTLD_NEXT isn't available then try just using NULL */
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#ifdef RTLD_NEXT
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#define LIB_HANDLE RTLD_NEXT
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#else
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#define LIB_HANDLE NULL
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#endif
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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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static gboolean
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get_gl_version (const gchar *version_string,
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int *major_out, int *minor_out)
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{
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const char *major_end, *minor_end;
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int major = 0, minor = 0;
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if (version_string == NULL)
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return FALSE;
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/* Extract the major number */
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for (major_end = version_string; *major_end >= '0'
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&& *major_end <= '9'; major_end++)
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major = (major * 10) + *major_end - '0';
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/* If there were no digits or the major number isn't followed by a
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dot then it is invalid */
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if (major_end == version_string || *major_end != '.')
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return FALSE;
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/* Extract the minor number */
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for (minor_end = major_end + 1; *minor_end >= '0'
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&& *minor_end <= '9'; minor_end++)
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minor = (minor * 10) + *minor_end - '0';
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/* If there were no digits or there is an unexpected character then
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it is invalid */
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if (minor_end == major_end + 1
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|| (*minor_end && *minor_end != ' ' && *minor_end != '.'))
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return FALSE;
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*major_out = major;
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*minor_out = minor;
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return TRUE;
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}
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const GLubyte *
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glGetString (GLenum name)
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{
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const gchar *ret = NULL;
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static GetStringFunc func = NULL;
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static gchar *extensions = NULL;
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static gchar *version = NULL;
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if (func == NULL
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&& (func = (GetStringFunc) dlsym (LIB_HANDLE, "glGetString")) == NULL)
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fprintf (stderr, "dlsym: %s\n", dlerror ());
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else if (func == glGetString)
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fprintf (stderr, "dlsym returned the wrapper of glGetString\n");
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else
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{
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ret = (const gchar *) (* 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 = 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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gchar *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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gchar *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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else if (name == GL_VERSION)
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{
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int gl_major, gl_minor;
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/* If the GL version is >= 2.0 then Cogl will assume it
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supports NPOT textures anyway so we need to tweak it */
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if (get_gl_version ((const gchar *) ret,
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&gl_major, &gl_minor) && gl_major >= 2)
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{
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if (version == NULL)
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{
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const gchar *tail = strchr (ret, ' ');
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if (tail)
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{
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version = malloc (3 + strlen (tail) + 1);
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if (version)
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{
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strcpy (version + 3, tail);
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memcpy (version, "1.9", 3);
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}
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}
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else
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version = strdup ("1.9");
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}
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ret = version;
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}
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}
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}
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return (const GLubyte *) ret;
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}
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