1 /**************************************************************************
3 * Copyright 2008 VMware, Inc.
6 **************************************************************************/
10 * Code to implement GL_OES_query_matrix. See the spec at:
11 * http://www.khronos.org/registry/gles/extensions/OES/OES_query_matrix.txt
18 #include "querymatrix.h"
23 * This is from the GL_OES_query_matrix extension specification:
25 * GLbitfield glQueryMatrixxOES( GLfixed mantissa[16],
26 * GLint exponent[16] )
27 * mantissa[16] contains the contents of the current matrix in GLfixed
28 * format. exponent[16] contains the unbiased exponents applied to the
29 * matrix components, so that the internal representation of component i
30 * is close to mantissa[i] * 2^exponent[i]. The function returns a status
31 * word which is zero if all the components are valid. If
32 * status & (1<<i) != 0, the component i is invalid (e.g., NaN, Inf).
33 * The implementations are not required to keep track of overflows. In
34 * that case, the invalid bits are never set.
37 #define INT_TO_FIXED(x) ((GLfixed) ((x) << 16))
38 #define FLOAT_TO_FIXED(x) ((GLfixed) ((x) * 65536.0))
41 #if _MSC_VER < 1800 /* Not required on VS2013 and above. */
42 /* Oddly, the fpclassify() function doesn't exist in such a form
43 * on MSVC. This is an implementation using slightly different
44 * lower-level Windows functions.
48 enum {FP_NAN
, FP_INFINITE
, FP_ZERO
, FP_SUBNORMAL
, FP_NORMAL
}
52 case _FPCLASS_SNAN
: /* signaling NaN */
53 case _FPCLASS_QNAN
: /* quiet NaN */
55 case _FPCLASS_NINF
: /* negative infinity */
56 case _FPCLASS_PINF
: /* positive infinity */
58 case _FPCLASS_NN
: /* negative normal */
59 case _FPCLASS_PN
: /* positive normal */
61 case _FPCLASS_ND
: /* negative denormalized */
62 case _FPCLASS_PD
: /* positive denormalized */
64 case _FPCLASS_NZ
: /* negative zero */
65 case _FPCLASS_PZ
: /* positive zero */
68 /* Should never get here; but if we do, this will guarantee
69 * that the pattern is not treated like a number.
74 #endif /* _MSC_VER < 1800 */
76 #elif defined(__APPLE__) || defined(__CYGWIN__) || defined(__FreeBSD__) || \
77 defined(__OpenBSD__) || defined(__NetBSD__) || defined(__DragonFly__) || \
78 (defined(__sun) && defined(__C99FEATURES__)) || defined(__MINGW32__) || \
79 (defined(__sun) && defined(__GNUC__)) || defined(ANDROID) || defined(__HAIKU__)
81 /* fpclassify is available. */
83 #elif !defined(_XOPEN_SOURCE) || _XOPEN_SOURCE < 600
85 enum {FP_NAN
, FP_INFINITE
, FP_ZERO
, FP_SUBNORMAL
, FP_NORMAL
}
88 /* XXX do something better someday */
94 GLbitfield GLAPIENTRY
_mesa_QueryMatrixxOES(GLfixed mantissa
[16], GLint exponent
[16])
98 GLenum currentMode
= GL_FALSE
;
99 GLenum desiredMatrix
= GL_FALSE
;
100 /* The bitfield returns 1 for each component that is invalid (i.e.
101 * NaN or Inf). In case of error, everything is invalid.
104 register unsigned int i
;
107 /* This data structure defines the mapping between the current matrix
108 * mode and the desired matrix identifier.
112 GLenum desiredMatrix
;
114 {GL_MODELVIEW
, GL_MODELVIEW_MATRIX
},
115 {GL_PROJECTION
, GL_PROJECTION_MATRIX
},
116 {GL_TEXTURE
, GL_TEXTURE_MATRIX
},
119 /* Call Mesa to get the current matrix in floating-point form. First,
120 * we have to figure out what the current matrix mode is.
122 _mesa_GetIntegerv(GL_MATRIX_MODE
, &tmp
);
123 currentMode
= (GLenum
) tmp
;
125 /* The mode is either GL_FALSE, if for some reason we failed to query
126 * the mode, or a given mode from the above table. Search for the
127 * returned mode to get the desired matrix; if we don't find it,
128 * we can return immediately, as _mesa_GetInteger() will have
129 * logged the necessary error already.
131 for (i
= 0; i
< sizeof(modes
)/sizeof(modes
[0]); i
++) {
132 if (modes
[i
].currentMode
== currentMode
) {
133 desiredMatrix
= modes
[i
].desiredMatrix
;
137 if (desiredMatrix
== GL_FALSE
) {
138 /* Early error means all values are invalid. */
142 /* Now pull the matrix itself. */
143 _mesa_GetFloatv(desiredMatrix
, matrix
);
146 for (i
= 0, bit
= 1; i
< 16; i
++, bit
<<=1) {
147 float normalizedFraction
;
150 switch (fpclassify(matrix
[i
])) {
151 /* A "subnormal" or denormalized number is too small to be
152 * represented in normal format; but despite that it's a
153 * valid floating point number. FP_ZERO and FP_NORMAL
154 * are both valid as well. We should be fine treating
155 * these three cases as legitimate floating-point numbers.
160 normalizedFraction
= (GLfloat
)frexp(matrix
[i
], &exp
);
161 mantissa
[i
] = FLOAT_TO_FIXED(normalizedFraction
);
162 exponent
[i
] = (GLint
) exp
;
165 /* If the entry is not-a-number or an infinity, then the
166 * matrix component is invalid. The invalid flag for
167 * the component is already set; might as well set the
168 * other return values to known values. We'll set
169 * distinct values so that a savvy end user could determine
170 * whether the matrix component was a NaN or an infinity,
171 * but this is more useful for debugging than anything else
172 * since the standard doesn't specify any such magic
176 mantissa
[i
] = INT_TO_FIXED(0);
177 exponent
[i
] = (GLint
) 0;
182 /* Return +/- 1 based on whether it's a positive or
186 mantissa
[i
] = INT_TO_FIXED(1);
189 mantissa
[i
] = -INT_TO_FIXED(1);
191 exponent
[i
] = (GLint
) 0;
195 /* We should never get here; but here's a catching case
196 * in case fpclassify() is returnings something unexpected.
199 mantissa
[i
] = INT_TO_FIXED(2);
200 exponent
[i
] = (GLint
) 0;
205 } /* for each component */