1/**************************************************************************
2 *
3 * Copyright 2008 Tungsten Graphics, Inc., Cedar Park, Texas.
4 * All Rights Reserved.
5 *
6 **************************************************************************/
7
8
9/**
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
12 */
13
14
15#include <stdlib.h>
16#include <math.h>
17#include "GLES/gl.h"
18#include "GLES/glext.h"
19
20
21/**
22 * This is from the GL_OES_query_matrix extension specification:
23 *
24 *  GLbitfield glQueryMatrixxOES( GLfixed mantissa[16],
25 *                                GLint   exponent[16] )
26 *  mantissa[16] contains the contents of the current matrix in GLfixed
27 *  format.  exponent[16] contains the unbiased exponents applied to the
28 *  matrix components, so that the internal representation of component i
29 *  is close to mantissa[i] * 2^exponent[i].  The function returns a status
30 *  word which is zero if all the components are valid. If
31 *  status & (1<<i) != 0, the component i is invalid (e.g., NaN, Inf).
32 *  The implementations are not required to keep track of overflows.  In
33 *  that case, the invalid bits are never set.
34 */
35
36#define INT_TO_FIXED(x) ((GLfixed) ((x) << 16))
37#define FLOAT_TO_FIXED(x) ((GLfixed) ((x) * 65536.0))
38
39#if defined(_MSC_VER)
40/* Oddly, the fpclassify() function doesn't exist in such a form
41 * on MSVC.  This is an implementation using slightly different
42 * lower-level Windows functions.
43 */
44#include <float.h>
45
46enum {FP_NAN, FP_INFINITE, FP_ZERO, FP_SUBNORMAL, FP_NORMAL}
47fpclassify(double x)
48{
49    switch(_fpclass(x)) {
50        case _FPCLASS_SNAN: /* signaling NaN */
51        case _FPCLASS_QNAN: /* quiet NaN */
52            return FP_NAN;
53        case _FPCLASS_NINF: /* negative infinity */
54        case _FPCLASS_PINF: /* positive infinity */
55            return FP_INFINITE;
56        case _FPCLASS_NN:   /* negative normal */
57        case _FPCLASS_PN:   /* positive normal */
58            return FP_NORMAL;
59        case _FPCLASS_ND:   /* negative denormalized */
60        case _FPCLASS_PD:   /* positive denormalized */
61            return FP_SUBNORMAL;
62        case _FPCLASS_NZ:   /* negative zero */
63        case _FPCLASS_PZ:   /* positive zero */
64            return FP_ZERO;
65        default:
66            /* Should never get here; but if we do, this will guarantee
67             * that the pattern is not treated like a number.
68             */
69            return FP_NAN;
70    }
71}
72
73#elif defined(__APPLE__) || defined(__CYGWIN__) || defined(__FreeBSD__) || \
74     defined(__OpenBSD__) || defined(__NetBSD__) || defined(__DragonFly__) || \
75     (defined(__sun) && defined(__C99FEATURES__)) || defined(__MINGW32__) || \
76     (defined(__sun) && defined(__GNUC__)) || defined(ANDROID) || defined(__HAIKU__)
77
78/* fpclassify is available. */
79
80#elif !defined(_XOPEN_SOURCE) || _XOPEN_SOURCE < 600
81
82enum {FP_NAN, FP_INFINITE, FP_ZERO, FP_SUBNORMAL, FP_NORMAL}
83fpclassify(double x)
84{
85   /* XXX do something better someday */
86   return FP_NORMAL;
87}
88
89#endif
90
91extern GLbitfield GL_APIENTRY _es_QueryMatrixxOES(GLfixed mantissa[16], GLint exponent[16]);
92
93/* The Mesa functions we'll need */
94extern void GL_APIENTRY _mesa_GetIntegerv(GLenum pname, GLint *params);
95extern void GL_APIENTRY _mesa_GetFloatv(GLenum pname, GLfloat *params);
96
97GLbitfield GL_APIENTRY _es_QueryMatrixxOES(GLfixed mantissa[16], GLint exponent[16])
98{
99    GLfloat matrix[16];
100    GLint tmp;
101    GLenum currentMode = GL_FALSE;
102    GLenum desiredMatrix = GL_FALSE;
103    /* The bitfield returns 1 for each component that is invalid (i.e.
104     * NaN or Inf).  In case of error, everything is invalid.
105     */
106    GLbitfield rv;
107    register unsigned int i;
108    unsigned int bit;
109
110    /* This data structure defines the mapping between the current matrix
111     * mode and the desired matrix identifier.
112     */
113    static struct {
114        GLenum currentMode;
115        GLenum desiredMatrix;
116    } modes[] = {
117        {GL_MODELVIEW, GL_MODELVIEW_MATRIX},
118        {GL_PROJECTION, GL_PROJECTION_MATRIX},
119        {GL_TEXTURE, GL_TEXTURE_MATRIX},
120    };
121
122    /* Call Mesa to get the current matrix in floating-point form.  First,
123     * we have to figure out what the current matrix mode is.
124     */
125    _mesa_GetIntegerv(GL_MATRIX_MODE, &tmp);
126    currentMode = (GLenum) tmp;
127
128    /* The mode is either GL_FALSE, if for some reason we failed to query
129     * the mode, or a given mode from the above table.  Search for the
130     * returned mode to get the desired matrix; if we don't find it,
131     * we can return immediately, as _mesa_GetInteger() will have
132     * logged the necessary error already.
133     */
134    for (i = 0; i < sizeof(modes)/sizeof(modes[0]); i++) {
135        if (modes[i].currentMode == currentMode) {
136            desiredMatrix = modes[i].desiredMatrix;
137            break;
138        }
139    }
140    if (desiredMatrix == GL_FALSE) {
141        /* Early error means all values are invalid. */
142        return 0xffff;
143    }
144
145    /* Now pull the matrix itself. */
146    _mesa_GetFloatv(desiredMatrix, matrix);
147
148    rv = 0;
149    for (i = 0, bit = 1; i < 16; i++, bit<<=1) {
150        float normalizedFraction;
151        int exp;
152
153        switch (fpclassify(matrix[i])) {
154            /* A "subnormal" or denormalized number is too small to be
155             * represented in normal format; but despite that it's a
156             * valid floating point number.  FP_ZERO and FP_NORMAL
157             * are both valid as well.  We should be fine treating
158             * these three cases as legitimate floating-point numbers.
159             */
160            case FP_SUBNORMAL:
161            case FP_NORMAL:
162            case FP_ZERO:
163                normalizedFraction = (GLfloat)frexp(matrix[i], &exp);
164                mantissa[i] = FLOAT_TO_FIXED(normalizedFraction);
165                exponent[i] = (GLint) exp;
166                break;
167
168            /* If the entry is not-a-number or an infinity, then the
169             * matrix component is invalid.  The invalid flag for
170             * the component is already set; might as well set the
171             * other return values to known values.  We'll set
172             * distinct values so that a savvy end user could determine
173             * whether the matrix component was a NaN or an infinity,
174             * but this is more useful for debugging than anything else
175             * since the standard doesn't specify any such magic
176             * values to return.
177             */
178            case FP_NAN:
179                mantissa[i] = INT_TO_FIXED(0);
180                exponent[i] = (GLint) 0;
181                rv |= bit;
182                break;
183
184            case FP_INFINITE:
185                /* Return +/- 1 based on whether it's a positive or
186                 * negative infinity.
187                 */
188                if (matrix[i] > 0) {
189                    mantissa[i] = INT_TO_FIXED(1);
190                }
191                else {
192                    mantissa[i] = -INT_TO_FIXED(1);
193                }
194                exponent[i] = (GLint) 0;
195                rv |= bit;
196                break;
197
198            /* We should never get here; but here's a catching case
199             * in case fpclassify() is returnings something unexpected.
200             */
201            default:
202                mantissa[i] = INT_TO_FIXED(2);
203                exponent[i] = (GLint) 0;
204                rv |= bit;
205                break;
206        }
207
208    } /* for each component */
209
210    /* All done */
211    return rv;
212}
213