Mercurial > sdl-ios-xcode
annotate src/video/e_log.h @ 4384:6800e2560310 SDL-1.2
Fixed bugs #882 and 865, re-opening bug #634
Ronald Lamprecht to SDL
Hi,
Sam Lantinga wrote:
The problem with that fix is that it breaks IME events again. Maybe
we can handle keyboard events differently to prevent this issue?
Spending an hour reading MSDN, analysing SDL and another hour testing the reality on XP I am really wondering how patch r4990 could have ever worked in any situation. It's main effect is to break the unicode translation and causing spurious activation events!
Why does TranslateMessage(&msg) nothing useful? Simply because it does not affect "msg" at all! All keyboard events are dispatched without the slightest change (see MSDN). TranslateMessage() just appends additional WM_CHAR, WM_DEADCHAR, WM_SYSCHAR, WM_SYSDEADCHAR event messages to the queue. But I could not find any SDL event handling routine that catches these events and transforms them to proper SDL keyevents while eliminating the corresponding WM_KEYDOWN, etc. events. Thus any IME input like the '@' generated by "Alt + 6(Numpad) + 4(Numpad)" is simply lost.
But the situation is even worse! Up to r4990 the TranslateKey()/ToUnicode() calls did evaluate dead keys and did deliver proper key events for subsequent key strokes like '´' + 'e' resulting in 'é'. ToUnicode() needs proper key state informations to be able to handle these substitutions. But unfortunatly TranslateMessage() needs the same state information and eats it up while generating the WM_CHAR messages :-( Thus the current 1.2.14 breakes the partial IME support of previous releases, too.
The key state race condition between ToUnicode() and TranslateMessage() requires to avoid any ToUnicode() usage for receiving proper WM_CHAR, etc. messages generated by TranslateMessage(). (Yes - the '@' and 'é' appear as WM_CHAR messages when unicode is switched off).
The spurious SDL activation events are *not* caused by additional WM_ACTIVATE Windows messages! Besides DIB_HandleMessage() SDL_PrivateAppActive() is called by another source which I am not yet aware of - any hints?
Thus I do strongly recommend the deletion of the TranslateMessage(&msg) call as a quick fix.
A proper support of unicode and IME requires a clean SDL keyboard input concept first. Which SDL keyboards events should be transmitted to the app when the user presses '´' + 'e' ? Within the current unicode handling the first key stroke is hidden. Even though ToUnicode() delivers the proper key SDL does ignore it in TranslateKey(). Just the composed key event is transmitted to the app. That is what you expect for text input, but the app can no longer use keys like '^' as a key button because it will never receive a key event for it!
With a given concept it seems to be necessary to regenerate SDL key events out of the WM_CHAR, etc. events and to drop all related direct WM_KEYDOWN, etc. events while the remaining basic WM_KEYDOWN, etc. events would still have to result in SDL key events.
Anyway the source of the spurious WM_ACTIVATE should be located to avoid future trouble.
Greets,
Ronald
author | Sam Lantinga <slouken@libsdl.org> |
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date | Tue, 17 Nov 2009 04:59:13 +0000 |
parents | 450721ad5436 |
children | 782fd950bd46 c121d94672cb |
rev | line source |
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1 /* @(#)e_log.c 5.1 93/09/24 */ |
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2 /* |
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3 * ==================================================== |
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4 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved. |
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5 * |
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6 * Developed at SunPro, a Sun Microsystems, Inc. business. |
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7 * Permission to use, copy, modify, and distribute this |
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8 * software is freely granted, provided that this notice |
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9 * is preserved. |
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10 * ==================================================== |
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11 */ |
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12 |
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13 #if defined(LIBM_SCCS) && !defined(lint) |
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14 static char rcsid[] = "$NetBSD: e_log.c,v 1.8 1995/05/10 20:45:49 jtc Exp $"; |
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15 #endif |
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16 |
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17 /* __ieee754_log(x) |
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18 * Return the logrithm of x |
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19 * |
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20 * Method : |
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21 * 1. Argument Reduction: find k and f such that |
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22 * x = 2^k * (1+f), |
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23 * where sqrt(2)/2 < 1+f < sqrt(2) . |
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24 * |
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25 * 2. Approximation of log(1+f). |
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26 * Let s = f/(2+f) ; based on log(1+f) = log(1+s) - log(1-s) |
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27 * = 2s + 2/3 s**3 + 2/5 s**5 + ....., |
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28 * = 2s + s*R |
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29 * We use a special Reme algorithm on [0,0.1716] to generate |
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30 * a polynomial of degree 14 to approximate R The maximum error |
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31 * of this polynomial approximation is bounded by 2**-58.45. In |
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32 * other words, |
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33 * 2 4 6 8 10 12 14 |
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34 * R(z) ~ Lg1*s +Lg2*s +Lg3*s +Lg4*s +Lg5*s +Lg6*s +Lg7*s |
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35 * (the values of Lg1 to Lg7 are listed in the program) |
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36 * and |
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37 * | 2 14 | -58.45 |
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38 * | Lg1*s +...+Lg7*s - R(z) | <= 2 |
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39 * | | |
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40 * Note that 2s = f - s*f = f - hfsq + s*hfsq, where hfsq = f*f/2. |
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41 * In order to guarantee error in log below 1ulp, we compute log |
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42 * by |
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43 * log(1+f) = f - s*(f - R) (if f is not too large) |
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44 * log(1+f) = f - (hfsq - s*(hfsq+R)). (better accuracy) |
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45 * |
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46 * 3. Finally, log(x) = k*ln2 + log(1+f). |
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47 * = k*ln2_hi+(f-(hfsq-(s*(hfsq+R)+k*ln2_lo))) |
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48 * Here ln2 is split into two floating point number: |
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49 * ln2_hi + ln2_lo, |
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50 * where n*ln2_hi is always exact for |n| < 2000. |
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51 * |
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52 * Special cases: |
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53 * log(x) is NaN with signal if x < 0 (including -INF) ; |
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54 * log(+INF) is +INF; log(0) is -INF with signal; |
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55 * log(NaN) is that NaN with no signal. |
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56 * |
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57 * Accuracy: |
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58 * according to an error analysis, the error is always less than |
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59 * 1 ulp (unit in the last place). |
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60 * |
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61 * Constants: |
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62 * The hexadecimal values are the intended ones for the following |
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63 * constants. The decimal values may be used, provided that the |
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64 * compiler will convert from decimal to binary accurately enough |
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65 * to produce the hexadecimal values shown. |
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66 */ |
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67 |
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68 /*#include "math.h"*/ |
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69 #include "math_private.h" |
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70 |
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71 #ifdef __STDC__ |
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72 static const double |
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73 #else |
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74 static double |
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75 #endif |
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76 ln2_hi = 6.93147180369123816490e-01, /* 3fe62e42 fee00000 */ |
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77 ln2_lo = 1.90821492927058770002e-10, /* 3dea39ef 35793c76 */ |
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78 Lg1 = 6.666666666666735130e-01, /* 3FE55555 55555593 */ |
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79 Lg2 = 3.999999999940941908e-01, /* 3FD99999 9997FA04 */ |
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80 Lg3 = 2.857142874366239149e-01, /* 3FD24924 94229359 */ |
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81 Lg4 = 2.222219843214978396e-01, /* 3FCC71C5 1D8E78AF */ |
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82 Lg5 = 1.818357216161805012e-01, /* 3FC74664 96CB03DE */ |
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83 Lg6 = 1.531383769920937332e-01, /* 3FC39A09 D078C69F */ |
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84 Lg7 = 1.479819860511658591e-01; /* 3FC2F112 DF3E5244 */ |
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85 |
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86 #ifdef __STDC__ |
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87 double __ieee754_log(double x) |
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88 #else |
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89 double __ieee754_log(x) |
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90 double x; |
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91 #endif |
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92 { |
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93 double hfsq,f,s,z,R,w,t1,t2,dk; |
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94 int32_t k,hx,i,j; |
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95 u_int32_t lx; |
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96 |
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97 EXTRACT_WORDS(hx,lx,x); |
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98 |
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99 k=0; |
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100 if (hx < 0x00100000) { /* x < 2**-1022 */ |
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101 if (((hx&0x7fffffff)|lx)==0) |
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102 return -two54/zero; /* log(+-0)=-inf */ |
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103 if (hx<0) return (x-x)/zero; /* log(-#) = NaN */ |
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104 k -= 54; x *= two54; /* subnormal number, scale up x */ |
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105 GET_HIGH_WORD(hx,x); |
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106 } |
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107 if (hx >= 0x7ff00000) return x+x; |
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108 k += (hx>>20)-1023; |
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109 hx &= 0x000fffff; |
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110 i = (hx+0x95f64)&0x100000; |
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111 SET_HIGH_WORD(x,hx|(i^0x3ff00000)); /* normalize x or x/2 */ |
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112 k += (i>>20); |
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113 f = x-1.0; |
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114 if((0x000fffff&(2+hx))<3) { /* |f| < 2**-20 */ |
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115 if(f==zero) {if(k==0) return zero; else {dk=(double)k; |
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116 return dk*ln2_hi+dk*ln2_lo;} |
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117 } |
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118 R = f*f*(0.5-0.33333333333333333*f); |
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119 if(k==0) return f-R; else {dk=(double)k; |
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120 return dk*ln2_hi-((R-dk*ln2_lo)-f);} |
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121 } |
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122 s = f/(2.0+f); |
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123 dk = (double)k; |
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124 z = s*s; |
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125 i = hx-0x6147a; |
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126 w = z*z; |
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127 j = 0x6b851-hx; |
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128 t1= w*(Lg2+w*(Lg4+w*Lg6)); |
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129 t2= z*(Lg1+w*(Lg3+w*(Lg5+w*Lg7))); |
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130 i |= j; |
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131 R = t2+t1; |
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132 if(i>0) { |
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133 hfsq=0.5*f*f; |
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134 if(k==0) return f-(hfsq-s*(hfsq+R)); else |
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135 return dk*ln2_hi-((hfsq-(s*(hfsq+R)+dk*ln2_lo))-f); |
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136 } else { |
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137 if(k==0) return f-s*(f-R); else |
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138 return dk*ln2_hi-((s*(f-R)-dk*ln2_lo)-f); |
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139 } |
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140 } |