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comparison src/video/SDL_gamma.c @ 3012:7e30c2dc7783

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Fixed Visual C++ release build for Visual C++ 2005 * Some math functions become intrinsic in release mode, so we need to convert all the math functions into SDL math functions, like we did with the stdlib functions. * Constant initializers of 8-bit values become calls to memset() in release mode, but memset() itself is an intrinsic when explicitly called. So we'll just explicitly call memset() in those cases.
author Sam Lantinga <slouken@libsdl.org>
date Sat, 10 Jan 2009 18:32:24 +0000
parents 99210400e8b9
children 62d4992e5a92
comparison
equal deleted inserted replaced
3011:8f4ed5ec2b06 3012:7e30c2dc7783
20 slouken@libsdl.org 20 slouken@libsdl.org
21 */ 21 */
22 #include "SDL_config.h" 22 #include "SDL_config.h"
23 23
24 /* Gamma correction support */ 24 /* Gamma correction support */
25
26 #include "../libm/math.h"
27 25
28 #include "SDL_sysvideo.h" 26 #include "SDL_sysvideo.h"
29 27
30 28
31 static void 29 static void
50 /* Calculate a real gamma ramp */ 48 /* Calculate a real gamma ramp */
51 { 49 {
52 int value; 50 int value;
53 gamma = 1.0f / gamma; 51 gamma = 1.0f / gamma;
54 for (i = 0; i < 256; ++i) { 52 for (i = 0; i < 256; ++i) {
55 value = (int) (pow((double) i / 256.0, gamma) * 65535.0 + 0.5); 53 value = (int) (SDL_pow((double) i / 256.0, gamma) * 65535.0 + 0.5);
56 if (value > 65535) { 54 if (value > 65535) {
57 value = 65535; 55 value = 65535;
58 } 56 }
59 ramp[i] = (Uint16) value; 57 ramp[i] = (Uint16) value;
60 } 58 }
73 *gamma = 1.0; 71 *gamma = 1.0;
74 for (i = 1; i < 256; ++i) { 72 for (i = 1; i < 256; ++i) {
75 if ((ramp[i] != 0) && (ramp[i] != 65535)) { 73 if ((ramp[i] != 0) && (ramp[i] != 65535)) {
76 double B = (double) i / 256.0; 74 double B = (double) i / 256.0;
77 double A = ramp[i] / 65535.0; 75 double A = ramp[i] / 65535.0;
78 sum += (float) (log(A) / log(B)); 76 sum += (float) (SDL_log(A) / SDL_log(B));
79 count++; 77 count++;
80 } 78 }
81 } 79 }
82 if (count && sum > 0.0f) { 80 if (count && sum > 0.0f) {
83 *gamma = 1.0f / (sum / count); 81 *gamma = 1.0f / (sum / count);