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comparison test/testgamma.c @ 0:74212992fb08

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Initial revision
author Sam Lantinga <slouken@lokigames.com>
date Thu, 26 Apr 2001 16:45:43 +0000
parents
children be9c9c8f6d53
comparison
equal deleted inserted replaced
-1:000000000000 0:74212992fb08
1
2 /* Bring up a window and manipulate the gamma on it */
3
4 #include <stdlib.h>
5 #include <stdio.h>
6 #include <string.h>
7 #include <math.h>
8
9 #include "SDL.h"
10
11 /* Turn a normal gamma value into an appropriate gamma ramp */
12 void CalculateGamma(double gamma, Uint16 *ramp)
13 {
14 int i, value;
15
16 gamma = 1.0 / gamma;
17 for ( i=0; i<256; ++i ) {
18 value = (int)(pow((double)i/256.0, gamma)*65535.0 + 0.5);
19 if ( value > 65535 ) {
20 value = 65535;
21 }
22 ramp[i] = (Uint16)value;
23 }
24 }
25
26 /* This can be used as a general routine for all of the test programs */
27 int get_video_args(char *argv[], int *w, int *h, int *bpp, Uint32 *flags)
28 {
29 int i;
30
31 *w = 640;
32 *h = 480;
33 *bpp = 0;
34 *flags = SDL_SWSURFACE;
35
36 for ( i=1; argv[i]; ++i ) {
37 if ( strcmp(argv[i], "-width") == 0 ) {
38 if ( argv[i+1] ) {
39 *w = atoi(argv[++i]);
40 }
41 } else
42 if ( strcmp(argv[i], "-height") == 0 ) {
43 if ( argv[i+1] ) {
44 *h = atoi(argv[++i]);
45 }
46 } else
47 if ( strcmp(argv[i], "-bpp") == 0 ) {
48 if ( argv[i+1] ) {
49 *bpp = atoi(argv[++i]);
50 }
51 } else
52 if ( strcmp(argv[i], "-fullscreen") == 0 ) {
53 *flags |= SDL_FULLSCREEN;
54 } else
55 if ( strcmp(argv[i], "-hw") == 0 ) {
56 *flags |= SDL_HWSURFACE;
57 } else
58 if ( strcmp(argv[i], "-hwpalette") == 0 ) {
59 *flags |= SDL_HWPALETTE;
60 } else
61 break;
62 }
63 return i;
64 }
65
66 int main(int argc, char *argv[])
67 {
68 SDL_Surface *screen;
69 SDL_Surface *image;
70 float gamma;
71 int i;
72 int w, h, bpp;
73 Uint32 flags;
74 Uint16 ramp[256];
75 Uint16 red_ramp[256];
76 Uint32 then, timeout;
77
78 /* Check command line arguments */
79 argv += get_video_args(argv, &w, &h, &bpp, &flags);
80
81 /* Initialize SDL */
82 if ( SDL_Init(SDL_INIT_VIDEO) < 0 ) {
83 fprintf(stderr,
84 "Couldn't initialize SDL: %s\n", SDL_GetError());
85 exit(1);
86 }
87 atexit(SDL_Quit);
88
89 /* Initialize the display, always use hardware palette */
90 screen = SDL_SetVideoMode(w, h, bpp, flags | SDL_HWPALETTE);
91 if ( screen == NULL ) {
92 fprintf(stderr, "Couldn't set %dx%d video mode: %s\n",
93 w, h, SDL_GetError());
94 exit(1);
95 }
96
97 /* Set the window manager title bar */
98 SDL_WM_SetCaption("SDL gamma test", "testgamma");
99
100 /* Set the desired gamma, if any */
101 gamma = 1.0f;
102 if ( *argv ) {
103 gamma = (float)atof(*argv);
104 }
105 if ( SDL_SetGamma(gamma, gamma, gamma) < 0 ) {
106 fprintf(stderr, "Unable to set gamma: %s\n", SDL_GetError());
107 exit(1);
108 }
109
110 #if 0 /* This isn't supported. Integrating the gamma ramps isn't exact */
111 /* See what gamma was actually set */
112 float real[3];
113 if ( SDL_GetGamma(&real[0], &real[1], &real[2]) < 0 ) {
114 printf("Couldn't get gamma: %s\n", SDL_GetError());
115 } else {
116 printf("Set gamma values: R=%2.2f, G=%2.2f, B=%2.2f\n",
117 real[0], real[1], real[2]);
118 }
119 #endif
120
121 /* Do all the drawing work */
122 image = SDL_LoadBMP("sample.bmp");
123 if ( image ) {
124 SDL_Rect dst;
125
126 dst.x = (screen->w - image->w)/2;
127 dst.y = (screen->h - image->h)/2;
128 dst.w = image->w;
129 dst.h = image->h;
130 SDL_BlitSurface(image, NULL, screen, &dst);
131 SDL_UpdateRects(screen, 1, &dst);
132 }
133
134 /* Wait a bit, handling events */
135 then = SDL_GetTicks();
136 timeout = (5*1000);
137 while ( (SDL_GetTicks()-then) < timeout ) {
138 SDL_Event event;
139
140 while ( SDL_PollEvent(&event) ) {
141 switch (event.type) {
142 case SDL_QUIT: /* Quit now */
143 timeout = 0;
144 break;
145 case SDL_KEYDOWN:
146 switch (event.key.keysym.sym) {
147 case SDLK_SPACE: /* Go longer.. */
148 timeout += (5*1000);
149 break;
150 case SDLK_UP:
151 gamma += 0.2f;
152 SDL_SetGamma(gamma, gamma, gamma);
153 break;
154 case SDLK_DOWN:
155 gamma -= 0.2f;
156 SDL_SetGamma(gamma, gamma, gamma);
157 break;
158 case SDLK_ESCAPE:
159 timeout = 0;
160 break;
161 default:
162 break;
163 }
164 break;
165 }
166 }
167 }
168
169 /* Perform a gamma flash to red using color ramps */
170 while ( gamma < 10.0 ) {
171 /* Increase the red gamma and decrease everything else... */
172 gamma += 0.1f;
173 CalculateGamma(gamma, red_ramp);
174 CalculateGamma(1.0/gamma, ramp);
175 SDL_SetGammaRamp(red_ramp, ramp, ramp);
176 }
177 /* Finish completely red */
178 memset(red_ramp, 255, sizeof(red_ramp));
179 memset(ramp, 0, sizeof(ramp));
180 SDL_SetGammaRamp(red_ramp, ramp, ramp);
181
182 /* Now fade out to black */
183 for ( i=(red_ramp[0] >> 8); i >= 0; --i ) {
184 memset(red_ramp, i, sizeof(red_ramp));
185 SDL_SetGammaRamp(red_ramp, NULL, NULL);
186 }
187 SDL_Delay(1*1000);
188
189 return(0);
190 }