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1 /*
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2 * testpalette.c
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3 *
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4 * A simple test of runtime palette modification for animation
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5 * (using the SDL_SetPalette() API).
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6 */
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7
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8 #include <stdio.h>
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9 #include <stdlib.h>
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10 #include <string.h>
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11 #include <math.h>
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12
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13 /* This isn't in the Windows headers */
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14 #ifndef M_PI
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15 #define M_PI 3.14159265358979323846
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16 #endif
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17
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18 #include <SDL.h>
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19
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20 /* screen size */
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21 #define SCRW 640
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22 #define SCRH 480
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23
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24 #define NBOATS 5
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25 #define SPEED 2
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26
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27 #ifndef MIN
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28 #define MIN(a, b) ((a) < (b) ? (a) : (b))
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29 #endif
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30 #ifndef MAX
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31 #define MAX(a, b) ((a) > (b) ? (a) : (b))
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32 #endif
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33
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34 /*
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35 * wave colours: Made by taking a narrow cross-section of a wave picture
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36 * in Gimp, saving in PPM ascii format and formatting with Emacs macros.
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37 */
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38 static SDL_Color wavemap[] = {
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39 {0,2,103}, {0,7,110}, {0,13,117}, {0,19,125},
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40 {0,25,133}, {0,31,141}, {0,37,150}, {0,43,158},
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41 {0,49,166}, {0,55,174}, {0,61,182}, {0,67,190},
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42 {0,73,198}, {0,79,206}, {0,86,214}, {0,96,220},
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43 {5,105,224}, {12,112,226}, {19,120,227}, {26,128,229},
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44 {33,135,230}, {40,143,232}, {47,150,234}, {54,158,236},
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45 {61,165,238}, {68,173,239}, {75,180,241}, {82,188,242},
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46 {89,195,244}, {96,203,246}, {103,210,248}, {112,218,250},
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47 {124,224,250}, {135,226,251}, {146,229,251}, {156,231,252},
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48 {167,233,252}, {178,236,252}, {189,238,252}, {200,240,252},
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49 {211,242,252}, {222,244,252}, {233,247,252}, {242,249,252},
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50 {237,250,252}, {209,251,252}, {174,251,252}, {138,252,252},
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51 {102,251,252}, {63,250,252}, {24,243,252}, {7,225,252},
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52 {4,203,252}, {3,181,252}, {2,158,252}, {1,136,251},
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53 {0,111,248}, {0,82,234}, {0,63,213}, {0,50,192},
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54 {0,39,172}, {0,28,152}, {0,17,132}, {0,7,114}
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55 };
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56
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57 static void sdlerr(char *when)
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58 {
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59 fprintf(stderr, "SDL error: %s: %s\n", when, SDL_GetError());
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60 exit(1);
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61 }
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62
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63 /* create a background surface */
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64 static SDL_Surface *make_bg(SDL_Surface *screen, int startcol)
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65 {
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66 int i;
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67 SDL_Surface *bg = SDL_CreateRGBSurface(SDL_SWSURFACE, screen->w, screen->h,
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68 8, 0, 0, 0, 0);
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69 if(!bg)
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70 sdlerr("creating background surface");
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71
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72 /* set the palette to the logical screen palette so that blits
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73 won't be translated */
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74 SDL_SetColors(bg, screen->format->palette->colors, 0, 256);
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75
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76 /* Make a wavy background pattern using colours 0-63 */
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77 if(SDL_LockSurface(bg) < 0)
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78 sdlerr("locking background");
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79 for(i = 0; i < SCRH; i++) {
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80 Uint8 *p = (Uint8 *)bg->pixels + i * bg->pitch;
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81 int j, d;
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82 d = 0;
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83 for(j = 0; j < SCRW; j++) {
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84 int v = MAX(d, -2);
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85 v = MIN(v, 2);
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86 if(i > 0)
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87 v += p[-bg->pitch] + 65 - startcol;
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88 p[j] = startcol + (v & 63);
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89 d += ((rand() >> 3) % 3) - 1;
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90 }
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91 }
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92 SDL_UnlockSurface(bg);
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93 return(bg);
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94 }
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95
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96 /*
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97 * Return a surface flipped horisontally. Only works for 8bpp;
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98 * extension to arbitrary bitness is left as an exercise for the reader.
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99 */
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100 static SDL_Surface *hflip(SDL_Surface *s)
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101 {
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102 int i;
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103 SDL_Surface *z = SDL_CreateRGBSurface(SDL_SWSURFACE, s->w, s->h, 8,
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104 0, 0, 0, 0);
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105 /* copy palette */
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106 SDL_SetColors(z, s->format->palette->colors,
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107 0, s->format->palette->ncolors);
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108 if(SDL_LockSurface(s) < 0 || SDL_LockSurface(z) < 0)
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109 sdlerr("locking flip images");
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110
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111 for(i = 0; i < s->h; i++) {
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112 int j;
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113 Uint8 *from = (Uint8 *)s->pixels + i * s->pitch;
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114 Uint8 *to = (Uint8 *)z->pixels + i * z->pitch + s->w - 1;
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115 for(j = 0; j < s->w; j++)
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116 to[-j] = from[j];
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117 }
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118
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119 SDL_UnlockSurface(z);
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120 SDL_UnlockSurface(s);
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121 return z;
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122 }
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123
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124 int main(int argc, char **argv)
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125 {
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126 SDL_Color cmap[256];
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127 SDL_Surface *screen;
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128 SDL_Surface *bg;
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129 SDL_Surface *boat[2];
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130 unsigned vidflags = 0;
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131 unsigned start;
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132 int fade_max = 400;
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133 int fade_level, fade_dir;
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134 int boatcols, frames, i, red;
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135 int boatx[NBOATS], boaty[NBOATS], boatdir[NBOATS];
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136 int gamma_fade = 0;
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137 int gamma_ramp = 0;
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138
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139 if(SDL_Init(SDL_INIT_VIDEO) < 0)
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140 sdlerr("initialising SDL");
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141
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142 atexit(SDL_Quit);
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143
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144 while(--argc) {
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145 ++argv;
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146 if(strcmp(*argv, "-hw") == 0)
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147 vidflags |= SDL_HWSURFACE;
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148 else if(strcmp(*argv, "-fullscreen") == 0)
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149 vidflags |= SDL_FULLSCREEN;
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150 else if(strcmp(*argv, "-nofade") == 0)
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151 fade_max = 1;
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152 else if(strcmp(*argv, "-gamma") == 0)
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153 gamma_fade = 1;
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154 else if(strcmp(*argv, "-gammaramp") == 0)
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155 gamma_ramp = 1;
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156 else {
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157 fprintf(stderr,
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158 "usage: testpalette "
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159 " [-hw] [-fullscreen] [-nofade] [-gamma] [-gammaramp]\n");
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160 return 1;
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161 }
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162 }
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163
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164 /* Ask explicitly for 8bpp and a hardware palette */
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165 if(!(screen = SDL_SetVideoMode(SCRW, SCRH, 8, vidflags | SDL_HWPALETTE))) {
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166 fprintf(stderr, "error setting %dx%d 8bpp indexed mode: %s\n",
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167 SCRW, SCRH, SDL_GetError());
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168 return 1;
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169 }
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170
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171 if(!(boat[0] = SDL_LoadBMP("sail.bmp")))
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172 sdlerr("loading sail.bmp");
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173 /* We've chosen magenta (#ff00ff) as colour key for the boat */
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174 SDL_SetColorKey(boat[0], SDL_SRCCOLORKEY | SDL_RLEACCEL,
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175 SDL_MapRGB(boat[0]->format, 0xff, 0x00, 0xff));
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176 boatcols = boat[0]->format->palette->ncolors;
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177 boat[1] = hflip(boat[0]);
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178 SDL_SetColorKey(boat[1], SDL_SRCCOLORKEY | SDL_RLEACCEL,
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179 SDL_MapRGB(boat[1]->format, 0xff, 0x00, 0xff));
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180
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181 /*
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182 * First set the physical screen palette to black, so the user won't
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183 * see our initial drawing on the screen.
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184 */
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185 memset(cmap, 0, sizeof(cmap));
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186 SDL_SetPalette(screen, SDL_PHYSPAL, cmap, 0, 256);
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187
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188 /*
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189 * Proper palette management is important when playing games with the
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190 * colormap. We have divided the palette as follows:
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191 *
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192 * index 0..(boatcols-1): used for the boat
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193 * index boatcols..(boatcols+63): used for the waves
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194 */
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195 SDL_SetPalette(screen, SDL_LOGPAL,
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196 boat[0]->format->palette->colors, 0, boatcols);
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197 SDL_SetPalette(screen, SDL_LOGPAL, wavemap, boatcols, 64);
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198
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199 /*
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200 * Now the logical screen palette is set, and will remain unchanged.
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201 * The boats already have the same palette so fast blits can be used.
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202 */
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203 memcpy(cmap, screen->format->palette->colors, 256 * sizeof(SDL_Color));
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204
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205 /* save the index of the red colour for later */
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206 red = SDL_MapRGB(screen->format, 0xff, 0x00, 0x00);
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207
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208 bg = make_bg(screen, boatcols); /* make a nice wavy background surface */
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209
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210 /* initial screen contents */
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211 if(SDL_BlitSurface(bg, NULL, screen, NULL) < 0)
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212 sdlerr("blitting background to screen");
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213 SDL_Flip(screen); /* actually put the background on screen */
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214
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215 /* determine initial boat placements */
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216 for(i = 0; i < NBOATS; i++) {
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217 boatx[i] = (rand() % (SCRW + boat[0]->w)) - boat[0]->w;
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218 boaty[i] = i * (SCRH - boat[0]->h) / (NBOATS - 1);
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219 boatdir[i] = ((rand() >> 5) & 1) * 2 - 1;
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220 }
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221
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222 start = SDL_GetTicks();
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223 frames = 0;
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224 fade_dir = 1;
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225 fade_level = 0;
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226 do {
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227 SDL_Event e;
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228 SDL_Rect updates[NBOATS];
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229 SDL_Rect r;
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230 int redphase;
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231
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232 /* A small event loop: just exit on any key or mouse button event */
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233 while(SDL_PollEvent(&e)) {
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234 if(e.type == SDL_KEYDOWN || e.type == SDL_QUIT
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235 || e.type == SDL_MOUSEBUTTONDOWN) {
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236 if(fade_dir < 0)
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237 fade_level = 0;
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238 fade_dir = -1;
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239 }
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240 }
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241
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242 /* move boats */
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243 for(i = 0; i < NBOATS; i++) {
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244 int old_x = boatx[i];
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245 /* update boat position */
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246 boatx[i] += boatdir[i] * SPEED;
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247 if(boatx[i] <= -boat[0]->w || boatx[i] >= SCRW)
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248 boatdir[i] = -boatdir[i];
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249
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250 /* paint over the old boat position */
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251 r.x = old_x;
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252 r.y = boaty[i];
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253 r.w = boat[0]->w;
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254 r.h = boat[0]->h;
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255 if(SDL_BlitSurface(bg, &r, screen, &r) < 0)
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256 sdlerr("blitting background");
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257
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258 /* construct update rectangle (bounding box of old and new pos) */
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259 updates[i].x = MIN(old_x, boatx[i]);
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260 updates[i].y = boaty[i];
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261 updates[i].w = boat[0]->w + SPEED;
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262 updates[i].h = boat[0]->h;
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263 /* clip update rectangle to screen */
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264 if(updates[i].x < 0) {
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265 updates[i].w += updates[i].x;
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266 updates[i].x = 0;
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267 }
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268 if(updates[i].x + updates[i].w > SCRW)
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269 updates[i].w = SCRW - updates[i].x;
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270 }
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271
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272 for(i = 0; i < NBOATS; i++) {
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273 /* paint boat on new position */
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274 r.x = boatx[i];
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275 r.y = boaty[i];
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276 if(SDL_BlitSurface(boat[(boatdir[i] + 1) / 2], NULL,
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277 screen, &r) < 0)
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278 sdlerr("blitting boat");
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279 }
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280
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281 /* cycle wave palette */
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282 for(i = 0; i < 64; i++)
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283 cmap[boatcols + ((i + frames) & 63)] = wavemap[i];
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284
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285 if(fade_dir) {
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286 /* Fade the entire palette in/out */
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287 fade_level += fade_dir;
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288
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289 if(gamma_fade) {
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290 /* Fade linearly in gamma level (lousy) */
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291 float level = (float)fade_level / fade_max;
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292 if(SDL_SetGamma(level, level, level) < 0)
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293 sdlerr("setting gamma");
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294
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295 } else if(gamma_ramp) {
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296 /* Fade using gamma ramp (better) */
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297 Uint16 ramp[256];
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298 for(i = 0; i < 256; i++)
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299 ramp[i] = (i * fade_level / fade_max) << 8;
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300 if(SDL_SetGammaRamp(ramp, ramp, ramp) < 0)
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301 sdlerr("setting gamma ramp");
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302
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303 } else {
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304 /* Fade using direct palette manipulation (best) */
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305 memcpy(cmap, screen->format->palette->colors,
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306 boatcols * sizeof(SDL_Color));
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307 for(i = 0; i < boatcols + 64; i++) {
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308 cmap[i].r = cmap[i].r * fade_level / fade_max;
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309 cmap[i].g = cmap[i].g * fade_level / fade_max;
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310 cmap[i].b = cmap[i].b * fade_level / fade_max;
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311 }
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312 }
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313 if(fade_level == fade_max)
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314 fade_dir = 0;
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315 }
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316
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317 /* pulse the red colour (done after the fade, for a night effect) */
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318 redphase = frames % 64;
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319 cmap[red].r = (int)(255 * sin(redphase * M_PI / 63));
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320
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321 SDL_SetPalette(screen, SDL_PHYSPAL, cmap, 0, boatcols + 64);
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322
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323 /* update changed areas of the screen */
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324 SDL_UpdateRects(screen, NBOATS, updates);
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325 frames++;
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326 } while(fade_level > 0);
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327
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328 printf("%d frames, %.2f fps\n",
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329 frames, 1000.0 * frames / (SDL_GetTicks() - start));
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330 return 0;
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331 }
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332
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