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#include <stdio.h>
#include <SDL/SDL.h>
#include <emscripten.h>
#include <string.h>
static const int COLOR_COUNT = 32;
static SDL_Surface *screen;
static SDL_Color pal[COLOR_COUNT +1];
void pallete(int red, int green, int blue) {
//initialize sdl palette
//with gradient colors
pal[0].r = 0;
pal[0].g = 0;
pal[0].b = 0;
pal[0].unused = 0;
for (int i=1; i< 1 + COLOR_COUNT; i++) {
pal[i].r = (float) red / COLOR_COUNT * i;
pal[i].g = (float) green / COLOR_COUNT * i;
pal[i].b = (float) blue / COLOR_COUNT * i;
pal[i].unused = 0;
}
SDL_SetColors(screen, pal, 0, 1 + COLOR_COUNT);
}
int main(int argc, char** argv) {
SDL_Init(SDL_INIT_VIDEO);
screen = SDL_SetVideoMode(600, 450, 8, SDL_HWSURFACE | SDL_HWPALETTE);
//test empty pallete
SDL_LockSurface(screen);
SDL_UnlockSurface(screen);
//Draw gradient
SDL_LockSurface(screen);
int size = screen->h * screen->pitch;
char *color = screen->pixels;
int divider = size / COLOR_COUNT;
int i = 0;
while (i < size) {
*color = 1 + (i / divider); //red
color++;
i++;
}
SDL_UnlockSurface(screen);
//Set pallete
if (argc > 1) {
printf("%s\n", argv[1]);
if (strcmp(argv[1], "-r") == 0) {
printf("set [red]\n");
pallete(255, 0, 0);
}
if (strcmp(argv[1], "-g") == 0) {
printf("set [green]\n");
pallete(0, 255, 0);
}
if (strcmp(argv[1], "-b") == 0) {
printf("set [blue]\n");
pallete(0, 0, 255);
}
}
//refreshing
SDL_LockSurface(screen);
SDL_UnlockSurface(screen);
SDL_Quit();
return 0;
}
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