#include <stdlib.h>

#include <math.h>

#include <SDL_events.h>

#include <SDL_rect.h>

#include <SDL_pixels.h>

#include <SDL_video.h>

#include <SDL_shape.h>

#define SHAPED_WINDOW_X 150

#define SHAPED_WINDOW_Y 150

#define SHAPED_WINDOW_DIMENSION 640

int main(int argc,char** argv) {

if(argc < 2) {

printf("SDL_Shape requires at least one bitmap file as argument.\n");

exit(-1);

}

if(SDL_VideoInit(NULL,0) == -1) {

printf("Could not initialize SDL video.\n");

exit(-2);

}

Uint8 num_pictures = argc - 1;

SDL_Surface **pictures = malloc(sizeof(SDL_Surface*)*num_pictures);

int i = 0;

for(i=0;i<num_pictures;i++)

pictures[i] = NULL;

for(i=0;i<num_pictures;i++) {

SDL_Surface *original = SDL_LoadBMP(argv[i+1]);

if(original == NULL) {

int j = 0;

for(j=0;j<num_pictures;j++)

if(pictures[j] != NULL)

SDL_FreeSurface(pictures[j]);

free(pictures);

SDL_VideoQuit();

printf("Could not load surface from named bitmap file.\n");

exit(-3);

}

//THIS CONVERSION ROUTINE IS FRAGILE! It relies in the fact that only certain portions of the format structure must be filled in to use it.

SDL_PixelFormat format = {NULL,0,0,0,0,0,0,0,0,0,0,0,0,0,0};

SDL_PixelFormatEnumToMasks(SDL_PIXELFORMAT_RGBA8888,&format.BitsPerPixel,&format.Rmask,&format.Gmask,&format.Bmask,&format.Amask);

format.BytesPerPixel = format.BitsPerPixel / 8 + (format.BitsPerPixel % 8 > 0 ? 1 : 0);

pictures[i] = SDL_ConvertSurface(original,&format,0);

//We have no more need of the original now that we have our desired format.

SDL_FreeSurface(original);

if(pictures[i] == NULL) {

int j = 0;

for(j=0;j<num_pictures;j++)

if(pictures[j] != NULL)

SDL_FreeSurface(pictures[j]);

free(pictures);

SDL_VideoQuit();

printf("Could not convert bitmap surface to desired format.\n");

exit(-3);

}

if(SDL_MUSTLOCK(pictures[i]))

SDL_LockSurface(pictures[i]);

void* pixels = pictures[i]->pixels;

unsigned int pitch = pictures[i]->pitch;

int y =0,x = 0;

for(y=0;y<pictures[i]->h;y++)

for(x=0;x<pictures[i]->w;x++) {

Uint32* pixel = pixels+y*pitch+x*pictures[i]->format->BytesPerPixel;

Uint8 r = 0,g = 0,b = 0;

SDL_GetRGB(*pixel,pictures[i]->format,&r,&g,&b);

if(r == g == b == 0x00)

*pixel = SDL_MapRGBA(pictures[i]->format,r,g,b,0);

}

if(SDL_MUSTLOCK(pictures[i]))

SDL_UnlockSurface(pictures[i]);

}

SDL_Window *window = SDL_CreateShapedWindow("SDL_Shape test",SHAPED_WINDOW_X,SHAPED_WINDOW_Y,SHAPED_WINDOW_DIMENSION,SHAPED_WINDOW_DIMENSION,SDL_WINDOW_RESIZABLE | SDL_WINDOW_SHOWN);

if(window == NULL) {

for(i=0;i<num_pictures;i++)

SDL_FreeSurface(pictures[i]);

free(pictures);

SDL_VideoQuit();

printf("Could not create shaped window for SDL_Shape.\n");

exit(-4);

}

if(SDL_CreateRenderer(window,-1,SDL_RENDERER_PRESENTFLIP2) == -1) {

SDL_DestroyWindow(window);

for(i=0;i<num_pictures;i++)

SDL_FreeSurface(pictures[i]);

free(pictures);

SDL_VideoQuit();

printf("Could not create rendering context for SDL_Shape window.\n");

exit(-5);

}

SDL_Texture **textures = malloc(sizeof(SDL_Texture*)*num_pictures);

for(i=0;i<num_pictures;i++)

textures[i] = NULL;

for(i=0;i<num_pictures;i++) {

textures[i] = SDL_CreateTextureFromSurface(0,pictures[i]);

if(textures[i] == NULL) {

int j = 0;

for(j=0;j<num_pictures;i++)

if(textures[i] != NULL)

SDL_DestroyTexture(textures[i]);

free(textures);

for(i=0;i<num_pictures;i++)

SDL_FreeSurface(pictures[i]);

free(pictures);

SDL_DestroyRenderer(window);

SDL_DestroyWindow(window);

SDL_VideoQuit();

printf("Could not create texture for SDL_shape.\n");

exit(-6);

}

}

SDL_Event event;

int event_pending = 0;

event_pending = SDL_PollEvent(&event);

unsigned int current_picture = 0;

SDL_WindowShapeMode mode = {ShapeModeDefault,1};

SDL_SetWindowShape(window,pictures[current_picture],&mode);

int mouse_down = 0;

Uint32 format,access;

SDL_Rect texture_dimensions = {0,0,0,0};

SDL_QueryTexture(textures[current_picture],&format,&access,&texture_dimensions.w,&texture_dimensions.h);

SDL_SetWindowSize(window,texture_dimensions.w,texture_dimensions.h);

while(event.type != SDL_QUIT) {

if(event.type == SDL_MOUSEBUTTONDOWN)

mouse_down = 1;

if(mouse_down && event.type == SDL_MOUSEBUTTONUP) {

mouse_down = 0;

current_picture += 1;

if(current_picture >= num_pictures)

current_picture = 0;

SDL_QueryTexture(textures[current_picture],&format,&access,&texture_dimensions.w,&texture_dimensions.h);

SDL_SetWindowSize(window,texture_dimensions.w,texture_dimensions.h);

SDL_SetWindowShape(window,pictures[current_picture],&mode);

}

SDL_SelectRenderer(window);

//Clear render-target to blue.

SDL_SetRenderDrawColor(0x00,0x00,0xff,0xff);

SDL_RenderClear();

//Render the texture.

SDL_RenderCopy(textures[current_picture],&texture_dimensions,&texture_dimensions);

SDL_RenderPresent();

event_pending = SDL_PollEvent(&event);

}

//Free the textures.

for(i=0;i<num_pictures;i++)

SDL_DestroyTexture(textures[i]);

free(textures);

//Destroy the window.

SDL_DestroyWindow(window);

//Free the original surfaces backing the textures.

for(i=0;i<num_pictures;i++)

SDL_FreeSurface(pictures[i]);

free(pictures);

//Call SDL_VideoQuit() before quitting.

SDL_VideoQuit();

}