mirror of
https://github.com/libsdl-org/SDL.git
synced 2025-11-03 17:24:34 +00:00
111 lines
3.1 KiB
C
111 lines
3.1 KiB
C
/*
|
|
Copyright (C) 1997-2025 Sam Lantinga <slouken@libsdl.org>
|
|
|
|
This software is provided 'as-is', without any express or implied
|
|
warranty. In no event will the authors be held liable for any damages
|
|
arising from the use of this software.
|
|
|
|
Permission is granted to anyone to use this software for any purpose,
|
|
including commercial applications, and to alter it and redistribute it
|
|
freely.
|
|
*/
|
|
#include <SDL3/SDL.h>
|
|
#include <SDL3/SDL_main.h>
|
|
|
|
#define SQUARE_SIZE 100.0f
|
|
|
|
/* Draw opaque red squares at the four corners of the form, and draw a red square with an alpha value of 180 in the center of the form */
|
|
static void draw(SDL_Renderer *renderer)
|
|
{
|
|
SDL_FRect rect = { 0.0f, 0.0f, SQUARE_SIZE, SQUARE_SIZE };
|
|
int w, h;
|
|
|
|
SDL_GetCurrentRenderOutputSize(renderer, &w, &h);
|
|
|
|
SDL_SetRenderDrawColor(renderer, 0, 0, 0, 0);
|
|
SDL_RenderClear(renderer);
|
|
|
|
if (w >= 3 * SQUARE_SIZE && h >= 3 * SQUARE_SIZE) {
|
|
SDL_SetRenderDrawColor(renderer, 255, 0, 0, 255);
|
|
|
|
rect.x = 0.0f;
|
|
rect.y = 0.0f;
|
|
SDL_RenderFillRect(renderer, &rect);
|
|
|
|
rect.y = h - SQUARE_SIZE;
|
|
SDL_RenderFillRect(renderer, &rect);
|
|
|
|
rect.x = w - SQUARE_SIZE;
|
|
SDL_RenderFillRect(renderer, &rect);
|
|
|
|
rect.y = 0.0f;
|
|
SDL_RenderFillRect(renderer, &rect);
|
|
}
|
|
|
|
SDL_SetRenderDrawColor(renderer, 255, 0, 0, 180);
|
|
rect.x = (w - SQUARE_SIZE) / 2;
|
|
rect.y = (h - SQUARE_SIZE) / 2;
|
|
SDL_RenderFillRect(renderer, &rect);
|
|
}
|
|
|
|
int main(int argc, char *argv[])
|
|
{
|
|
SDL_Window *window = NULL;
|
|
SDL_Renderer *renderer = NULL;
|
|
bool done = false;
|
|
SDL_Event event;
|
|
|
|
int return_code = 1;
|
|
|
|
window = SDL_CreateWindow("SDL Software Renderer Transparent Test", 800, 600, SDL_WINDOW_TRANSPARENT | SDL_WINDOW_RESIZABLE);
|
|
if (!window) {
|
|
SDL_Log("Couldn't create transparent window: %s", SDL_GetError());
|
|
goto quit;
|
|
}
|
|
|
|
/* Create a software renderer */
|
|
renderer = SDL_CreateRenderer(window, SDL_SOFTWARE_RENDERER);
|
|
if (!renderer) {
|
|
SDL_Log("Couldn't create renderer: %s", SDL_GetError());
|
|
goto quit;
|
|
}
|
|
|
|
/* Make sure we're setting the alpha channel while drawing */
|
|
SDL_SetRenderDrawBlendMode(renderer, SDL_BLENDMODE_NONE);
|
|
|
|
/* We're ready to go! */
|
|
while (!done) {
|
|
while (SDL_PollEvent(&event)) {
|
|
switch (event.type) {
|
|
case SDL_EVENT_KEY_DOWN:
|
|
if (event.key.key == SDLK_ESCAPE) {
|
|
done = true;
|
|
}
|
|
break;
|
|
case SDL_EVENT_WINDOW_EXPOSED:
|
|
/* The software renderer is persistent, so only redraw as-needed */
|
|
draw(renderer);
|
|
break;
|
|
case SDL_EVENT_QUIT:
|
|
done = true;
|
|
break;
|
|
default:
|
|
break;
|
|
}
|
|
}
|
|
|
|
/* Show everything on the screen and wait a bit */
|
|
SDL_RenderPresent(renderer);
|
|
SDL_Delay(100);
|
|
}
|
|
|
|
/* Success! */
|
|
return_code = 0;
|
|
|
|
quit:
|
|
SDL_DestroyRenderer(renderer);
|
|
SDL_DestroyWindow(window);
|
|
SDL_Quit();
|
|
return return_code;
|
|
}
|