reinventant la roda

source/demo1_sdl_main_callbacks.cpp

@@ -0,0 +1,106 @@
+#define _USE_MATH_DEFINES
+#define SDL_MAIN_USE_CALLBACKS
+
+#include <SDL3/SDL.h>
+#include <SDL3/SDL_main.h>
+#include <cmath>
+
+static SDL_Window* window = nullptr;
+static SDL_Renderer* renderer = nullptr;
+static SDL_Texture* texture = nullptr;
+
+constexpr int WIDTH = 160;
+constexpr int HEIGHT = 160;
+constexpr int SIZE = WIDTH * HEIGHT;
+constexpr int ZOOM = 4;
+
+static Uint8 surface_buffer[SIZE];
+static Uint32 palette[2] = { 0xFF000000, 0xFFFFFFFF };
+
+SDL_AppResult SDL_AppInit(void **appstate, int argc, char **argv)
+{
+    if (!SDL_Init(SDL_INIT_VIDEO)) {
+        return SDL_APP_FAILURE;
+    }
+
+    window = SDL_CreateWindow("pixels", WIDTH * ZOOM, HEIGHT * ZOOM, 0);
+    renderer = SDL_CreateRenderer(window, nullptr);
+    SDL_SetRenderLogicalPresentation(renderer, WIDTH, HEIGHT, SDL_LOGICAL_PRESENTATION_INTEGER_SCALE);
+
+    texture = SDL_CreateTexture(renderer,
+                                SDL_PIXELFORMAT_ARGB8888,
+                                SDL_TEXTUREACCESS_STREAMING,
+                                WIDTH, HEIGHT);
+    SDL_SetTextureScaleMode(texture, SDL_SCALEMODE_NEAREST);
+
+    return SDL_APP_CONTINUE;
+}
+
+SDL_AppResult SDL_AppEvent(void *appstate, SDL_Event *event)
+{
+    if (event->type == SDL_EVENT_QUIT ||
+        (event->type == SDL_EVENT_KEY_DOWN && event->key.key == SDLK_ESCAPE))
+    {
+        return SDL_APP_SUCCESS;
+    }
+
+    return SDL_APP_CONTINUE;
+}
+
+SDL_AppResult SDL_AppIterate(void *appstate)
+{
+    Uint32* pixels;
+    int pitch;
+
+    SDL_LockTexture(texture, nullptr, (void**)&pixels, &pitch);
+
+    // limpiar surface
+    for (int i = 0; i < SIZE; ++i)
+        surface_buffer[i] = 0;
+
+    // dibujar efecto
+    float time = SDL_GetTicks() / 1000.0f;
+    int rad = 96;
+    int dx = (WIDTH - (rad * 2)) / 2;
+    int dy = (HEIGHT - (rad * 2)) / 2;
+
+    for (int j = -rad; j <= rad; j += 3)
+    {
+        for (int i = -rad; i <= rad; i += 2)
+        {
+            float dist = sqrt(i * i + j * j);
+            float z = cos((dist / 40 - time) * M_PI * 2) * 6;
+
+            int X = rad + i + dx;
+            int Y = rad + j - z + dy;
+
+            if (X >= 0 && X < WIDTH && Y >= 0 && Y < HEIGHT)
+                surface_buffer[X + Y * WIDTH] = 1;
+        }
+    }
+
+    int pixel_pitch = pitch / sizeof(Uint32);
+    for (int y = 0; y < HEIGHT; ++y)
+    {
+        for (int x = 0; x < WIDTH; ++x)
+        {
+            int idx = x + y * WIDTH;
+            pixels[x + y * pixel_pitch] = palette[surface_buffer[idx]];
+        }
+    }
+
+    SDL_UnlockTexture(texture);
+
+    SDL_RenderTexture(renderer, texture, nullptr, nullptr);
+    SDL_RenderPresent(renderer);
+
+    return SDL_APP_CONTINUE;
+}
+
+void SDL_AppQuit(void *appstate, SDL_AppResult result)
+{
+    SDL_DestroyTexture(texture);
+    SDL_DestroyRenderer(renderer);
+    SDL_DestroyWindow(window);
+    SDL_Quit();
+}