// x-run: make run
#include <math.h>
#include <raylib.h>

int main(int argc, char **argv) {
  SetTraceLogLevel(LOG_ERROR);
  SetConfigFlags(FLAG_WINDOW_RESIZABLE);
  InitWindow(__WINDOW_WIDTH * 2, __WINDOW_HEIGHT * 2, "__PROJECT");
  const int _window_size[2] = { __WINDOW_WIDTH, __WINDOW_HEIGHT };

  Image canvas = GenImageColor(__WINDOW_WIDTH, __WINDOW_HEIGHT, BLANK);
  Texture2D t_canvas = LoadTextureFromImage(canvas);
  SetTextureFilter(t_canvas, TEXTURE_FILTER_BILINEAR);
  Shader shd_upscale = LoadShader(0, "upscale.frag");
  int shdloc_texsize = GetShaderLocation(shd_upscale, "texture0_size");
  int shdloc_scale = GetShaderLocation(shd_upscale, "px_per_tx");

  for (int frame = 0; !WindowShouldClose(); frame++) {
    BeginDrawing();
    int window_width = GetScreenWidth(), window_height = GetScreenHeight();
    float scale = fminf(window_width / (float)__WINDOW_WIDTH, window_height / (float)__WINDOW_HEIGHT);
    { // BEGIN frame
      ImageClearBackground(&canvas, GetColor(0x1A1A1AFF));
      ImageDrawText(&canvas, TextFormat("scale: %7.2fx", scale), 20, 20, 20, WHITE);
    } // END frame
    { // BEGIN update
      UpdateTexture(t_canvas, canvas.data);
      BeginShaderMode(shd_upscale);
      SetShaderValue(shd_upscale, shdloc_texsize, _window_size, SHADER_UNIFORM_IVEC2);
      SetShaderValue(shd_upscale, shdloc_scale, &scale, SHADER_UNIFORM_FLOAT);
      int texture_width = scale * __WINDOW_WIDTH, texture_height = scale * __WINDOW_HEIGHT;

      ClearBackground(BLACK);
      DrawTexturePro(t_canvas, (Rectangle) {
        0, 0, __WINDOW_WIDTH, __WINDOW_HEIGHT
      }, (Rectangle) {
        floorf((window_width - texture_width) / 2.0),
        floorf((window_height - texture_height) / 2.0),
        texture_width, texture_height
      }, (Vector2) { 0, 0 }, 0.0, WHITE);
      EndShaderMode();
    } // END update
    EndDrawing();
  }
}