Add example primitives.pas

Author: Free-Pascal-meets-SDL-Website

examples/primitives.pas

@@ -0,0 +1,80 @@
+{
+  This file is part of:
+
+    SDL3 for Pascal
+    (https://github.com/PascalGameDevelopment/SDL3-for-Pascal)
+    SPDX-License-Identifier: Zlib
+}
+
+{ Example is based on examples/renderer/02-primitives/primitives.c }
+
+program primitives;
+
+uses
+  SDL3, SysUtils;
+
+var
+  Window: PSDL_Window = nil;
+  Renderer: PSDL_Renderer = nil;
+  Points: array[0..499] of TSDL_FPoint;
+  Rect: TSDL_FRect;
+  I: Integer;
+
+begin
+  if not SDL_Init(SDL_INIT_VIDEO) then
+  begin
+
+    SDL_Log(PChar(Format('Couldn''t initialize SDL: %s', [SDL_GetError])));
+    Exit;
+  end;
+
+  if not SDL_CreateWindowAndRenderer('primitives', 640, 480, 0, @Window, @Renderer) then
+  begin
+    SDL_Log(PChar(Format('Couldn''t create window/renderer: %s', [SDL_GetError])));
+    Exit;
+  end;
+
+  { Set up some random points }
+  Randomize;
+  for i := 0 to High(Points)-1 do
+  begin
+    Points[I].x:=(Random(10000)/100)*4.4 + 100.0;
+    Points[I].y:=(Random(10000)/100)*2.8 + 100.0;
+  end;
+
+  { as you can see from this, rendering draws over whatever was drawn before it. }
+  SDL_SetRenderDrawColor(Renderer, 33, 33, 33, SDL_ALPHA_OPAQUE);  { dark gray, full alpha }
+  SDL_RenderClear(Renderer);  { start with a blank canvas. }
+
+  { draw a filled rectangle in the middle of the canvas. }
+  SDL_SetRenderDrawColor(Renderer, 0, 0, 255, SDL_ALPHA_OPAQUE);  { blue, full alpha }
+  Rect.x := 100;
+  Rect.y := 100;
+  Rect.w := 440;
+  Rect.h := 280;
+  SDL_RenderFillRect(Renderer, @Rect);
+
+  { draw some points across the canvas. }
+  SDL_SetRenderDrawColor(Renderer, 255, 0, 0, SDL_ALPHA_OPAQUE);  { red, full alpha }
+  SDL_RenderPoints(Renderer, @Points[0], High(Points)-1);
+
+  { draw a unfilled Rectangle in-set a little bit. }
+  SDL_SetRenderDrawColor(Renderer, 0, 255, 0, SDL_ALPHA_OPAQUE);  { green, full alpha }
+  Rect.x := Rect.x+30;
+  Rect.y := Rect.y+30;
+  Rect.w := Rect.w-60;
+  Rect.h := Rect.h-60;
+  SDL_RenderRect(Renderer, @Rect);
+
+  { draw two lines in an X across the whole canvas. }
+  SDL_SetRenderDrawColor(Renderer, 255, 255, 0, SDL_ALPHA_OPAQUE);  { yellow, full alpha }
+  SDL_RenderLine(Renderer, 0, 0, 640, 480);
+  SDL_RenderLine(Renderer, 0, 480, 640, 0);
+
+  SDL_RenderPresent(Renderer);  { put it all on the screen! }
+
+  SDL_Delay(2000);
+
+  SDL_Quit();
+end.
+