-- ----------------------------------------------------------------- --
-- --
-- This is free software; you can redistribute it and/or --
-- modify it under the terms of the GNU General Public --
-- License as published by the Free Software Foundation; either --
-- version 2 of the License, or (at your option) any later version. --
-- --
-- This software is distributed in the hope that it will be useful, --
-- but WITHOUT ANY WARRANTY; without even the implied warranty of --
-- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU --
-- General Public License for more details. --
-- --
-- You should have received a copy of the GNU General Public --
-- License along with this library; if not, write to the --
-- Free Software Foundation, Inc., 59 Temple Place - Suite 330, --
-- Boston, MA 02111-1307, USA. --
-- --
-- ----------------------------------------------------------------- --
-- ----------------------------------------------------------------- --
-- This is a translation, to the Ada programming language, of the --
-- original C test files written by Sam Lantinga - www.libsdl.org --
-- translation made by Antonio F. Vargas - www.adapower.net/~avargas --
-- ----------------------------------------------------------------- --
-- ----------------------------------------------------------------- --
-- WARNING WARNING WARNING WARNING WARNING WARNING WARNING WARNING
-- ----------------------------------------------------------------- --
-- SERIOUS WARNING: The Ada code in this files may, at some points,
-- rely directly on pointer arithmetic which is considered very
-- unsafe and PRONE TO ERROR. The AdaSDL_Framebuffer examples are
-- more appropriate and easier to understand. They should be used in
-- replacement of this files. Please go there.
-- This file exists only for the sake of completness and to test
-- AdaSDL without the dependency of AdaSDL_Framebuffer.
-- ----------------------------------------------------------------- --
-- WARNING WARNING WARNING WARNING WARNING WARNING WARNING WARNING
-- ----------------------------------------------------------------- --
with Interfaces.C.Pointers;
with Interfaces.C.Strings;
with Ada.Numerics.Generic_Elementary_Functions;
with Ada.Text_IO; use Ada.Text_IO;
with Ada.Float_Text_IO; use Ada.Float_Text_IO;
with Ada.Command_Line;
with Ada.Characters.Handling;
with GNAT.OS_Lib;
with SDL.Types; use SDL.Types;
with SDL.Video;
with SDL.Timer;
with SDL.Error;
with SDL.Events;
with SDL.Mouse;
with SDL.Quit;
with Lib_C;
procedure Testalpha is
package C renames Interfaces.C;
use type C.int;
package CS renames Interfaces.C.Strings;
package Uint8_IO is new Modular_IO (Uint8);
package CL renames Ada.Command_Line;
package CH renames Ada.Characters.Handling;
use type SDL.Init_Flags;
package V renames SDL.Video;
use type V.Surface_Flags;
use type V.Surface_ptr;
use type V.Palette_ptr;
package T renames SDL.Timer;
package Er renames SDL.Error;
package Ev renames SDL.Events;
package M renames SDL.Mouse;
Screen_Width : constant := 800; -- 1024; -- 640;
Screen_Height : constant := 600; -- 768; -- 480;
package AN is
new Ada.Numerics.Generic_Elementary_Functions (float);
FRAME_TICKS : constant := 1000 / 30;
-- ===========================================================
-- Create a "light" -- a yellowish surface with variable alpha
function CreateLight (screen : V.Surface_ptr; radius : C.int)
return V.Surface_ptr
is
trans, alphamask : Uint8;
the_range, addition : C.int;
xdist, ydist : C.int;
skip : Uint16;
pixel : Uint32;
light : V.Surface_ptr;
-- use Uint16_Ptrs;
-- use Uint16_PtrOps;
-- buf : Uint16_ptrs.Object_Pointer;
use Uint32_Ptrs;
use Uint32_PtrOps;
use type Interfaces.Unsigned_32;
buf : Uint32_Ptrs.Object_Pointer;
begin
-- Create a 16 (4/4/4/4) bpp square with a full 4-bit alpha channel
-- Note: this isn't any faster than a 32 bit alpha surface
-- alphamask := 16#0000000F#;
-- light := V.CreateRGBSurface (V.SWSURFACE, 2*radius, 2*radius, 16,
-- 16#0000F000#, 16#00000F00#, alphamask);
-- Create a 32 (8/8/8/8) bpp square with a full 8-bit alpha channel
alphamask := 16#000000FF#;
light := V.CreateRGBSurface (V.SWSURFACE, 2 * radius, 2 * radius, 32,
16#FF000000#, 16#00FF0000#, 16#0000FF00#, Uint32(alphamask));
if light = null then
Put_Line ("Couldn't create light: " & Er.Get_Error);
return null;
end if;
-- Fill with a light a yellow-orange color
skip :=Uint16 (light.pitch -
Uint16 ((light.w *
C.int (light.format.BytesPerPixel))));
buf := To_Pointer (light.pixels);
-- Get a transparent pixel value - we'll add alpha later
pixel := V.MapRGBA (light.format, 16#FF#, 16#DD#, 16#88#, 0);
for y in 0 .. light.h - 1 loop
for x in 0 .. light.w - 1 loop
buf.all := pixel;
buf := Object_Pointer (Pointer (buf) + 1 );
end loop;
buf := Object_Pointer (Pointer (buf) + C.ptrdiff_t (skip));
end loop;
buf := To_Pointer (light.pixels);
for y in 0 .. light.h - 1 loop
for x in 0 .. light.w - 1 loop
-- Slow distance formula (from center of light)
xdist := x - (light.w / 2);
ydist := y - (light.h / 2);
the_range := C.int (
AN.Sqrt (float (xdist**2 + ydist**2)));
-- Scale distance to range of transparency (0-255)
if the_range > radius then
trans := alphamask;
else
-- Increasing transparency with distance
trans := Uint8 (
float (the_range * C.int (alphamask)) / float (radius));
-- Lights are very transparent
addition := C.int (float (alphamask + 1) / 8.0);
if C.int (trans) + addition > C.int (alphamask) then
trans := alphamask;
else
trans := trans + Uint8 (addition);
end if;
end if;
-- We set the alpha component as the right N bits
buf.all := Uint32 (
Interfaces.Unsigned_32 (buf.all) or
Interfaces.Unsigned_32 (255 - trans));
Increment (Pointer(buf));
end loop;
buf := Object_Pointer (Pointer (buf) + C.ptrdiff_t (skip));
end loop;
-- Enable RLE acceleration of this alpha surface
V.SetAlpha (light, V.SRCALPHA or V.RLEACCEL, 0);
-- we're done!
return light;
end CreateLight;
-- ===========================================================
flashes : Uint32 := 0;
flashtime : Uint32 := 0;
-- ===========================================================
procedure FlashLight (screen : V.Surface_ptr;
light : V.Surface_ptr;
x, y : Uint16)
is
position : V.Rect;
ticks1 : Uint32;
ticks2 : Uint32;
begin
-- Easy, center light
position.x := Sint16 (x - Uint16 (light.w / 2));
position.y := Sint16 (y - Uint16 (light.h / 2));
position.w := Uint16 (light.w);
position.h := Uint16 (light.h);
ticks1 := T.GetTicks;
V.BlitSurface(light, null, screen, position);
ticks2 := T.GetTicks;
V.Update_Rect(screen, position);
flashes := flashes + 1;
-- Update time spend doing alpha blitting
flashtime := flashtime + (ticks2 - ticks1);
end FlashLight;
-- ===========================================================
sprite_visible : C.int := 0;
sprite : V.Surface_ptr;
backing : V.Surface_ptr;
position : V.Rect;
x_vel, y_vel : C.int;
alpha_vel : C.int;
-- ===========================================================
function LoadSprite (screen : V.Surface_ptr; file : String)
return C.int
is
converted : V.Surface_ptr;
use Uint8_Ptrs;
begin
-- Load the sprite image
sprite := V.LoadBMP (CS.New_String (file));
if sprite = null then
Put_Line ("Couldn't load " & file & Er.Get_Error);
return -1;
end if;
-- set transparent pixel as the pixel as (0,0)
if sprite.format.palette /= null then
V.SetColorKey (sprite, V.SRCCOLORKEY,
Uint32 (To_Pointer ( sprite.pixels).all));
end if;
-- Convert sprite to video format
converted := V.DisplayFormat (sprite);
V.FreeSurface (sprite);
if converted = null then
Put_Line ("Couldn't convert background: " & Er.Get_Error);
return -1;
end if;
sprite := converted;
-- Create the background
backing := V.CreateRGBSurface (
V.SWSURFACE, sprite.w, sprite.h,
8, 0, 0, 0, 0);
if backing = null then
V.FreeSurface (sprite);
return -1;
end if;
-- Create background to video format
converted := V.DisplayFormat (backing);
V.FreeSurface (backing);
if converted = null then
Put_Line ("Couldn't convert background: " & Er.Get_Error);
V.FreeSurface (sprite);
return -1;
end if;
backing := converted;
-- Set the initial position of the sprite
position.x := Sint16 (screen.w - sprite.w) / 2;
position.y := Sint16 (screen.h - sprite.h) / 2;
position.w := Uint16 (sprite.w);
position.h := Uint16 (sprite.h);
x_vel := 0; y_vel := 0;
alpha_vel := 1;
-- we're ready to roll
return 0;
end LoadSprite;
-- ===========================================================
procedure AttractSprite (x : Uint16; y : Uint16) is
begin
x_vel := (C.int (x) - C.int (position.x)) / 10;
y_vel := (C.int (y) - C.int (position.y)) / 10;
end AttractSprite;
-- ===========================================================
procedure MoveSprite (screen : V.Surface_ptr;
light : V.Surface_ptr)
is
updates : V.Rects_Array (0 .. 1);
alpha : Uint8;
begin
-- Erase the sprite if it was visible;
if sprite_visible /= 0 then
updates (0) := position;
V.BlitSurface (backing, null, screen, updates (0));
else
-- updates (0).x := 0; updates (0).y := 0;
-- updates (0).w := 0; updates (0).h := 0;
updates (0) := (0, 0, 0, 0);
sprite_visible := 1;
end if;
-- Since the sprite is off the screen, we can do other drawing
-- without being overwriten by the saved area behing the sprite
if light /= null then
declare
x, y : C.int;
State : M.Mouse_State;
begin
M.Get_Mouse_State (State, x, y);
FlashLight (screen, light, Uint16 (x), Uint16 (y));
end;
end if;
-- Move the sprite, bounce at the wall
position.x := position.x + Sint16 (x_vel);
if (position.x < 0) or (C.int (position.x) >= screen.w) then
x_vel := -x_vel;
position.x := position.x + Sint16 (x_vel);
end if;
position.y := position.y + Sint16 (y_vel);
if (position.y < 0) or (C.int (position.y) >= screen.h) then
y_vel := -y_vel;
position.y := position.y + Sint16 (y_vel);
end if;
-- Update transparency (fade in and out)
alpha := sprite.format.alpha;
if (C.int (alpha) + alpha_vel) < 0 then
alpha_vel := -alpha_vel;
elsif (C.int (alpha) + alpha_vel) > 255 then
alpha_vel := -alpha_vel;
end if;
V.SetAlpha (sprite, V.SRCALPHA, alpha + Uint8 (alpha_vel));
-- Save the area behind the sprite
updates (1) := position;
V.BlitSurface (screen, updates (1), backing, null);
-- Blit the sprite onto the screen
updates (1) := position;
V.BlitSurface (sprite, null, screen, updates (1));
-- Make it so!
V.UpdateRects(screen, updates'Length, updates);
end MoveSprite;
-- ===========================================================
procedure WarpSprite (screen : V.Surface_ptr; x, y : C.int)
is
updates : V.Rects_Array (0 .. 1);
begin
-- Erase, move, Draw, update
updates (0) := position;
V.BlitSurface (backing, null, screen, updates (0));
position.x := Sint16 (x - sprite.w / 2); -- Center about X
position.y := Sint16 (y - sprite.h / 2); -- Center about Y
updates (1) := position;
V.BlitSurface (screen, updates (1), backing, null);
updates (1) := position;
V.BlitSurface (sprite, null, screen, updates (1));
V.UpdateRects (screen, updates'Length, updates);
end WarpSprite;
-- ===========================================================
use Uint8_Ptrs;
use Uint8_PtrOps;
info : V.VideoInfo_ConstPtr;
screen : V.Surface_ptr;
video_bpp : Uint8;
videoflags : V.Surface_Flags;
buffer : Uint8_Ptrs.Object_Pointer;
done : C.int;
event : Ev.Event;
light : V.Surface_ptr;
mouse_pressed : C.int;
ticks, lastticks : Uint32;
argc : Integer := CL.Argument_Count;
PollEvent_Result : C.int;
begin
-- Initialize SDL
if SDL.Init (SDL.INIT_VIDEO or SDL.INIT_JOYSTICK) < 0 then
Put_Line ("Couldn't initialize SDL: " & Er.Get_Error);
GNAT.OS_Lib.OS_Exit (1);
end if;
SDL.Quit.atexit (SDL.SDL_Quit'Access);
-- Alpha blending doesn't work well at 8-bit color
info := V.GetVideoInfo;
if info.vfmt.BitsPerPixel > 8 then
video_bpp := info.vfmt.BitsPerPixel;
else
video_bpp := 16;
end if;
videoflags := V.SWSURFACE;
while argc > 0 loop
if (argc > 1) and then
(CL.Argument (argc - 1) = "-bpp") and then
CH.Is_Digit (CL.Argument (argc) (1)) then
declare
last : Positive;
begin
Uint8_IO.Get (CL.Argument (argc), video_bpp, last);
end;
argc := argc - 2;
Put_Line ("-bpp" & Uint8'Image (video_bpp));
elsif CL.Argument (argc) = "-hw" then
videoflags := videoflags or V.HWSURFACE;
argc := argc - 1;
Put_Line ("-hw");
elsif CL.Argument (argc) = "-warp" then
videoflags := videoflags or V.HWPALETTE;
argc := argc -1;
Put_Line ("-warp");
elsif CL.Argument (argc) = "-fullscreen" then
videoflags := videoflags or V.FULLSCREEN;
argc := argc - 1;
Put_Line ("-fullscreen");
else
Put_Line ("Usage: " & CL.Command_Name & " " &
"[-bpp N] [-warp] [-hw] [-fullscreen]");
GNAT.OS_Lib.OS_Exit (1);
end if;
end loop;
-- Set video mode
screen := V.SetVideoMode (Screen_Width, Screen_Height,
C.int (video_bpp), videoflags);
if screen = null then
Put_Line ("Couldn't set " & Integer'Image (Screen_Width) &
"x" & Integer'Image (Screen_Height) &
" video mode: " & Er.Get_Error);
GNAT.OS_Lib.OS_Exit (2);
end if;
-- Set the surface pixels and refresh
if V.LockSurface (screen) < 0 then
Put_Line ("Couldn't lock the display surface: " & Er.Get_Error);
GNAT.OS_Lib.OS_Exit (2);
end if;
buffer := To_Pointer (screen.pixels);
for i in 0 .. screen.h - 1 loop
buffer := To_Pointer (
Lib_C.memset (To_Address (buffer),
(i * 255) / screen.h,
C.size_t (screen.pitch)));
buffer := Object_Pointer (
Pointer (buffer) + C.ptrdiff_t (screen.pitch));
end loop;
V.UnlockSurface (screen);
V.UpdateRect (screen, 0, 0, 0, 0);
-- Create the light
light := CreateLight (screen, 82);
if light = null then
GNAT.OS_Lib.OS_Exit (1);
end if;
-- Load the sprite
if LoadSprite (screen, "icon.bmp") < 0 then
V.FreeSurface (light);
GNAT.OS_Lib.OS_Exit (1);
end if;
-- Set a clipping rectangle do clip the outside edge of the screen
declare
clip : V.Rect;
begin
clip.x := 32;
clip.y := 32;
clip.w := Uint16 (screen.w - (2 * 32));
clip.h := Uint16 (screen.h - (2 * 32));
V.SetClipRect (screen, clip);
end;
-- Wait for a keystroke
lastticks := T.GetTicks;
done := 0;
mouse_pressed := 0;
while done = 0 loop
-- Update the frame -- move the sprite
if mouse_pressed /= 0 then
MoveSprite (screen, light);
mouse_pressed := 0;
else
MoveSprite (screen, null);
end if;
-- Slow down the loop to 30 frames / second
ticks := T.GetTicks;
if (ticks - lastticks) < FRAME_TICKS then
-- if CHECK_SLEEP_GRANULARITY
-- Put_Line ("Sleeping " &
-- Uint32'Image (FRAME_TICKS - (ticks - lastticks)) &
-- " ticks");
T.SDL_Delay (FRAME_TICKS - (ticks - lastticks));
-- if CHECK_SLEEP_GRANULARIRY
-- Put_Line ("Slept " &
-- Uint32'Image (FRAME_TICKS - (ticks - lastticks)) &
-- " ticks");
end if;
lastticks := ticks;
-- Check for events
loop
Ev.PollEventVP (PollEvent_Result, event);
exit when PollEvent_Result = 0;
case event.the_type is
when Ev.MOUSEMOTION =>
if event.motion.state /= 0 then
AttractSprite (event.motion.x,
event.motion.y);
mouse_pressed := 1;
end if;
when Ev.MOUSEBUTTONDOWN =>
if event.button.button = 1 then
AttractSprite (event.button.x,
event.button.y);
mouse_pressed := 1;
else
declare
area : V.Rect;
begin
area.x := Sint16 (event.button.x - 16);
area.y := Sint16 (event.button.y - 16);
area.w := 32;
area.h := 32;
V.FillRect (screen, area, 0);
V.Update_Rect (screen, area);
end;
end if;
when Ev.KEYDOWN =>
-- Any keypress quits the app ...
done := 1;
when Ev.QUIT =>
done := 1;
when others => null;
end case;
end loop;
end loop;
V.FreeSurface (light);
V.FreeSurface (sprite);
V.FreeSurface (backing);
-- print out some timing information
if flashes > 0 then
Put (Uint32'Image (flashes) &
" alpha blits, ~");
Put (Float (flashtime) / Float (flashes), 3, 2, 0);
Put_Line (" ms per blit");
end if;
end Testalpha;
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