TheGameCreators - CodeBase - Even faster starfield

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Category: 2D Effects

Version: 1.1

Information

Uploaded: 15th Sep 2003 16:18

Modified: 23rd Jul 2004 15:54

Author: IanM

Summary

This is an even faster version of a starfield, and is more flexible than the tutorials

Full Description

Even faster than the 'fast' memblock version of the same code with the sprite disabled, and this one is more flexible (it doesn't depend on card specific features).<br /> <br /> On my laptop, the memblock tutorial gives me 40fps. This code gives me 89fps (recently improved to give an 11% increase in speed).<br /> <br /> If you can make it faster without making it unreadable, let me know.

DarkBASIC Professional Source Code

` This code was downloaded from The Game Creators

` It is reproduced here with full permission

` http://www.thegamecreators.com

` Fast starfield  demonstrating types

` The star field is controlled by the following constants. The speed of movement is controlled by the cursor keys.

` Window details for the stars

#constant STARS_TOP     0

#constant STARS_LEFT    0

#constant STARS_WIDTH   640

#constant STARS_HEIGHT  480

#constant STARS_MAX     3000

sync rate 0

sync on

hide mouse

type Stars_t

X as float

Y as float

Speed as float

Colour as dword

endtype

global dim StarField(STARS_MAX) as Stars_t

` Generate the star settings

SetupStarField()

repeat

cls

MoveStarField()

DrawStarField()

text 0, 0, str$( screen fps() )

sync

until spacekey()

function SetupStarField()

local i as integer

` Generate random colours positions and speeds for all sprites

for i = 0 to STARS_MAX

StarField(i).X = rnd(STARS_WIDTH)

StarField(i).Y = rnd(STARS_HEIGHT)

StarField(i).Speed = (rnd(17)+3)/8.0

StarField(i).Colour = rgb(rnd(128)+127, rnd(128)+127, rnd(128)+127)

next i

endfunction

function MoveStarField()

local HorizontalDir as integer

local VerticalDir as integer

local i as integer

` Cache the cursor key settings for star movement

if leftkey() then HorizontalDir = -1

if rightkey() then HorizontalDir = 1

if upkey() then VerticalDir = -1

if downkey() then VerticalDir = 1

` Adjust the position of all stars

for i = 0 to STARS_MAX

` Standard drift to the left

dec StarField(i).X, StarField(i).Speed

` Adjust the movement by which cursor keys are pressed

if HorizontalDir < 0 then inc StarField(i).X, StarField(i).Speed/2.0

if HorizontalDir > 0 then dec StarField(i).X, StarField(i).Speed

if VerticalDir < 0   then inc StarField(i).Y, StarField(i).Speed

if VerticalDir > 0   then dec StarField(i).Y, StarField(i).Speed

` If the coordinate of the star is outside the displayab;e range, move it back in the other side

If StarField(i).X < 0             then inc StarField(i).X, STARS_WIDTH

if StarField(i).X >= STARS_WIDTH  then dec StarField(i).X, STARS_WIDTH

if StarField(i).Y < 0             then inc StarField(i).Y, STARS_HEIGHT

if StarField(i).Y >= STARS_HEIGHT then dec StarField(i).Y, STARS_HEIGHT

next a

endfunction

function DrawStarField()

local i as integer

` Faster update of the display

lock pixels

`Display each start

for i = 0 to STARS_MAX

dot StarField(i).X + STARS_LEFT, StarField(i).Y + STARS_TOP, StarField(i).Colour

Author Name:	IanM
CodeBase Entries:	26

CodeBase - Even faster starfield

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DarkBASIC Professional Source Code

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