I dug up some old code I posted on a thread relating to double jumping yonk ago. Anyway, you can apply it to a 3D plane scroller too. It's just some mechanics.
remstart
nonZero's cheap@$$ tutorial! >_<
This is just to teach some basic concepts. Everything here is done "manually", meaning I haven't used many of the
DBPro "make-life-easier" commands. The idea is to give an understanding. Things here can (and should) be done in
a far more efficient way. The code has been broken down and done in longer steps forunderstanding purposes. You
should be able to use it as a basic outline though.
remend
#CONSTANT camsmooth 50 `You can change this before run. You must decide how smoothly your camera follows
`bearing in mind that higher number = more resources used. Since this value is a
`#CONSTANT, it is substitued for the real number before compile, meaning it uses no
`extra resources the way a variable may.
`Create a texture for the ground
FOR a = 1 TO 20
FOR b = 1 TO 20
r = RND(150) + 100
v = RND(50)
INK RGB(r, r - v, 0), RGB(0,0,0)
DOT a, b
NEXT b
NEXT a
GET IMAGE 1, 0,0,20,20, 1
CLS
`Create texture for sphere
INK RGB(200,200,200), RGB(0,0,0)
BOX 0, 0, 10, 20
INK RGB(140,140,140), RGB(0,0,0)
BOX 11, 0, 20, 20
GET IMAGE 2, 0,0,20,20, 1
CLS
`Set autocam off to prevent it from repositioning during object creation
AUTOCAM OFF
SYNC RATE 60 `Important to decide on your FPS from start. 60 is recommended. This setting affects the appearance of all motion!
SET AMBIENT LIGHT 0
SET AMBIENT LIGHT 40
SET NORMALIZATION ON
POSITION LIGHT 0, -0, 50, 1000
POINT LIGHT 0, 0, 0, 0
`MAKE LIGHT
`POSITION LIGHT 0, 0,100,1000
`POINT LIGHT 0, 0, 0, -400
COLOR BACKDROP RGB(150,150,250)
`make the floor
MAKE OBJECT PLAIN 1, 800, 800
TEXTURE OBJECT 1, 1
XROTATE OBJECT 1, -90
POSITION OBJECT 1, 0,-4,0
`make a sun
MAKE OBJECT SPHERE 2, 150
POSITION OBJECT 2, 0, 100, 1000
SET OBJECT EMISSIVE 2, RGB(250,250,0)
`make the player
sphere = 99
MAKE OBJECT SPHERE sphere, 1
`Take note of the notation. The axact point of cantact is the sphere's y-radius and the plain's y-position (in this scenario)
POSITION OBJECT sphere, 0, OBJECT POSITION Y(1) + (OBJECT SIZE Y(sphere) / 2), 5
TEXTURE OBJECT sphere, 2
SET OBJECT LIGHT sphere, 0
SET SHADOW SHADING ON sphere
`These are following distances for the camera. In order to place the camera perfectly outside the
`model, we use 1/2 hieght and width as the object position is the center of the model. We can now
`control our following distance manually without needing to do any calculations in the future.
obj_zrad# = OBJECT SIZE Z(sphere, 1) / 2 `This is z-radius of the object's width, the center being inside the object.
obj_yrad# = OBJECT SIZE Y(sphere, 1) / 2 `Same as above but with height
walkspeed# = 0.5 `You should have a walking speed variable that you can tailor to your game. Allows running too!
spherev# = 0.0 `This is your velocity when 0, you're touching the ground
jumpheight# = 4 `Determines your jumping height. Change it based on environment changes, ie underwater.
jumping = 0 `Flag determines if jumping
jumpvelocity# = 0.15 `Your jump's velocity you can use this to alter the speed of your jumping
gravity# = -0.15 `Your gravity. Change it based on thing like planet, environment, etc.
DO
`This shall be our camera's following distance. It can be changed easily depending on the "room".
`Change the numbers 3 and 5 for different results.
followdist# = 10.0 + obj_zrad#
followheight# = 2.0 + obj_yrad#
`These variable here are for easy reference, you can pass these functions directly to other functions
spherex# = OBJECT POSITION X(sphere) `sphere's x position: sphere X
spherey# = OBJECT POSITION Y(sphere)
spherez# = OBJECT POSITION Z(sphere)
sphereAx# = OBJECT ANGLE X(sphere) `sphere's x angle: sphere Angle X
sphereAy# = OBJECT ANGLE Y(sphere)
sphereAz# = OBJECT ANGLE Z(sphere)
`Now we set the camera to follow the sphere's x and y coords and offset them byour following distances.
POSITION CAMERA 0, spherex#, spherey# + followheight#, spherez# - followdist#
`Controls for the object
IF UPKEY() = 1
YROTATE OBJECT sphere, 0
MOVE OBJECT sphere, walkspeed#
ENDIF
IF DOWNKEY() = 1
YROTATE OBJECT sphere, 180
MOVE OBJECT sphere, walkspeed#
ENDIF
IF LEFTKEY() = 1
YROTATE OBJECT sphere, -90
POSITION OBJECT sphere, spherex# - walkspeed#, spherey#, spherez#
ENDIF
IF RIGHTKEY() = 1
YROTATE OBJECT sphere, 90
POSITION OBJECT sphere, spherex# + walkspeed#, spherey#, spherez#
ENDIF
`Jumping bit
IF SPACEKEY() = 1
`First check if space has been released, if so
IF spacepushed = 0
`Check jumping. If jumping = 1, it means we're in mid jump/fall so we can dbl-jump
IF jumping = 1
`Since we're double-jumping, set jumping to 2
jumping = 2
`I just added a little velocity on the second jump for fun.
spherev# = jumpvelocity# + (jumpvelocity / 10)
`Now spacebar's been pressed so set flag to 1
spacepushed = 1
ENDIF
ENDIF
`Check to see if were in the process of a jump. If not, this is our first, so
IF jumping = 0
`set the spacekey falg to 1
spacepushed = 1
`Set jumping to 1 (1st jump)
jumping = 1
`Set volocity to our jump velocity
spherev# = jumpVelocity#
ENDIF
ELSE
`If the spacekey is not being pushed, set the spacepushed flag to 0
spacepushed = 0
ENDIF
`This bit must be repeated to update the variable agian. This is why you should directly pass
`OBJECT POSITION/ANGLE. As I said, this is just to make code more readable
spherex# = OBJECT POSITION X(sphere) `sphere's x position: sphere X
spherey# = OBJECT POSITION Y(sphere)
spherez# = OBJECT POSITION Z(sphere)
sphereAx# = OBJECT ANGLE X(sphere) `sphere's x angle: sphere Angle X
sphereAy# = OBJECT ANGLE Y(sphere)
sphereAz# = OBJECT ANGLE Z(sphere)
`This but handles jumping/falling. To save CPU power, it only bothers to do anything if the velocity is not 0
IF spherev# <> 0
POSITION OBJECT sphere, spherex#, spherey# + spherev#, spherez#
ENDIF
`Handles the gravity and jumping
`Check if the sphere's y-position is higher than the ground position + the jump height
IF OBJECT POSITION Y(sphere) > OBJECT POSITION Y(1) + jumpheight#
`If so, check to see if jumping phase is 2
IF jumping = 2
`If it is 2, we check to see if the sphere's y-position is dbl the jumpheight from ground level
IF OBJECT POSITION Y(sphere) > OBJECT POSITION Y(1) + (jumpheight# * 2)
`If it is, we set jumping to 3 to signify that no more jumps can be performed.
`We also set the object's velocity to that of the gravity (a negative number)
spherev# = gravity#
jumping = 3
ENDIF
ELSE
`Now if jumping did not equal two it means we've reached the end of our height and must begin descending.
`In this case we set the sphere's velocity to the gravity.
spherev# = gravity#
ENDIF
ENDIF
`The esiest way to prevent falling through the ground it to check the actual positions.
`On a non-flat surfuce you'de have to check collisions.
IF OBJECT POSITION Y(sphere) < OBJECT POSITION Y(1)
`So if the sphere is lower than the ground, our jump has ended.
`Hence we set jumping to 0 and velocity to 0
spherev# = 0.0
jumping = 0
`Then we place the object on the ground
POSITION OBJECT sphere, OBJECT POSITION X(sphere), OBJECT POSITION Y(1) + (OBJECT SIZE Y(sphere) / 2), OBJECT POSITION Z(sphere)
ENDIF
`Handlers to keep you on the map... Hahahaha, no escape!
IF OBJECT POSITION Z(sphere) > 380: POSITION OBJECT sphere, OBJECT POSITION X(sphere), OBJECT POSITION Y(sphere), 380: ENDIF
IF OBJECT POSITION Z(sphere) < -380: POSITION OBJECT sphere, OBJECT POSITION X(sphere), OBJECT POSITION Y(sphere), -380: ENDIF
IF OBJECT POSITION X(sphere) > 380: POSITION OBJECT sphere, 380, OBJECT POSITION Y(sphere), OBJECT POSITION Z(sphere): ENDIF
IF OBJECT POSITION X(sphere) < -380: POSITION OBJECT sphere, -380, OBJECT POSITION Y(sphere), OBJECT POSITION Z(sphere): ENDIF
LOOP
You are the ball. you can move with arrow keys and jump with space. I'm afraid I haven't editted it so it's more relevant to the thread I posted it on. Anyhow, it's been broken down a lot so you should be able to get something from it.
