view - Fortran fast 3D renderer to a linux framebuffer device

Example asteroids game:

features

Uses quaternion multiplication for smooth rotation of spatial vectors. The scene is displayed using ray casting based on the spherical coordinates of the object's vertecies; rather than a projection onto a rectangular plane as most 3D engines do, this allows for a more realistic rendering for wide fields of view without suffering from strange rectangular distorion, however it would appear as though looking through a fish-eye lense.

The original invokation of this program is to specify an object to render and a configuration for the framebuffer device and display position.
However, the current intention is to load objects from a scene file, and specify that alone. Example scene files are found in the scene directory. Example screenshots are in the screenshot directory. Example objects can be found in the objFiles directory. Programs that may help with object file formatting and creation are located in utils.

Requirements

may need to make yourself part of the 'video' group to write to '/dev/fb0'
Depends on fcurses, fbMod, and stringParseMods. These can be found from the same github repository that this is from.

Source files

-renderMod.f90
Uses fbMod2.f90 for drawing to the screen and handles the objects and their positions in the scene.

-view.f90
Main routine for handling the orientation of the camera and any specific utility, this example has the capability for an asteroids game.

-shareMods.f90
This small module is used to share variables between renderMod and view.

Internal Commandline Options

The view program allows for an internal commandline capability when ":" is pressed. The subroutine is called from renderMod to read the line and interpret the duty.
These commands can also be used in the scene.rc files to setup the initial scene.

Commands that take parameters show their values when executed sans parms

Command Parameters	Description
help	Displays this help message
q,quit,exit	terminates the program
echo	displays anything else on line to the screen
exec	executes anything else on line as shell command
fbpath F	path to framebuffer device, must have write permissions
dumpfile F	path for dump file for keyboard screenshots
tmpdir F	path to a temporary directory for scratch files
interactive	puts program into interactive rather than single render
contact N	calculates contact conditions for dynamic objects; N is the type of contact algorithm, 0=off, 1=elastic-Frictionless
FOV x y	field of view angles (radians)
subscreen x1 y1 x2 y2	pixel ranges, top-left and bottom right, (row column)
timestep r	time between frames for animation
dtheta r	angle change for key press
dspace r	distance increment for key press
width n	pixel width of screen
height n	pixel height of screen
timeout n	animation steps to run
linelength N	frame buffer line length Bytes
NobjectBuff N	allocate the object buffer to this many objects. WARNING will delete all existing objects
LoadObject FILE	will load object from file FILE
dataColumns i(8)	list the column numbers of a data file that correspond to x,y,z,radius,transparency,color(3). color depends on dataColor
dataRange [xyzrthsvRGB] min max	corresponding to the data in the data file.
dataColorHSV	indicate that color(3) specified in dataColumns are HSV
dataColorRGB	indicate that color(3) specified in dataColumns are RGB
dataPoint STR	object mode type for data points [point,circ,fcirc,sph,cloud]
LoadData FILE	FILE is a data file with columns, e.g. CSV, SSV. Loads into th enext available object.
camera_pos x y z	location of camera
camera_orient a u v w	angle-axis orientation of camera
universe c x y z	set a universal shape (c=box
periodic	sets the universal size to be periodic else will rebound
fbclear	clear the pixel buffer
dynamics	run one step of object dynamics to update relative vectors
fbinit	initializes the framebuffer, needed for 'draw'
bgColor C(3)	draw a filled rectangle in subscreen with RGB color C(3)
draw	draws current objects to the display buffer (not screen)
redraw	writes the current pixel buffer to the frame buffer
pause	stops rendering animation
run	resumes rendering animation
picture [F]	take a screen shot, if F is not given, F='dumpfile'
record	toggle recording mode (video)
follow I	camera follows surface of object I
impulseControl	set input key mode to impulse
spatialControl	set input key mode to spatial
cpo I J (K)	copy object ID I to J (through K)
nearest,closest	reports the nearest vertex relative sph position and obj
underAim	reports the obj, tri, and node at center of screen
o I c	object ID 'I' definition 'c' object command 'c' can be:
save s	save this object as file name 's'
name s	set name of object 'I'
mode s	set render mode of object 'I', (point
mass r	set object's total mass (for collision)
radius r	set object's average radius (for contact)
offset x y z	set position offset of object 'I'
velocity u v w	set velocity of object 'I'
orient a u v w	set angle and rotation axis of object 'I'
spin a u v w	set angle rate and rotation axis of object 'I'
scale r	scale all local positions of object 'I' by multiple 'r'
add J	add a node to triangle J of object 'I', default J=underAIM
point J x y z	set local position of point 'J' in object 'I'
disp J u v w	displace local position of point 'J' in object 'I'
color J r g b	set color of point 'J' in object 'I' (J=0 for all points)
smooth J k	set smoothness of point J in object I (J=0 for all points)

orand c i j v(:)	randomizes objects i-j property 'c' with ranges v(:)

Future Work

FEATURES:

• differnent light source direction

• transfer frictional torque
  i.e. no translational friction
  i.e. rotation axis = contact vector

• auto-orientation i.e. auto-pilot

• editing objects
  select node under Aim [done]
  provide its attributes or provide relative displacemnts, etc.

• custom Heads Up Display (HUD)

GAMES/APPLICATIONS:

• 3D asteroids
  impulse controls [done]
  explosion mechanics (object spawn) [doneish]
  scoreing [kinda, shows Nobjects and quites when =0]
  radar [kinda]
  contact damage [just die]
  relative PBCs [done]

• billiards/snooker
  3D physics
  box rebounds
  felt rolling friction

• Winding Road
  progressively tortuous road
  drive off road=crash
  driving mechanics
  requires random trees progressively getting wilder

• fbpaint [done part of fbMod2.f90]
  2D image editor
  simple geometries
  wrapper for converting image formats

• object editor
  rotate object not camera
  more intuitive attribute control
  save objects [done]
  subdivide triangles [done]
  delete nodes and triangles