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Debug mode MAV if MD2 animation speed is too big

Archives Forums/Blitz3D Bug Reports/Debug mode MAV if MD2 animation speed is too big

Placekeeper(Posted 2007) [#1]
If you use AnimateMD2 with a speed bigger than the difference between the first and last frame, the program will eventually crash at RenderWorld (displaying the message "Memory Access Violation" even in debug mode)

This happens in loop (1) and pingpong (2) mode. I couldn't reproduce it in play-once (3) mode for any speed.

Usually this isn't too big a problem because the speeds just are not that high.
But I want to adjust the animation speed to the mean framerate at least at the beginning of the animation.

To do this, I calculate the mean framerate of the last x seconds. When I start an animation, I multiply the mean framerate with an FPS independent speed constant (i.e. animation frames per second instead of animation frames per rendered frame)

If now the frame rate drops for some reason, and at the same time an animation is started (with a big calculated speed now), and some time later, a MAV will happen at RenderWorld, if the animation hasn't been stopped until that.

I'll provide a modified version of the dragon example from the b3d demos.

Note the lines
; !! HERE: Use animation speed bigger than (end - start) 
;speed#=65 ; will crash at frame no. 2
speed#=1.5 ; will crash at frame no. 319
AnimateMD2 dragon, 1, speed#, 39, 40



Here it starts: 

;0,40  : idle
;40,46 : run
;46,54 : attack
;54,58 : paina
;58,62 : painb
;62,66 : painc
;66,72 : jump
;72,84 : flip

Global info1$="Dragon Demo"
Global info2$="Use arrows keys to pan, A/Z to zoom"
Global info3$="MD2 Dragon model courtesy of Polycount"

Include "../start.bb"

;environment cube
cube=CreateCube()
FitMesh cube,-250,0,-250,500,500,500
FlipMesh cube
tex=LoadTexture( "chorme-2.bmp" )
ScaleTexture tex,1.0/3,1.0/3
EntityTexture cube,tex
EntityAlpha cube,.4
EntityFX cube,1

;floor mirror
m=CreateMirror()

;simple light
light=CreateLight()
TurnEntity light,45,45,0

;camera
camera=CreateCamera()
cam_xr#=30:cam_yr#=0:cam_zr#=0:cam_z#=-100

;cool dragon model!
tex=LoadTexture( "model\dragon.bmp" )
dragon=LoadMD2( "model\dragon.md2" )
EntityTexture dragon,tex
PositionEntity dragon,0,25,0
TurnEntity dragon,0,150,0

; !! HERE: Use animation speed bigger than (end - start) 
;speed#=65 ; will crash at frame no. 2
speed#=1.5 ; will crash at frame no. 319
AnimateMD2 dragon, 1, speed#, 39, 40

While Not KeyHit(1)
	played#=played#+speed#
	frames=frames+1
	
	If KeyDown(203)
		cam_yr=cam_yr-2
	Else If KeyDown(205)
		cam_yr=cam_yr+2
	EndIf
	
	If KeyDown(200)
		cam_xr=cam_xr+2
		If cam_xr>90 cam_xr=90
	Else If KeyDown(208)
		cam_xr=cam_xr-2
		If cam_xr<5 cam_xr=5
	EndIf
	
	If KeyDown(26)
		cam_zr=cam_zr+2
	Else If KeyDown(27)
		cam_zr=cam_zr-2
	EndIf
	
	If KeyDown(30)
		cam_z=cam_z+1:If cam_z>-10 cam_z=-10
	Else If KeyDown(44)
		cam_z=cam_z-1:If cam_z<-180 cam_z=-180
	EndIf
	
	PositionEntity camera,0,0,0
	RotateEntity camera,cam_xr,cam_yr,cam_zr
	MoveEntity camera,0,0,cam_z

	UpdateWorld
	RenderWorld
	Text 10, 10, "Frames rendered: " + frames
	Text 10, 20, "Animation frames played: " + played#
	Flip
Wend

End



Crash times: 

speed	frames	frames*speed
129	1	129
65	2	130
33	4	132
17	9	153
9	19	171
5	39	195
3	79	237
2	159	318
1.5	319	478.5
1.25	639	798.75
1.125	1279	1438.88
1.0625	2559	2718.94
161	[will crash before first frame]



Placekeeper(Posted 2007) [#2]
Over that, it will crash at RenderWorld if the end frame is out of range

speed#=1000
AnimateMD2 dragon, 1, speed#, 83, 200