If I wanted to move around and display a large number of individual pixels (ie vertexes in OpenGL), would it be best to have them in a display list, and if so is that display list stored in main memory or videoram? What the best/fastest way to plot a lot of colored pixels as in a particle system?
Where are vertex's stored?
BlitzMax Forums/BlitzMax Programming/Where are vertex's stored? Probably vertex arrays. Vertex arrays store all the data in one big block of system memory, then send it all across to the card in one go. (There's also Vertex Buffers, which stores the data in video RAM, but they're only faster if the data doesn't change at all, like static 3D meshes.)
The head demo in the samples folder uses vertex arrays, IIRC.
I did a test with sprites a few days ago to see if it was faster drawing lots of them using VAs or just using DrawImage. VAs were faster, but only by a small amount on my system (1% or so). YMMV.
The head demo in the samples folder uses vertex arrays, IIRC.
I did a test with sprites a few days ago to see if it was faster drawing lots of them using VAs or just using DrawImage. VAs were faster, but only by a small amount on my system (1% or so). YMMV.
Display lists are stored in internal, video card friendly formats, and they may indeed be cached in video ram. Vertex array have neither of these properties.
For the highest performance, display lists are the way to go. For smallish models, you might not notice a huge difference, however.
For the highest performance, display lists are the way to go. For smallish models, you might not notice a huge difference, however.
always thought that VBO are the far best performance wise ...
And if you need to animate each of the vertexes individually?
vertices.
look up a book called something like "computer graphics, a top-down approach using opengl"....i remember using this in school and doing a sierpinski gasket exercise, one in 2D and one in 3D......can't remember exactly the method used, but it was just pushing a ton of pixels on screen, and the 3D version also rotated/translated those pixels.
also a cool way of learning recursion, for those who don't know about it....
look up a book called something like "computer graphics, a top-down approach using opengl"....i remember using this in school and doing a sierpinski gasket exercise, one in 2D and one in 3D......can't remember exactly the method used, but it was just pushing a ton of pixels on screen, and the 3D version also rotated/translated those pixels.
also a cool way of learning recursion, for those who don't know about it....
And if you need to animate each of the vertexes individually?
Vertex Arrays or individual vertices. VBs and display lists are only an advantage for static vertex lists that you don't change.
I have seen mention of display lists but nothing about vertex arrays. are they supported in blitzmaX? how?
glhead.bmx uses them.
Also,
Sorry about the length of that - what's the name of the tag that puts it in a scrollable box?
EDIT: Thanks, mephtis.
BTW, don't worry about the maths in the SetPos method. I just copied and pasted it (on the whole) from DrawImage. It basically sets four vertex co-ordinates per sprite (top-left, top-right, bottom-right, bottom-left in turn) with texture co-ordinates to match. It's more complex than it could be, because I've left in the transform bits that could potentially let you rotate the sprites.
Also,
Rem Teamonkey's simple vertex array demo End Rem Strict Const ARRAY_SIZE = 1000 ' 1000 sprites Const SCREEN_W = 800 Const SCREEN_H = 600 Type TImageArray Field image:Int Field img_width:Int, img_height:Int, tex_width:Int, tex_height:Int Field frame:Int = 0 Field size:Int Field ver:Float[] ' Vertex array Field tex:Float[] ' Texture co-ordinates array Function Create:TImageArray(pixmap_in:TPixmap, size_in:Int) Assert(size_in > 0) Local timg:TImageArray = New TImageArray timg.image = bglTexFromPixmap(pixmap_in) timg.img_width = pixmap_in.width timg.img_height = pixmap_in.height timg.tex_width = timg.img_width timg.tex_height = timg.img_height bglAdjustTexSize timg.tex_width,timg.tex_height timg.ver = New Float[size_in*8] ' 2*4 vertices per index timg.tex = New Float[size_in*8] timg.size = size_in Assert(timg.ver.length=size_in*8 And timg.tex.length=size_in*8) Return timg End Function Method DrawAll() glEnable GL_TEXTURE_2D glBindTexture GL_TEXTURE_2D,image glTexParameteri GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,GL_LINEAR glTexParameteri GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,GL_LINEAR glEnableClientState(GL_VERTEX_ARRAY) glEnableClientState(GL_TEXTURE_COORD_ARRAY) glVertexPointer(2,GL_FLOAT,0,ver) glTexCoordPointer(2,GL_FLOAT,0,tex) glDrawArrays(GL_QUADS, 0, size*4) End Method Method SetPos(index:Int, x#, y#) Assert(index>=0 And index<size) Local origin_x#, origin_y# GetOrigin(origin_x, origin_y) Local x0# = 0.0 Local x1# = tex_width Local y0# = 0.0 Local y1# = tex_height Local tx# = x + origin_x Local ty# = y + origin_y ' These are transform parameters. Const ix# = 1.0 Const iy# = 0.0 Const jx# = 0.0 Const jy# = 1.0 ' Texture co-ordinates. Local u0# = 0.0 Local u1# = Float(tex_width)/Float(img_width) Local v0# = 0.0 Local v1# = Float(tex_height)/Float(img_height) ' Calculate vertex positions ver[index*8 + 0] = x0*ix + y0*iy + tx ' x first ver[index*8 + 2] = x1*ix + y0*iy + tx ver[index*8 + 4] = x1*ix + y1*iy + tx ver[index*8 + 6] = x0*ix + y1*iy + tx ver[index*8 + 1] = x0*jx + y0*jy + ty ' now the y's ver[index*8 + 3] = x1*jx + y0*jy + ty ver[index*8 + 5] = x1*jx + y1*jy + ty ver[index*8 + 7] = x0*jx + y1*jy + ty ' Extract texture co-ordinates tex[index*8 + 0] = u0 tex[index*8 + 2] = u1 tex[index*8 + 4] = u1 tex[index*8 + 6] = u0 tex[index*8 + 1] = v0 tex[index*8 + 3] = v0 tex[index*8 + 5] = v1 tex[index*8 + 7] = v1 End Method End Type ' ***** ' START ' ***** Graphics SCREEN_W, SCREEN_H, 0 Cls Local img:TPixmap = LoadPixmap("ball.png") Local imgArr:TImageArray = TImageArray.Create(img, ARRAY_SIZE) SetBlend ALPHABLEND For Local i=0 To (ARRAY_SIZE)-1 Local x# = RndFloat()*SCREEN_W Local y# = RndFloat()*SCREEN_H imgArr.SetPos(i,x,y) Next imgArr.DrawAll() Flip WaitKey
Sorry about the length of that - what's the name of the tag that puts it in a scrollable box?
EDIT: Thanks, mephtis.
BTW, don't worry about the maths in the SetPos method. I just copied and pasted it (on the whole) from DrawImage. It basically sets four vertex co-ordinates per sprite (top-left, top-right, bottom-right, bottom-left in turn) with texture co-ordinates to match. It's more complex than it could be, because I've left in the transform bits that could potentially let you rotate the sprites.
codebox
To run the code, you must have ball.png from the samples in the same directory.