Creating a tiled mesh at runtime

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Creating a tiled mesh at runtime

Postby ninth » Sun Jun 26, 2011 4:34 pm

This sample needs an additional three image files to use as the textures, wich should named as '1.png', '2.png', '3.png' and placed in the same dir with the script.

Code: Select all
from pandac.PandaModules import *
loadPrcFileData("editor-startup", "show-frame-rate-meter #t")
import direct.directbase.DirectStart
from random import randint

node = GeomNode('gnode')
geoms = []
textures_count = 3
# Creating a separate geom for the each textures
# and prepearing the vertex data format for this geom
for i in xrange(textures_count):
    gvd = GeomVertexData('name', GeomVertexFormat.getV3t2(), Geom.UHStatic)
    geom = Geom(gvd)
    prim = GeomTriangles(Geom.UHStatic)
    vertex = GeomVertexWriter(gvd, 'vertex')
    texcoord = GeomVertexWriter(gvd, 'texcoord')
    tex = loader.loadTexture('%i.png' % (i+1))

# Making and filling the mesh data
for x in xrange(0,100):
    for z in xrange(0,100):
        t_img = randint(0,textures_count - 1) # assign with random texture
        i = geoms[t_img]['index']
        geoms[t_img]['vertex'].addData3f(x, 0, z)
        geoms[t_img]['texcoord'].addData2f(0, 0)
        geoms[t_img]['vertex'].addData3f(x, 0, z+1)
        geoms[t_img]['texcoord'].addData2f(0, 1)
        geoms[t_img]['vertex'].addData3f(x+1, 0, z+1)
        geoms[t_img]['texcoord'].addData2f(1, 1)
        geoms[t_img]['vertex'].addData3f(x+1, 0, z)
        geoms[t_img]['texcoord'].addData2f(1, 0)
        # d: index displace, becouse we use one vertex pool for the all geoms
        d = i * (textures_count + 1)
        geoms[t_img]['prim'].addVertices(d, d + 2, d + 1)
        geoms[t_img]['prim'].addVertices(d, d + 3, d + 2)
        geoms[t_img]['index'] += 1

# Close a primitive, add them to the geom and add the texture attribute
for i in xrange(3):
    node.setGeomState(i, node.getGeomState(i).addAttrib(TextureAttrib.make(geoms[i]['texture'])))

terrain = render.attachNewNode(node)


Code: Select all
1 total nodes (including 0 instances); 0 LODNodes.
0 transforms; 0% of nodes have some render attribute.
3 Geoms, with 3 GeomVertexDatas and 1 GeomVertexFormats, appear on 1 GeomNodes.
40000 vertices, 0 normals, 0 colors, 40000 texture coordinates.
GeomVertexData arrays occupy 782K memory.
GeomPrimitive arrays occupy 118K memory.
20000 triangles:
  0 of these are on 0 tristrips.
  20000 of these are independent triangles.
3 textures, estimated minimum 192K texture memory required.

Last edited by ninth on Mon Jun 27, 2011 10:09 am, edited 1 time in total.
Vodka, bears, balalaika... hmm... sorry for my English =)
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Postby ThomasEgi » Mon Jun 27, 2011 3:56 am

a very useful little snippet indeed. thx for sharing.
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Postby EdBighead » Mon Nov 21, 2011 8:59 pm

Neat stuff. I'm unfamiliar with creating geoms - is there a quick way to alter them once they've been created? Say, for example, that I wanted to remove every fifth quad of the 10000, or maybe add some more at a different height, or change the color of a few?



I figured out the different heights, but I'm still at a loss for removing at runtime.
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Postby ninth » Tue Nov 22, 2011 5:32 pm

As I know, you can modify an exist geometry, but you can not to add or remove vertices at usual way. I think the easiest way to do this is recreating your geom without that vertices. If you want to do this in runtime, then it make sense to split a big geom into the some parts and recreate the needed parts separately.
Vodka, bears, balalaika... hmm... sorry for my English =)
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Postby ZetronMan » Thu Jan 12, 2012 11:32 am

Sorry to resurrect a dead thread, but this topic is of a lot of interest to me as I think this technique is the only way to increase my frame rate to acceptable levels. The only problem I have is, I have no clue how to modify this to create cubes instead of a flat plane.

I think what I need to do is add an additional xrange (for y in xrange) in between the x and z lines, then add the four additional points I would need to make this a cube. But I'm getting tripped up on actual implementation.

If someone has already done this, or knows how, any chance you can provide some guidance?

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