TheGameCreators - CodeBase - Heightmaps from USGS .flt files

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Category: Basic 3D

Version: 1.0

Information

Uploaded: 10th Sep 2009 01:54

Modified: 10th Sep 2009 11:44

Author: Visigoth

Summary

function to create greyscale, or color maps with some tweaking, of USGS .flt files.

Full Description

DarkBASIC Professional Source Code

` This code was downloaded from The Game Creators

` It is reproduced here with full permission

` http://www.thegamecreators.com

function make_flt_heightmap(infile$,in_cols,in_rows,left,top,right,bottom,outfile$)

//params are:

//infile$ is the filename of the USGS .flt file, in_cols is the number of columns in the .flt file

//in_rows is the number of rows in the .flt file, top,left,bottom,right are the coordinates of the image

//you want to grab, outfile$ is the filename to save the .bmp"

open to read 1,infile$

make memblock from file 1,1

close file 1

dim vertices(3,in_rows,in_cols) as integer

//find lowest, highest height

lo_height# = 20000

hi_height# = 0

for r = 1 to in_rows

for c = 1 to in_cols

height# = memblock float(1,mem_pos)

if height# > hi_height#

hi_height# = height#

endif

if height# < lo_height#

lo_height# = height#

endif

inc mem_pos,4

next c

next r

//compute the color scale

c_scale# = (255.0 / (hi_height# - lo_height#))

//set the color value for each position, load into array

mem_pos = 0

for r = 1 to in_rows

for c = 1 to in_cols

height# = memblock float(1,mem_pos)

color = int((height# - lo_height#) * c_scale#)

vertices(1,r,c) = color //you can have different color settings if you want to use certain channels

vertices(2,r,c) = color

vertices(3,r,c) = color

inc mem_pos,4

next c

next r

delete memblock 1

//make the bitmap

make memblock 1,((in_cols * in_rows) * 4) + 12

write memblock dword 1,0,in_cols

write memblock dword 1,4,in_rows

write memblock dword 1,8,32

mem_pos = 12

for r = 1 to in_rows

for c = 1 to in_cols

write memblock byte 1,mem_pos,int(vertices(1,r,c)) : inc mem_pos,1 		//blue

write memblock byte 1,mem_pos,int(vertices(2,r,c)) : inc mem_pos,1		//green

write memblock byte 1,mem_pos,int(vertices(3,r,c)) : inc mem_pos,1		//red

write memblock byte 1,mem_pos,0 : inc mem_pos,1

next c

next r

make bitmap from memblock 1,1

set current bitmap 1

get image 1,left,top,right,bottom,1

save image outfile$,1

delete bitmap 1

delete image 1

delete memblock 1

undim vertices()

endfunction

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Author Name:	Visigoth
CodeBase Entries:	18

CodeBase - Heightmaps from USGS .flt files

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DarkBASIC Professional Source Code

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