58 lines
1.3 KiB
GLSL
58 lines
1.3 KiB
GLSL
|
// This source code is property of the Computer Graphics and Visualization
|
|||
|
|
// chair of the TU Dresden. Do not distribute!
|
|||
|
|
// Copyright (C) CGV TU Dresden - All Rights Reserved
|
|||
|
|
#version 330
|
|||
|
|
|
|||
|
|
in vec4 position;
|
|||
|
|
|
|||
|
|
|
|||
|
|
|
|||
|
|
uniform mat4 mvp;
|
|||
|
|
|
|||
|
|
//Returns the height of the procedural terrain at a given xz position
|
|||
|
|
float getTerrainHeight(vec2 p);
|
|||
|
|
|
|||
|
|
|
|||
|
|
|
|||
|
|
void main()
|
|||
|
|
{
|
|||
|
|
gl_Position = mvp * position;
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
//source: https://gist.github.com/patriciogonzalezvivo/670c22f3966e662d2f83
|
|||
|
|
float rand(vec2 c)
|
|||
|
|
{
|
|||
|
|
return 2 * fract(sin(dot(c.xy ,vec2(12.9898,78.233))) * 43758.5453) - 1;
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
float perlinNoise(vec2 p )
|
|||
|
|
{
|
|||
|
|
vec2 ij = floor(p);
|
|||
|
|
vec2 xy = p - ij;
|
|||
|
|
//xy = 3.*xy*xy-2.*xy*xy*xy;
|
|||
|
|
xy = .5*(1.-cos(3.1415926 * xy));
|
|||
|
|
float a = rand((ij+vec2(0.,0.)));
|
|||
|
|
float b = rand((ij+vec2(1.,0.)));
|
|||
|
|
float c = rand((ij+vec2(0.,1.)));
|
|||
|
|
float d = rand((ij+vec2(1.,1.)));
|
|||
|
|
float x1 = mix(a, b, xy.x);
|
|||
|
|
float x2 = mix(c, d, xy.x);
|
|||
|
|
return mix(x1, x2, xy.y);
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
//based on https://www.seedofandromeda.com/blogs/58-procedural-heightmap-terrain-generation
|
|||
|
|
float getTerrainHeight(vec2 p)
|
|||
|
|
{
|
|||
|
|
float total = 0.0;
|
|||
|
|
float maxAmplitude = 0.0;
|
|||
|
|
float amplitude = 1.0;
|
|||
|
|
float frequency = 0.02;
|
|||
|
|
for (int i = 0; i < 11; i++)
|
|||
|
|
{
|
|||
|
|
total += ((1.0 - abs(perlinNoise(p * frequency))) * 2.0 - 1.0) * amplitude;
|
|||
|
|
frequency *= 2.0;
|
|||
|
|
maxAmplitude += amplitude;
|
|||
|
|
amplitude *= 0.45;
|
|||
|
|
}
|
|||
|
|
return 15 * total / maxAmplitude;
|
|||
|
|
}
|