terrain.cl

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#define CAMERA_POSITIONS_LENGTH 1
#define CAMERA_POSITIONS_ARRAY { (float4)(0, -10, 0, 0) }
 
#define CAMERA_FACING_DIRECTIONS_LENGTH 1
#define CAMERA_FACING_DIRECTIONS_ARRAY { (float4)(normalise((float3)(-10, -10, -10)), 0.0f) }
 
#define SCENE_BACKGROUND_COLOUR (float3)(0.5f, 0.8f, 0.9f)
 
#define MAXIMUM_MARCH_STEPS 300
#define MAXIMUM_MARCH_DISTANCE 200.0f
#define SURFACE_INTERSECTION_EPSILON 0.00001f
 
#define CAMERA_FOCUS_DISTANCE 0.01f
 
#define USE_BOUNDING_VOLUME true
//#define DISPLAY_BOUNDING_VOLUME true
//#define DO_RENDER_MARCHING_ITERATIONS true
 
 
#define FORCE_FREE_CAMERA true
#define CAMERA_SPEED 5.0f
 
#include "simplexnoise1234.cl"
#include "types.cl"
#include "sdf.cl"
 
#define SCALE 0.025f
#define AMPLITUDE 10.0f
#define ITERATIONS 3
 
#define FREQUENCY_MULTIPLIER 2
#define AMPLITUDE_MULTIPLIER 0.4f
 
float getHeightAt(float x, float y)
{
    float frequency = SCALE;
    float amplitude = AMPLITUDE;
    float height = 0.0f;
 
    for (int j = 0; j < ITERATIONS; j++)
    {
        height += amplitude * snoise2(x * frequency, y * frequency);
        frequency *= FREQUENCY_MULTIPLIER;
        amplitude *= AMPLITUDE_MULTIPLIER;
    }
 
    return height;
}
 
Light getLight(float time)
{
    Light light;
    light.ambient = (float3)(0.2f, 0.2f, 0.2f);
    light.diffuse = (float3)(0.5f, 0.5f, 0.5f);
    light.specular = (float3)(1.0f, 1.0f, 1.0f);
    light.position = (float3)(0.0, -100, 0);
 
    return light;
}
 
Material SDF(const float3 position, const float time, float* distance)
{
    // https://fileadmin.cs.lth.se/cs/Education/EDAN35/projects/16NiklasJohan_Terrain.pdf
 
    float height = getHeightAt(position.x, position.z);
    *distance = f_abs(position.y) - max(height, 0.0f);
 
    float3 colour;
 
    // Water
    if (height <= 0.0f)
    {
        colour = (float3)(0, 0.05, 0.8);
    }
    // Land
    else
    {
        // Snow
        if (height >= 8.0f)
        {
            colour = (float3)(0.9, 0.9, 1);
        }
        // Grass
        else
        {
            colour = (float3)(0.1, 0.5, 0.2);
        }
    }
 
    // Material
    Material material;
    material.ambient = colour;
    material.diffuse = material.ambient;
    material.specular = (float3)(0, 0, 0);
    material.shininess = 25.0f;
 
    return material;
}
 
Material getMaterial(float3 position, float time)
{
    float distance;
    return SDF(position, time, &distance);
}
 
float boundingVolumeDE(float3 position, float time)
{
    return fabs(position.y) - 12.0f;
}
 
float DE(float3 position, float time)
{
    float distance;
    SDF(position, time, &distance);
    return distance;
}
 
#include "main.cl"