Terrain::GetSlope

This method gets the terrain slope at the specified coordinate or 3D position.

Syntax

• float GetSlope(const int tx, const int ty)
• float GetSlope(const iVec2& coord)
• float GetSlope(const Vec3& coord)
• float GetSlope(const float x, const float y, const float z)

Returns

Returns the terrain slope in degrees at the specified coordinate or the interpolated normal at the specified position in global space.

Example

This example applies a material to a terrain based on the slope at each point.

#include "UltraEngine.h"
#include "Components/Player/CameraControls.hpp"

using namespace UltraEngine;

int main(int argc, const char* argv[])
{
    //Get the display list
    auto displays = GetDisplays();

    //Create a window
    auto window = CreateWindow("Ultra Engine", 0, 0, 1280, 720, displays[0], WINDOW_CENTER | WINDOW_TITLEBAR);

    //Create a world
    auto world = CreateWorld();
    world->SetAmbientLight(0);

    //Create a framebuffer
    auto framebuffer = CreateFramebuffer(window);

    //Create a camera
    auto camera = CreateCamera(world);
    camera->SetFov(70);
    camera->SetPosition(0, 50, 0);
    camera->SetRotation(45, 0, 0);
    camera->SetClearColor(0.125);

    //Create a light
    auto light = CreateDirectionalLight(world);
    light->SetRotation(35, 45, 0);
    light->SetColor(2);

    //Create terrain
    auto terrain = CreateTerrain(world, 512);
    terrain->LoadHeightmap("https://raw.githubusercontent.com/UltraEngine/Documentation/master/Assets/Terrain/512.r16");
    terrain->SetScale(1, 100, 1);

    //Create base material
    auto ground = CreateMaterial();
    auto diffusemap = LoadTexture("https://raw.githubusercontent.com/UltraEngine/Documentation/master/Assets/Materials/Ground/river_small_rocks_diff_4k.dds");
    auto normalmap = LoadTexture("https://raw.githubusercontent.com/UltraEngine/Documentation/master/Assets/Materials/Ground/river_small_rocks_nor_gl_4k.dds");
    ground->SetTexture(diffusemap, TEXTURE_BASE);
    ground->SetTexture(normalmap, TEXTURE_NORMAL);
    terrain->SetMaterial(ground);

    //Create paint material
    auto rocks = CreateMaterial();
    diffusemap = LoadTexture("https://raw.githubusercontent.com/UltraEngine/Documentation/master/Assets/Materials/Ground/Rocks_Dirt_Ground_2k.dds");
    normalmap = LoadTexture("https://raw.githubusercontent.com/UltraEngine/Documentation/master/Assets/Materials/Ground/Rocks_Dirt_Ground_2k_dot3.dds");
    auto dispmap = LoadTexture("https://raw.githubusercontent.com/UltraEngine/Documentation/master/Assets/Materials/Ground/Rocks_Dirt_Ground_2k_disp.dds");
    rocks->SetTexture(diffusemap, TEXTURE_BASE);
    rocks->SetTexture(normalmap, TEXTURE_NORMAL);
    rocks->SetTexture(dispmap, TEXTURE_DISPLACEMENT);
    auto rocklayer = terrain->AddLayer(rocks);

    //Apply material based on terrain slope
    for (int x = 0; x < terrain->resolution.x; ++x)
    {
        for (int y = 0; y < terrain->resolution.y; ++y)
        {
            float slope = terrain->GetSlope(x, y);
            if (slope > 15.0f)
            {
                float wt = Min((slope - 15.0f) / 10.0f, 1.0f);
                terrain->SetLayerWeight(rocklayer, x, y, wt);
            }
        }
    }

    //Camera controls
    camera->AddComponent<CameraControls>();

    //Main loop
    while (window->Closed() == false and window->KeyDown(KEY_ESCAPE) == false)
    {
        world->Update();
        world->Render(framebuffer);
    }
    return 0;
}