Collision detection library for C3 language

Contains algorithms needed for detecting collision on 3D meshes

Currently contains

• SpatialHash Grid (Broad collision detection)
• GJK (Narrow collision detection)
• EPA (Contact resolving)
• AABB
• BVH for triangles (terrain collision)
• Physics world resolver

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Video_2025-09-14_21-36-32.mp4

Code examples

Import the library

import collision;

    
    Vec3[] cube = {
        {-0.5, -0.5, -0.5}, {0.5, -0.5, -0.5}, {0.5, 0.5, -0.5}, {-0.5, 0.5, -0.5},
        {-0.5, -0.5, 0.5}, {0.5, -0.5, 0.5}, {0.5, 0.5, 0.5}, {-0.5, 0.5, 0.5}
    };

    ConvexPolyhedron shape_1 = {.vertices = cube};

    // Add transforms
    TransformedConvex transformed_shape_1 = {
        .shape = &shape_1, 
        .position = {-2.0, 0, 0}, 
        .scale = {1, 1, 1},
        .rotation {0.5, 0, 0, 1}
    };
    
    TransformedConvex transformed_shape_2 = {
        .shape = &shape_1, 
        .position = {2.0, 0, 0}, 
        .scale = {1, 1, 1},
    };

    // Check collision
    assert(!collision::check_collision(&transformed_shape_1, &transformed_shape_2).collided);

Use spatial hashmap, to optimize which meshes to detect collision on.

    
    SpatialHash3D spatial_map = { .cell_size = 1.0 };
    defer spatial_map.free();

    Aabb3[] boxes = {
        {{0,0,0}, {1,1,1}},
        {{1,1,1}, {2.5,2.5,2.5}},
        {{5,5,5}, {6,6,6}},
    };

    // Add AABB boxes to the map
    foreach (usz i, item: boxes) spatial_map.insert({.min = item.min, .max = item.max, .id = i })!!;

    spatial_map.@get_pairs(;Pair pair) { 
        // Detect collsion for pairs that are close to eachother    
    };

Basic AABB collision detecting

    Aabb3 box = {
        .min = {1,1,1}, 
        .max = {2.5,2.5,2.5},
    };

    Aabb3 box2 = {
        .min = {2,2,2}, 
        .max = {3,3,3},
    };

    // Transform a box based on Matrix4
    box.transform(MATRIX4F_IDENTITY);

    // Detect if collides
    if (first.aabb.collides(second.aabb)) {}

Physics world resolver basic example is here

Usage example with vulkan and gltf here