mittens-engine 0.7.0

A Vulkan and OpenXR scene engine with ECS, reactive signals, and Meow Meow scripting
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// Phase 5 + 8 demo: procedural spawning with for/in, range(), and while
//
// Spawns a 4×4 grid of cubes, coloured by position, with a gap in the middle
// (where both i and j are 1 or 2) — exercising break/continue.

fn grid_color(i, j) {
    if i == 0.0 { return 1.0 }
    if j == 0.0 { return 0.5 }
    return 0.2
}

for i in range(4) {
    for j in range(4) {
        // skip a 2×2 hole in the centre of the grid
        if i == 1.0 { if j == 1.0 { continue } }
        if i == 1.0 { if j == 2.0 { continue } }
        if i == 2.0 { if j == 1.0 { continue } }
        if i == 2.0 { if j == 2.0 { continue } }

        let r = grid_color(i, j)
        T.position(i*1.1, 0.0, j*1.1) {
            R.cube() {
                C.rgba(r, 0.4, 0.8, 1.0)
                NV {}
            }
        }
    }
}

// light rig
let light_rig = T {
    T.position(5, -5, 0) {
        DL {
            intensity(1.0)
            C.rgba(1.0, 0.95, 0.1, 1.0)
        }
    }

    T.position(-5, 5, 0) {
        DL {
            intensity(1.0)
            C.rgba(0.1, 0.95, 1.0, 1.0)
        }
    }

    T.position(0, 5, 5) {
        DL {
            intensity(1.0)
            C.rgba(1.0, 0.1, 0.95, 1.0)
        }
    }
}

light_rig

BGC {
    C.rgba(0.9, 0.9, 0.9, 1.0)
}
AL {
    C.rgba(0.2,0.2,0.2, 1.0)
}


// ── while loop: build an arch via accumulation ────────────────────────────────
//
// while loops are useful when the stop condition depends on accumulated state
// rather than a fixed iterable — e.g. placing blocks until a height is reached.

let height = 0.0
let step = 0.35
while height < 4.0 {
    let t = height / 4.0                     // 0..1 progress
    let r = t
    let g = 1.0 - t
    T.position(5.5, height, -3.0) {
        R.cube() { C.rgba(r, g, 0.4, 1.0) }
    }
    height = height + step
}

// Note: the natural extension of while loops is timed background processes:
//
//   spawn fn() {
//       while true {
//           wait(500)    // suspend for 500ms — HostCall, not an OS sleep
//           do_thing()
//       }
//   }
//
// wait(ms: Int) is planned as a HostCall (requires MeowMeowSession + scheduler).
// See docs/meow_meow/draft/reply-channel-and-session.md for the design.

for z in range(128) {
    for x in range(128) {
        let r = 0.1 + (x % 32 / 32.0)
        let g = 0.1 + (z % 32 / 32.0)
        
        let x2 = x - 64.0
        let z2 = z - 64.0

        let y = -2.0;

        if (z > 64 || x > 64) {
            y = 2.0 + ((x + z) % 16);
        }

        if (z > 96 || x > 96) {
            y = 2.0 + ((x + z) % 32);
        }

        let b = 0.1 + ((x + z + y) % 16 / 16.0)

        T.position(x2, y, z2) {
            R.cube() {
                C.rgba(r, g, b, 1.0)
            }
        }
    } 
}