srs2dge-core 0.2.0

Simple Rust 2D Game Engine
Documentation 
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use crate::{
    color::Color,
    prelude::{DefaultVertex, Mesh, TexturePosition},
};
use glam::{Vec2, Vec3, Vec3Swizzles, Vec4, Vec4Swizzles};
use std::array::IntoIter;
use wgpu::PrimitiveTopology;

//

#[derive(Debug, Clone, Copy, Default)]
pub struct QuadMesh {
    pub pos: Vec2,
    pub size: Vec2,
    pub col: Color,
    pub tex: TexturePosition,
}

#[derive(Debug, Clone, Copy, Default)]
pub struct IsoQuadMesh {
    pub pos: Vec2,
    pub size: Vec2,
    pub col: Color,
    // TODO:
    // pub tex: TexturePosition,
}

//

impl Mesh<DefaultVertex> for QuadMesh {
    const PRIM: PrimitiveTopology = PrimitiveTopology::TriangleStrip;

    type VertexIter = IntoIter<DefaultVertex, 4>;
    type IndexIter = IntoIter<u32, 5>;

    fn vertices(&self) -> Self::VertexIter {
        let radius = self.size * 0.5;
        let top_left = self.pos - radius;
        let bottom_right = self.pos + radius;
        let p = Vec4::new(top_left.x, top_left.y, bottom_right.x, bottom_right.y);
        let c = Vec4::new(
            self.tex.top_left.x,
            self.tex.bottom_right.y,
            self.tex.bottom_right.x,
            self.tex.top_left.y,
        );
        IntoIterator::into_iter([
            DefaultVertex::new(p.xy(), self.col, c.xy()),
            DefaultVertex::new(p.xw(), self.col, c.xw()),
            DefaultVertex::new(p.zy(), self.col, c.zy()),
            DefaultVertex::new(p.zw(), self.col, c.zw()),
        ])
    }

    fn indices(&self, offset: u32) -> Self::IndexIter {
        IntoIterator::into_iter([offset, offset + 1, offset + 2, offset + 3, !0])
    }

    fn index_step(&self) -> u32 {
        4
    }
}

impl Mesh<DefaultVertex> for IsoQuadMesh {
    const PRIM: PrimitiveTopology = PrimitiveTopology::TriangleStrip;

    type VertexIter = IntoIter<DefaultVertex, 4>;
    type IndexIter = IntoIter<u32, 5>;

    fn vertices(&self) -> Self::VertexIter {
        let c = Vec3::new(0.0, 0.5, 1.0);
        IntoIterator::into_iter([
            DefaultVertex::new(self.pos + self.size * c.xy(), self.col, c.xx()),
            DefaultVertex::new(self.pos + self.size * c.yz(), self.col, c.xz()),
            DefaultVertex::new(self.pos + self.size * c.yx(), self.col, c.zx()),
            DefaultVertex::new(self.pos + self.size * c.zy(), self.col, c.zz()),
        ])
    }

    fn indices(&self, offset: u32) -> Self::IndexIter {
        IntoIterator::into_iter([offset, offset + 1, offset + 2, offset + 3, !0])
    }

    fn index_step(&self) -> u32 {
        4
    }
}