renderer.rs

  1use std::{ffi::c_void, mem};
  2
  3use self::shaders::ToUchar4;
  4
  5use super::window::RenderContext;
  6use crate::{color::ColorU, scene::Layer, Scene};
  7use anyhow::{anyhow, Result};
  8use metal::{MTLResourceOptions, NSRange};
  9use shaders::ToFloat2 as _;
 10
 11const SHADERS_METALLIB: &'static [u8] =
 12    include_bytes!(concat!(env!("OUT_DIR"), "/shaders.metallib"));
 13const INSTANCE_BUFFER_SIZE: u64 = 1024 * 1024;
 14
 15pub struct Renderer {
 16    quad_pipeline_state: metal::RenderPipelineState,
 17    quad_vertices: metal::Buffer,
 18    instances: metal::Buffer,
 19}
 20
 21impl Renderer {
 22    pub fn new(device: &metal::DeviceRef, pixel_format: metal::MTLPixelFormat) -> Result<Self> {
 23        let library = device
 24            .new_library_with_data(SHADERS_METALLIB)
 25            .map_err(|message| anyhow!("error building metal library: {}", message))?;
 26
 27        let quad_vertices = [
 28            (0., 0.).to_float2(),
 29            (1., 0.).to_float2(),
 30            (0., 1.).to_float2(),
 31            (0., 1.).to_float2(),
 32            (1., 0.).to_float2(),
 33            (1., 1.).to_float2(),
 34        ];
 35        let quad_vertices = device.new_buffer_with_data(
 36            quad_vertices.as_ptr() as *const c_void,
 37            (quad_vertices.len() * mem::size_of::<shaders::vector_float2>()) as u64,
 38            MTLResourceOptions::StorageModeManaged,
 39        );
 40        let instances =
 41            device.new_buffer(INSTANCE_BUFFER_SIZE, MTLResourceOptions::StorageModeManaged);
 42
 43        Ok(Self {
 44            quad_pipeline_state: build_pipeline_state(
 45                device,
 46                &library,
 47                "quad",
 48                "quad_vertex",
 49                "quad_fragment",
 50                pixel_format,
 51            )?,
 52            quad_vertices,
 53            instances,
 54        })
 55    }
 56
 57    pub fn render(&mut self, scene: &Scene, ctx: &RenderContext) {
 58        ctx.command_encoder.set_viewport(metal::MTLViewport {
 59            originX: 0.0,
 60            originY: 0.0,
 61            width: ctx.drawable_size.x() as f64,
 62            height: ctx.drawable_size.y() as f64,
 63            znear: 0.0,
 64            zfar: 1.0,
 65        });
 66
 67        for layer in scene.layers() {
 68            self.render_quads(layer, ctx);
 69        }
 70    }
 71
 72    fn render_quads(&mut self, layer: &Layer, ctx: &RenderContext) {
 73        ctx.command_encoder
 74            .set_render_pipeline_state(&self.quad_pipeline_state);
 75        ctx.command_encoder.set_vertex_buffer(
 76            shaders::GPUIQuadInputIndex_GPUIQuadInputIndexVertices as u64,
 77            Some(&self.quad_vertices),
 78            0,
 79        );
 80        ctx.command_encoder.set_vertex_buffer(
 81            shaders::GPUIQuadInputIndex_GPUIQuadInputIndexQuads as u64,
 82            Some(&self.instances),
 83            0,
 84        );
 85        ctx.command_encoder.set_vertex_bytes(
 86            shaders::GPUIQuadInputIndex_GPUIQuadInputIndexUniforms as u64,
 87            mem::size_of::<shaders::GPUIQuadUniforms>() as u64,
 88            [shaders::GPUIQuadUniforms {
 89                viewport_size: ctx.drawable_size.to_float2(),
 90            }]
 91            .as_ptr() as *const c_void,
 92        );
 93
 94        let batch_size = self.instances.length() as usize / mem::size_of::<shaders::GPUIQuad>();
 95
 96        let buffer_contents = self.instances.contents() as *mut shaders::GPUIQuad;
 97        for quad_batch in layer.quads().chunks(batch_size) {
 98            for (ix, quad) in quad_batch.iter().enumerate() {
 99                unsafe {
100                    *(buffer_contents.offset(ix as isize)) = shaders::GPUIQuad {
101                        origin: quad.bounds.origin().to_float2(),
102                        size: quad.bounds.size().to_float2(),
103                        background_color: quad
104                            .background
105                            .unwrap_or(ColorU::transparent_black())
106                            .to_uchar4(),
107                    };
108                }
109            }
110            self.instances.did_modify_range(NSRange {
111                location: 0,
112                length: (quad_batch.len() * mem::size_of::<shaders::GPUIQuad>()) as u64,
113            });
114
115            ctx.command_encoder.draw_primitives_instanced(
116                metal::MTLPrimitiveType::Triangle,
117                0,
118                6,
119                quad_batch.len() as u64,
120            );
121        }
122    }
123}
124
125fn build_pipeline_state(
126    device: &metal::DeviceRef,
127    library: &metal::LibraryRef,
128    label: &str,
129    vertex_fn_name: &str,
130    fragment_fn_name: &str,
131    pixel_format: metal::MTLPixelFormat,
132) -> Result<metal::RenderPipelineState> {
133    let vertex_fn = library
134        .get_function(vertex_fn_name, None)
135        .map_err(|message| anyhow!("error locating vertex function: {}", message))?;
136    let fragment_fn = library
137        .get_function(fragment_fn_name, None)
138        .map_err(|message| anyhow!("error locating fragment function: {}", message))?;
139
140    let descriptor = metal::RenderPipelineDescriptor::new();
141    descriptor.set_label(label);
142    descriptor.set_vertex_function(Some(vertex_fn.as_ref()));
143    descriptor.set_fragment_function(Some(fragment_fn.as_ref()));
144    descriptor
145        .color_attachments()
146        .object_at(0)
147        .unwrap()
148        .set_pixel_format(pixel_format);
149
150    device
151        .new_render_pipeline_state(&descriptor)
152        .map_err(|message| anyhow!("could not create render pipeline state: {}", message))
153}
154
155mod shaders {
156    #![allow(non_upper_case_globals)]
157    #![allow(non_camel_case_types)]
158    #![allow(non_snake_case)]
159
160    use crate::{color::ColorU, geometry::vector::Vector2F};
161    use std::mem;
162
163    include!(concat!(env!("OUT_DIR"), "/shaders.rs"));
164
165    pub trait ToFloat2 {
166        fn to_float2(&self) -> vector_float2;
167    }
168
169    pub trait ToUchar4 {
170        fn to_uchar4(&self) -> vector_uchar4;
171    }
172
173    impl ToFloat2 for (f32, f32) {
174        fn to_float2(&self) -> vector_float2 {
175            unsafe {
176                let mut output = mem::transmute::<_, u32>(self.1.to_bits()) as vector_float2;
177                output <<= 32;
178                output |= mem::transmute::<_, u32>(self.0.to_bits()) as vector_float2;
179                output
180            }
181        }
182    }
183
184    impl ToFloat2 for Vector2F {
185        fn to_float2(&self) -> vector_float2 {
186            unsafe {
187                let mut output = mem::transmute::<_, u32>(self.y().to_bits()) as vector_float2;
188                output <<= 32;
189                output |= mem::transmute::<_, u32>(self.x().to_bits()) as vector_float2;
190                output
191            }
192        }
193    }
194
195    impl ToUchar4 for ColorU {
196        fn to_uchar4(&self) -> vector_uchar4 {
197            let mut vec = self.a as vector_uchar4;
198            vec <<= 8;
199            vec |= self.b as vector_uchar4;
200            vec <<= 8;
201            vec |= self.g as vector_uchar4;
202            vec <<= 8;
203            vec |= self.r as vector_uchar4;
204            vec
205        }
206    }
207}