From 83f360600075d56416a53eb8d6ed7979c33585fd Mon Sep 17 00:00:00 2001
From: Jarrod Doyle <thejarroddoyle@gmail.com>
Date: Fri, 26 Apr 2024 21:14:01 +0100
Subject: [PATCH] Add render pipeline builder

---
 src/lib.rs      |   2 +
 src/pipeline.rs | 108 ++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 110 insertions(+)
 create mode 100644 src/pipeline.rs

diff --git a/src/lib.rs b/src/lib.rs
index 27bd34d..3097707 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -1,12 +1,14 @@
 mod bind_group;
 mod buffer;
 mod context;
+mod pipeline;
 mod texture;
 
 pub use self::{
     bind_group::{BindGroupBuilder, BindGroupLayoutBuilder},
     buffer::{BufferExt, BulkBufferBuilder},
     context::{Context, ContextBuilder},
+    pipeline::RenderPipelineBuilder,
     texture::{Texture, TextureBuilder},
 };
 
diff --git a/src/pipeline.rs b/src/pipeline.rs
new file mode 100644
index 0000000..bba9446
--- /dev/null
+++ b/src/pipeline.rs
@@ -0,0 +1,108 @@
+use std::num::NonZeroU32;
+
+use crate::Context;
+
+pub struct RenderPipelineBuilder<'a> {
+    label: &'a str,
+    shader: &'a wgpu::ShaderModule,
+    layout_descriptor: Option<wgpu::PipelineLayoutDescriptor<'a>>,
+    vertex: wgpu::VertexState<'a>,
+    fragment: Option<wgpu::FragmentState<'a>>,
+    primitive: wgpu::PrimitiveState,
+    depth_stencil: Option<wgpu::DepthStencilState>,
+    multisample: wgpu::MultisampleState,
+    multiview: Option<NonZeroU32>,
+}
+
+impl<'a> RenderPipelineBuilder<'a> {
+    pub fn new(label: &'a str, shader: &'a wgpu::ShaderModule) -> Self {
+        Self {
+            label,
+            shader,
+            layout_descriptor: None,
+            vertex: wgpu::VertexState {
+                module: shader,
+                entry_point: "vertex",
+                buffers: &[],
+            },
+            fragment: None,
+            primitive: wgpu::PrimitiveState::default(),
+            depth_stencil: None,
+            multisample: wgpu::MultisampleState::default(),
+            multiview: None,
+        }
+    }
+
+    pub fn with_layout(
+        mut self,
+        label: &'a str,
+        bind_group_layouts: &'a [&wgpu::BindGroupLayout],
+        push_constant_ranges: &'a [wgpu::PushConstantRange],
+    ) -> Self {
+        let layout_descriptor = wgpu::PipelineLayoutDescriptor {
+            label: Some(label),
+            bind_group_layouts,
+            push_constant_ranges,
+        };
+
+        self.layout_descriptor = Some(layout_descriptor);
+        self
+    }
+
+    pub fn with_vertex_buffers(mut self, buffers: &'a [wgpu::VertexBufferLayout<'a>]) -> Self {
+        self.vertex.buffers = buffers;
+        self
+    }
+
+    pub fn with_fragment_targets(mut self, targets: &'a [Option<wgpu::ColorTargetState>]) -> Self {
+        self.fragment = Some(wgpu::FragmentState {
+            module: self.shader,
+            entry_point: "fragment",
+            targets,
+        });
+        self
+    }
+
+    pub fn with_primitive(mut self, primitive: wgpu::PrimitiveState) -> Self {
+        self.primitive = primitive;
+        self
+    }
+
+    pub fn with_depth_stencil(mut self, depth_stencil: wgpu::DepthStencilState) -> Self {
+        self.depth_stencil = Some(depth_stencil);
+        self
+    }
+
+    pub fn with_multisample(mut self, multisample: wgpu::MultisampleState) -> Self {
+        self.multisample = multisample;
+        self
+    }
+
+    pub fn with_multiview(mut self, multiview: NonZeroU32) -> Self {
+        self.multiview = Some(multiview);
+        self
+    }
+
+    pub fn build(self, context: &Context) -> wgpu::RenderPipeline {
+        let raw_layout;
+        let layout = if let Some(descriptor) = self.layout_descriptor {
+            raw_layout = context.device.create_pipeline_layout(&descriptor);
+            Some(&raw_layout)
+        } else {
+            None
+        };
+
+        context
+            .device
+            .create_render_pipeline(&wgpu::RenderPipelineDescriptor {
+                label: Some(self.label),
+                layout,
+                vertex: self.vertex,
+                fragment: self.fragment,
+                primitive: self.primitive,
+                depth_stencil: self.depth_stencil,
+                multisample: self.multisample,
+                multiview: self.multiview,
+            })
+    }
+}