From 1081051084e88fd8d42a57208dce0575e7931a06 Mon Sep 17 00:00:00 2001
From: Steins7 <steinsset@gmail.com>
Date: Sat, 20 Aug 2022 14:43:29 +0200
Subject: [PATCH] Got model matrix to work

For now the matrix is sent as a push constant but since WebGL doesn't
support them and will likely never support them big enough for a matrix,
they will in the future be sent in a uniform buffer
---
 Cargo.toml               |  2 +-
 src/renderer.rs          | 44 +++++++++++++++++++---------------------
 src/shaders/texture.wgsl |  5 ++++-
 3 files changed, 26 insertions(+), 25 deletions(-)

diff --git a/Cargo.toml b/Cargo.toml
index 96d5f07..7498155 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -11,7 +11,7 @@ log = "^0.4.17"
 chrono = "^0.4.19"
 fern = { version = "^0.6.1", features = ["colored"] }
 bitflags = "^1.3.2"
-cgmath = "^0.18.0"
+cgmath = { version = "^0.18.0", features = ["bytemuck"] }
 pollster = "^0.2.5"
 
 # surface creation
diff --git a/src/renderer.rs b/src/renderer.rs
index c1155e4..a4ad260 100644
--- a/src/renderer.rs
+++ b/src/renderer.rs
@@ -26,7 +26,6 @@ pub struct WgpuRenderer {
     texture_bind_group_layout: wgpu::BindGroupLayout,
     texture_render_pipeline: wgpu::RenderPipeline,
     shape_render_pipeline: wgpu::RenderPipeline,
-    texture_quad: GpuMesh<TextureVertex, 4, 6>,
     quad_mesh: GpuMesh<ColorVertex, 4, 6>,  //TODO temporary, to be moved to shapes.rs
     output: Option<wgpu::SurfaceTexture>,
 }
@@ -42,6 +41,8 @@ impl WgpuRenderer {
         let instance = wgpu::Instance::new(wgpu::Backends::all());
         let surface = unsafe { instance.create_surface(window) };
 
+        //let adapters = instance.enumerate_adapters(
+
         let adapter = instance.request_adapter(
             &wgpu::RequestAdapterOptions {
                 //for now, integrated GPU is enough, may be revised later
@@ -51,11 +52,14 @@ impl WgpuRenderer {
             },
         ).await.unwrap();
 
+        let mut limits = wgpu::Limits::downlevel_defaults();
+        limits.max_push_constant_size = 36;
+
         let (device, queue) = adapter.request_device(
             &wgpu::DeviceDescriptor {
                 //using minimum requirements possible since 2D isn't very demanding anyway
-                features: wgpu::Features::empty(),
-                limits: wgpu::Limits::downlevel_webgl2_defaults(),
+                features: wgpu::Features::PUSH_CONSTANTS,
+                limits,
                 label: None,
             },
             None, // Trace path
@@ -97,6 +101,11 @@ impl WgpuRenderer {
                 label: Some("texture_bind_group_layout"),
         });
 
+        let mvp_push_constant = wgpu::PushConstantRange {
+            stages: wgpu::ShaderStages::VERTEX,
+            range: 0..36,
+        };
+
         let texture_render_pipeline = {
             let shader = device.create_shader_module(wgpu::ShaderModuleDescriptor {
                 label: Some("texture shader"),
@@ -107,7 +116,7 @@ impl WgpuRenderer {
                 device.create_pipeline_layout(&wgpu::PipelineLayoutDescriptor {
                     label: Some("texture render pipeline layout"),
                     bind_group_layouts: &[&texture_bind_group_layout],
-                    push_constant_ranges: &[],
+                    push_constant_ranges: &[mvp_push_constant],
             });
 
             device.create_render_pipeline(&wgpu::RenderPipelineDescriptor {
@@ -209,23 +218,6 @@ impl WgpuRenderer {
             })
         };
 
-        let texture_quad = {
-            let mesh = Mesh {
-                vertices: [
-                    TextureVertex { position: [0.0, 0.0], tex_coords: [0.0, 1.0] },
-                    TextureVertex { position: [1.0, 0.0], tex_coords: [1.0, 1.0] },
-                    TextureVertex { position: [1.0, 1.0], tex_coords: [1.0, 0.0] },
-                    TextureVertex { position: [0.0, 1.0], tex_coords: [0.0, 0.0] },
-                ],
-                indices: [
-                    0, 1, 2,
-                    0, 2, 3,
-                ],
-            };
-
-            GpuMesh::create(&device, mesh)
-        };
-
         let quad_mesh = {
             let mesh = Mesh {
                 vertices: [
@@ -255,7 +247,6 @@ impl WgpuRenderer {
             texture_bind_group_layout,
             texture_render_pipeline,
             shape_render_pipeline,
-            texture_quad,
             quad_mesh,
             output,
         })
@@ -318,7 +309,14 @@ impl WgpuRenderer {
                 render_pass.set_index_buffer(gpu_mesh.index_buffer.slice(..), 
                                              wgpu::IndexFormat::Uint16);
                 render_pass.set_bind_group(0, &texture.bind_group,  &[]);
-                render_pass.draw_indexed(0..self.texture_quad.index_number, 0, 0..1);
+                let matrix = {
+                    use cgmath::SquareMatrix;
+                    cgmath::Matrix3::<f32>::from_nonuniform_scale(720.0/1280.0, 1.0)
+                };
+                render_pass.set_push_constants(wgpu::ShaderStages::VERTEX, 
+                                               0, 
+                                               bytemuck::bytes_of(&matrix));
+                render_pass.draw_indexed(0..gpu_mesh.index_number, 0, 0..1);
 
                 drop(render_pass);
                 self.queue.submit(std::iter::once(encoder.finish()));
diff --git a/src/shaders/texture.wgsl b/src/shaders/texture.wgsl
index 7bd28b3..04111f3 100644
--- a/src/shaders/texture.wgsl
+++ b/src/shaders/texture.wgsl
@@ -1,5 +1,7 @@
 // Vertex shader
 
+var<push_constant> model_matrix: mat3x3<f32>;
+
 struct VertexInput {
     @location(0) position: vec2<f32>,
     @location(1) tex_coords: vec2<f32>,
@@ -15,7 +17,8 @@ fn vs_main(model: VertexInput) -> VertexOutput {
 
     var out: VertexOutput;
     out.tex_coords = model.tex_coords;
-    out.clip_position = vec4<f32>(model.position, 0.0, 1.0);
+	out.clip_position 
+		= vec4<f32>(model_matrix * vec3<f32>(model.position, 0.0), 1.0);
     return out;
 }