Merge pull request #6 from LykenSol/mouse

Shadertoy-like mouse support.

Author: eddyb

shaders/src/lib.rs

@@ -4,7 +4,7 @@
 #![register_attr(spirv)]
 
 use shared::*;
-use spirv_std::glam::{vec2, vec3, Vec2, Vec3, Vec4};
+use spirv_std::glam::{vec2, vec3, vec4, Vec2, Vec3, Vec4};
 use spirv_std::storage_class::{Input, Output, PushConstant};
 
 pub mod a_lot_of_spheres;
@@ -58,7 +58,17 @@ pub fn fs(constants: &ShaderConstants, mut frag_coord: Vec2) -> Vec4 {
         0.0,
     );
     let time = constants.time;
-    let mouse = Vec4::zero();
+    let mouse = vec4(
+        constants.last_lmb_down_x / COLS as f32,
+        constants.last_lmb_down_y / ROWS as f32,
+        constants.last_click_x / COLS as f32
+            * if constants.mouse_left_pressed {
+                1.0
+            } else {
+                -1.0
+            },
+        constants.last_click_y / ROWS as f32 * if constants.mouse_clicked { 1.0 } else { -1.0 },
+    );
 
     let col = (frag_coord.x / resolution.x) as usize;
     let row = (frag_coord.y / resolution.y) as usize;

shared/src/lib.rs

@@ -21,6 +21,12 @@ pub struct ShaderConstants {
     pub width: u32,
     pub height: u32,
     pub time: f32,
+    pub last_lmb_down_x: f32,
+    pub last_lmb_down_y: f32,
+    pub last_click_x: f32,
+    pub last_click_y: f32,
+    pub mouse_left_pressed: bool,
+    pub mouse_clicked: bool,
 }
 
 pub fn saturate(x: f32) -> f32 {

src/main.rs

@@ -1,6 +1,6 @@
 use shared::ShaderConstants;
 use winit::{
-    event::{Event, KeyboardInput, VirtualKeyCode, WindowEvent},
+    event::{ElementState, Event, KeyboardInput, MouseButton, VirtualKeyCode, WindowEvent},
     event_loop::{ControlFlow, EventLoop},
     window::Window,
 };
@@ -101,6 +101,11 @@ async fn run(
         .map(|surface| device.create_swap_chain(&surface, &sc_desc));
 
     let start = std::time::Instant::now();
+    let mut mouse_left_pressed = false;
+    let (mut cursor_x, mut cursor_y) = (0.0, 0.0);
+    let (mut last_lmb_down_x, mut last_lmb_down_y) = (0.0, 0.0);
+    let mut mouse_clicked = false;
+    let (mut last_click_x, mut last_click_y) = (0.0, 0.0);
 
     event_loop.run(move |event, _, control_flow| {
         // Have the closure take ownership of the resources.
@@ -157,7 +162,14 @@ async fn run(
                             width: window.inner_size().width,
                             height: window.inner_size().height,
                             time: start.elapsed().as_secs_f32(),
+                            last_lmb_down_x,
+                            last_lmb_down_y,
+                            last_click_x,
+                            last_click_y,
+                            mouse_left_pressed,
+                            mouse_clicked,
                         };
+                        mouse_clicked = false;
                         rpass.set_pipeline(&render_pipeline);
                         rpass.set_push_constants(wgpu::ShaderStage::all(), 0, unsafe {
                             any_as_u32_slice(&push_constants)
@@ -184,6 +196,35 @@ async fn run(
                     },
                 ..
             } => *control_flow = ControlFlow::Exit,
+            Event::WindowEvent {
+                event:
+                    WindowEvent::MouseInput {
+                        state,
+                        button: MouseButton::Left,
+                        ..
+                    },
+                ..
+            } => {
+                mouse_left_pressed = state == ElementState::Pressed;
+                if mouse_left_pressed {
+                    last_lmb_down_x = cursor_x;
+                    last_lmb_down_y = cursor_y;
+                    last_click_x = cursor_x;
+                    last_click_y = cursor_y;
+                    mouse_clicked = true;
+                }
+            }
+            Event::WindowEvent {
+                event: WindowEvent::CursorMoved { position, .. },
+                ..
+            } => {
+                cursor_x = position.x as f32;
+                cursor_y = position.y as f32;
+                if mouse_left_pressed {
+                    last_lmb_down_x = cursor_x;
+                    last_lmb_down_y = cursor_y;
+                }
+            }
             _ => {}
         }
     });