Shamelessly stolen light code

shaders/lighting.glsl

@@ -1,16 +1,44 @@
 uniform sampler2D texture;
-uniform float ambient;
+uniform vec2 resolution;
+uniform vec2 mouse;
+uniform float time;
 uniform bool has_texture;
 
-void main()
-{
-    // lookup the pixel in the texture
-    vec4 pixel = texture2D(texture, gl_TexCoord[0].xy);
+// The RGB values are the ambient light color
+// and the alpha is the ambient intensity
+uniform vec4 ambientData;
+// The RGB values are the light color
+// and the alpha is the light intensity
+uniform vec4 lightData;
+// Maximum radius of the light
+uniform float lightSize;
 
-    // multiply it by the color
-    vec4 col = gl_Color;
-    if (has_texture) {
-        col = gl_Color * pixel;
-    }
-    gl_FragColor = vec4(col.x * ambient, col.y * ambient, col.z * ambient, col.w);
+void main() {
+  // Light's position
+  vec2 position = mouse/resolution.xx;
+
+  // Makes the light change its size slightly to make a fire effect
+  float maxDistance = lightSize + 0.015*sin(time);
+  // Gets the distance from the light's position and the fragment coord
+  float distance = distance(gl_FragCoord.xy/resolution.xx, position);
+  // Calculates the amount of light for the fragment
+  float value = 1.0 - smoothstep(-0.2, maxDistance, distance);
+
+  // Gets the original color from the texture
+  vec4 pixel = texture2D(texture, gl_TexCoord[0].xy);
+  if (!has_texture) {
+    pixel = gl_Color;
+  }
+
+  // Applies the ambient light to the original pixel color
+  vec3 ambient = pixel.rgb * ambientData.rgb * ambientData.a;
+
+  // Calculates the light color for the pixel
+  vec3 light = lightData.rgb * lightData.a * clamp(value, 0.0, 1.0);
+
+  // Applies the light to the pixel
+  vec3 intensity = ambient + light;
+  vec3 final = pixel.rgb * intensity;
+
+  gl_FragColor = vec4(final, 1.0);
 }

src/game.rs

@@ -1,8 +1,13 @@
 mod player;
 
-use sfml::graphics::{
-    Color, Rect, RectangleShape, RenderStates, RenderTarget, RenderWindow, Shape, Sprite,
-    Transformable,
+use sfml::{
+    graphics::{
+        glsl::{Vec2, Vec4},
+        Color, Rect, RectangleShape, RenderStates, RenderTarget, RenderWindow, Shape, Sprite,
+        Transformable,
+    },
+    system::Clock,
+    SfBox,
 };
 
 use crate::{
@@ -25,6 +30,7 @@ pub struct GameState {
     pub prev_biome: Biome,
     pub worldgen: Worldgen,
     pub ambient_light: f32,
+    pub clock: SfBox<Clock>,
 }
 
 #[derive(PartialEq, Eq, Clone, Copy)]
@@ -77,8 +83,39 @@ impl GameState {
         rw.draw(&rect_sh);
     }
     pub fn render_pre_step(&mut self, res: &mut Res) {
+        res.lighting_shader.set_uniform_current_texture("texture");
         res.lighting_shader
-            .set_uniform_float("ambient", self.ambient_light);
+            .set_uniform_float("time", self.clock.elapsed_time().as_seconds() * 10.0);
+        res.lighting_shader.set_uniform_vec2(
+            "mouse",
+            Vec2::new(
+                NATIVE_RESOLUTION.w as f32 / 2.0,
+                NATIVE_RESOLUTION.h as f32 / 2.0,
+            ),
+        );
+        res.lighting_shader.set_uniform_vec2(
+            "resolution",
+            Vec2::new(NATIVE_RESOLUTION.w as f32, NATIVE_RESOLUTION.h as f32),
+        );
+        res.lighting_shader.set_uniform_vec4(
+            "lightData",
+            Vec4 {
+                x: 1.0,
+                y: 0.8,
+                z: 0.2,
+                w: 2.0,
+            },
+        );
+        res.lighting_shader.set_uniform_vec4(
+            "ambientData",
+            Vec4 {
+                x: 0.3,
+                y: 0.3,
+                z: 0.8,
+                w: 0.3,
+            },
+        );
+        res.lighting_shader.set_uniform_float("lightSize", 0.3);
     }
 }
 
@@ -113,6 +150,7 @@ impl Default for GameState {
             prev_biome: Biome::Surface,
             worldgen: Worldgen::default(),
             ambient_light: 1.0,
+            clock: Clock::start(),
         }
     }
 }