Add pulsing effect when invulnerable/intangible, make airdodge make the player intangible. (#75)

Reviewed-on: #75
Co-authored-by: Álex Román Núñez <eirexe@eirteam.moe>

src/materials/shaders/fighter.wgsl

@@ -0,0 +1,67 @@
+#import bevy_pbr::{
+    pbr_fragment::pbr_input_from_standard_material,
+    pbr_functions::alpha_discard,
+}
+
+#ifdef PREPASS_PIPELINE
+#import bevy_pbr::{
+    prepass_io::{VertexOutput, FragmentOutput},
+    pbr_deferred_functions::deferred_output,
+}
+#else
+#import bevy_pbr::{
+    forward_io::{VertexOutput, FragmentOutput},
+    pbr_functions::{apply_pbr_lighting, main_pass_post_lighting_processing},
+}
+#endif
+
+struct FighterExtendedMaterial {
+    status_color: vec4<f32>,
+    status_color_intensity: f32,
+#ifdef SIXTEEN_BYTE_ALIGNMENT
+    // Web examples WebGL2 support: structs must be 16 byte aligned.
+    _webgl2_padding_8b: u32,
+    _webgl2_padding_12b: u32,
+    _webgl2_padding_16b: u32,
+#endif
+}
+
+@group(#{MATERIAL_BIND_GROUP}) @binding(100)
+var<uniform> fighter_material: FighterExtendedMaterial;
+
+@fragment
+fn fragment(
+    in: VertexOutput,
+    @builtin(front_facing) is_front: bool,
+) -> FragmentOutput {
+    // generate a PbrInput struct from the StandardMaterial bindings
+    var pbr_input = pbr_input_from_standard_material(in, is_front);
+
+    // we can optionally modify the input before lighting and alpha_discard is applied
+    //pbr_input.material.base_color.b = pbr_input.material.base_color.r;
+
+    // alpha discard
+    pbr_input.material.base_color = alpha_discard(pbr_input.material, pbr_input.material.base_color);
+
+#ifdef PREPASS_PIPELINE
+    // in deferred mode we can't modify anything after that, as lighting is run in a separate fullscreen shader.
+    let out = deferred_output(in, pbr_input);
+#else
+    var out: FragmentOutput;
+    // apply lighting
+    out.color = apply_pbr_lighting(pbr_input);
+
+    // we can optionally modify the lit color before post-processing is applied
+    var quantize_steps: i32 = 2;
+    out.color = vec4<f32>(vec4<u32>(out.color * f32(quantize_steps))) / f32(quantize_steps);
+
+    // apply in-shader post processing (fog, alpha-premultiply, and also tonemapping, debanding if the camera is non-hdr)
+    // note this does not include fullscreen postprocessing effects like bloom.
+    out.color = main_pass_post_lighting_processing(pbr_input, out.color);
+
+    out.color = mix(out.color, fighter_material.status_color, fighter_material.status_color_intensity * 0.5);
+
+#endif
+
+    return out;
+}