[RELEASE] u22-v03

This version is submitted to U22 breau.

core/loshader/bullet.fshader

@@ -0,0 +1,53 @@
+in vec2  v_aa;
+in float v_bullet_id;
+in vec2  v_uv;
+in vec2  v_size;
+in float v_time;
+in vec4  v_color;
+
+out vec4 o_color;
+
+float dot(in vec2 p, in vec2 q) {
+  return p.x*q.y - p.y*q.x;
+}
+
+vec4 light(void) {
+  vec4 color = v_color;
+  color.a *= 1.-pow(length(v_uv), 1.5);
+  return color;
+}
+
+vec4 square(void) {
+  vec4 color = v_color;
+
+  float t = 1.-v_time;
+
+  vec2 uv = abs(v_uv);
+  color.a *= max(step(t-v_aa.x, uv.x), step(t-v_aa.y, uv.y));
+  return color;
+}
+
+vec4 triangle(void) {
+  const vec2 disp = vec2(-1./12., 0.);
+
+  float t = 1. - v_time;
+  vec2 v1 = vec2( 1.,  0.)*t + disp*v_time;
+  vec2 v2 = vec2(-1., -1.)*t + disp*v_time;
+  vec2 v3 = vec2(-1.,  1.)*t + disp*v_time;
+
+  float b1 = dot(v_uv-v2, v1-v2);
+  float b2 = dot(v_uv-v3, v2-v3);
+  float b3 = dot(v_uv-v1, v3-v1);
+
+  vec4 color = v_color;
+  color.a *= b1*b2 > 0. && b2*b3 > 0.? 0.: 1.;
+  return color;
+}
+
+void main(void) {
+  o_color =
+      v_bullet_id == 0.? light():
+      v_bullet_id == 1.? square():
+      v_bullet_id == 2.? triangle():
+      vec4(0.);
+}