i shouldn't have taken such a long break. Feels like starting over

experiments/draw_poly/main.frag

@@ -0,0 +1,48 @@
+#ifdef GL_ES
+precision mediump float;
+#endif
+
+uniform vec2 u_resolution;
+uniform vec2 u_mouse;
+uniform float u_time;
+
+#define PI 3.14159265359
+
+// this does not work, i'm drawing over what i've drawn before.
+float v_line(vec2 st, float xcor, float width, float y1, float y2) {
+  return step(xcor-width,st.x) - step(xcor+width, st.x)- (1.0-step(y1, st.y)) - step(y2, st.y);
+}
+
+float h_line(vec2 st, float ycor, float width, float x1, float x2) {
+  return step(ycor-width, st.y) - step(ycor+width, st.y) - (1.0-step(x1, st.x)) - step(x2, st.x);
+}
+
+void main() {
+  vec2 st = gl_FragCoord.xy/u_resolution;
+  vec3 color = vec3(0.0,0.0,0.0);
+  //float width = 0.001;
+  //color += v_line(st, 0.4, 0.001, 0.25, 0.75) * vec3(1.0);
+  //color += h_line(st, 0.75, 0.001, 0.5, 0.6) * vec3(1.0);
+  //color += h_line(st, 0.25, 0.001, 0.4, 0.6) * vec3(1.0);
+  //color += v_line(st, 0.6, 0.001, 0.25, 0.75) * vec3(1.0);
+  //float temp = step(0.4-width, st.x)-step(0.4+width, st.x)-(1.0-step(0.25, st.y))-step(0.75, st.y)
+  //+step(0.6-width, st.x)-step(0.6+width,st.x)
+  //+step(0.75-width,st.y)-step(0.75+width,st.y)-(1.0-step(0.4-width, st.x))-step(0.6+width,st.x)
+  //+step(0.25-width, st.y) - step(0.25+width, st.y);
+
+
+  //now the simple solution
+
+  float box = step(0.4, st.x)-(1.0-step(0.25,st.y)) - step(0.6, st.x)-step(0.75, st.y);
+  float r = sin(u_time/200.0);
+  float g = sin(u_time/3000000.333);
+  float b = sin(u_time);
+  color.r = r;
+  color.g = g;
+  color.b = b;
+  color = color;
+
+  gl_FragColor = vec4(color, box);
+
+  
+}