use GLShader for LineTexLayer

vtm/resources/assets/shaders/linetex_layer.glsl

@@ -0,0 +1,53 @@
+#ifdef GLES
+precision mediump float;
+#endif
+uniform mat4 u_mvp;
+uniform vec4 u_color;
+uniform float u_pscale;
+uniform float u_width;
+attribute vec4 a_pos0;
+attribute vec4 a_pos1;
+attribute vec2 a_len0;
+attribute vec2 a_len1;
+attribute float a_flip;
+varying vec2 v_st;
+void
+main(){
+  vec4 pos;
+  if (a_flip == 0.0) {
+    //    vec2 dir = u_width * a_pos0.zw;
+    pos = vec4(a_pos0.xy + (u_width * a_pos0.zw), 0.0, 1.0);
+    v_st = vec2(a_len0.x / u_pscale, 1.0);
+  }
+  else {
+    //    vec2 dir = u_width * a_pos1.zw;
+    pos = vec4(a_pos1.xy - (u_width * a_pos1.zw), 0.0, 1.0);
+    v_st = vec2(a_len1.x / u_pscale, -1.0);
+  }
+  gl_Position = u_mvp * pos;
+}
+
+$$
+
+#extension GL_OES_standard_derivatives : enable
+#ifdef GLES
+precision mediump float;
+#endif
+uniform vec4 u_color;
+uniform vec4 u_bgcolor;
+uniform float u_pwidth;
+varying vec2 v_st;
+void
+main(){
+  /* distance on perpendicular to the line */
+  float dist = abs(v_st.t);
+  float fuzz = fwidth(v_st.t);
+  float fuzz_p = fwidth(v_st.s);
+  float line_w = smoothstep(0.0, fuzz, 1.0 - dist);
+  float stipple_w = smoothstep(0.0, fuzz, u_pwidth - dist);
+  /* triangle waveform in the range 0..1 for regular pattern */
+  float phase = abs(mod(v_st.s, 2.0) - 1.0);
+  /* interpolate between on/off phase, 0.5 = equal phase length */
+  float stipple_p = smoothstep(0.5 - fuzz_p, 0.5 + fuzz_p, phase);
+  gl_FragColor = line_w * mix(u_bgcolor, u_color, min(stipple_w, stipple_p));
+}