render: Add vector path rendering module.

1 files changed, 93 insertions, 0 deletions

diff --git a/data/shaders/path-frag.glsl b/data/shaders/path-frag.glsl
new file mode 100644
index 0000000..a38f1d0
--- /dev/null
+++ b/data/shaders/path-frag.glsl
@@ -0,0 +1,93 @@
+// -*- mode: c -*-
+
+#ifdef GLSL330
+out vec4 fragColor;
+#endif
+
+#ifdef GLSL120
+attribute vec2 fragTex;
+attribute float fragStrokeLength;
+#else
+in vec2 fragTex;
+in float fragStrokeLength;
+#endif
+
+uniform int mode;
+uniform vec4 color;
+uniform float feather;
+uniform int strokeClosed;
+uniform float strokeWidth;
+uniform int strokeCap;
+uniform int strokeMiterStyle;
+uniform float strokeMiterLimit;
+
+float infinity = 1.0 / 0.0;
+
+void main(void) {
+  if (color.a <= 0.0) {
+    discard;
+  }
+
+  // fill mode
+  if(mode == 0) {
+#ifdef GLSL330
+    fragColor = color;
+#else
+    gl_FragColor = color;
+#endif
+  } else if(mode == 1) { // stroke mode
+    float hw = strokeWidth / 2.0;
+    float u = fragTex.x;
+    float v = fragTex.y;
+    float dx;
+    float dy;
+    float d;
+
+    // Stroke caps.
+    if (u < 0 || u > fragStrokeLength) {
+      if (u < 0) {
+        dx = abs(u);
+      } else {
+        dx = u - fragStrokeLength;
+      }
+      dy = abs(v);
+
+      if (strokeCap == 0) { // none
+        d = infinity;
+      } else if (strokeCap == 1) { // butt
+        d = max(dx + hw - 2 * feather, dy);
+      } else if (strokeCap == 2) { // square
+        d = max(dx, dy);
+      } else if (strokeCap == 3) { // round
+        d = sqrt(dx * dx + dy * dy);
+      } else if (strokeCap == 4) { // triangle out
+        d = dx + dy;
+      } else if (strokeCap == 5) { // triangle in
+        d = max(dy, hw - feather + dx - dy);
+      }
+    // Stroke inner/join
+    } else {
+      d = abs(v);
+    }
+
+    if(d <= hw) {
+#ifdef GLSL330
+      fragColor = color;
+#else
+      gl_FragColor = color;
+#endif
+    } else {
+      vec4 c = vec4(color.rgb, color.a * (1.0 - ((d - hw) / feather)));
+
+      if (c.a <= 0.0) {
+        discard;
+      }
+
+#ifdef GLSL330
+      fragColor = c;
+#else
+      gl_FragColor = c;
+#endif
+    }
+  }
+}