shader

2 files changed, 34 insertions, 0 deletions

diff --git a/assets/platform_f.glsl b/assets/platform_f.glsl
new file mode 100644
index 0000000..1969a46
--- /dev/null
+++ b/assets/platform_f.glsl
@@ -0,0 +1,15 @@
+varying vec4 color;
+varying vec2 p1, p2;
+varying vec2 pos;
+uniform float thickness;
+
+void main() {
+	// thanks to https://www.youtube.com/watch?v=PMltMdi1Wzg
+	float h = clamp(dot(pos-p1, p2-p1) / dot(p2-p1, p2-p1), 0.0, 1.0);
+	float d = length(pos - p1 - (p2-p1) * h);
+	
+	float v = max(thickness - d, 0.0);
+	v /= thickness;
+
+	gl_FragColor = color * v;
+}
diff --git a/assets/platform_v.glsl b/assets/platform_v.glsl
new file mode 100644
index 0000000..472f9df
--- /dev/null
+++ b/assets/platform_v.glsl
@@ -0,0 +1,19 @@
+// "position" within line (0,0) = bottom-left corner, (1,1) = top-right corner
+attribute vec2 vertex_p1, vertex_p2;
+varying vec4 color;
+varying vec2 p1, p2;
+varying vec2 pos;
+uniform float thickness;
+
+void main() {
+	gl_Position = gl_Vertex;
+	pos = gl_Vertex.xy;
+	color = gl_Color;
+#if 1
+	p1 = vertex_p1 + thickness * normalize(vertex_p2 - vertex_p1);
+	p2 = vertex_p2 + thickness * normalize(vertex_p1 - vertex_p2);
+#else
+	p1 = vertex_p1;
+	p2 = vertex_p2;
+#endif
+}