new idea: function sandbox

1 files changed, 9 insertions, 0 deletions

diff --git a/grainv.glsl b/grainv.glsl
new file mode 100644
index 0000000..2584fd3
--- /dev/null
+++ b/grainv.glsl
@@ -0,0 +1,9 @@
+attribute vec3 v_pos;
+uniform mat4 u_transform;
+uniform sampler2D u_offset_tex;
+
+void main() {
+	ivec2 texel_pos = ivec2(gl_InstanceID & 1023, gl_InstanceID >> 10);
+	vec3 offset = texelFetch(u_offset_tex, texel_pos, 0).xyz;
+	gl_Position = u_transform * vec4(v_pos + offset, 1.0);
+}