some small grass and shader test

grass/grass.gdshader

@@ -0,0 +1,38 @@
+shader_type spatial;
+render_mode cull_disabled;
+
+uniform vec3 color: source_color;
+uniform vec3 shade: source_color;
+uniform sampler2D noise: source_color;
+uniform float noiseScale = 1.0;
+uniform float windSpeedScale = 1.0;
+uniform float windVertexOffsetScale = 1.0;
+
+varying vec3 worldPos;
+varying vec3 instance_origin;
+
+void vertex() {
+	worldPos = (MODEL_MATRIX * vec4(VERTEX, 1.0)).xyz;
+	instance_origin = MODELVIEW_MATRIX[3].xyz;
+	
+	vec2 timeOffset = vec2(TIME/windSpeedScale);
+	float noiseLevel = texture(noise, timeOffset + worldPos.xz/noiseScale).r;
+	float vertexWindOffset = noiseLevel * worldPos.y * windVertexOffsetScale;
+	VERTEX += vec3(1.0, 0.0, 1.0)*vertexWindOffset;
+    // billboarding
+    // MODELVIEW_MATRIX = VIEW_MATRIX * mat4(INV_VIEW_MATRIX[0],INV_VIEW_MATRIX[1],INV_VIEW_MATRIX[2],MODEL_MATRIX[3]);
+}
+
+void fragment() {
+	vec2 timeOffset = vec2(TIME/windSpeedScale);
+	float noiseLevel = texture(noise, timeOffset + worldPos.xz/noiseScale).r;
+	NORMAL = (VIEW_MATRIX * vec4(0.0, 1.0, 0.0, 0.0)).xyz;
+	ALBEDO = mix(color, shade, UV.y) * mix(color, shade, noiseLevel);
+	LIGHT_VERTEX = instance_origin;
+}
+
+ void light() {
+ 	float lambert = clamp(dot(NORMAL, LIGHT), 0.0, 1.0);
+ 	float halfLambert = pow(lambert*0.5 + 0.5, 5);
+    DIFFUSE_LIGHT += halfLambert * ATTENUATION * LIGHT_COLOR / PI;
+ }