1 files changed, 83 insertions, 0 deletions
diff --git a/game/addons/zylann.hterrain/shaders/simple4_global.gdshader b/game/addons/zylann.hterrain/shaders/simple4_global.gdshader
new file mode 100644
index 0000000..f504c48
--- /dev/null
+++ b/game/addons/zylann.hterrain/shaders/simple4_global.gdshader
@@ -0,0 +1,83 @@
+shader_type spatial;
+
+// This shader is used to bake the global albedo map.
+// It exposes a subset of the main shader API, so uniform names were not modified.
+
+// I had to remove `hint_albedo` from colormap in Godot 3 because it makes sRGB conversion kick in,
+// which snowballs to black when doing GPU painting on that texture...
+uniform sampler2D u_terrain_colormap;// : hint_albedo;
+uniform sampler2D u_terrain_splatmap;
+
+uniform sampler2D u_ground_albedo_bump_0 : source_color;
+uniform sampler2D u_ground_albedo_bump_1 : source_color;
+uniform sampler2D u_ground_albedo_bump_2 : source_color;
+uniform sampler2D u_ground_albedo_bump_3 : source_color;
+
+// Keep depth blending because it has a high effect on the final result
+uniform bool u_depth_blending = true;
+uniform float u_ground_uv_scale = 20.0;
+
+
+vec4 get_depth_blended_weights(vec4 splat, vec4 bumps) {
+	float dh = 0.2;
+
+	vec4 h = bumps + splat;
+	
+	h *= smoothstep(0, 0.05, splat);
+	
+	vec4 d = h + dh;
+	d.r -= max(h.g, max(h.b, h.a));
+	d.g -= max(h.r, max(h.b, h.a));
+	d.b -= max(h.g, max(h.r, h.a));
+	d.a -= max(h.g, max(h.b, h.r));
+	
+	return clamp(d, 0, 1);
+}
+
+void vertex() {
+	vec4 wpos = MODEL_MATRIX * vec4(VERTEX, 1);
+	vec2 cell_coords = wpos.xz;
+	// Must add a half-offset so that we sample the center of pixels,
+	// otherwise bilinear filtering of the textures will give us mixed results (#183)
+	cell_coords += vec2(0.5);
+
+	// Normalized UV
+	UV = (cell_coords / vec2(textureSize(u_terrain_splatmap, 0)));
+}
+
+void fragment() {
+	// These were moved from vertex to fragment,
+	// so we can generate part of the global map with just one quad and we get full quality
+	vec4 tint = texture(u_terrain_colormap, UV);
+	vec4 splat = texture(u_terrain_splatmap, UV);
+
+	// Get bump at normal resolution so depth blending is accurate
+	vec2 ground_uv = UV / u_ground_uv_scale;
+	float b0 = texture(u_ground_albedo_bump_0, ground_uv).a;
+	float b1 = texture(u_ground_albedo_bump_1, ground_uv).a;
+	float b2 = texture(u_ground_albedo_bump_2, ground_uv).a;
+	float b3 = texture(u_ground_albedo_bump_3, ground_uv).a;
+
+	// Take the center of the highest mip as color, because we can't see details from far away.
+	vec2 ndc_center = vec2(0.5, 0.5);
+	vec3 col0 = textureLod(u_ground_albedo_bump_0, ndc_center, 10.0).rgb;
+	vec3 col1 = textureLod(u_ground_albedo_bump_1, ndc_center, 10.0).rgb;
+	vec3 col2 = textureLod(u_ground_albedo_bump_2, ndc_center, 10.0).rgb;
+	vec3 col3 = textureLod(u_ground_albedo_bump_3, ndc_center, 10.0).rgb;
+	
+	vec4 w;
+	if (u_depth_blending) {
+		w = get_depth_blended_weights(splat, vec4(b0, b1, b2, b3));
+	} else {
+		w = splat.rgba;
+	}
+	
+	float w_sum = (w.r + w.g + w.b + w.a);
+	
+	ALBEDO = tint.rgb * (
+		w.r * col0 + 
+		w.g * col1 + 
+		w.b * col2 + 
+		w.a * col3) / w_sum;
+}
+