255 lines
8.2 KiB
Text
255 lines
8.2 KiB
Text
|
shader_type spatial;
|
||
|
|
|
||
|
|
// WIP
|
||
|
|
// This shader uses a texture array with multiple splatmaps, allowing up to 16 textures.
|
||
|
|
// Only the 4 textures having highest blending weight are sampled.
|
||
|
|
|
||
|
|
#include "include/heightmap_rgb8_encoding.gdshaderinc"
|
||
|
|
|
||
|
|
uniform sampler2D u_terrain_heightmap;
|
||
|
|
uniform sampler2D u_terrain_normalmap;
|
||
|
|
// I had to remove source_color` 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;
|
||
|
|
uniform sampler2D u_terrain_splatmap;
|
||
|
|
uniform sampler2D u_terrain_splatmap_1;
|
||
|
|
uniform sampler2D u_terrain_splatmap_2;
|
||
|
|
uniform sampler2D u_terrain_splatmap_3;
|
||
|
|
uniform sampler2D u_terrain_globalmap : source_color;
|
||
|
|
uniform mat4 u_terrain_inverse_transform;
|
||
|
|
uniform mat3 u_terrain_normal_basis;
|
||
|
|
|
||
|
|
uniform sampler2DArray u_ground_albedo_bump_array : source_color;
|
||
|
|
|
||
|
|
uniform float u_ground_uv_scale = 20.0;
|
||
|
|
uniform bool u_depth_blending = true;
|
||
|
|
uniform float u_globalmap_blend_start;
|
||
|
|
uniform float u_globalmap_blend_distance;
|
||
|
|
|
||
|
|
varying float v_hole;
|
||
|
|
varying vec3 v_tint;
|
||
|
|
varying vec2 v_terrain_uv;
|
||
|
|
varying vec3 v_ground_uv;
|
||
|
|
varying float v_distance_to_camera;
|
||
|
|
|
||
|
|
// TODO Can't put this in a constant: https://github.com/godotengine/godot/issues/44145
|
||
|
|
//const int TEXTURE_COUNT = 16;
|
||
|
|
|
||
|
|
|
||
|
|
vec3 unpack_normal(vec4 rgba) {
|
||
|
|
vec3 n = rgba.xzy * 2.0 - vec3(1.0);
|
||
|
|
// Had to negate Z because it comes from Y in the normal map,
|
||
|
|
// and OpenGL-style normal maps are Y-up.
|
||
|
|
n.z *= -1.0;
|
||
|
|
return n;
|
||
|
|
}
|
||
|
|
|
||
|
|
// Blends weights according to the bump of detail textures,
|
||
|
|
// so for example it allows to have sand fill the gaps between pebbles
|
||
|
|
vec4 get_depth_blended_weights(vec4 splat, vec4 bumps) {
|
||
|
|
float dh = 0.2;
|
||
|
|
|
||
|
|
vec4 h = bumps + splat;
|
||
|
|
|
||
|
|
// TODO Keep improving multilayer blending, there are still some edge cases...
|
||
|
|
// Mitigation: nullify layers with near-zero 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);
|
||
|
|
}
|
||
|
|
|
||
|
|
vec3 get_triplanar_blend(vec3 world_normal) {
|
||
|
|
vec3 blending = abs(world_normal);
|
||
|
|
blending = normalize(max(blending, vec3(0.00001))); // Force weights to sum to 1.0
|
||
|
|
float b = blending.x + blending.y + blending.z;
|
||
|
|
return blending / vec3(b, b, b);
|
||
|
|
}
|
||
|
|
|
||
|
|
vec4 texture_triplanar(sampler2D tex, vec3 world_pos, vec3 blend) {
|
||
|
|
vec4 xaxis = texture(tex, world_pos.yz);
|
||
|
|
vec4 yaxis = texture(tex, world_pos.xz);
|
||
|
|
vec4 zaxis = texture(tex, world_pos.xy);
|
||
|
|
// blend the results of the 3 planar projections.
|
||
|
|
return xaxis * blend.x + yaxis * blend.y + zaxis * blend.z;
|
||
|
|
}
|
||
|
|
|
||
|
|
void get_splat_weights(vec2 uv, out vec4 out_high_indices, out vec4 out_high_weights) {
|
||
|
|
vec4 ew0 = texture(u_terrain_splatmap, uv);
|
||
|
|
vec4 ew1 = texture(u_terrain_splatmap_1, uv);
|
||
|
|
vec4 ew2 = texture(u_terrain_splatmap_2, uv);
|
||
|
|
vec4 ew3 = texture(u_terrain_splatmap_3, uv);
|
||
|
|
|
||
|
|
float weights[16] = {
|
||
|
|
ew0.r, ew0.g, ew0.b, ew0.a,
|
||
|
|
ew1.r, ew1.g, ew1.b, ew1.a,
|
||
|
|
ew2.r, ew2.g, ew2.b, ew2.a,
|
||
|
|
ew3.r, ew3.g, ew3.b, ew3.a
|
||
|
|
};
|
||
|
|
|
||
|
|
// float weights_sum = 0.0;
|
||
|
|
// for (int i = 0; i < 16; ++i) {
|
||
|
|
// weights_sum += weights[i];
|
||
|
|
// }
|
||
|
|
// for (int i = 0; i < 16; ++i) {
|
||
|
|
// weights_sum /= weights_sum;
|
||
|
|
// }
|
||
|
|
// weights_sum=1.1;
|
||
|
|
|
||
|
|
// Now we have to pick the 4 highest weights and use them to blend textures.
|
||
|
|
|
||
|
|
// Using arrays because Godot's shader version doesn't support dynamic indexing of vectors
|
||
|
|
// TODO We should not need to initialize, but apparently we don't always find 4 weights
|
||
|
|
int high_indices_array[4] = {0, 0, 0, 0};
|
||
|
|
float high_weights_array[4] = {0.0, 0.0, 0.0, 0.0};
|
||
|
|
int count = 0;
|
||
|
|
// We know weights are supposed to be normalized.
|
||
|
|
// That means the highest value of the pivot above which we can find 4 results
|
||
|
|
// is 1.0 / 4.0. However that would mean exactly 4 textures have exactly that weight,
|
||
|
|
// which is very unlikely. If we consider 1.0 / 5.0, we are a bit more likely to find
|
||
|
|
// 4 results, and finding 5 results remains almost impossible.
|
||
|
|
float pivot = /*weights_sum*/1.0 / 5.0;
|
||
|
|
|
||
|
|
for (int i = 0; i < 16; ++i) {
|
||
|
|
if (weights[i] > pivot) {
|
||
|
|
high_weights_array[count] = weights[i];
|
||
|
|
high_indices_array[count] = i;
|
||
|
|
weights[i] = 0.0;
|
||
|
|
++count;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
while (count < 4 && pivot > 0.0) {
|
||
|
|
float max_weight = 0.0;
|
||
|
|
int max_index = 0;
|
||
|
|
|
||
|
|
for (int i = 0; i < 16; ++i) {
|
||
|
|
if (/*weights[i] <= pivot && */weights[i] > max_weight) {
|
||
|
|
max_weight = weights[i];
|
||
|
|
max_index = i;
|
||
|
|
weights[i] = 0.0;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
high_indices_array[count] = max_index;
|
||
|
|
high_weights_array[count] = max_weight;
|
||
|
|
++count;
|
||
|
|
pivot = max_weight;
|
||
|
|
}
|
||
|
|
|
||
|
|
out_high_weights = vec4(
|
||
|
|
high_weights_array[0], high_weights_array[1],
|
||
|
|
high_weights_array[2], high_weights_array[3]);
|
||
|
|
|
||
|
|
out_high_indices = vec4(
|
||
|
|
float(high_indices_array[0]), float(high_indices_array[1]),
|
||
|
|
float(high_indices_array[2]), float(high_indices_array[3]));
|
||
|
|
|
||
|
|
out_high_weights /=
|
||
|
|
out_high_weights.r + out_high_weights.g + out_high_weights.b + out_high_weights.a;
|
||
|
|
}
|
||
|
|
|
||
|
|
void vertex() {
|
||
|
|
vec4 wpos = MODEL_MATRIX * vec4(VERTEX, 1);
|
||
|
|
vec2 cell_coords = (u_terrain_inverse_transform * 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_heightmap, 0));
|
||
|
|
|
||
|
|
// Height displacement
|
||
|
|
float h = decode_height_from_rgb8_unorm(texture(u_terrain_heightmap, UV).rgb);
|
||
|
|
VERTEX.y = h;
|
||
|
|
wpos.y = h;
|
||
|
|
|
||
|
|
vec3 base_ground_uv = vec3(cell_coords.x, h * MODEL_MATRIX[1][1], cell_coords.y);
|
||
|
|
v_ground_uv = base_ground_uv / u_ground_uv_scale;
|
||
|
|
|
||
|
|
// Putting this in vertex saves a fetch from the fragment shader,
|
||
|
|
// which is good for performance at a negligible quality cost,
|
||
|
|
// provided that geometry is a regular grid that decimates with LOD.
|
||
|
|
// (downside is LOD will also decimate it, but it's not bad overall)
|
||
|
|
vec4 tint = texture(u_terrain_colormap, UV);
|
||
|
|
v_hole = tint.a;
|
||
|
|
v_tint = tint.rgb;
|
||
|
|
|
||
|
|
// Need to use u_terrain_normal_basis to handle scaling.
|
||
|
|
NORMAL = u_terrain_normal_basis * unpack_normal(texture(u_terrain_normalmap, UV));
|
||
|
|
|
||
|
|
v_distance_to_camera = distance(wpos.xyz, CAMERA_POSITION_WORLD);
|
||
|
|
}
|
||
|
|
|
||
|
|
void fragment() {
|
||
|
|
if (v_hole < 0.5) {
|
||
|
|
// TODO Add option to use vertex discarding instead, using NaNs
|
||
|
|
discard;
|
||
|
|
}
|
||
|
|
|
||
|
|
vec3 terrain_normal_world =
|
||
|
|
u_terrain_normal_basis * unpack_normal(texture(u_terrain_normalmap, UV));
|
||
|
|
terrain_normal_world = normalize(terrain_normal_world);
|
||
|
|
|
||
|
|
float globalmap_factor = clamp((v_distance_to_camera - u_globalmap_blend_start)
|
||
|
|
* u_globalmap_blend_distance, 0.0, 1.0);
|
||
|
|
globalmap_factor *= globalmap_factor; // slower start, faster transition but far away
|
||
|
|
vec3 global_albedo = texture(u_terrain_globalmap, UV).rgb;
|
||
|
|
ALBEDO = global_albedo;
|
||
|
|
|
||
|
|
// Doing this branch allows to spare a bunch of texture fetches for distant pixels.
|
||
|
|
// Eventually, there could be a split between near and far shaders in the future,
|
||
|
|
// if relevant on high-end GPUs
|
||
|
|
if (globalmap_factor < 1.0) {
|
||
|
|
vec4 high_indices;
|
||
|
|
vec4 high_weights;
|
||
|
|
get_splat_weights(UV, high_indices, high_weights);
|
||
|
|
|
||
|
|
vec4 ab0 = texture(u_ground_albedo_bump_array, vec3(v_ground_uv.xz, high_indices.x));
|
||
|
|
vec4 ab1 = texture(u_ground_albedo_bump_array, vec3(v_ground_uv.xz, high_indices.y));
|
||
|
|
vec4 ab2 = texture(u_ground_albedo_bump_array, vec3(v_ground_uv.xz, high_indices.z));
|
||
|
|
vec4 ab3 = texture(u_ground_albedo_bump_array, vec3(v_ground_uv.xz, high_indices.w));
|
||
|
|
|
||
|
|
vec3 col0 = ab0.rgb * v_tint;
|
||
|
|
vec3 col1 = ab1.rgb * v_tint;
|
||
|
|
vec3 col2 = ab2.rgb * v_tint;
|
||
|
|
vec3 col3 = ab3.rgb * v_tint;
|
||
|
|
|
||
|
|
vec4 w;
|
||
|
|
// TODO An #ifdef macro would be nice! Or copy/paste everything in a different shader...
|
||
|
|
if (u_depth_blending) {
|
||
|
|
w = get_depth_blended_weights(high_weights, vec4(ab0.a, ab1.a, ab2.a, ab3.a));
|
||
|
|
} else {
|
||
|
|
w = high_weights;
|
||
|
|
}
|
||
|
|
|
||
|
|
float w_sum = (w.r + w.g + w.b + w.a);
|
||
|
|
|
||
|
|
ALBEDO = (
|
||
|
|
w.r * col0.rgb +
|
||
|
|
w.g * col1.rgb +
|
||
|
|
w.b * col2.rgb +
|
||
|
|
w.a * col3.rgb) / w_sum;
|
||
|
|
|
||
|
|
ALBEDO = mix(ALBEDO, global_albedo, globalmap_factor);
|
||
|
|
ROUGHNESS = mix(ROUGHNESS, 1.0, globalmap_factor);
|
||
|
|
|
||
|
|
// if(count < 3) {
|
||
|
|
// ALBEDO = vec3(1.0, 0.0, 0.0);
|
||
|
|
// }
|
||
|
|
// Show splatmap weights
|
||
|
|
//ALBEDO = w.rgb;
|
||
|
|
}
|
||
|
|
// Highlight all pixels undergoing no splatmap at all
|
||
|
|
// else {
|
||
|
|
// ALBEDO = vec3(1.0, 0.0, 0.0);
|
||
|
|
// }
|
||
|
|
|
||
|
|
NORMAL = (VIEW_MATRIX * (vec4(terrain_normal_world, 0.0))).xyz;
|
||
|
|
}
|