ile-de-test/addons/zylann.hterrain/tools/brush/decal.gdshader
2023-10-05 20:02:23 +02:00

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shader_type spatial;
render_mode unshaded;//, depth_test_disabled;
#include "res://addons/zylann.hterrain/shaders/include/heightmap.gdshaderinc"
uniform sampler2D u_terrain_heightmap;
uniform mat4 u_terrain_inverse_transform;
uniform mat3 u_terrain_normal_basis;
uniform float u_distance_from_ground = 0.1;
float get_height(sampler2D heightmap, vec2 uv) {
return sample_heightmap(heightmap, uv);
}
void vertex() {
vec2 cell_coords = (u_terrain_inverse_transform * MODEL_MATRIX * vec4(VERTEX, 1)).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);
vec2 ps = vec2(1.0) / vec2(textureSize(u_terrain_heightmap, 0));
vec2 uv = ps * cell_coords;
// Get terrain normal
float k = 1.0;
float left = get_height(u_terrain_heightmap, uv + vec2(-ps.x, 0)) * k;
float right = get_height(u_terrain_heightmap, uv + vec2(ps.x, 0)) * k;
float back = get_height(u_terrain_heightmap, uv + vec2(0, -ps.y)) * k;
float fore = get_height(u_terrain_heightmap, uv + vec2(0, ps.y)) * k;
vec3 n = normalize(vec3(left - right, 2.0, back - fore));
n = u_terrain_normal_basis * n;
float h = get_height(u_terrain_heightmap, uv);
VERTEX.y = h;
// Offset the decal a little above terrain so it doesn't Z-fight with it
VERTEX += u_distance_from_ground * n;
NORMAL = n;//vec3(0.0, 1.0, 0.0);
}
void fragment() {
float len = length(2.0 * UV - 1.0);
float g = clamp(1.0 - 15.0 * abs(0.9 - len), 0.0, 1.0);
ALBEDO = vec3(1.0, 0.1, 0.1);
ALPHA = g;
}