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shader_type spatial;
// Development shader used to debug or help authoring.
#include "include/heightmap.gdshaderinc"
uniform sampler2D u_terrain_heightmap;
uniform sampler2D u_terrain_normalmap;
uniform sampler2D u_terrain_colormap;
uniform sampler2D u_map; // This map will control color
uniform mat4 u_terrain_inverse_transform;
uniform mat3 u_terrain_normal_basis;
varying float v_hole;
vec3 unpack_normal(vec4 rgba) {
// If we consider texture space starts from top-left corner and Y goes down,
// then Y+ in pixel space corresponds to Z+ in terrain space,
// while X+ also corresponds to X+ in terrain space.
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;
}
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 = sample_heightmap(u_terrain_heightmap, UV);
VERTEX.y = h;
wpos.y = h;
// Putting this in vertex saves 2 fetches 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 tint and splat, but it's not bad overall)
vec4 tint = texture(u_terrain_colormap, UV);
v_hole = tint.a;
// Need to use u_terrain_normal_basis to handle scaling.
NORMAL = u_terrain_normal_basis * unpack_normal(texture(u_terrain_normalmap, UV));
}
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);
vec3 normal = terrain_normal_world;
vec4 value = texture(u_map, UV);
// TODO Blend toward checker pattern to show the alpha channel
ALBEDO = value.rgb;
ROUGHNESS = 0.5;
NORMAL = (VIEW_MATRIX * (vec4(normal, 0.0))).xyz;
}
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zaaarf