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-rw-r--r--game/addons/zylann.hterrain/shaders/include/heightmap.gdshaderinc66
1 files changed, 66 insertions, 0 deletions
diff --git a/game/addons/zylann.hterrain/shaders/include/heightmap.gdshaderinc b/game/addons/zylann.hterrain/shaders/include/heightmap.gdshaderinc
new file mode 100644
index 0000000..c023e52
--- /dev/null
+++ b/game/addons/zylann.hterrain/shaders/include/heightmap.gdshaderinc
@@ -0,0 +1,66 @@
+
+// Use functions from this file everywhere a heightmap is used,
+// so it is easy to track and change the format
+
+float sample_heightmap(sampler2D spl, vec2 pos) {
+ // RF
+ return texture(spl, pos).r;
+}
+
+vec4 encode_height_to_viewport(float h) {
+ //return vec4(encode_height_to_rgb8_unorm(h), 1.0);
+
+ // Encode regular floats into an assumed RGBA8 output color.
+ // This is used because Godot 4.0 doesn't support RF viewports,
+ // and the irony is, even if float viewports get supported, it's likely it will end up RGBAF,
+ // which is wasting bandwidth because we are only interested in R...
+ uint u = floatBitsToUint(h);
+ return vec4(
+ float((u >> 0u) & 255u),
+ float((u >> 8u) & 255u),
+ float((u >> 16u) & 255u),
+ float((u >> 24u) & 255u)
+ ) / vec4(255.0);
+}
+
+float decode_height_from_viewport(vec4 c) {
+ uint u = uint(c.r * 255.0)
+ | (uint(c.g * 255.0) << 8u)
+ | (uint(c.b * 255.0) << 16u)
+ | (uint(c.a * 255.0) << 24u);
+ return uintBitsToFloat(u);
+}
+
+float sample_height_from_viewport(sampler2D screen, vec2 uv) {
+ ivec2 ts = textureSize(screen, 0);
+ vec2 norm_to_px = vec2(ts);
+
+ // Convert to pixels and apply a small offset so we interpolate from pixel centers
+ vec2 uv_px_f = uv * norm_to_px - vec2(0.5);
+
+ ivec2 uv_px = ivec2(uv_px_f);
+
+ // Get interpolation pixel positions
+ ivec2 p00 = uv_px;
+ ivec2 p10 = uv_px + ivec2(1, 0);
+ ivec2 p01 = uv_px + ivec2(0, 1);
+ ivec2 p11 = uv_px + ivec2(1, 1);
+
+ // Get pixels
+ vec4 c00 = texelFetch(screen, p00, 0);
+ vec4 c10 = texelFetch(screen, p10, 0);
+ vec4 c01 = texelFetch(screen, p01, 0);
+ vec4 c11 = texelFetch(screen, p11, 0);
+
+ // Decode heights
+ float h00 = decode_height_from_viewport(c00);
+ float h10 = decode_height_from_viewport(c10);
+ float h01 = decode_height_from_viewport(c01);
+ float h11 = decode_height_from_viewport(c11);
+
+ // Linear filter
+ vec2 f = fract(uv_px_f);
+ float h = mix(mix(h00, h10, f.x), mix(h01, h11, f.x), f.y);
+
+ return h;
+}