Fry3DX 0.4: an easy 3D modeller

Shapes with live settings, shape editing, knife and hole tools, drawing
shapes onto other objects, combining objects (add / subtract / overlap),
copies, thickness, painting with stickers and layers, a Layout tab, a
Print tab with checks, packed .fry files with autosave, export to GLB,
glTF, FBX, OBJ, 3MF, STL and PLY, folders in Layers, its own crash
screen, and a website for GitHub Pages in docs/.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01NMSrd5oe1GpUD7E6d825KP

engine/shaders/backend_vk.glsl

@@ -0,0 +1,35 @@
+// Vulkan: one global descriptor array of textures, separate samplers, push constants.
+#extension GL_EXT_nonuniform_qualifier : require
+#extension GL_EXT_buffer_reference : require
+layout(set = 0, binding = 0) uniform texture2D u_textures[];
+layout(set = 0, binding = 1) uniform sampler u_sampler;
+layout(set = 0, binding = 2) uniform sampler u_shadowSampler; // depth compare, linear: bilinear PCF
+layout(set = 0, binding = 3) uniform sampler u_clampSampler;  // render targets, for the screen-space passes
+// Post passes (#define KEEL_POST before including): every lookup clamps at the edges.
+#ifdef KEEL_POST
+#define KEEL_SAMPLER u_clampSampler
+#else
+#define KEEL_SAMPLER u_sampler
+#endif
+
+#define PUSH_BLOCK layout(push_constant) uniform Push
+#define VERTEX_ID gl_VertexIndex
+
+vec4 sampleTex(uint index, vec2 uv) {
+    return texture(sampler2D(u_textures[nonuniformEXT(index)], KEEL_SAMPLER), uv);
+}
+
+ivec2 texSize(uint index) { return textureSize(sampler2D(u_textures[nonuniformEXT(index)], KEEL_SAMPLER), 0); }
+
+vec4 fetchTex(uint index, ivec2 p) {
+    return texelFetch(sampler2D(u_textures[nonuniformEXT(index)], KEEL_SAMPLER), p, 0);
+}
+
+vec4 sampleTexLod(uint index, vec2 uv, float lod) {
+    return textureLod(sampler2D(u_textures[nonuniformEXT(index)], KEEL_SAMPLER), uv, lod);
+}
+
+// 1 = lit. Hardware-filtered depth compare at uv (clamped inside [lo, hi]).
+float shadowTap(uint index, vec2 uv, vec2 lo, vec2 hi, float ref) {
+    return textureLod(sampler2DShadow(u_textures[nonuniformEXT(index)], u_shadowSampler), vec3(clamp(uv, lo, hi), ref), 0.0);
+}