feat: default projection mapping with shift + M

default/frag9.glsl

@@ -6,8 +6,40 @@
 in vec2 vUV;
 out vec4 fragColor;
 
+#include inc_map.glsl
+
 uniform sampler2D iTex0;
+uniform int iAutoRand;
+uniform vec3 iGroup2_4[7];
 
 void main() {
-    fragColor = texture(iTex0, vUV);
+    bool visible = iAutoRand < 1 && iGroup2_4[0].x > 0;
+    bool invert = iAutoRand < 1 && iGroup2_4[0].y > 0;
+    bool rect = iAutoRand < 1 && iGroup2_4[0].z > 0;
+
+    vec2 uv2 = vUV;
+
+    if (visible) {
+        vec2 p1 = iAutoRand < 1 ? vec2(iGroup2_4[6].xy) : vec2(0);
+        vec2 p2 = iAutoRand < 1 ? vec2(iGroup2_4[1].xy) : vec2(0);
+        vec2 p3 = iAutoRand < 1 ? vec2(iGroup2_4[3].xy) : vec2(0);
+        vec2 p4 = iAutoRand < 1 ? vec2(iGroup2_4[5].xy) : vec2(0);
+
+        p2.x = 1 - p2.x;
+        p3.y = 1 - p3.y;
+        p4.x = 1 - p4.x;
+        p4.y = 1 - p4.y;
+
+        uv2 = project_4p(vUV, p1, p2, p3, p4);
+    }
+
+    vec4 color = texture(iTex0, invert ? vUV : uv2);
+
+    if (visible) {
+        float mask = step(0, uv2.x) * step(-1, -uv2.x) * step(0, uv2.y) * step(-1, -uv2.y);
+        color *= mix(mask, 1 - mask, invert ? 1 : 0);
+        color = mix(color, mix(color, color + mask * vec4(1), step(uv2.x, 0.01) + step(uv2.y, 0.01) + step(1 - uv2.y, 0.01) + step(1 - uv2.x, 0.01)), rect ? 1 : 0);
+    }
+
+    fragColor = color;
 }