Create/Update assets for version 1.21-rc1

assets/minecraft/shaders/program/invert.vsh

@@ -0,0 +1,20 @@
+#version 150
+
+in vec4 Position;
+
+uniform mat4 ProjMat;
+uniform vec2 InSize;
+uniform vec2 OutSize;
+
+out vec2 texCoord;
+
+void main(){
+    vec4 outPos = ProjMat * vec4(Position.xy, 0.0, 1.0);
+    gl_Position = vec4(outPos.xy, 0.2, 1.0);
+
+    vec2 sizeRatio = OutSize / InSize;
+    texCoord = Position.xy / OutSize;
+    texCoord.x = texCoord.x * sizeRatio.x;
+    texCoord.y = texCoord.y * sizeRatio.y;
+    texCoord.y = sizeRatio.y - texCoord.y;
+}