Create/Update assets for version 1.21.3

assets/minecraft/shaders/core/terrain.vsh

@@ -0,0 +1,30 @@
+#version 150
+
+#moj_import <minecraft:light.glsl>
+#moj_import <minecraft:fog.glsl>
+
+in vec3 Position;
+in vec4 Color;
+in vec2 UV0;
+in ivec2 UV2;
+in vec3 Normal;
+
+uniform sampler2D Sampler2;
+
+uniform mat4 ModelViewMat;
+uniform mat4 ProjMat;
+uniform vec3 ModelOffset;
+uniform int FogShape;
+
+out float vertexDistance;
+out vec4 vertexColor;
+out vec2 texCoord0;
+
+void main() {
+    vec3 pos = Position + ModelOffset;
+    gl_Position = ProjMat * ModelViewMat * vec4(pos, 1.0);
+
+    vertexDistance = fog_distance(pos, FogShape);
+    vertexColor = Color * minecraft_sample_lightmap(Sampler2, UV2);
+    texCoord0 = UV0;
+}