Add squadron-based position information to vertices

4 files changed, 43 insertions, 5 deletions

diff --git a/src/main/java/makamys/neodymium/renderer/ChunkMesh.java b/src/main/java/makamys/neodymium/renderer/ChunkMesh.java
index fcfebf0..e175167 100644
--- a/src/main/java/makamys/neodymium/renderer/ChunkMesh.java
+++ b/src/main/java/makamys/neodymium/renderer/ChunkMesh.java
@@ -233,7 +233,7 @@ public class ChunkMesh extends Mesh {
     }
 
     private ByteBuffer createBuffer(List<? extends MeshQuad> quads, int quadCount) {
-        ByteBuffer buffer = BufferUtils.createByteBuffer(quadCount * 6 * 7 * 4);
+        ByteBuffer buffer = BufferUtils.createByteBuffer(quadCount * 6 * MeshQuad.getStride());
         BufferWriter out = new BufferWriter(buffer);
         
         try {
@@ -301,7 +301,7 @@ public class ChunkMesh extends Mesh {
     }
     
     public int getStride() {
-        return (3 * 4 + (flags.hasTexture ? 8 : 0) + (flags.hasBrightness ? 4 : 0) + (flags.hasColor ? 4 : 0) + (flags.hasNormals ? 4 : 0));
+        return MeshQuad.getStride();
     }
     
     static void saveChunks(List<Integer> coords) {
diff --git a/src/main/java/makamys/neodymium/renderer/MeshQuad.java b/src/main/java/makamys/neodymium/renderer/MeshQuad.java
index 6d1221e..bebdafd 100644
--- a/src/main/java/makamys/neodymium/renderer/MeshQuad.java
+++ b/src/main/java/makamys/neodymium/renderer/MeshQuad.java
@@ -21,6 +21,13 @@ import net.minecraft.util.EnumFacing;
  *  |  |
  *  3--0
  * 
+ * We can glue quads together, forming a "quad squadron", or "squadron" for short.
+ * In the fragment shader we need to know which quad of the squadron we are operating on.
+ * For this reason, we store the "squadron X" and "squadron Y" coordinates in the vertices.
+ * Their values at vertex 0: (0, 0)
+ * Their values at vertex 1: (0, squadron height)
+ * Their values at vertex 2: (squadron width, squadron height)
+ * Their values at vertex 3: (squadron width, 0)
  */
 
 public class MeshQuad {
@@ -44,8 +51,8 @@ public class MeshQuad {
     public int offset;
     public ChunkMesh.Flags flags;
     
-    // 0: quads glued together on edge 0-1 or 2-3 ("row length")
-    // 1: quads glued together on edge 1-2 or 3-0 ("column length")
+    // 0: quads glued together on edge 0-1 or 2-3 ("squadron row length")
+    // 1: quads glued together on edge 1-2 or 3-0 ("squadron column length")
     private int[] quadCountByDirection = {1, 1}; 
     public static int[] totalMergeCountByPlane = new int[3];
     
@@ -126,10 +133,27 @@ public class MeshQuad {
             
             out.writeInt(c);
             
+            out.writeByte(vi < 2 ? (byte)0 : (byte)quadCountByDirection[0]); // squadron x
+            out.writeByte((vi == 0 || vi == 3) ? (byte)0 : (byte)quadCountByDirection[1]); // quad z
+            out.writeByte(vi < 2 ? (byte)0 : 1); // which squadron corner x
+            out.writeByte((vi == 0 || vi == 3) ? (byte)0 : 1); // which squadron corner z
+            
+            assert out.position() % getStride() == 0;
+            
             //System.out.println("[" + vertexI + "] x: " + x + ", y: " + y + " z: " + z + ", u: " + u + ", v: " + v + ", b: " + b + ", c: " + c);
         }
     }
     
+    public static int getStride() {
+        return
+                3 * 4    // XYZ          (float)
+                + 2 * 4  // UV           (float)
+                + 4      // B            (int)
+                + 4      // C            (int))
+                + 4
+                ; // squadron XY  (byte)
+    }
+    
     private boolean isTranslatedCopyOf(MeshQuad o, boolean checkValid) {
         if((!isValid(this) && checkValid) || !isValid(o) || plane != o.plane) return false;
         
diff --git a/src/main/java/makamys/neodymium/renderer/NeoRenderer.java b/src/main/java/makamys/neodymium/renderer/NeoRenderer.java
index cd15bda..8cc32f5 100644
--- a/src/main/java/makamys/neodymium/renderer/NeoRenderer.java
+++ b/src/main/java/makamys/neodymium/renderer/NeoRenderer.java
@@ -9,6 +9,7 @@ import static org.lwjgl.opengl.GL11.GL_PROJECTION_MATRIX;
 import static org.lwjgl.opengl.GL11.GL_SHORT;
 import static org.lwjgl.opengl.GL11.GL_TRIANGLES;
 import static org.lwjgl.opengl.GL11.GL_UNSIGNED_BYTE;
+import static org.lwjgl.opengl.GL11.GL_UNSIGNED_INT;
 import static org.lwjgl.opengl.GL11.GL_VIEWPORT;
 import static org.lwjgl.opengl.GL11.glGetFloat;
 import static org.lwjgl.opengl.GL11.glGetInteger;
@@ -420,17 +421,20 @@ public class NeoRenderer {
         
         glBindBuffer(GL_ARRAY_BUFFER, mem.VBO);
         
-        int stride = 7 * 4;
+        int stride = MeshQuad.getStride();
         
         glVertexAttribPointer(0, 3, GL_FLOAT, false, stride, 0);
         glVertexAttribPointer(1, 2, GL_FLOAT, false, stride, 3 * 4);
         glVertexAttribPointer(2, 2, GL_SHORT, false, stride, 5 * 4);
         glVertexAttribPointer(3, 4, GL_UNSIGNED_BYTE, false, stride, 6 * 4);
+        glVertexAttribPointer(4, 4, GL_UNSIGNED_BYTE, false, stride, 7 * 4);
+        // we only need 2 bytes for attribute 4, but GL freaks out if the stride isn't a multiple of 4, so we have 2 unused bytes
         
         glEnableVertexAttribArray(0);
         glEnableVertexAttribArray(1);
         glEnableVertexAttribArray(2);
         glEnableVertexAttribArray(3);
+        glEnableVertexAttribArray(4);
         
         for(int i = 0; i < 2; i++) {
             piFirst[i] = BufferUtils.createIntBuffer(MAX_MESHES);
diff --git a/src/main/java/makamys/neodymium/util/BufferWriter.java b/src/main/java/makamys/neodymium/util/BufferWriter.java
index 901f5dc..617bd7a 100644
--- a/src/main/java/makamys/neodymium/util/BufferWriter.java
+++ b/src/main/java/makamys/neodymium/util/BufferWriter.java
@@ -43,4 +43,14 @@ public class BufferWriter {
         incrementPosition(4);
     }
     
+    public void writeByte(byte x) {
+        buf.put(x); // this increments the buffer position by 1
+        
+        incrementPosition(0);
+    }
+    
+    public int position() {
+        return buf.position();
+    }
+    
 }
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