From b83603cd8f3a6f773ba29876f6d4ddd6d4140cc5 Mon Sep 17 00:00:00 2001
From: shadowislord <shadowislord@gmail.com>
Date: Fri, 7 Nov 2014 21:04:55 -0500
Subject: [PATCH] Added support for ETC1 compression (regular OGL only for now)

---
 jme3-core/src/main/java/com/jme3/renderer/Caps.java  |  7 ++++++-
 jme3-core/src/main/java/com/jme3/texture/Image.java  |  9 ++++++++-
 .../java/com/jme3/renderer/lwjgl/LwjglRenderer.java  |  7 +++++++
 .../java/com/jme3/renderer/lwjgl/TextureUtil.java    | 12 +++++++++++-
 4 files changed, 32 insertions(+), 3 deletions(-)

diff --git a/jme3-core/src/main/java/com/jme3/renderer/Caps.java b/jme3-core/src/main/java/com/jme3/renderer/Caps.java
index d4a7ae79e..f698859d2 100644
--- a/jme3-core/src/main/java/com/jme3/renderer/Caps.java
+++ b/jme3-core/src/main/java/com/jme3/renderer/Caps.java
@@ -251,7 +251,12 @@ public enum Caps {
     /**
      * Supports anisotropic texture filtering.
      */
-    TextureFilterAnisotropic;
+    TextureFilterAnisotropic,
+    
+    /**
+     * Supports {@link Format#ETC1} texture compression.
+     */
+    TextureCompressionETC1;
 
     /**
      * Returns true if given the renderer capabilities, the texture
diff --git a/jme3-core/src/main/java/com/jme3/texture/Image.java b/jme3-core/src/main/java/com/jme3/texture/Image.java
index 42cbdfb10..3916d1800 100644
--- a/jme3-core/src/main/java/com/jme3/texture/Image.java
+++ b/jme3-core/src/main/java/com/jme3/texture/Image.java
@@ -317,7 +317,14 @@ public class Image extends NativeObject implements Savable /*, Cloneable*/ {
          * It is also a required format, so you can count on it
          * being present.
          */
-        RGB10_A2(32, false);
+        RGB10_A2(32, false),
+        
+        /**
+         * Ericsson Texture Compression. Typically used on Android.
+         * 
+         * Requires {@link Caps#TextureCompressionETC1}.
+         */
+        ETC1(4, false, true, false);
 
         private int bpp;
         private boolean isDepth;
diff --git a/jme3-lwjgl/src/main/java/com/jme3/renderer/lwjgl/LwjglRenderer.java b/jme3-lwjgl/src/main/java/com/jme3/renderer/lwjgl/LwjglRenderer.java
index 3d0e580d0..2c53f2a37 100644
--- a/jme3-lwjgl/src/main/java/com/jme3/renderer/lwjgl/LwjglRenderer.java
+++ b/jme3-lwjgl/src/main/java/com/jme3/renderer/lwjgl/LwjglRenderer.java
@@ -356,6 +356,10 @@ public class LwjglRenderer implements Renderer {
         if (hasExtension("GL_EXT_texture_compression_latc")) {
             caps.add(Caps.TextureCompressionLATC);
         }
+        
+        if (hasExtension("GL_ARB_ES3_compatibility")) {
+            caps.add(Caps.TextureCompressionETC1);
+        }
 
         if (hasExtension("GL_EXT_packed_float") || caps.contains(Caps.OpenGL30)) {
             // This format is part of the OGL3 specification
@@ -2208,6 +2212,9 @@ public class LwjglRenderer implements Renderer {
                     throw new UnsupportedOperationException("Unknown buffer format.");
             }
         } else {
+            // Invalidate buffer data (orphan) before uploading new data.
+            
+            
             switch (vb.getFormat()) {
                 case Byte:
                 case UnsignedByte:
diff --git a/jme3-lwjgl/src/main/java/com/jme3/renderer/lwjgl/TextureUtil.java b/jme3-lwjgl/src/main/java/com/jme3/renderer/lwjgl/TextureUtil.java
index 2eca2a06b..b9855a144 100644
--- a/jme3-lwjgl/src/main/java/com/jme3/renderer/lwjgl/TextureUtil.java
+++ b/jme3-lwjgl/src/main/java/com/jme3/renderer/lwjgl/TextureUtil.java
@@ -42,10 +42,10 @@ import java.util.EnumSet;
 import java.util.logging.Level;
 import java.util.logging.Logger;
 import static org.lwjgl.opengl.ARBDepthBufferFloat.*;
+import org.lwjgl.opengl.ARBES3Compatibility;
 import static org.lwjgl.opengl.ARBHalfFloatPixel.*;
 import static org.lwjgl.opengl.ARBTextureFloat.*;
 import static org.lwjgl.opengl.ARBTextureMultisample.*;
-import org.lwjgl.opengl.ContextCapabilities;
 import static org.lwjgl.opengl.EXTPackedDepthStencil.*;
 import static org.lwjgl.opengl.EXTPackedFloat.*;
 import static org.lwjgl.opengl.EXTTextureArray.*;
@@ -142,6 +142,11 @@ class TextureUtil {
         // LTC/LATC/3Dc formats
         setFormat(Format.LTC,  GL_COMPRESSED_LUMINANCE_LATC1_EXT,       GL_LUMINANCE,       GL_UNSIGNED_BYTE, true);
         setFormat(Format.LATC, GL_COMPRESSED_LUMINANCE_ALPHA_LATC2_EXT, GL_LUMINANCE_ALPHA, GL_UNSIGNED_BYTE, true);
+        
+        // ETC1 support on regular OpenGL requires ES3 compatibility extension.
+        // NOTE: ETC2 is backwards compatible with ETC1, so we can 
+        // upload ETC1 textures as ETC2.
+        setFormat(Format.ETC1, ARBES3Compatibility.GL_COMPRESSED_RGB8_ETC2, GL_RGB, GL_UNSIGNED_BYTE, true);
     }
     
     //sRGB formats        
@@ -160,6 +165,11 @@ class TextureUtil {
 
     public static GLImageFormat getImageFormat(EnumSet<Caps> caps, Format fmt, boolean isSrgb){
         switch (fmt){
+            case ETC1:
+                if (!caps.contains(Caps.TextureCompressionETC1)) {
+                    return null;
+                }
+                break;
             case DXT1:
             case DXT1A:
             case DXT3: