diff --git a/opengl/libagl/mipmap.cpp b/opengl/libagl/mipmap.cpp
new file mode 100644
index 0000000..ccd77b7
--- /dev/null
+++ b/opengl/libagl/mipmap.cpp
@@ -0,0 +1,192 @@
+/* libs/opengles/mipmap.cpp
+**
+** Copyright 2006, The Android Open Source Project
+**
+** Licensed under the Apache License, Version 2.0 (the "License"); 
+** you may not use this file except in compliance with the License. 
+** You may obtain a copy of the License at 
+**
+**     http://www.apache.org/licenses/LICENSE-2.0 
+**
+** Unless required by applicable law or agreed to in writing, software 
+** distributed under the License is distributed on an "AS IS" BASIS, 
+** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 
+** See the License for the specific language governing permissions and 
+** limitations under the License.
+*/
+
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "context.h"
+#include "state.h"
+#include "texture.h"
+#include "TextureObjectManager.h"
+
+namespace android {
+
+// ----------------------------------------------------------------------------
+
+status_t buildAPyramid(ogles_context_t* c, EGLTextureObject* tex)
+{
+    int level = 0;
+    const GGLSurface* base = &tex->surface;    
+    const GGLFormat& pixelFormat(c->rasterizer.formats[base->format]);
+
+    int w = base->width;
+    int h = base->height;
+    if ((w&h) == 1)
+        return NO_ERROR;
+
+    w = (w>>1) ? : 1;
+    h = (h>>1) ? : 1;
+
+    while(true) {
+        ++level;
+        const int bpr = w * pixelFormat.size;
+        if (tex->reallocate(level, w, h, w,
+                base->format, base->compressedFormat, bpr) != NO_ERROR) {
+            return NO_MEMORY;
+        }
+    
+        int stride = w;
+        int bs = base->stride;
+        GGLSurface& cur = tex->editMip(level);
+
+        if (base->format == GGL_PIXEL_FORMAT_RGB_565)
+        {
+            uint16_t const * src = (uint16_t const *)base->data;
+            uint16_t* dst = (uint16_t*)cur.data;
+            const uint32_t mask = 0x07E0F81F;
+            for (int y=0 ; y<h ; y++) {
+                size_t offset = (y*2) * bs;
+                for (int x=0 ; x<w ; x++) {
+                    uint32_t p00 = src[offset];
+                    uint32_t p10 = src[offset+1];
+                    uint32_t p01 = src[offset+bs];
+                    uint32_t p11 = src[offset+bs+1];
+                    p00 = (p00 | (p00 << 16)) & mask;
+                    p01 = (p01 | (p01 << 16)) & mask;
+                    p10 = (p10 | (p10 << 16)) & mask;
+                    p11 = (p11 | (p11 << 16)) & mask;
+                    uint32_t grb = ((p00 + p10 + p01 + p11) >> 2) & mask;
+                    uint32_t rgb = (grb & 0xFFFF) | (grb >> 16);
+                    dst[x + y*stride] = rgb;
+                    offset += 2;
+                }
+            }
+        }
+        else if (base->format == GGL_PIXEL_FORMAT_RGBA_5551)
+        {
+            uint16_t const * src = (uint16_t const *)base->data;
+            uint16_t* dst = (uint16_t*)cur.data;
+            for (int y=0 ; y<h ; y++) {
+                size_t offset = (y*2) * bs;
+                for (int x=0 ; x<w ; x++) {
+                    uint32_t p00 = src[offset];
+                    uint32_t p10 = src[offset+1];
+                    uint32_t p01 = src[offset+bs];
+                    uint32_t p11 = src[offset+bs+1];
+                    uint32_t r = ((p00>>11)+(p10>>11)+(p01>>11)+(p11>>11)+2)>>2;
+                    uint32_t g = (((p00>>6)+(p10>>6)+(p01>>6)+(p11>>6)+2)>>2)&0x3F;
+                    uint32_t b = ((p00&0x3E)+(p10&0x3E)+(p01&0x3E)+(p11&0x3E)+4)>>3;
+                    uint32_t a = ((p00&1)+(p10&1)+(p01&1)+(p11&1)+2)>>2;
+                    dst[x + y*stride] = (r<<11)|(g<<6)|(b<<1)|a;
+                    offset += 2;
+                }
+            }
+        }
+        else if (base->format == GGL_PIXEL_FORMAT_RGBA_8888)
+        {
+            uint32_t const * src = (uint32_t const *)base->data;
+            uint32_t* dst = (uint32_t*)cur.data;
+            for (int y=0 ; y<h ; y++) {
+                size_t offset = (y*2) * bs;
+                for (int x=0 ; x<w ; x++) {
+                    uint32_t p00 = src[offset];
+                    uint32_t p10 = src[offset+1];
+                    uint32_t p01 = src[offset+bs];
+                    uint32_t p11 = src[offset+bs+1];
+                    uint32_t rb00 = p00 & 0x00FF00FF;
+                    uint32_t rb01 = p01 & 0x00FF00FF;
+                    uint32_t rb10 = p10 & 0x00FF00FF;
+                    uint32_t rb11 = p11 & 0x00FF00FF;
+                    uint32_t ga00 = (p00 >> 8) & 0x00FF00FF;
+                    uint32_t ga01 = (p01 >> 8) & 0x00FF00FF;
+                    uint32_t ga10 = (p10 >> 8) & 0x00FF00FF;
+                    uint32_t ga11 = (p11 >> 8) & 0x00FF00FF;
+                    uint32_t rb = (rb00 + rb01 + rb10 + rb11)>>2;
+                    uint32_t ga = (ga00 + ga01 + ga10 + ga11)>>2;
+                    uint32_t rgba = (rb & 0x00FF00FF) | ((ga & 0x00FF00FF)<<8);
+                    dst[x + y*stride] = rgba;
+                    offset += 2;
+                }
+            }
+        }
+        else if ((base->format == GGL_PIXEL_FORMAT_RGB_888) ||
+                 (base->format == GGL_PIXEL_FORMAT_LA_88) ||
+                 (base->format == GGL_PIXEL_FORMAT_A_8) ||
+                 (base->format == GGL_PIXEL_FORMAT_L_8))
+        {
+            int skip;
+            switch (base->format) {
+            case GGL_PIXEL_FORMAT_RGB_888:  skip = 3;   break;
+            case GGL_PIXEL_FORMAT_LA_88:    skip = 2;   break;
+            default:                        skip = 1;   break;
+            }
+            uint8_t const * src = (uint8_t const *)base->data;
+            uint8_t* dst = (uint8_t*)cur.data;            
+            bs *= skip;
+            stride *= skip;
+            for (int y=0 ; y<h ; y++) {
+                size_t offset = (y*2) * bs;
+                for (int x=0 ; x<w ; x++) {
+                    for (int c=0 ; c<skip ; c++) {
+                        uint32_t p00 = src[c+offset];
+                        uint32_t p10 = src[c+offset+skip];
+                        uint32_t p01 = src[c+offset+bs];
+                        uint32_t p11 = src[c+offset+bs+skip];
+                        dst[x + y*stride + c] = (p00 + p10 + p01 + p11) >> 2;
+                    }
+                    offset += 2*skip;
+                }
+            }
+        }
+        else if (base->format == GGL_PIXEL_FORMAT_RGBA_4444)
+        {
+            uint16_t const * src = (uint16_t const *)base->data;
+            uint16_t* dst = (uint16_t*)cur.data;
+            for (int y=0 ; y<h ; y++) {
+                size_t offset = (y*2) * bs;
+                for (int x=0 ; x<w ; x++) {
+                    uint32_t p00 = src[offset];
+                    uint32_t p10 = src[offset+1];
+                    uint32_t p01 = src[offset+bs];
+                    uint32_t p11 = src[offset+bs+1];
+                    p00 = ((p00 << 12) & 0x0F0F0000) | (p00 & 0x0F0F);
+                    p10 = ((p10 << 12) & 0x0F0F0000) | (p10 & 0x0F0F);
+                    p01 = ((p01 << 12) & 0x0F0F0000) | (p01 & 0x0F0F);
+                    p11 = ((p11 << 12) & 0x0F0F0000) | (p11 & 0x0F0F);
+                    uint32_t rbga = (p00 + p10 + p01 + p11) >> 2;
+                    uint32_t rgba = (rbga & 0x0F0F) | ((rbga>>12) & 0xF0F0);
+                    dst[x + y*stride] = rgba;
+                    offset += 2;
+                }
+            }
+        } else {
+            LOGE("Unsupported format (%d)", base->format);
+            return BAD_TYPE;
+        }
+
+        // exit condition: we just processed the 1x1 LODs
+        if ((w&h) == 1)
+            break;
+
+        base = &cur;
+        w = (w>>1) ? : 1;
+        h = (h>>1) ? : 1;
+    }
+    return NO_ERROR;
+}
+
+}; // namespace android