Significantly improved performance

I went back to a much simpler traversal algorithm that generates pages
immediately, and fixed texture loading to occur in a separate thread. I
still need to set the initial texture of a new page to the texture of
the parent to avoid the loading flicker.

Source/RAGeometry.h

@@ -20,7 +20,8 @@
 @property (assign, nonatomic) NSInteger colorOffset;    // GLFloat r, g, b, a
 @property (assign, nonatomic) NSInteger textureOffset;  // GLFloat s, t
 
-@property (strong, nonatomic) RATextureWrapper * texture;
+@property (strong, nonatomic) RATextureWrapper * texture0;
+@property (strong, nonatomic) RATextureWrapper * texture1;
 @property (assign, nonatomic) GLKVector4 color;         // set 1st component to -1 to disable
 @property (retain, nonatomic) GLKEffectPropertyMaterial * material;
 @property (assign, nonatomic) GLenum elementStyle;      // default: GL_TRIANGLES

Source/RAGeometry.m

@@ -33,13 +33,15 @@ @implementation RAGeometry {
 
     NSMutableData * _indexData;
     GLint           _indexStride;
+
+    BOOL            _needsSetup;
 }
 
 @synthesize positionOffset = _positionOffset;
 @synthesize normalOffset = _normalOffset;
 @synthesize colorOffset = _colorOffset;
 @synthesize textureOffset = _textureOffset;
-@synthesize texture = _texture;
+@synthesize texture0 = _texture0, texture1 = _texture1;
 @synthesize color = _color;
 @synthesize material = _material;
 @synthesize elementStyle = _elementStyle;
@@ -63,6 +65,8 @@ - (id)init
 
         _color = GLKVector4Make(-1, -1, -1, -1);
         _elementStyle = GL_TRIANGLES;
+
+        _needsSetup = YES;
     }
     return self;
 }
@@ -144,6 +148,8 @@ - (void)setIndexData:(const void *)data withSize:(NSUInteger)length withStride:(
 
 - (void)setupGL
 {
+    if ( _needsSetup == NO ) return;
+
     // create vertex array if needed
     if ( _vertexArray == BUFFER_INVALID ) {
         glGenVertexArraysOES(1, &_vertexArray);
@@ -184,11 +190,16 @@ - (void)setupGL
         glVertexAttribPointer(GLKVertexAttribColor, 4, GL_FLOAT, GL_FALSE, _vertexStride, (const GLvoid *)_colorOffset);
     }
 
-    if ( _textureOffset >= 0 ) {
+    if ( _textureOffset >= 0 && _texture0 ) {
         glEnableVertexAttribArray(GLKVertexAttribTexCoord0);
         glVertexAttribPointer(GLKVertexAttribTexCoord0, 2, GL_FLOAT, GL_FALSE, _vertexStride, (const GLvoid *)_textureOffset);
     }
 
+    if ( _textureOffset >= 0 && _texture1 ) {
+        glEnableVertexAttribArray(GLKVertexAttribTexCoord1);
+        glVertexAttribPointer(GLKVertexAttribTexCoord1, 2, GL_FLOAT, GL_FALSE, _vertexStride, (const GLvoid *)_textureOffset);
+    }
+
     glBindVertexArrayOES(0);
 }
 
@@ -201,6 +212,8 @@ - (void)releaseGL
     _vertexBuffer = BUFFER_INVALID;
     _indexBuffer = BUFFER_INVALID;
     _vertexArray = BUFFER_INVALID;
+
+    _needsSetup = YES;
 }
 
 - (void)renderGL

Source/RAPage.h

@@ -29,8 +29,6 @@
 @property (strong) RAGeometry * geometry;
 @property (strong) UIImage * image;
 
-@property (weak) NSOperation * buildOp;
-@property (assign) BOOL needsUpdate;
 @property (assign) NSTimeInterval lastRequestTime;
 
 - (RAPage *)initWithTileID:(TileID)t andParent:(RAPage *)parent;
@@ -41,7 +39,4 @@
 
 - (void)setCenter:(GLKVector3)center andRadius:(double)radius;
 
-- (void)setupGL;
-- (void)releaseGL;
-
 @end

Source/RAPage.m

@@ -24,7 +24,7 @@ @implementation RAPage {
 @synthesize geometry = _geometry;
 @synthesize image = _image;
 @synthesize parent = _parent, child1, child2, child3, child4;
-@synthesize buildOp, needsUpdate, lastRequestTime;
+@synthesize lastRequestTime;
 
 - (RAPage *)initWithTileID:(TileID)t andParent:(RAPage *)parent;
 {
@@ -65,30 +65,4 @@ - (BOOL)isLeaf {
     return ( child1 == nil && child2 == nil && child3 == nil && child4 == nil );
 }
 
-- (void)setupGL {
-    if ( self.needsUpdate == NO ) return;
-
-    // create texture
-    GLKTextureInfo * textureInfo = nil;
-    if ( _image ) {
-        NSError * err = nil;
-        NSDictionary * options = [NSDictionary dictionaryWithObject:[NSNumber numberWithBool:YES] forKey:GLKTextureLoaderOriginBottomLeft];
-        textureInfo = [GLKTextureLoader textureWithCGImage:[_image CGImage] options:options error:&err];
-        if ( err ) NSLog(@"Error loading texture: %@", err);
-
-        self.geometry.texture = [[RATextureWrapper alloc] initWithTextureInfo:textureInfo];
-    } /*else {
-        NSLog(@"No image available for tile %@.", key);
-    }*/
-
-    self.needsUpdate = NO;
-}
-
-- (void)releaseGL {
-    [self.geometry releaseGL];
-
-    // release texture
-    self.needsUpdate = YES;
-}
-
 @end

Source/RARenderVisitor.m

@@ -89,16 +89,24 @@ - (void)renderWithEffect:(GLKBaseEffect *)effect
         effect.useConstantColor = child.geometry.color.x > -1;
         effect.constantColor = child.geometry.color;
 
-        if (child.geometry.texture != nil) {
+        if (child.geometry.texture0 != nil) {
             effect.texture2d0.envMode = GLKTextureEnvModeModulate;
             effect.texture2d0.target = GLKTextureTarget2D;
-            effect.texture2d0.name = child.geometry.texture.name;
+            effect.texture2d0.name = child.geometry.texture0.name;
             effect.texture2d0.enabled = YES;
         } else {
-            effect.texture2d0.name = child.geometry.texture.name;
             effect.texture2d0.enabled = NO;
         }
-
+
+        if (child.geometry.texture1 != nil) {
+            effect.texture2d1.envMode = GLKTextureEnvModeModulate;
+            effect.texture2d1.target = GLKTextureTarget2D;
+            effect.texture2d1.name = child.geometry.texture1.name;
+            effect.texture2d1.enabled = YES;
+        } else {
+            effect.texture2d1.enabled = NO;
+        }
+
         [effect prepareToDraw];
         [child.geometry renderGL];
     }];

Source/RASceneGraphController.m

@@ -115,6 +115,9 @@ - (void)viewDidLoad
 
     manipulator.view = self.view;
 
+    // create another context to load textures into
+    pager.loadingContext = [[EAGLContext alloc] initWithAPI:kEAGLRenderingAPIOpenGLES2 sharegroup:[context sharegroup]];
+
     [self setupGL];
 }
 

Source/RATilePager.h

@@ -8,7 +8,7 @@
 
 #import <Foundation/Foundation.h>
 
-#import <GLKit/GLKMathTypes.h>
+#import <GLKit/GLKit.h>
 
 #import "RATileDatabase.h"
 #import "RAGeographicUtils.h"
@@ -20,6 +20,7 @@
 @interface RATilePager : NSObject
 
 @property (strong) RATileDatabase * database;
+@property (strong) EAGLContext * loadingContext;
 
 @property (readonly) RAGroup * nodes;
 @property (readonly) NSSet * rootPages;