Texture loading with GLKTextureLoader

//
//  GameController.m
//
//  Created by Sidharth Juyal on 13/01/12.
//  Copyright (c) 2012 whackylabs. All rights reserved.
//

#import "GameController.h"
#import "Scene.h"
#import "GameScene.h"
//#import "ResourceManager.h"

@implementation GameController
-(void)dealloc{
    free(data);
    [context_ release];
    [super dealloc];
}

- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
    self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
    if (self) {
        self.preferredFramesPerSecond = 30;
        data = nil;
    }
    return self;
}

-(void)loadView{
    [super loadView];

    context_ = [[EAGLContext alloc] initWithAPI:kEAGLRenderingAPIOpenGLES2];
//  GameScene *scene = [[GameScene alloc] initWithFrame:[[UIScreen mainScreen]bounds] context:context_];
//  [self setView:scene];
//  [scene release];


    [(GLKView *)self.view setContext:context_];
    [(GLKView *)self.view setDelegate:self];

}

- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation{
    return (interfaceOrientation == UIInterfaceOrientationLandscapeRight);
}

-(void)loadData{
    data = (UserData *)malloc(sizeof(UserData));

    glClearColor(131.0f/255.0f, 151.0f/255.0f, 188.0f/255.0f, 1.0f);
    CGSize winSz = self.view.bounds.size;
    glViewport(0, 0, (GLsizei)winSz.width, (GLsizei)winSz.height);

    //build shader
    GLuint vShader = [self buildShaderType:GL_VERTEX_SHADER path:[[NSBundle mainBundle] pathForResource:@"texture" ofType:@"vsh"]];
    GLuint fShader = [self buildShaderType:GL_FRAGMENT_SHADER path:[[NSBundle mainBundle]pathForResource:@"texture" ofType:@"fsh"]];
    [self compileProgramForVertexShader:vShader fragShader:fShader];

    data->positionLoc = glGetAttribLocation ( data->programObject, "a_position" );
    data->texCoordLoc = glGetAttribLocation ( data->programObject, "a_texCoord" );

    // Get the sampler location
    data->samplerLoc = glGetUniformLocation ( data->programObject, "s_texture" );
    data->textureId = 0;
}

-(void)update{
    //[(GameScene *)self.view update:self.timeSinceLastUpdate];
    if(!data)
        [self loadData];

    [(GLKView *)self.view setNeedsDisplay];
}


-(void)glkView:(GLKView *)view drawInRect:(CGRect)rect{

    if(!data)
        [self loadData];

    GLfloat vVertices[] = { -0.5f,  0.5f, 0.0f,  // Position 0
        0.0f,  0.0f,        // TexCoord 0
        -0.5f, -0.5f, 0.0f,  // Position 1
        0.0f,  1.0f,        // TexCoord 1
        0.5f, -0.5f, 0.0f,  // Position 2
        1.0f,  1.0f,        // TexCoord 2
        0.5f,  0.5f, 0.0f,  // Position 3
        1.0f,  0.0f         // TexCoord 3
    };
    GLushort indices[] = { 0, 1, 2, 0, 2, 3 };

    // Load the vertex position
    glVertexAttribPointer ( data->positionLoc, 3, GL_FLOAT, GL_FALSE, 5 * sizeof(GLfloat), vVertices );
    // Load the texture coordinate
    glVertexAttribPointer ( data->texCoordLoc, 2, GL_FLOAT, GL_FALSE, 5 * sizeof(GLfloat), &vVertices[3] );
    glEnableVertexAttribArray ( data->positionLoc );
    glEnableVertexAttribArray ( data->texCoordLoc );
    // Bind the texture
    if(data->textureId == 0){
        data->textureId = [[GLKTextureLoader textureWithCGImage:[[UIImage imageNamed:@"Tree Short.png"]CGImage] options:nil error:nil] name];
    }
    glActiveTexture ( GL_TEXTURE0 );
    glBindTexture ( GL_TEXTURE_2D, data->textureId );
    // Set the sampler texture unit to 0
    glUniform1i ( data->samplerLoc, 0 );
    glDrawElements ( GL_TRIANGLES, 6, GL_UNSIGNED_SHORT, indices );

}

#pragma mark - Build Shader -
-(void)compileProgramForVertexShader:(GLuint)vShader fragShader:(GLuint)fShader{
    NSLog(@"compiling shaders");
    data->programObject = glCreateProgram();
    glAttachShader(data->programObject, vShader);
    glAttachShader(data->programObject, fShader);
    glLinkProgram(data->programObject);

    GLint logLength;
    glGetProgramiv(data->programObject, GL_INFO_LOG_LENGTH, &logLength);
    if (logLength > 0)
    {
        GLchar *log = (GLchar *)malloc(logLength);
        glGetProgramInfoLog(data->programObject, logLength, &logLength, log);
        NSLog(@"Program link log:\n%s", log);
        free(log);
    }

    GLint status;
    glGetProgramiv(data->programObject, GL_LINK_STATUS, &status);
    if (status == GL_FALSE)
        NSLog(@"Failed to link program %d", data->programObject);

    glUseProgram(data->programObject);
}

-(GLuint)buildShaderType:(GLenum)shaderType path:(NSString *)path{
    NSError *error = nil;
    NSString *shaderStr = [NSString stringWithContentsOfFile:path encoding:NSUTF8StringEncoding error:&error];
    if(error)
        NSLog(@"shader string invalid: %@",[error debugDescription]);
    const GLchar *shaderStrPtr = (GLchar *)[shaderStr UTF8String];
    GLint len = (GLint)[shaderStr length];
    GLuint shader = glCreateShader(shaderType);
    glShaderSource(shader, 1, &shaderStrPtr, &len);
    glCompileShader(shader);

    GLint logLength;
    glGetShaderiv(shader, GL_INFO_LOG_LENGTH, &logLength);
    if (logLength > 0)
    {
        GLchar *log = (GLchar *)malloc(logLength);
        glGetShaderInfoLog(shader, logLength, &logLength, log);
        NSLog(@"Shader compile log:\n%s", log);
        free(log);
    }

    GLint status;
    glGetShaderiv(shader, GL_COMPILE_STATUS, &status);
    if (status == GL_FALSE){
        NSLog(@"Failed to compile shader:\n");
    }

    return shader;
}

@end