//-------------------------------------------------------------------------

//

//  File: Fur.m

//

//  Abstract: Fur GLSL Exhibit

//           

//  Author: "OpenGL Shading Language" book. (a.k.a "the orange book")

//

//  Disclaimer: IMPORTANT:  This Apple software is supplied to you by

//  Apple Inc. ("Apple") in consideration of your agreement to the

//  following terms, and your use, installation, modification or

//  redistribution of this Apple software constitutes acceptance of these

//  terms.  If you do not agree with these terms, please do not use,

//  install, modify or redistribute this Apple software.

//  

//  In consideration of your agreement to abide by the following terms, and

//  subject to these terms, Apple grants you a personal, non-exclusive

//  license, under Apple's copyrights in this original Apple software (the

//  "Apple Software"), to use, reproduce, modify and redistribute the Apple

//  Software, with or without modifications, in source and/or binary forms;

//  provided that if you redistribute the Apple Software in its entirety and

//  without modifications, you must retain this notice and the following

//  text and disclaimers in all such redistributions of the Apple Software. 

//  Neither the name, trademarks, service marks or logos of Apple Inc.

//  may be used to endorse or promote products derived from the Apple

//  Software without specific prior written permission from Apple.  Except

//  as expressly stated in this notice, no other rights or licenses, express

//  or implied, are granted by Apple herein, including but not limited to

//  any patent rights that may be infringed by your derivative works or by

//  other works in which the Apple Software may be incorporated.

//  

//  The Apple Software is provided by Apple on an "AS IS" basis.  APPLE

//  MAKES NO WARRANTIES, EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION

//  THE IMPLIED WARRANTIES OF NON-INFRINGEMENT, MERCHANTABILITY AND FITNESS

//  FOR A PARTICULAR PURPOSE, REGARDING THE APPLE SOFTWARE OR ITS USE AND

//  OPERATION ALONE OR IN COMBINATION WITH YOUR PRODUCTS.

//  

//  IN NO EVENT SHALL APPLE BE LIABLE FOR ANY SPECIAL, INDIRECT, INCIDENTAL

//  OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF

//  SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS

//  INTERRUPTION) ARISING IN ANY WAY OUT OF THE USE, REPRODUCTION,

//  MODIFICATION AND/OR DISTRIBUTION OF THE APPLE SOFTWARE, HOWEVER CAUSED

//  AND WHETHER UNDER THEORY OF CONTRACT, TORT (INCLUDING NEGLIGENCE),

//  STRICT LIABILITY OR OTHERWISE, EVEN IF APPLE HAS BEEN ADVISED OF THE

//  POSSIBILITY OF SUCH DAMAGE.

// 

//  Copyright (c) 2004-2007 Apple Inc., All rights reserved.

//

//-------------------------------------------------------------------------

#import "Fur.h"

static const GLint    kShells            = 10;

static const GLfloat  kFurHeight         = 0.25f;

static const GLfloat  kRatio             = 40.0f; // (float)kShells / kFurHeight;

static const GLfloat  kShellTransparency = 0.3f;

@implementation Fur

- (void) getTextures

{

    noiseTexture  = [self loadTextureFromResource: @"Noise" ];

    colorTexture  = [self loadTextureFromResource: @"Leopard" ];

} // getTextures

- (void) getUniforms

{

    glUseProgramObjectARB(programObject);

    glUniform1fARB([self getUniformLocation:programObject uniformName:"ambient"], 0.2);

    glUniform3fARB([self getUniformLocation:programObject uniformName:"lightPosition"], 0.0, 0.0, 5.0);

    glUniform1fARB([self getUniformLocation:programObject uniformName:"spacing"], 1);

    glUniform1iARB([self getUniformLocation:programObject uniformName:"noiseTexture"], 0);

    glUniform1iARB([self getUniformLocation:programObject uniformName:"colorTexture"], 1);

} // getUniforms

- (void) newSolidTeapotList

{

    static BOOL teapotInited = NO;

    if( !teapotInited )

    {

        teapotInited = YES;

        solidTeapotDisplayList = glGenLists(1);

        glNewList(solidTeapotDisplayList, GL_COMPILE);

            [model drawModel:kModelSolidTeapot];

        glEndList();

    } // if

} // newSolidTeapotList

- (void) drawSolidTeapotList

{

    GLint    i;

    GLint    furHeightLoc = [self getUniformLocation:programObject uniformName:"furHeight"];

    GLfloat  v0;

    for (i = 1; i < kShells; i++)

    {

        v0 = (GLfloat)i / kRatio;

        glUniform1fARB(furHeightLoc, v0);

        glCallList(solidTeapotDisplayList);

    } // for

} // drawSolidTeapotList

- (void) initLazy

{

    [super initLazy];

    // Setup GLSL

    // Here we get a new model

    model = [[Models alloc] init];

    // get all the textures

    [self getTextures];

    // Load vertex and fragment shaders

    [self loadShadersFromResource:@"Fur" ];

    // Setup uniforms

    [self getUniforms];

    // Create a display list for the teapot (especially important with the number of

    // teapots per frame in this shell-based approach)

    [self newSolidTeapotList];

} // initLazy

- (void) dealloc

{

    glDeleteTextures(1, &noiseTexture);

    glDeleteTextures(1, &colorTexture);

    glDeleteLists(solidTeapotDisplayList, 1);

    [model dealloc];

    [super dealloc];

} // dealloc

- (NSString *) name

{

    return @"Fur";

} // name

- (NSString *) descriptionFilename

{

    return [appBundle pathForResource: @"Fur" ofType: @"rtf"];

} // descriptionFilename

- (void) renderFrameInitialSetup

{

    glDisable(GL_TEXTURE_3D);

    glDisable(GL_TEXTURE_2D);

    glEnable(GL_LIGHTING);

    glEnable(GL_LIGHT0);

} // renderFrameInitialSetup

- (void) renderFrameMoreSetup

{

    GLint transparencyLoc = 0;

    GLint furHeightLoc    = 0;

    glColor3f(0.9, 0.65, 0.4);

    glEnable(GL_COLOR_MATERIAL);

    glCallList(solidTeapotDisplayList);

    glUseProgramObjectARB(programObject);

    glColor3f(1.0, 1.0, 1.0);

    glDisable(GL_COLOR_MATERIAL);

    glActiveTexture(GL_TEXTURE0);

    glBindTexture(GL_TEXTURE_2D, noiseTexture);

    glActiveTexture(GL_TEXTURE1);

    glBindTexture(GL_TEXTURE_2D, colorTexture);

    glActiveTexture(GL_TEXTURE0);

    glEnable(GL_BLEND);

    glBlendFunc (GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);

    transparencyLoc = [self getUniformLocation:programObject uniformName:"transparency"];

    furHeightLoc    = [self getUniformLocation:programObject uniformName:"furHeight"];

    glUniform1fARB(transparencyLoc, 1);

    glUniform1fARB(furHeightLoc, 0);

    glUniform1fARB(transparencyLoc, kShellTransparency);

    glEnable(GL_CULL_FACE);

} // renderFrameMoreSetup

- (void) renderFrame

{

    [super renderFrame];

    glPushAttrib(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT | GL_ENABLE_BIT | GL_TEXTURE_BIT | GL_CURRENT_BIT);

        [self renderFrameInitialSetup];

        // Draw the skin before the fur

        [self renderFrameMoreSetup];

        [self drawSolidTeapotList];

        glUseProgramObjectARB(NULL);

    glPopAttrib();

} // renderFrame

@end