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

//

//  File: Plasma.m

//

//  Abstract: Plasma GLSL Exhibit

//           

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

//

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

#import "Plasma.h"

@implementation Plasma

- (void) initPalette

{

    GLfloat   palette[512][3];

    GLfloat   x[3];

    GLint     i;

    for (i=0; i< 256;i++)

    {

        x[0] = (GLfloat)i;

        x[1] = 3.1415 * x[0];

        x[2] = x[1] / 256.0;

        palette[i][0] = 1.0f - sin(x[2]);

        palette[i][1] = (128.0f + 128.0f * sin(x[1] / 128.0))/384.0f;

        palette[i][2] = sin(x[2]);

    } // for

    glActiveTexture(GL_TEXTURE1);

    glGenTextures(1, &paletteID);

    glBindTexture(GL_TEXTURE_1D, paletteID);

    glTexImage1D(GL_TEXTURE_1D, 0, GL_RGBA, 256, 0, GL_RGB, GL_FLOAT, palette);

    glTexParameteri(GL_TEXTURE_1D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);

    glTexParameteri(GL_TEXTURE_1D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);

} // initPalette

- (void) initPattern

{

    GLfloat  *pattern;

    GLfloat   f;

    GLfloat   x;

    GLfloat   y;

    GLsizei   size   = 128;

    GLsizei   width  = size;

    GLsizei   height = size;

    GLint     i;

    GLint     j;

    GLint     l;

    GLint     m;

    GLint     n;

    glActiveTexture(GL_TEXTURE0);

    glGenTextures(1, &patternID);

    glBindTexture(GL_TEXTURE_2D, patternID);

    // Create the pattern texture, use symmetry to get rid of the seams

    pattern = (GLfloat *)malloc(sizeof(GLfloat) * width * height * 3);

    if ( pattern != NULL )

    {

        for (i = 0; i < 64; i++)

        {

            y = (GLfloat)i;

            for (j=0; j< 64; j++)

            {

                x = (GLfloat) j;

                f = 0.25*(sin(x/16.0) + sin(y/16.0) + sin((x+y)/16.0) + sin(sqrtf(x*x+y*y)/8.0));

                l = i * size;

                m = ( 127 - i ) * size;

                n = 127 - j;

                pattern[l+j] = f;

                pattern[l+n] = f;

                pattern[m+j] = f;

                pattern[m+n] = f;

            } // for

        } // for

        glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_LUMINANCE, GL_FLOAT, pattern);

        free( pattern );

    } // if

} // initPattern

- (void) setupUniforms

{

    glUseProgramObjectARB(programObject);

    // Create the palette

    [self initPalette];

    // Create the plasma pattern

    [self initPattern];

    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);

    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);

    glUniform3fARB([self getUniformLocation:programObject uniformName:"LightPosition"], 0.0, 0.0, 20.0);

    offsetUniform = [self getUniformLocation:programObject uniformName:"offset"];

    // Set the texture units for the samplers

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

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

} // setupUniforms

- (void) initLazy

{

    [super initLazy];

    // Setup GLSL

    // Here we get a new model

    model = [[Models alloc] init];

    // Load vertex and fragment shaders

    [self loadShadersFromResource:@"Plasma" ];

    // Setup uniforms

    [self setupUniforms];

} // initLazy

- (void) dealloc

{

    glDeleteTextures(1, &patternID);

    glDeleteTextures(1, &paletteID);

    [model dealloc];

    [super dealloc];

} // dealloc

- (NSString *) name

{

    return @"Plasma";

} // name

- (NSString *) descriptionFilename

{

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

} // descriptionFilename

- (void) updateOffset

{

    offset += 1.0/256.0;

    if (offset > 1.0)

    {

        offset = 0;

    } // if

} // updateOffset

- (void) renderFrame

{

    [super renderFrame];

    glUseProgramObjectARB(programObject);

    glActiveTexture(GL_TEXTURE1);

    glBindTexture(GL_TEXTURE_1D, paletteID);

    glActiveTexture(GL_TEXTURE0);

    glBindTexture(GL_TEXTURE_2D, patternID);

    glUniform1fvARB(offsetUniform, 1,&offset);

    [self updateOffset];

    [model drawModel:kModelSolidTeapot];

    glUseProgramObjectARB(NULL);

} // renderFrame

@end