Recreation of Openframeworks graphicsExample

C4WorkSpace.m

//
//  C4WorkSpace.m
//  Examples
//
//  Created by Travis Kirton
//

#import "C4WorkSpace.h"
#import "SquaresGL.h"

@implementation C4WorkSpace {
    C4GL *gl;
    C4Shape *circle1, *circle2;
    C4Shape *greenRect, *redRect1, *redRect2;
}

-(void)setup {
    //circles
    circle1 = [C4Shape ellipse:CGRectMake(0,0,100,100)];
    circle1.center = CGPointMake(140,420);
    circle1.lineWidth = 1.0f;
    circle1.fillColor = [UIColor clearColor];
    circle1.strokeColor = [UIColor colorWithWhite:0.7 alpha:1.0f];
    [self.canvas addShape:circle1];
    
    circle2 = [C4Shape ellipse:CGRectMake(0, 0, 70, 70)];
    circle2.center = circle1.center;
    circle2.fillColor = [UIColor orangeColor];
    circle2.lineWidth = 0.0f;
    [self.canvas addShape:circle2];
    
    //opengl
    gl = [[C4GL alloc] initWithRenderer:[SquaresGL new]];
    gl.frame = CGRectMake(0,0,80,80);
    gl.center = CGPointMake(140, 300);
    [self.canvas addGL:gl];
    
    //transparency squares
    greenRect = [C4Shape rect:CGRectMake(0, 0, 70, 70)];
    greenRect.origin = CGPointMake(100, 180);
    greenRect.fillColor = [UIColor greenColor];
    greenRect.lineWidth = 0.0f;
    [self.canvas addShape:greenRect];
    
    redRect1 = [C4Shape rect:CGRectMake(0, 0, 22, 70)];
    redRect1.fillColor = [UIColor redColor];
    redRect1.alpha = 0.0f;
    redRect1.lineWidth = 0.0f;
    redRect1.origin = CGPointMake(115, 145);
    [self.canvas addShape:redRect1];
    
    redRect2 = [C4Shape rect:CGRectMake(0, 0, 22, 70)];
    redRect2.fillColor = [[UIColor redColor] colorWithAlphaComponent:0.33];
    redRect2.lineWidth = 0.0f;
    redRect2.origin = CGPointMake(156, 145);
    [self.canvas addShape:redRect2];
    
    
    for(int i = 0; i < 20; i++) {
        CGPoint endPoints[2] = {CGPointMake(50+i*3, 100), CGPointMake(25+i*6, 0)};
        C4Shape *l = [C4Shape line:endPoints];
        l.lineWidth = 1.0f;
        [self.canvas addShape:l];
    }
    
    C4Label *label;
    label = [C4Label labelWithText:@"circle"];
    label.center = CGPointMake(160, 420);
    label.rotation = PI;
    [self.canvas addLabel:label];
}

@end

SquaresGL.h

//
//  SquaresGL.h
//  C4iOS
//
//  Created by Travis Kirton
//

#import "C4EAGLES1Renderer.h"

@interface SquaresGL : C4EAGLES1Renderer

@end

SquaresGL.m

//
//  SquaresGL.m
//  C4iOS
//
//  Created by moi on 12-08-03.
//  Copyright (c) 2012 POSTFL. All rights reserved.
//

#import "SquaresGL.h"

@implementation SquaresGL
-(void)render {
    
    [EAGLContext setCurrentContext:self.eaglContext];
    
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    //reigns in the drawing area because the layer will clip to its viewport
    glOrthof(-1.0f, 1.0f, -1.0f, 1.0f, -1.0f, 1.0f);
    glMatrixMode(GL_MODELVIEW);
    
    glBindFramebufferOES(GL_FRAMEBUFFER_OES, self.frameBuffer);
    glViewport(0, 0, self.width, self.height);
    
    glClearColor(0, 0, 0, 0);
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
    
    glEnableClientState(GL_VERTEX_ARRAY);
    
    for(int i = 0; i < 200; i ++){
        GLfloat x = ((random()%180)-100)/100.0f;
        GLfloat y = ((random()%180)-100)/100.0f;
        GLfloat w = (0.1f + (random()%10)/50.0f);
        
        GLfloat squareVertices[8] = {
            x,y,
            x+w, y,
            x,  y+w,
            x+w,  y+w,
        };
        
        GLfloat r = (random()%255)/255.0f;
        GLfloat g = (random()%255)/255.0f;
        GLfloat b = (random()%255)/255.0f;
        glColor4f(r,g,b, 1.0);
        
        glVertexPointer(2, GL_FLOAT, 0, squareVertices);
        glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
    }
    glDisableClientState(GL_VERTEX_ARRAY);
    
    glBindRenderbufferOES(GL_RENDERBUFFER_OES, self.renderBuffer);
    [self.eaglContext presentRenderbuffer:GL_RENDERBUFFER_OES];
    
    glFinish();
}
@end