Cinder ES2 Sample

ESTwoApp.cpp

#include "cinder/app/AppCocoaTouch.h"
#include "cinder/Camera.h"
#include "cinder/gl/GlslProg.h"

using namespace ci;
using namespace ci::app;
using namespace std;

class ESTwoApp : public AppCocoaTouch {
  public:
	virtual void	setup();
	virtual void	draw();
	
	Matrix44f		mModelView;
	Matrix44f		mProjection;
private:
	gl::GlslProg	mPassthrough;
	GLuint			mTriangleId;
};

void ESTwoApp::setup()
{
	try
	{
		mPassthrough = gl::GlslProg( loadResource("res/passthrough_vert.glsl"), loadResource("res/passthrough_frag.glsl") );
	} catch ( gl::GlslProgCompileExc &exc )
	{
		console() << "Failed to load shader: " << exc.what() << endl;
	}
	
	// create a triangle and store it on the GPU
	GLfloat positions[] = { 	0, 1.0f, 0.0f,
								-1.0f, -1.0f, 0.0f,
								1.0f, -1.0f, 0.0f };
	glGenBuffers( 1, &mTriangleId );
	glBindBuffer( GL_ARRAY_BUFFER, mTriangleId );
	glBufferData( GL_ARRAY_BUFFER, 9 * sizeof(GLfloat), positions, GL_STATIC_DRAW );
	glBindBuffer( GL_ARRAY_BUFFER, 0 );
	
	// spit out locations of things on GPU to make sure they exist
	console() << "Triangle buffer: " << mTriangleId << endl;
	console() << "Positions attrib: " << mPassthrough.getAttribLocation("positions") << endl;
	console() << "Projection Matrix: " << mPassthrough.getUniformLocation("pMatrix") << endl;
	
	mProjection.setToIdentity();
	mModelView.setToIdentity();
}

void ESTwoApp::draw()
{
	gl::setViewport( getWindowBounds() );
	gl::clear( Color( 0.0f, 0.0f, 1.0f ) );
	gl::enableDepthRead();

	mPassthrough.bind();
	mPassthrough.uniform( "mvMatrix", mModelView );
	mPassthrough.uniform( "pMatrix", mProjection );
	glEnableVertexAttribArray( mPassthrough.getAttribLocation("positions") );
	// bind buffer and attribpointer specify what buffer (bound) goes where (pointer)
	glBindBuffer( GL_ARRAY_BUFFER, mTriangleId );
	glVertexAttribPointer( mPassthrough.getAttribLocation("positions"), 3, GL_FLOAT, false, 0, 0);
	glDrawArrays( GL_TRIANGLES, 0, 3 );
	
	glDisableVertexAttribArray( mTriangleId );
}

CINDER_APP_COCOA_TOUCH( ESTwoApp, RendererGl )

gistfile1.txt

attribute vec3 positions;

uniform mat4 pMatrix;
uniform mat4 mvMatrix;

void main()
{
	gl_Position = pMatrix * mvMatrix * vec4(positions, 1.0);
}

passthrough_frag.glsl

void main(void)
{
	gl_FragColor = vec4(1.0, 0.0, 0.0, 1.0);
}

This gist relies on notlion's es2 branch of Cinder, available here:
https://github.com/notlion/Cinder/tree/es2