//

// Copyright (c) 2014 The ANGLE Project Authors. All rights reserved.

// Use of this source code is governed by a BSD-style license that can be

// found in the LICENSE file.

//

// Based on Simple_VertexShader.c from

// Book: OpenGL(R) ES 2.0 Programming Guide

// Authors: Aaftab Munshi, Dan Ginsburg, Dave Shreiner

// ISBN-10: 0321502795

// ISBN-13: 9780321502797

// Publisher: Addison-Wesley Professional

// URLs: http://safari.informit.com/9780321563835

// http://www.opengles-book.com

#include "SampleApplication.h"

#include "shader_utils.h"

#include "texture_utils.h"

#include "geometry_utils.h"

#include "Vector.h"

#include "Matrix.h"

#include <cmath>

#include <iostream>

class PostSubBufferSample : public SampleApplication

{

public:

PostSubBufferSample()

: SampleApplication("PostSubBuffer", 1280, 720)

{

}

virtual bool initialize()

{

mPostSubBufferNV = (PFNEGLPOSTSUBBUFFERNVPROC)eglGetProcAddress("eglPostSubBufferNV");

if (!mPostSubBufferNV)

{

std::cerr << "Could not load eglPostSubBufferNV.";

return false;

}

const std::string vs = SHADER_SOURCE

(

uniform mat4 u_mvpMatrix;

attribute vec4 a_position;

attribute vec2 a_texcoord;

varying vec2 v_texcoord;

void main()

{

gl_Position = u_mvpMatrix * a_position;

v_texcoord = a_texcoord;

}

);

const std::string fs = SHADER_SOURCE

(

precision mediump float;

varying vec2 v_texcoord;

void main()

{

gl_FragColor = vec4(v_texcoord.x, v_texcoord.y, 1.0, 1.0);

}

);

mProgram = CompileProgram(vs, fs);

if (!mProgram)

{

return false;

}

// Get the attribute locations

mPositionLoc = glGetAttribLocation(mProgram, "a_position");

mTexcoordLoc = glGetAttribLocation(mProgram, "a_texcoord");

// Get the uniform locations

mMVPMatrixLoc = glGetUniformLocation(mProgram, "u_mvpMatrix");

// Generate the geometry data

GenerateCubeGeometry(0.5f, &mCube);

// Set an initial rotation

mRotation = 45.0f;

// Clear the whole window surface to blue.

glClearColor(0.0f, 0.0f, 1.0f, 0.0f);

glClear(GL_COLOR_BUFFER_BIT);

SampleApplication::swap();

glClearColor(0.0f, 0.0f, 0.0f, 0.0f);

glCullFace(GL_BACK);

glEnable(GL_CULL_FACE);

return true;

}

virtual void destroy()

{

glDeleteProgram(mProgram);

}

virtual void step(float dt, double totalTime)

{

mRotation = fmod(mRotation + (dt * 40.0f), 360.0f);

Matrix4 perspectiveMatrix = Matrix4::perspective(60.0f, float(getWindow()->getWidth()) / getWindow()->getHeight(),

1.0f, 20.0f);

Matrix4 modelMatrix = Matrix4::translate(Vector3(0.0f, 0.0f, -2.0f)) *

Matrix4::rotate(mRotation, Vector3(1.0f, 0.0f, 1.0f));

Matrix4 viewMatrix = Matrix4::identity();

Matrix4 mvpMatrix = perspectiveMatrix * viewMatrix * modelMatrix;

// Load the matrices

glUniformMatrix4fv(mMVPMatrixLoc, 1, GL_FALSE, mvpMatrix.data);

}

virtual void draw()

{

// Set the viewport

glViewport(0, 0, getWindow()->getWidth(), getWindow()->getHeight());

// Clear the color buffer

glClear(GL_COLOR_BUFFER_BIT);

// Use the program object

glUseProgram(mProgram);

// Load the vertex position

glVertexAttribPointer(mPositionLoc, 3, GL_FLOAT, GL_FALSE, 0, mCube.positions.data());

glEnableVertexAttribArray(mPositionLoc);

// Load the texcoord data

glVertexAttribPointer(mTexcoordLoc, 2, GL_FLOAT, GL_FALSE, 0, mCube.texcoords.data());

glEnableVertexAttribArray(mTexcoordLoc);

// Draw the cube

glDrawElements(GL_TRIANGLES, static_cast<GLsizei>(mCube.indices.size()), GL_UNSIGNED_SHORT,

mCube.indices.data());

}

virtual void swap()

{

// Instead of letting the application call eglSwapBuffers, call eglPostSubBufferNV here instead

EGLint windowWidth = static_cast<EGLint>(getWindow()->getWidth());

EGLint windowHeight = static_cast<EGLint>(getWindow()->getHeight());

EGLDisplay display = getDisplay();

EGLSurface surface = getSurface();

mPostSubBufferNV(display, surface, 60, 60, windowWidth - 120, windowHeight - 120);

}

private:

// Handle to a program object

GLuint mProgram;

// Attribute locations

GLint mPositionLoc;

GLint mTexcoordLoc;

// Uniform locations

GLuint mMVPMatrixLoc;

// Current rotation

float mRotation;

// Geometry data

CubeGeometry mCube;

// eglPostSubBufferNV entry point

PFNEGLPOSTSUBBUFFERNVPROC mPostSubBufferNV;

};

int main(int argc, char **argv)

{

PostSubBufferSample app;

return app.run();

}