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//
// Copyright 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 "texture_utils.h"
#include "util/Matrix.h"
#include "util/geometry_utils.h"
#include "util/shader_utils.h"
#include <cmath>
#include <iostream>
class PostSubBufferSample : public SampleApplication
{
public:
PostSubBufferSample(int argc, char **argv) : SampleApplication("PostSubBuffer", argc, argv) {}
bool initialize() override
{
constexpr char kVS[] = R"(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;
})";
constexpr char kFS[] = R"(precision mediump float;
varying vec2 v_texcoord;
void main()
{
gl_FragColor = vec4(v_texcoord.x, v_texcoord.y, 1.0, 1.0);
})";
mProgram = CompileProgram(kVS, kFS);
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;
}
void destroy() override { glDeleteProgram(mProgram); }
void step(float dt, double totalTime) override
{
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(angle::Vector3(0.0f, 0.0f, -2.0f)) *
Matrix4::rotate(mRotation, angle::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);
}
void draw() override
{
// 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());
}
void swap() override
{
// 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();
eglPostSubBufferNV(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;
};
int main(int argc, char **argv)
{
PostSubBufferSample app(argc, argv);
return app.run();
}
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