OGLplus (0.52.0) a C++ wrapper for OpenGL

oglplus/002_rect.cpp

Shows how to draw a shaded rectangle

002_rect.png

Copyright 2008-2013 Matus Chochlik. Distributed under the Boost Software License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)

#include <oglplus/gl.hpp>
#include <oglplus/all.hpp>
#include "example.hpp"
#include <sstream>
namespace oglplus {
class RectangleExample : public Example
{
private:
// wrapper around the current OpenGL context
Context gl;
// Vertex and fragment shader
Shader vs, fs;
// Program
Program prog;
// A vertex array object for the rendered rectangle
VertexArray rectangle;
// VBOs for the rectangle's vertices and colors
Buffer verts;
Buffer colors;
public:
RectangleExample(void)
{
// this could be any istream
std::stringstream vs_source(
"#version 330\n"
"in vec2 Position;"
"in vec3 Color;"
"out vec3 vertColor;"
"void main(void)"
"{"
" vertColor = Color;"
" gl_Position = vec4(Position, 0.0, 1.0);"
"}"
);
// set the vertex shader source
vs.Source(GLSLSource::FromStream(vs_source));
// compile it
vs.Compile();
std::stringstream fs_source(
"#version 330\n"
"in vec3 vertColor;"
"out vec4 fragColor;"
"void main(void)"
"{"
" fragColor = vec4(vertColor, 1.0);"
"}"
);
// set the fragment shader source
fs.Source(GLSLSource::FromStream(fs_source));
// compile it
fs.Compile();
// attach the shaders to the program
prog.AttachShader(vs);
prog.AttachShader(fs);
// link and use it
prog.Link();
prog.Use();
// bind the VAO for the rectangle
rectangle.Bind();
GLfloat rectangle_verts[8] = {
-1.0f, -1.0f,
-1.0f, 1.0f,
1.0f, -1.0f,
1.0f, 1.0f
};
// bind the VBO for the rectangle vertices
verts.Bind(Buffer::Target::Array);
// upload the data
Buffer::Data(Buffer::Target::Array, 8, rectangle_verts);
// setup the vertex attribs array for the vertices
VertexArrayAttrib vert_attr(prog, "Position");
vert_attr.Setup<Vec2f>().Enable();
GLfloat rectangle_colors[12] = {
1.0f, 1.0f, 1.0f,
1.0f, 0.0f, 0.0f,
0.0f, 1.0f, 0.0f,
0.0f, 0.0f, 1.0f,
};
// bind the VBO for the rectangle colors
colors.Bind(Buffer::Target::Array);
// upload the data
Buffer::Data(Buffer::Target::Array, 12, rectangle_colors);
// setup the vertex attribs array for the vertices
VertexArrayAttrib color_attr(prog, "Color");
color_attr.Setup<Vec3f>().Enable();
//
gl.Disable(Capability::DepthTest);
}
void Reshape(GLuint width, GLuint height)
{
gl.Viewport(width, height);
}
void Render(double)
{
gl.DrawArrays(PrimitiveType::TriangleStrip, 0, 4);
}
};
void setupExample(ExampleParams& /*params*/){ }
std::unique_ptr<ExampleThread> makeExampleThread(
Example& /*example*/,
unsigned /*thread_id*/,
const ExampleParams& /*params*/
){ return std::unique_ptr<ExampleThread>(); }
std::unique_ptr<Example> makeExample(const ExampleParams& /*params*/)
{
return std::unique_ptr<Example>(new RectangleExample);
}
} // namespace oglplus

Copyright © 2010-2014 Matúš Chochlík, University of Žilina, Žilina, Slovakia.
<matus.chochlik -at- fri.uniza.sk>
<chochlik -at -gmail.com>
Documentation generated on Mon Sep 22 2014 by Doxygen (version 1.8.6).