OGLplus (0.52.0) a C++ wrapper for OpenGL

oglplus/003_rect.cpp

Shows how to draw a shaded rectangle

003_rect.png

Copyright 2008-2014 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"
namespace oglplus {
class RectangleExample : public Example
{
private:
// wrapper around the current OpenGL context
Context gl;
// Vertex shader
// Fragment shader
// Program
Program prog;
// A vertex array object for the rendered rectangle
VertexArray rectangle;
// VBOs for the rectangle's vertices
Buffer verts;
public:
RectangleExample(void)
{
// Set the vertex shader source
vs.Source(" \
#version 330\n \
in vec2 Position; \
out vec2 vertCoord; \
void main(void) \
{ \
gl_Position = vec4(Position, 0.0, 1.0); \
vertCoord = vec2( \
(Position.x + 1.0)/2.0, \
(Position.y + 1.0)/2.0 \
); \
} \
");
// compile it
vs.Compile();
// set the fragment shader source
fs.Source(" \
#version 330\n \
in vec2 vertCoord; \
out vec4 fragColor; \
void main(void) \
{ \
fragColor = vec4( \
vertCoord.x - vertCoord.x * vertCoord.y,\
vertCoord.y - vertCoord.x * vertCoord.y,\
vertCoord.x * vertCoord.y, \
1.0 \
); \
} \
");
// compile it
fs.Compile();
// attach the shaders to the program
prog.AttachShader(vs).AttachShader(fs);
// link and use it
prog.Link().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>();
vert_attr.Enable();
//
gl.Disable(Capability::DepthTest);
}
void Reshape(GLuint width, GLuint height)
{
gl.Viewport(width, height);
}
void Render(double)
{
gl.Clear().ColorBuffer();
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).