QuadDemo.cpp

Demonstration how to render a very simple geometry in Vish using OpenGL 1 calls.

Demonstration how to render a very simple geometry in Vish using OpenGL 1 calls.

See also

Background.cpp for a more basic example.

#include <ocean/GLvish/VGLRenderObject.hpp>
#include <ocean/plankton/VPipeline.hpp>
#include <ocean/GLvish/GLTexture.hpp>
 
 
namespace
{
        using namespace Wizt;
 
class   QuadDemo : public VGLRenderObject
{
public:
        QuadDemo(const string&name, int p, const RefPtr<VCreationPreferences>&VP);
 
        ~QuadDemo();
 
        bool    update(VRequest&R, double precision) override;
 
        bool    renderGL(VGLRenderContext&) const override;
};
 
QuadDemo::QuadDemo(const string&name, int p, const RefPtr<VCreationPreferences>&VP)
: VGLRenderObject(name, DEFAULT_OBJECT, VP)
{
}
 
QuadDemo::~QuadDemo()
{}
 
bool    QuadDemo::update(VRequest&Context, double precision)
{
        // nothing to be done here.
        // The update function in general is used to process data
        // in contrast to just rendering data.
        return true;
}
 
bool    QuadDemo::renderGL(VGLRenderContext&Context) const
{
        glDisable ( GL_COLOR_MATERIAL );
        glDisable ( GL_LIGHTING );
        glEnable(GL_TEXTURE_2D);
        glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP);
        glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP);
        glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
        glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_DECAL);
 
const   int W = 128, H = 128;
rgb_t   Image[W*H];
        for(int y=0; y<H; y++)
        for(int x=0; x<W; x++)
        {
                Image[x+W*y][0] = 2*x;
                Image[x+W*y][1] = 2*y;
                Image[x+W*y][2] = x+y;
 
        }
 
        glTexImage2D(GL_TEXTURE_2D, 0, 3, W,H, 0, GL_RGB,
                     GL_UNSIGNED_BYTE,
                     Image);
 
        glBegin(GL_QUADS);
        glTexCoord2f(0,0);
        glVertex3f  (0,-1,-1);
 
        glTexCoord2f( 0,1);
        glVertex3f  (0,-1,1);
 
        glTexCoord2f(1,1);
        glVertex3f  (0,1,1);
 
        glTexCoord2f(1, 0);
        glVertex3f  (0,1,-1);
        glEnd();
 
        /*
          The following line is important for geometric objects as it defines
          their bounding volume. This is important for setting OpenGL depth parameters
          correctly, as well as for camera navigation.
         */
        setBoundingBall( Context, new BoundingBox( point(0,-1,-1), point(0, 1, 1) ));
 
        return true;
}
 
 
 
using namespace Panthalassa;
 
static  VSink<QuadDemo>
        myCreator(  Category("Demo")
                    /VIdentifier("QuadDemo")
                    / Description("Display an image in two different coordinate systems")
                    ,
                    ObjectQuality::DEMO);
 
}