CODEWITHSUNDEEP
openglqt4
Valentin H
Valentin H

Reputation: 7458

Creating a 3D-terrain from an image using OpenGL

Is it possible to render a gray-scale image in 3D using pixel value as Z-coordinate? Where should I start? What is the command for drawing a point in OpenGL and what is the basic setup for ensuring this point is visible?

I'm using Qt, and was able to cmpile and run the Qt's OpenGL examples.

Upvotes: 1

Views: 971

Answers (1)

Valentin H
Valentin H

Reputation: 7458

Ok, I've found out how to do it and implemented a small demo using Qt:

https://github.com/vheinitz/Cell3DViewerDemo

The main thing to understand seemed to be how to create the list of vertexes:

glNewList(_vertexes, GL_COMPILE);
    GLenum mode = GL_TRIANGLES;//GL_TRIANGLES GL_POINTS GL_LINES GL_POINTS GL_TRIANGLE_STRIP GL_QUADS
    glBegin(mode);

    for (int y = 0; y < height - 2; y++) {
        int x = 0;
        float gy = y*sy -yo;
        float gy1 = (y+1)*sy-yo;
        for (x; x < width-2; x++) {

            float z = qGray(qimg.pixel(x, y));
            float gx = x*sx -xo;            
            float gx1 = (x+1)*sx -xo;   

            float gz = qGray(qimg.pixel(x, y))*sz -zo;
            glColor3f(0, gz, 0);
            glVertex3f(gx, gz, gy);

            gz = qGray(qimg.pixel(x, y+1))*sz -zo;
            glColor3f(0, gz, 0);
            glVertex3f(gx, gz, gy1);

            gz = qGray(qimg.pixel(x+1, y))*sz -zo;
            glColor3f(0, gz, 0);
            glVertex3f(gx1, gz, gy);

            glVertex3f(gx1, gz, gy);

            gz = qGray(qimg.pixel(x, y+1))*sz -zo;
            glColor3f(0, gz, 0);
            glVertex3f(gx, gz, gy1);

            gz = qGray(qimg.pixel(x+1, y+1))*sz -zo;
            glColor3f(0, gz, 0);
            glVertex3f(gx1, gz, gy1);

        }           
    }
    glEnd();
    glEndList();

Hight map demo

Upvotes: 2

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