Function updateFloatTexture

test/browser/test_gl_subdata.c:67–88

double alpha = 0; // use to make a simple funny effect;

static void updateFloatTexture() {
    int count = 0;
    for (float x=0; x < NUM_NODES; ++x ) {
        data[count].x = 0.2*pow(cos(alpha), 3) + (sin(alpha)*3. + 3.5) * x/NUM_NODES * cos(alpha + x/NUM_NODES * 16. * M_PI);
        data[count].y = 0.2*pow(sin(alpha), 3) + (sin(alpha)*3. + 3.5) * x/NUM_NODES * sin(alpha + x/NUM_NODES * 16. * M_PI);
        data[count].s = (16. + 16. * cos(alpha + x/NUM_NODES * 32. * M_PI)) + 8.;// * fmod(x/NUM_NODES + alpha, 1.) + 5.;
        data[count].c = 0.5 + 0.5 * sin(alpha + x/NUM_NODES * 32. * M_PI);
        ++count;
    }
    glBindTexture(GL_TEXTURE_2D, nodeTexture);
#ifdef __EMSCRIPTEN__ // In GLES2 and WebGL1, we must use unsized texture internal formats.
    const GLenum internalFormat = GL_RGBA;
#else
    // In desktop GL, we can also use sized internal formats.
    const GLenum internalFormat = GL_RGBA32F;
#endif
    glTexImage2D(GL_TEXTURE_2D, 0, internalFormat, NUM_NODES, 1, 0, GL_RGBA, GL_FLOAT, data);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
    glBindTexture(GL_TEXTURE_2D, 0);
    alpha -= 0.001;
}

static void glut_draw_callback(void) {
    glDisable(GL_CULL_FACE);