OpenGL/Utah teapot: Difference between revisions

=={{header|Kotlin}}==

{{trans|C}}

{{libheader|freeglut}}

{{works with|Ubuntu 14.04}}

Assuming that freeglut is already installed on your system in the default location(s), you first need to build opengl.klib using the following .def file and the cinterop tool:

<pre>

// opengl.def

headers = /usr/include/GL/glut.h

compilerOpts = -I/usr/include

linkerOpts = -L/usr/lib/x86_64-linux-gnu -lglut -lGL -lGLU

</pre>

You then need to compile the following Kotlin program, linking against opengl.klib, and run the resulting .kexe file to view the rotating teapot.

<lang scala>// Kotlin Native v0.6

import kotlinx.cinterop.*

import opengl.*

var rot = 0f

val matCol = floatArrayOf(1f, 0f, 0f, 0f)

fun display() {

glClear(GL_COLOR_BUFFER_BIT or GL_DEPTH_BUFFER_BIT)

glPushMatrix()

glRotatef(30f, 1f, 1f, 0f)

glRotatef(rot, 0f, 1f, 1f)

glMaterialfv(GL_FRONT, GL_DIFFUSE, matCol.toCValues())

glutWireTeapot(0.5)

glPopMatrix()

glFlush()

}

fun onIdle() {

rot += 0.1f

glutPostRedisplay()

}

fun init() {

val white = floatArrayOf(1f, 1f, 1f, 0f)

val shini = floatArrayOf(70f)

glClearColor(0.5f, 0.5f, 0.5f, 0f);

glShadeModel(GL_SMOOTH)

glLightfv(GL_LIGHT0, GL_AMBIENT, white.toCValues())

glLightfv(GL_LIGHT0, GL_DIFFUSE, white.toCValues())

glMaterialfv(GL_FRONT, GL_SHININESS, shini.toCValues())

glEnable(GL_LIGHTING)

glEnable(GL_LIGHT0)

glEnable(GL_DEPTH_TEST)

}

fun main(args: Array<String>) {

memScoped {

val argc = alloc<IntVar>().apply { value = 0 }

glutInit(argc.ptr, null)

}

glutInitDisplayMode(GLUT_SINGLE or GLUT_RGB or GLUT_DEPTH)

glutInitWindowSize(900, 700)

val title = "The Amazing, Rotating Utah Teapot brought to you in OpenGL via freeglut."

glutCreateWindow(title)

init()

glutDisplayFunc(staticCFunction(::display))

glutIdleFunc(staticCFunction(::onIdle))

glutMainLoop()

}</lang>