I’m so confused by the bindings generated by konan...

# kotlin-native

[norman784]

I’m so confused by the bindings generated by konan, don’t understand how to call this function, it is supposed to be just like this:

val vertexShaderSource: String = "...."
val vertexShader = glCreateShader(GL_VERTEX_SHADER)
glShaderSource(vertexShader, 1, vertexShaderSource, null)

Tried different thinks like .toCValues(), .cValuesOf(), .cstr.getPointer(this /* memscoped reference */), I find so complicated some of the bindings, don’t know if theres a better way to detect that the variable is a char array and do automatically the convertion between string a char array (and vice versa)

This is how the glShaderSource looks like in kotlin

public fun glShaderSource(shader: platform.OpenGLCommon.GLuint /* = <http://kotlin.Int|kotlin.Int> */, count: platform.OpenGLCommon.GLsizei /* = <http://kotlin.Int|kotlin.Int> */, string: kotlinx.cinterop.CValuesRef<kotlinx.cinterop.CPointerVar<platform.OpenGLCommon.GLcharVar /* = kotlinx.cinterop.ByteVarOf<platform.OpenGLCommon.GLchar /* = kotlin.Byte */> */> /* = kotlinx.cinterop.CPointerVarOf<kotlinx.cinterop.CPointer<kotlinx.cinterop.ByteVarOf<platform.OpenGLCommon.GLchar /* = kotlin.Byte */>>> */>?, length: kotlinx.cinterop.CValuesRef<platform.OpenGLCommon.GLintVar /* = kotlinx.cinterop.IntVarOf<platform.OpenGLCommon.GLint /* = kotlin.Int */> */>?): kotlin.Unit { /* compiled code */ }

And this is the c function

void glShaderSource(	GLuint shader,
 	GLsizei count,
 	const GLchar **string,
 	const GLint *length);

[svyatoslav.scherbina]

This should work:

memScoped {
    glShaderSource(vertexShader, 1, cValuesOf(vertexShaderSource.cstr.getPointer(memScope)), null)
}

Have you seen our OpenGL-based demo app?
https://github.com/JetBrains/kotlinconf-spinner/blob/f37a6ea758b04915d619fcf68273e4a21ae4d9fc/kotlin-native/samples/fullstack/clients/shared/src/main/kotlin/gl.kt#L103

don’t know if theres a better way to detect that the variable is a char array and do automatically the convertion between string a char array (and vice versa)

The thing is that const GLchar **string is not a char array, it is a pointer to char array. Or, to be more precise: a pointer to pointer to char.

[norman784]

Thanks, forgot to check there, but the weird thing is that I searched on google like this kotlin native glShaderSource and that repo didn’t appear.

Ok, I get, so maybe the official bindings maybe will be cool if theres some hand made changes to be much easier to interact with the API.