package engine;

import java.util.HashMap;
import java.util.Map;

import static org.lwjgl.opengl.GL20.*;

public class Shader {

    private boolean enabled = false;

    //Identifiant du programme resultat de la compilation des shaders
    private final int ID;
    private Map<String, Integer> locationCache = new HashMap<String, Integer>();

    /*
    Crée le fragment et le vertex shader les lie dans un programme dont il renvoie l'identifiant.
     */
    public Shader(String vertex, String fragment) {
        ID = ShaderUtils.load(vertex, fragment);
    }

    public int getUniform(String name){
        if (locationCache.containsKey(name)) return locationCache.get(name);
        int result = glGetUniformLocation(ID, name);
        if (result == -1) System.err.println("Could not find uniform variable " + name);
        else locationCache.put(name, result);
        return result;
    }

    public void setUniform1i(String name, int value) {
        if (!enabled) enable();
        glUniform1i(getUniform(name), value);
    }

    public void setUniform1f(String name, float value) {
        if (!enabled) enable();
        glUniform1f(getUniform(name), value);
    }

    public void setUniform2f(String name, float x, float y) {
        if (!enabled) enable();
        glUniform2f(getUniform(name), x, y);
    }

    public void setUniform3f(String name, Vector3f vector) {
        if (!enabled) enable();
        glUniform3f(getUniform(name), vector.x, vector.y, vector.z);
    }

    public void setUniformMat4f(String name, Matrix4f matrix){
        if (!enabled) enable();
        glUniformMatrix4fv(getUniform(name), false, matrix.toFloatBuffer());
    }

    public void enable() {
        glUseProgram(ID);
        enabled = true;
    }

    public void disable() {
        glUseProgram(0);
        enabled = false;
    }

}