drawing a triangle

 You have a 300x300 game screen. Explain what numbers you'd use as parameters in al_draw_triangle if you wanted to slice the square game screen in half diagonally. Make sure you both type the function out AND explain each number please :)

For al_draw_triangle i would do al_draw_triangle(100,100, 250, 250, 100, 250, al_map_rgb(128, 0, 0);

The first 2 100 are the coordinates of the first coordinates of a point on the triangle, the  two 250's are the second point of the triangle, and the last 2 cordinates are the the last points of the triangle. The last part is the color of the triangle.