I'm trying to use trapezoidal shadow mapping using http://www.comp.nus.edu.sg/~tants/tsm/TSM_recipe.html I've some problem. I generate the 8 point that create the trapezoid of the view frustum. Then I've transformed this 8 point with view x projection matrix of the light render target (view is the view matrix that go from lightposition to center of the scene, projection is a projection matrix with fov of 90°). With this 8 point projected I've calculated the 4 corner of the bounding trapezoid. Now the firsts question: 1)after projected the 8 point I should homogene the coordinate (v.xyz/v.w) or not? 2)what should be the correct value for the 4 points? I thinked that when the lights is far than camera the 4 point must be inside of the square -1,1 but it's not. 3)I'm working in directX, I can just transpose the final matrix to convert the result with ogl in directX? I'm using left hand camera please, anyone help me, I can't found any help with this