Godot Version
4.5.1
Question
Essentially I have a ColorRect node that calculates some data and pass it to its shader, everything works, like it’s a recreation of snes mode7 and it works in the editor by setting the values by hand however the shader doesn’t update on runtime
the color rect code is this:
func _calc_frustrum():
var KartPos = Vector2(Kart.global_position.x, Kart.global_position.y) - Vector2.UP.rotated(Kart.rotation) * 80
var KartA = Kart.rotation -PI/2
var FarX1:float = KartPos.x + cos(KartA - FOVHalf) * Far
var FarY1:float = KartPos.y + sin(KartA - FOVHalf) * Far
var FarX2:float = KartPos.x + cos(KartA + FOVHalf) * Far
var FarY2:float = KartPos.y + sin(KartA + FOVHalf) * Far
var NearX1:float = KartPos.x + cos(KartA - FOVHalf) * Near
var NearY1:float = KartPos.y + sin(KartA - FOVHalf) * Near
var NearX2:float = KartPos.x + cos(KartA + FOVHalf) * Near
var NearY2:float = KartPos.y + sin(KartA + FOVHalf) * Near
Polygon.polygon[0] = Vector2(FarX1, FarY1)
Polygon.polygon[1] = Vector2(FarX2, FarY2)
Polygon.polygon[2] = Vector2(NearX2, NearY2)
Polygon.polygon[3] = Vector2(NearX1, NearY1)
Camera.set_shader_parameter("vFar1", Vector2(FarX1, FarY1)/1024)
Camera.set_shader_parameter("vFar2", Vector2(FarX2, FarY2)/1024)
Camera.set_shader_parameter("vNear1", Vector2(NearX1, NearY1)/1024)
Camera.set_shader_parameter("vNear2", Vector2(NearX2, NearY2)/1024)
await get_tree().process_frame
_calc_frustrum()
print("Points:")
print("Far : ", Camera.get_shader_parameter("vFar1")," ", Camera.get_shader_parameter("vFar2"))
print("Near: ", Camera.get_shader_parameter("vNear1")," ", Camera.get_shader_parameter("vNear2"))
and the prints output logical data, like as I say I take the data out of those prints statements and I put it in the editor and I get sensible things. however on runtime nothing updates
here’s the shader if anyone needs it but as I said the shader works so I would be very surprise if that’s the issue:
shader_type canvas_item;
uniform vec2 vFar1 = vec2(0.0,0.0);
uniform vec2 vFar2 = vec2(0.0,0.0);
uniform vec2 vNear1 = vec2(0.0,0.0);
uniform vec2 vNear2 = vec2(0.0,0.0);
uniform sampler2D source_texture;
void fragment() {
float StartX = (vFar1.x - vNear1.x) / UV.y + vNear1.x;
float StartY = (vFar1.y - vNear1.y) / UV.y + vNear1.y;
float EndX = (vFar2.x - vNear2.x) / UV.y + vNear2.x;
float EndY = (vFar2.y - vNear2.y) / UV.y + vNear2.y;
float SampleX = (EndX - StartX) * UV.x + StartX;
float SampleY = (EndY - StartY) * UV.x + StartY;
COLOR = texture(source_texture, vec2(SampleX,SampleY));
}