#clear

1fn clear(inout self, color: vec4)

The clear function resets the current drawing result in the Sdf2d context by blending a specified color over the existing content, taking into account the alpha component for transparency. This is typically used to clear the drawing area before commencing new drawing operations.

#Parameters

• self (inout): A reference to the Sdf2d instance. The function modifies the result field of self in place.

• color (vec4): An RGBA color used to clear the drawing context.

#Returns

• void: This function does not return a value but updates the result field of self to reflect the new color after the blending operation.

#Example

1fn pixel(self) -> vec4 {
2    // Create an Sdf2d drawing context for the current viewport.
3    let sdf = Sdf2d::viewport(self.pos * self.rect_size);
4
5    // Clear the drawing context with a dark gray color.
6    sdf.clear(#181818);
7
8    // Draw a rectangle with rounded corners.
9    sdf.box(10.0, 10.0, self.rect_size.x - 20.0, self.rect_size.y - 20.0, 5.0);
10
11    // Fill the rectangle with red color.
12    sdf.fill(#f00);
13
14    // Return the final color result.
15    return sdf.result;
16}

#Explanation

In this example:

• Create Drawing Context: Initialize the Sdf2d context using the current position scaled by self.rect_size.

• Clear the Context: Call sdf.clear(#181818) to clear the drawing context with a dark gray color (#181818). This blends the specified color over any existing content, taking the alpha component into account.

• Draw Shape: Draw a rectangle starting at position (10.0, 10.0), with width and height adjusted to fit within the context (self.rect_size.x - 20.0, self.rect_size.y - 20.0), and with rounded corners of radius 5.0.

• Apply Fill: Fill the rectangle with red color using sdf.fill(#f00).

• Return Result: Return sdf.result, which contains the final rendered color.

#Notes

• Blending Behavior: The clear function blends the provided color with the existing content using the alpha component. If you want to completely overwrite the existing content, ensure that the alpha component is set to 1.0.

• Usage: Use sdf.clear() at the beginning of your pixel function to reset the drawing context before starting new drawing operations.

• Color Specification: Colors can be specified using hexadecimal notation (e.g., #181818 for dark gray) or as vec4 values.

• Order of Operations: The clear function should be called before any drawing operations to ensure the context is reset.