Pipeline color blend state attachment (used by [RenderingDevice]).
Controls how blending between source and destination fragments is performed when using [RenderingDevice].
For reference, this is how common user-facing blend modes are implemented in Godot's 2D renderer:
[b]Mix:[/b]
[codeblock]
var attachment = RDPipelineColorBlendStateAttachment.new()
attachment.enable_blend = true
attachment.color_blend_op = RenderingDevice.BLEND_OP_ADD
attachment.src_color_blend_factor = RenderingDevice.BLEND_FACTOR_SRC_ALPHA
attachment.dst_color_blend_factor = RenderingDevice.BLEND_FACTOR_ONE_MINUS_SRC_ALPHA
attachment.alpha_blend_op = RenderingDevice.BLEND_OP_ADD
attachment.src_alpha_blend_factor = RenderingDevice.BLEND_FACTOR_ONE
attachment.dst_alpha_blend_factor = RenderingDevice.BLEND_FACTOR_ONE_MINUS_SRC_ALPHA
[/codeblock]
[b]Add:[/b]
[codeblock]
var attachment = RDPipelineColorBlendStateAttachment.new()
attachment.enable_blend = true
attachment.alpha_blend_op = RenderingDevice.BLEND_OP_ADD
attachment.color_blend_op = RenderingDevice.BLEND_OP_ADD
attachment.src_color_blend_factor = RenderingDevice.BLEND_FACTOR_SRC_ALPHA
attachment.dst_color_blend_factor = RenderingDevice.BLEND_FACTOR_ONE
attachment.src_alpha_blend_factor = RenderingDevice.BLEND_FACTOR_SRC_ALPHA
attachment.dst_alpha_blend_factor = RenderingDevice.BLEND_FACTOR_ONE
[/codeblock]
[b]Subtract:[/b]
[codeblock]
var attachment = RDPipelineColorBlendStateAttachment.new()
attachment.enable_blend = true
attachment.alpha_blend_op = RenderingDevice.BLEND_OP_SUBTRACT
attachment.color_blend_op = RenderingDevice.BLEND_OP_SUBTRACT
attachment.src_color_blend_factor = RenderingDevice.BLEND_FACTOR_SRC_ALPHA
attachment.dst_color_blend_factor = RenderingDevice.BLEND_FACTOR_ONE
attachment.src_alpha_blend_factor = RenderingDevice.BLEND_FACTOR_SRC_ALPHA
attachment.dst_alpha_blend_factor = RenderingDevice.BLEND_FACTOR_ONE
[/codeblock]
[b]Multiply:[/b]
[codeblock]
var attachment = RDPipelineColorBlendStateAttachment.new()
attachment.enable_blend = true
attachment.alpha_blend_op = RenderingDevice.BLEND_OP_ADD
attachment.color_blend_op = RenderingDevice.BLEND_OP_ADD
attachment.src_color_blend_factor = RenderingDevice.BLEND_FACTOR_DST_COLOR
attachment.dst_color_blend_factor = RenderingDevice.BLEND_FACTOR_ZERO
attachment.src_alpha_blend_factor = RenderingDevice.BLEND_FACTOR_DST_ALPHA
attachment.dst_alpha_blend_factor = RenderingDevice.BLEND_FACTOR_ZERO
[/codeblock]
[b]Pre-multiplied alpha:[/b]
[codeblock]
var attachment = RDPipelineColorBlendStateAttachment.new()
attachment.enable_blend = true
attachment.alpha_blend_op = RenderingDevice.BLEND_OP_ADD
attachment.color_blend_op = RenderingDevice.BLEND_OP_ADD
attachment.src_color_blend_factor = RenderingDevice.BLEND_FACTOR_ONE
attachment.dst_color_blend_factor = RenderingDevice.BLEND_FACTOR_ONE_MINUS_SRC_ALPHA
attachment.src_alpha_blend_factor = RenderingDevice.BLEND_FACTOR_ONE
attachment.dst_alpha_blend_factor = RenderingDevice.BLEND_FACTOR_ONE_MINUS_SRC_ALPHA
[/codeblock]
Convenience method to perform standard mix blending with straight (non-premultiplied) alpha. This sets [member enable_blend] to [code]true[/code], [member src_color_blend_factor] to [constant RenderingDevice.BLEND_FACTOR_SRC_ALPHA], [member dst_color_blend_factor] to [constant RenderingDevice.BLEND_FACTOR_ONE_MINUS_SRC_ALPHA], [member src_alpha_blend_factor] to [constant RenderingDevice.BLEND_FACTOR_SRC_ALPHA] and [member dst_alpha_blend_factor] to [constant RenderingDevice.BLEND_FACTOR_ONE_MINUS_SRC_ALPHA].
The blend mode to use for the alpha channel.
The blend mode to use for the red/green/blue color channels.
Controls how the blend factor for the alpha channel is determined based on the destination's fragments.
Controls how the blend factor for the color channels is determined based on the destination's fragments.
If [code]true[/code], performs blending between the source and destination according to the factors defined in [member src_color_blend_factor], [member dst_color_blend_factor], [member src_alpha_blend_factor] and [member dst_alpha_blend_factor]. The blend modes [member color_blend_op] and [member alpha_blend_op] are also taken into account, with [member write_r], [member write_g], [member write_b] and [member write_a] controlling the output.
Controls how the blend factor for the alpha channel is determined based on the source's fragments.
Controls how the blend factor for the color channels is determined based on the source's fragments.
If [code]true[/code], writes the new alpha channel to the final result.
If [code]true[/code], writes the new blue color channel to the final result.
If [code]true[/code], writes the new green color channel to the final result.
If [code]true[/code], writes the new red color channel to the final result.