Class reference
RDPipelineColorBlendStateAttachment
Inherits RefCounted
Pipeline color blend state attachment (used by RenderingDevice).
Description
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 Redot's 2D renderer: Mix:
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
Add:
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
Subtract:
var attachment = RDPipelineColorBlendStateAttachment.new()
attachment.enable_blend = true
attachment.alpha_blend_op = RenderingDevice.BLEND_OP_REVERSE_SUBTRACT
attachment.color_blend_op = RenderingDevice.BLEND_OP_REVERSE_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
Multiply:
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
Pre-multiplied alpha:
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
Properties
int alpha_blend_op = 0
The blend mode to use for the alpha channel.
int color_blend_op = 0
The blend mode to use for the red/green/blue color channels.
int dst_alpha_blend_factor = 0
Controls how the blend factor for the alpha channel is determined based on the destination's fragments.
int dst_color_blend_factor = 0
Controls how the blend factor for the color channels is determined based on the destination's fragments.
bool enable_blend = false
If true, performs blending between the source and destination according to the factors defined in src_color_blend_factor, dst_color_blend_factor, src_alpha_blend_factor and dst_alpha_blend_factor. The blend modes color_blend_op and alpha_blend_op are also taken into account, with write_r, write_g, write_b and write_a controlling the output.
int src_alpha_blend_factor = 0
Controls how the blend factor for the alpha channel is determined based on the source's fragments.
int src_color_blend_factor = 0
Controls how the blend factor for the color channels is determined based on the source's fragments.
bool write_a = true
If true, writes the new alpha channel to the final result.
bool write_b = true
If true, writes the new blue color channel to the final result.
bool write_g = true
If true, writes the new green color channel to the final result.
bool write_r = true
If true, writes the new red color channel to the final result.
Methods
void set_as_mix()
Convenience method to perform standard mix blending with straight (non-premultiplied) alpha. This sets enable_blend to true, src_color_blend_factor to RenderingDevice.BLEND_FACTOR_SRC_ALPHA, dst_color_blend_factor to RenderingDevice.BLEND_FACTOR_ONE_MINUS_SRC_ALPHA, src_alpha_blend_factor to RenderingDevice.BLEND_FACTOR_SRC_ALPHA and dst_alpha_blend_factor to RenderingDevice.BLEND_FACTOR_ONE_MINUS_SRC_ALPHA.