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//!
//! Definitions of the input state needed for any draw call.
//!
///
/// A set of render specific states that has to be specified at each render call.
///
#[derive(Debug, Copy, Clone)]
pub struct RenderStates {
///
/// Defines which channels (red, green, blue, alpha and depth) to write to in a render call.
///
pub write_mask: WriteMask,
///
/// Defines the rectangle of pixels to write to in a render call. If none, all pixels in the current render target are possibly written into.
///
pub clip: Clip,
///
/// Defines the depth test in a render call.
/// The depth test determines whether or not a fragment from the current render call should be discarded
/// when comparing its depth with the depth of the current fragment.
///
pub depth_test: DepthTest,
///
/// Defines which type of blending to use for a render call.
/// Blending allows combining each color channel of a render call with the color already in the
/// color channels of the render target.
/// This is usually used to simulate transparency.
///
pub blend: Blend,
///
/// Defines whether the triangles that are backfacing, frontfacing or both should be skipped in a render call.
///
pub cull: Cull,
}
impl Default for RenderStates {
fn default() -> Self {
Self {
write_mask: WriteMask::default(),
depth_test: DepthTest::default(),
blend: Blend::default(),
clip: Clip::default(),
cull: Cull::default(),
}
}
}
///
/// Defines whether the triangles that are backfacing, frontfacing, both or none should be rendered in a render call.
///
#[derive(Debug, Copy, Clone, PartialEq)]
pub enum Cull {
/// Render both front- and backfacing triangles.
None,
/// Render only frontfacing triangles.
Back,
/// Render only backfacing triangles.
Front,
/// Render nothing.
FrontAndBack,
}
impl Default for Cull {
fn default() -> Self {
Self::None
}
}
///
/// Determines whether or not a fragment/pixel from the current render call should be discarded
/// when comparing its depth with the depth of the current fragment/pixel.
///
/// **Note:** Depth test is disabled if the render call is not writing to a depth texture.
/// This means depth testing does not work when writing to a [ColorTargetTexture2D](crate::core::ColorTargetTexture2D) or [ColorTargetTexture2DArray](crate::core::ColorTargetTexture2DArray),
/// but do work when writing to the [Screen](crate::core::Screen), a [RenderTarget](crate::core::RenderTarget), [RenderTargetArray](crate::core::RenderTargetArray),
/// [DepthTargetTexture2D](crate::core::DepthTargetTexture2D) or [DepthTargetTexture2DArray](crate::core::DepthTargetTexture2DArray).
///
#[allow(missing_docs)]
#[derive(Debug, Copy, Clone, PartialEq)]
pub enum DepthTest {
Never,
Less,
Equal,
LessOrEqual,
Greater,
NotEqual,
GreaterOrEqual,
Always,
}
impl Default for DepthTest {
fn default() -> Self {
Self::Less
}
}
///
/// Defines the rectangle of pixels to write to in a render call.
///
#[derive(Debug, Copy, Clone, PartialEq)]
pub enum Clip {
/// Only render inside the defined rectangle of the screen/render target.
Enabled {
/// The distance in pixels from the left edge of the screen/render target.
x: u32,
/// The distance in pixels from the top edge of the screen/render target.
y: u32,
/// The width of the rectangle.
width: u32,
/// The height of the rectangle.
height: u32,
},
/// Render inside the entire screen/render target.
Disabled,
}
impl Default for Clip {
fn default() -> Self {
Self::Disabled
}
}
///
/// Defines which channels (red, green, blue, alpha and depth) to write to in a render call.
///
#[allow(missing_docs)]
#[derive(Debug, Copy, Clone, PartialEq)]
pub struct WriteMask {
pub red: bool,
pub green: bool,
pub blue: bool,
pub alpha: bool,
pub depth: bool,
}
impl WriteMask {
///
/// Writes to all channels (red, green, blue, alpha and depth).
///
pub const COLOR_AND_DEPTH: Self = Self {
red: true,
green: true,
blue: true,
alpha: true,
depth: true,
};
///
/// Writes to all color channels (red, green, blue and alpha).
///
pub const COLOR: Self = Self {
red: true,
green: true,
blue: true,
alpha: true,
depth: false,
};
///
/// Writes to the depth channel only.
///
pub const DEPTH: Self = Self {
red: false,
green: false,
blue: false,
alpha: false,
depth: true,
};
///
/// Do not write to any channels.
///
pub const NONE: Self = Self {
red: false,
green: false,
blue: false,
alpha: false,
depth: false,
};
}
impl Default for WriteMask {
fn default() -> Self {
Self::COLOR_AND_DEPTH
}
}
///
/// Defines which type of blending to use for a render call.
/// Blending allows combining each color channel of a render call with the color already in the
/// color channels of the render target.
/// This is usually used to simulate transparency.
///
#[allow(missing_docs)]
#[derive(Debug, Copy, Clone, PartialEq)]
pub enum Blend {
Enabled {
source_rgb_multiplier: BlendMultiplierType,
source_alpha_multiplier: BlendMultiplierType,
destination_rgb_multiplier: BlendMultiplierType,
destination_alpha_multiplier: BlendMultiplierType,
rgb_equation: BlendEquationType,
alpha_equation: BlendEquationType,
},
Disabled,
}
impl Blend {
///
/// Standard OpenGL transparency blending parameters which, for the usual case of being able to see through objects, does not work on web.
/// In that case, use [Blend::TRANSPARENCY] instead which works the same way on desktop and web.
///
pub const STANDARD_TRANSPARENCY: Self = Self::Enabled {
source_rgb_multiplier: BlendMultiplierType::SrcAlpha,
source_alpha_multiplier: BlendMultiplierType::One,
destination_rgb_multiplier: BlendMultiplierType::OneMinusSrcAlpha,
destination_alpha_multiplier: BlendMultiplierType::Zero,
rgb_equation: BlendEquationType::Add,
alpha_equation: BlendEquationType::Add,
};
///
/// Transparency blending parameters that works on both desktop and web. For the standard OpenGL parameters, see [Blend::STANDARD_TRANSPARENCY].
///
pub const TRANSPARENCY: Self = Self::Enabled {
source_rgb_multiplier: BlendMultiplierType::SrcAlpha,
source_alpha_multiplier: BlendMultiplierType::Zero,
destination_rgb_multiplier: BlendMultiplierType::OneMinusSrcAlpha,
destination_alpha_multiplier: BlendMultiplierType::One,
rgb_equation: BlendEquationType::Add,
alpha_equation: BlendEquationType::Add,
};
///
/// Adds the color of the render target with the output color of the render call.
///
pub const ADD: Self = Self::Enabled {
source_rgb_multiplier: BlendMultiplierType::One,
source_alpha_multiplier: BlendMultiplierType::One,
destination_rgb_multiplier: BlendMultiplierType::One,
destination_alpha_multiplier: BlendMultiplierType::One,
rgb_equation: BlendEquationType::Add,
alpha_equation: BlendEquationType::Add,
};
}
impl Default for Blend {
fn default() -> Self {
Self::Disabled
}
}
///
/// Value multiplied with the source or target color or alpha value in [Blend].
///
#[allow(missing_docs)]
#[derive(Debug, Copy, Clone, PartialEq)]
pub enum BlendMultiplierType {
Zero,
One,
SrcColor,
OneMinusSrcColor,
DstColor,
OneMinusDstColor,
SrcAlpha,
OneMinusSrcAlpha,
DstAlpha,
OneMinusDstAlpha,
SrcAlphaSaturate,
}
///
/// How the source and target color or alpha value are combined in [Blend].
///
#[allow(missing_docs)]
#[derive(Debug, Copy, Clone, PartialEq)]
pub enum BlendEquationType {
Add,
Subtract,
ReverseSubtract,
Max,
Min,
}