bevy/crates/bevy_pbr/src/render/pbr_prepass.wgsl
JMS55 724e69bff4
Bias texture mipmaps (#7614)
# Objective

- Closes #7323 
- Reduce texture blurriness for TAA

## Solution

- Add a `MipBias` component and view uniform.
- Switch material `textureSample()` calls to `textureSampleBias()`.
- Add a `-1.0` bias to TAA.

---

## Changelog

- Added `MipBias` camera component, mostly for internal use.

---------

Co-authored-by: François <mockersf@gmail.com>
Co-authored-by: Carter Anderson <mcanders1@gmail.com>
2023-06-22 20:55:05 +00:00

138 lines
4.4 KiB
WebGPU Shading Language

#import bevy_pbr::prepass_bindings
#import bevy_pbr::pbr_bindings
#ifdef NORMAL_PREPASS
#import bevy_pbr::pbr_functions
#endif // NORMAL_PREPASS
struct FragmentInput {
@builtin(front_facing) is_front: bool,
@builtin(position) frag_coord: vec4<f32>,
#ifdef VERTEX_UVS
@location(0) uv: vec2<f32>,
#endif // VERTEX_UVS
#ifdef NORMAL_PREPASS
@location(1) world_normal: vec3<f32>,
#ifdef VERTEX_TANGENTS
@location(2) world_tangent: vec4<f32>,
#endif // VERTEX_TANGENTS
#endif // NORMAL_PREPASS
#ifdef MOTION_VECTOR_PREPASS
@location(3) world_position: vec4<f32>,
@location(4) previous_world_position: vec4<f32>,
#endif // MOTION_VECTOR_PREPASS
#ifdef DEPTH_CLAMP_ORTHO
@location(5) clip_position_unclamped: vec4<f32>,
#endif // DEPTH_CLAMP_ORTHO
};
// Cutoff used for the premultiplied alpha modes BLEND and ADD.
const PREMULTIPLIED_ALPHA_CUTOFF = 0.05;
// We can use a simplified version of alpha_discard() here since we only need to handle the alpha_cutoff
fn prepass_alpha_discard(in: FragmentInput) {
#ifdef MAY_DISCARD
var output_color: vec4<f32> = material.base_color;
#ifdef VERTEX_UVS
if (material.flags & STANDARD_MATERIAL_FLAGS_BASE_COLOR_TEXTURE_BIT) != 0u {
output_color = output_color * textureSampleBias(base_color_texture, base_color_sampler, in.uv, view.mip_bias);
}
#endif // VERTEX_UVS
let alpha_mode = material.flags & STANDARD_MATERIAL_FLAGS_ALPHA_MODE_RESERVED_BITS;
if alpha_mode == STANDARD_MATERIAL_FLAGS_ALPHA_MODE_MASK {
if output_color.a < material.alpha_cutoff {
discard;
}
} else if (alpha_mode == STANDARD_MATERIAL_FLAGS_ALPHA_MODE_BLEND || alpha_mode == STANDARD_MATERIAL_FLAGS_ALPHA_MODE_ADD) {
if output_color.a < PREMULTIPLIED_ALPHA_CUTOFF {
discard;
}
} else if alpha_mode == STANDARD_MATERIAL_FLAGS_ALPHA_MODE_PREMULTIPLIED {
if all(output_color < vec4(PREMULTIPLIED_ALPHA_CUTOFF)) {
discard;
}
}
#endif // MAY_DISCARD
}
#ifdef PREPASS_FRAGMENT
struct FragmentOutput {
#ifdef NORMAL_PREPASS
@location(0) normal: vec4<f32>,
#endif // NORMAL_PREPASS
#ifdef MOTION_VECTOR_PREPASS
@location(1) motion_vector: vec2<f32>,
#endif // MOTION_VECTOR_PREPASS
#ifdef DEPTH_CLAMP_ORTHO
@builtin(frag_depth) frag_depth: f32,
#endif // DEPTH_CLAMP_ORTHO
}
@fragment
fn fragment(in: FragmentInput) -> FragmentOutput {
prepass_alpha_discard(in);
var out: FragmentOutput;
#ifdef DEPTH_CLAMP_ORTHO
out.frag_depth = in.clip_position_unclamped.z;
#endif // DEPTH_CLAMP_ORTHO
#ifdef NORMAL_PREPASS
// NOTE: Unlit bit not set means == 0 is true, so the true case is if lit
if (material.flags & STANDARD_MATERIAL_FLAGS_UNLIT_BIT) == 0u {
let world_normal = prepare_world_normal(
in.world_normal,
(material.flags & STANDARD_MATERIAL_FLAGS_DOUBLE_SIDED_BIT) != 0u,
in.is_front,
);
let normal = apply_normal_mapping(
material.flags,
world_normal,
#ifdef VERTEX_TANGENTS
#ifdef STANDARDMATERIAL_NORMAL_MAP
in.world_tangent,
#endif // STANDARDMATERIAL_NORMAL_MAP
#endif // VERTEX_TANGENTS
#ifdef VERTEX_UVS
in.uv,
#endif // VERTEX_UVS
);
out.normal = vec4(normal * 0.5 + vec3(0.5), 1.0);
} else {
out.normal = vec4(in.world_normal * 0.5 + vec3(0.5), 1.0);
}
#endif // NORMAL_PREPASS
#ifdef MOTION_VECTOR_PREPASS
let clip_position_t = view.unjittered_view_proj * in.world_position;
let clip_position = clip_position_t.xy / clip_position_t.w;
let previous_clip_position_t = previous_view_proj * in.previous_world_position;
let previous_clip_position = previous_clip_position_t.xy / previous_clip_position_t.w;
// These motion vectors are used as offsets to UV positions and are stored
// in the range -1,1 to allow offsetting from the one corner to the
// diagonally-opposite corner in UV coordinates, in either direction.
// A difference between diagonally-opposite corners of clip space is in the
// range -2,2, so this needs to be scaled by 0.5. And the V direction goes
// down where clip space y goes up, so y needs to be flipped.
out.motion_vector = (clip_position - previous_clip_position) * vec2(0.5, -0.5);
#endif // MOTION_VECTOR_PREPASS
return out;
}
#else
@fragment
fn fragment(in: FragmentInput) {
prepass_alpha_discard(in);
}
#endif // PREPASS_FRAGMENT