bevy/crates/bevy_pbr/src/render/pbr_prepass.wgsl
robtfm 15445c990e
fix prepass normal_mapping (#8978)
# Objective

#5703 caused the normal prepass to fail as the prepass uses
`pbr_functions::apply_normal_mapping`, which uses
`mesh_view_bindings::view` to determine mip bias, which conflicts with
`prepass_bindings::view`.

## Solution

pass the mip bias to the `apply_normal_mapping` function explicitly.
2023-06-29 00:28:34 +00:00

140 lines
5 KiB
WebGPU Shading Language

#import bevy_pbr::prepass_bindings
#import bevy_pbr::pbr_bindings
#import bevy_pbr::pbr_types
#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> = bevy_pbr::pbr_bindings::material.base_color;
#ifdef VERTEX_UVS
if (bevy_pbr::pbr_bindings::material.flags & bevy_pbr::pbr_types::STANDARD_MATERIAL_FLAGS_BASE_COLOR_TEXTURE_BIT) != 0u {
output_color = output_color * textureSampleBias(bevy_pbr::pbr_bindings::base_color_texture, bevy_pbr::pbr_bindings::base_color_sampler, in.uv, bevy_pbr::prepass_bindings::view.mip_bias);
}
#endif // VERTEX_UVS
let alpha_mode = bevy_pbr::pbr_bindings::material.flags & bevy_pbr::pbr_types::STANDARD_MATERIAL_FLAGS_ALPHA_MODE_RESERVED_BITS;
if alpha_mode == bevy_pbr::pbr_types::STANDARD_MATERIAL_FLAGS_ALPHA_MODE_MASK {
if output_color.a < bevy_pbr::pbr_bindings::material.alpha_cutoff {
discard;
}
} else if (alpha_mode == bevy_pbr::pbr_types::STANDARD_MATERIAL_FLAGS_ALPHA_MODE_BLEND || alpha_mode == bevy_pbr::pbr_types::STANDARD_MATERIAL_FLAGS_ALPHA_MODE_ADD) {
if output_color.a < PREMULTIPLIED_ALPHA_CUTOFF {
discard;
}
} else if alpha_mode == bevy_pbr::pbr_types::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 (bevy_pbr::pbr_bindings::material.flags & bevy_pbr::pbr_types::STANDARD_MATERIAL_FLAGS_UNLIT_BIT) == 0u {
let world_normal = bevy_pbr::pbr_functions::prepare_world_normal(
in.world_normal,
(bevy_pbr::pbr_bindings::material.flags & bevy_pbr::pbr_types::STANDARD_MATERIAL_FLAGS_DOUBLE_SIDED_BIT) != 0u,
in.is_front,
);
let normal = bevy_pbr::pbr_functions::apply_normal_mapping(
bevy_pbr::pbr_bindings::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
bevy_pbr::prepass_bindings::view.mip_bias,
);
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 = bevy_pbr::prepass_bindings::view.unjittered_view_proj * in.world_position;
let clip_position = clip_position_t.xy / clip_position_t.w;
let previous_clip_position_t = bevy_pbr::prepass_bindings::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