Galactica/crates/render/shaders/object.wgsl

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// INCLUDE: global uniform header
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struct InstanceInput {
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@location(2) sprite_index: u32,
@location(3) object_index: u32,
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};
struct VertexInput {
@location(0) position: vec3<f32>,
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@location(1) texture_coords: vec2<f32>,
};
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struct VertexOutput {
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@builtin(position) position: vec4<f32>,
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@location(0) tween: f32,
@location(1) texture_index_a: u32,
@location(2) texture_coords_a: vec2<f32>,
@location(3) texture_index_b: u32,
@location(4) texture_coords_b: vec2<f32>,
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};
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@group(0) @binding(0)
var texture_array: binding_array<texture_2d<f32>>;
@group(0) @binding(1)
var sampler_array: binding_array<sampler>;
// INCLUDE: animate.wgsl
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fn transform_vertex(obj: ObjectData, vertex_position: vec2<f32>, sprite_index: u32) -> vec4<f32> {
// Object scale
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var scale: f32 = obj.size / (global_data.camera_zoom.x * obj.zpos);
if obj.is_child == 1u {
scale /= objects[obj.parent].zpos;
}
// Apply scale and sprite aspect
// Note that our mesh starts centered at (0, 0). This is important!
var pos: vec2<f32> = vec2(
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vertex_position.x * scale * global_sprites[sprite_index].aspect,
vertex_position.y * scale
);
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// Apply rotation
pos = mat2x2(
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vec2(cos(obj.angle - 1.5708), sin(obj.angle - 1.5708)),
vec2(-sin(obj.angle - 1.5708), cos(obj.angle - 1.5708))
) * pos;
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// Correct for screen aspect, preserving height
// This must be done AFTER rotation.
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// (It's thus done later if this is a child)
if obj.is_child == u32(0) {
pos = vec2(
pos.x / global_data.window_aspect.x,
pos.y
);
}
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// Translate
//
// Note that we divide camera zoom by two.
// The height of the viewport is `zoom` in game units,
// but it's 2 in screen units (since coordinates range from -1 to 1)
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if obj.is_child == u32(0) {
let trans = (vec2(obj.xpos, obj.ypos) - global_data.camera_position) / obj.zpos;
pos = pos + vec2(
trans.x / (global_data.camera_zoom.x / 2.0) / global_data.window_aspect.x,
trans.y / (global_data.camera_zoom.x / 2.0)
);
}
if obj.is_child == u32(1) {
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let parent = objects[obj.parent];
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// Apply translation relative to parent
// Note that obj.zpos is ignored
pos = pos + vec2(
obj.xpos / (global_data.camera_zoom.x / 2.0) / global_data.window_aspect.x,
obj.ypos / (global_data.camera_zoom.x / 2.0)
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) / parent.zpos;
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// Apply parent's rotation
pos = mat2x2(
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vec2(cos(parent.angle - 1.5708), sin(parent.angle - 1.5708)),
vec2(-sin(parent.angle - 1.5708), cos(parent.angle - 1.5708))
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) * pos;
// Correct for screen aspect, preserving height
pos = vec2(
pos.x / global_data.window_aspect.x,
pos.y
);
// Apply parent's translation
let ptrans = (vec2(parent.xpos, parent.ypos) - global_data.camera_position) / parent.zpos;
pos = pos + vec2(
ptrans.x / (global_data.camera_zoom.x / 2.0) / global_data.window_aspect.x,
ptrans.y / (global_data.camera_zoom.x / 2.0)
);
}
return vec4<f32>(pos, 0.0, 1.0);;
}
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@vertex
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fn vertex_main(
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vertex: VertexInput,
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instance: InstanceInput,
) -> VertexOutput {
var out: VertexOutput;
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out.position = transform_vertex(objects[instance.object_index], vertex.position.xy, instance.sprite_index);
// Compute texture coordinates
let age = global_data.current_time.x;
let frame = animate(instance.sprite_index, age, 0.0);
out.tween = fract(frame);
let t = global_atlas[u32(floor(frame))];
out.texture_index_a = u32(t.atlas_texture);
out.texture_coords_a = vec2(t.xpos, t.ypos);
if vertex.texture_coords.x == 1.0 {
out.texture_coords_a = out.texture_coords_a + vec2(t.width, 0.0);
}
if vertex.texture_coords.y == 1.0 {
out.texture_coords_a = out.texture_coords_a + vec2(0.0, t.height);
}
let b = global_atlas[u32(floor(animate(instance.sprite_index, age, 1.0)))];
out.texture_index_b = u32(b.atlas_texture);
out.texture_coords_b = vec2(b.xpos, b.ypos);
if vertex.texture_coords.x == 1.0 {
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out.texture_coords_b = out.texture_coords_b + vec2(b.width, 0.0);
}
if vertex.texture_coords.y == 1.0 {
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out.texture_coords_b = out.texture_coords_b + vec2(0.0, b.height);
}
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return out;
}
@fragment
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fn fragment_main(in: VertexOutput) -> @location(0) vec4<f32> {
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return mix(
textureSampleLevel(
texture_array[in.texture_index_a],
sampler_array[0],
in.texture_coords_a,
0.0
).rgba,
textureSampleLevel(
texture_array[in.texture_index_b],
sampler_array[0],
in.texture_coords_b,
0.0
).rgba,
in.tween
);
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}