102 lines
3.3 KiB
WebGPU Shading Language
102 lines
3.3 KiB
WebGPU Shading Language
// ----------------------------------------------------------------------------
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// Vertex shader
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// ----------------------------------------------------------------------------
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struct VertexInput {
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@location(0) position : vec3<f32>,
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@location(1) tex_coords : vec2<f32>,
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};
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struct InstanceInput {
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@location(5) src_top_left: vec2<f32>,
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@location(6) src_dims: vec2<f32>,
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@location(7) dest_top_left: vec2<f32>,
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@location(8) dest_dims: vec2<f32>,
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@location(9) color: vec4<f32>,
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};
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struct VertexOutput {
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@builtin(position) clip_position : vec4<f32>,
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@location(0) tex_coords : vec2<f32>,
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@location(1) color: vec4<f32>,
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};
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@vertex fn vs_main(vertex : VertexInput, instance : InstanceInput)->VertexOutput {
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var out : VertexOutput;
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out.tex_coords = instance.src_top_left + (vertex.tex_coords * instance.src_dims);
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out.color = instance.color;
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let in_pos = instance.dest_top_left + (vec2f(vertex.position.x, vertex.position.y) * instance.dest_dims);
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let position = adjust_for_resolution(in_pos);
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out.clip_position = vec4f(position.x, position.y, vertex.position.z, 1.0);
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return out;
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}
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// ----------------------------------------------------------------------------
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// Fragment shader
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// ----------------------------------------------------------------------------
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@group(1) @binding(0) var t_diffuse : texture_2d<f32>;
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@group(1) @binding(1) var s_diffuse : sampler;
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@fragment fn fs_main(in : VertexOutput)->@location(0) vec4<f32> {
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let tc = vec2(u32(in.tex_coords.x), u32(in.tex_coords.y));
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let c = textureLoad(t_diffuse, tc, 0);
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// If we were going to run this through the sampler it would look like
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// this... but I don't know if that'w what we should do? Right now the
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// direct load looks better?
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//
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// let tc = in.tex_coords / vec2<f32>(textureDimensions(t_diffuse));
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// let c = textureSample(t_diffuse, s_diffuse, tc);
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return vec4<f32>(
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c.r * in.color.x,
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c.r * in.color.y,
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c.r * in.color.z,
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c.r * in.color.a
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);
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//return vec4<f32>(1.0,1.0,1.0,1.0);
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}
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// ----------------------------------------------------------------------------
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// Resolution Handling
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// ----------------------------------------------------------------------------
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struct ScreenUniform {
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resolution : vec2f,
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};
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@group(0) @binding(0) // 1.
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var<uniform> screen : ScreenUniform;
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const RES = vec2f(320.0, 240.0); // The logical resolution of the screen.
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fn adjust_for_resolution(in_pos: vec2<f32>) -> vec2<f32> {
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// Adjust in_pos for the "resolution" of the screen.
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let RES_AR = RES.x / RES.y; // The aspect ratio of the logical screen.
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// the actual resolution of the screen.
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let screen_ar = screen.resolution.x / screen.resolution.y;
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// Compute the difference in resolution ... correctly?
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//
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// nudge is the amount to add to the logical resolution so that the pixels
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// stay the same size but we respect the aspect ratio of the screen. (So
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// there's more of them in either the x or y direction.)
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var nudge = vec2f(0.0);
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if (screen_ar > RES_AR) {
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nudge.x = (RES.y * screen_ar) - RES.x;
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} else {
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nudge.y = (RES.x / screen_ar) - RES.y;
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}
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var new_logical_resolution = RES + nudge;
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// Now we can convert the incoming position to clip space, in the new screen.
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let centered = in_pos + (nudge / 2.0);
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var position = (2.0 * centered / new_logical_resolution) - 1.0;
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position.y = -position.y;
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return position;
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}
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