diff options
Diffstat (limited to 'src/shaders/render')
| -rw-r--r-- | src/shaders/render/fullscreen_uv_vs.wgsl | 24 |
1 files changed, 19 insertions, 5 deletions
diff --git a/src/shaders/render/fullscreen_uv_vs.wgsl b/src/shaders/render/fullscreen_uv_vs.wgsl index f9ae427..5f76160 100644 --- a/src/shaders/render/fullscreen_uv_vs.wgsl +++ b/src/shaders/render/fullscreen_uv_vs.wgsl @@ -1,15 +1,29 @@ // Common vertex shader for fullscreen post-processing effects. -// Draws a single triangle that covers the entire screen, with uv -// coordinates in [0..1] +// Draws a single triangle that covers the entire screen. +// +// Screen-space convention: Y-UP, origin at BOTTOM-LEFT +// uv in [0,1]: (0,0) = bottom-left, (1,1) = top-right +// st in [-1,1]: NDC directly, y-up +// +// WebGPU textures are Y-DOWN ((0,0) at top-left). +// Use textureSampleYUp() instead of textureSample() when sampling with uv. struct VertexOutput { - @builtin(position) position: vec4f, - @location(0) uv: vec2f, + @builtin(position) position: vec4f, // in pixel screen units + @location(0) uv: vec2f, // in [0, 1] + @location(1) st: vec2f, // in [-1, 1] }; @vertex fn vs_main(@builtin(vertex_index) i: u32) -> VertexOutput { - let pos = array<vec4f, 3>(vec4f(-1, -1, 0, 1.), vec4f(3, -1, 2., 1.), vec4f(-1, 3, 0, -1)); + let pos = array<vec4f, 3>(vec4f(-1, -1, 0, 0.), vec4f(3, -1, 2., 0.), vec4f(-1, 3, 0, 2.)); var out: VertexOutput; out.position = vec4f(pos[i].xy, 0.0, 1.0); out.uv = pos[i].zw; + out.st = pos[i].xy; return out; } + +// Sample a texture using y-up UV coordinates (uv.y=0 at bottom). +// Flips Y to match WebGPU texture convention (texel (0,0) at top-left). +fn textureSampleYUp(tex: texture_2d<f32>, s: sampler, uv: vec2f) -> vec4f { + return textureSample(tex, s, vec2f(uv.x, 1.0 - uv.y)); +} |