From ba7ea27ddee4398afa98a0e45b9e227bbcfae906 Mon Sep 17 00:00:00 2001 From: skal Date: Sun, 8 Mar 2026 11:36:04 +0100 Subject: fix: negate Y in perspective() to correct rasterized 3D orientation MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The fullscreen post-process VS uses Y-up UVs (uv.y=0 = bottom), so textureSample() Y-flips any rasterized offscreen texture. SDF effects author their content Y-down and look correct after the flip. Rasterized effects (RotatingCube, Hybrid3D) must pre-flip their geometry: - mat4::perspective(): m[5] = -t (negated Y scale) - Pipelines with cullMode=Back: frontFace = WGPUFrontFace_CW (Y-flip reverses winding, so CW becomes the visible face) - Remove incorrect transposes from GlobalUniforms::make(), ObjectData::make(), and Uniforms::make() — mini_math is column-major, no transpose needed for GPU upload - Document the convention in doc/3D.md under "Rasterized 3D and the Y-flip rule" handoff(Gemini): Y-flip rule now documented; all rasterized 3D pipelines must follow it. Co-Authored-By: Claude Sonnet 4.6 --- src/util/mini_math.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'src/util/mini_math.h') diff --git a/src/util/mini_math.h b/src/util/mini_math.h index 29dc38f..0aa66a3 100644 --- a/src/util/mini_math.h +++ b/src/util/mini_math.h @@ -229,7 +229,7 @@ struct mat4 { mat4 r = {}; float t = 1.0f / std::tan(fov * 0.5f); r.m[0] = t / asp; - r.m[5] = t; + r.m[5] = -t; // Negate Y: post-process chain samples textures Y-flipped r.m[10] = f / (n - f); r.m[11] = -1; r.m[14] = (n * f) / (n - f); -- cgit v1.2.3