From 4e092022267e4f232429013653ba1bd4ac8b0a05 Mon Sep 17 00:00:00 2001 From: Yuri Kunde Schlesner Date: Tue, 21 Jul 2015 01:24:27 -0300 Subject: VideoCore: Saturate vertex colors before interpolating During testing, it was discovered that hardware does not interpolate colors output by the vertex shader as-is. Rather, it drops the sign and saturates the value to 1.0. This is done before interpolation, such that (e.g.) interpolating outputs 1.5 and -0.5 is equivalent to as if the shader had output the values 1.0 and 0.5 instead, with the interpolated value never crossing 0.0. This change has been tested against hardware. --- src/video_core/vertex_shader.cpp | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'src/video_core/vertex_shader.cpp') diff --git a/src/video_core/vertex_shader.cpp b/src/video_core/vertex_shader.cpp index b7750380..ff114fc3 100644 --- a/src/video_core/vertex_shader.cpp +++ b/src/video_core/vertex_shader.cpp @@ -610,6 +610,12 @@ OutputVertex RunShader(const InputVertex& input, int num_attributes, const Regs: } } + // The hardware takes the absolute and saturates vertex colors like this, *before* doing interpolation + for (int i = 0; i < 4; ++i) { + ret.color[i] = float24::FromFloat32( + std::fmin(std::fabs(ret.color[i].ToFloat32()), 1.0f)); + } + LOG_TRACE(Render_Software, "Output vertex: pos (%.2f, %.2f, %.2f, %.2f), col(%.2f, %.2f, %.2f, %.2f), tc0(%.2f, %.2f)", ret.pos.x.ToFloat32(), ret.pos.y.ToFloat32(), ret.pos.z.ToFloat32(), ret.pos.w.ToFloat32(), ret.color.x.ToFloat32(), ret.color.y.ToFloat32(), ret.color.z.ToFloat32(), ret.color.w.ToFloat32(), -- cgit v1.2.3