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Pica: Implement W-Buffer in SW rasterizer

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This commit is contained in:
Jannik Vogel 2016-03-20 01:53:49 +01:00
parent 006fe5fc0f
commit 4c98113b57
4 changed files with 43 additions and 11 deletions
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26
src/video_core/rasterizer.cpp
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@ -862,10 +862,30 @@ static void ProcessTriangleInternal(const Shader::OutputVertex& v0,
}
}
// interpolated_z = z / w
float interpolated_z_over_w = (v0.screenpos[2].ToFloat32() * w0 +
v1.screenpos[2].ToFloat32() * w1 +
v2.screenpos[2].ToFloat32() * w2) / wsum;
// Not fully accurate. About 3 bits in precision are missing.
// Z-Buffer (z / w * scale + offset)
float depth_scale = float24::FromRaw(regs.viewport_depth_range).ToFloat32();
float depth_offset = float24::FromRaw(regs.viewport_depth_near_plane).ToFloat32();
float depth = interpolated_z_over_w * depth_scale + depth_offset;
// Potentially switch to W-Buffer
if (regs.depthmap_enable == Pica::Regs::DepthBuffering::WBuffering) {
// W-Buffer (z * scale + w * offset = (z / w * scale + offset) * w)
depth *= interpolated_w_inverse.ToFloat32() * wsum;
}
// Clamp the result
depth = MathUtil::Clamp(depth, 0.0f, 1.0f);
// Convert float to integer
unsigned num_bits = Regs::DepthBitsPerPixel(regs.framebuffer.depth_format);
u32 z = (u32)((v0.screenpos[2].ToFloat32() * w0 +
v1.screenpos[2].ToFloat32() * w1 +
v2.screenpos[2].ToFloat32() * w2) * ((1 << num_bits) - 1) / wsum);
u32 z = (u32)(depth * ((1 << num_bits) - 1));
if (output_merger.depth_test_enable) {
u32 ref_z = GetDepth(x >> 4, y >> 4);