From 9675d19b47865c2dac5e662f5a265589bd03a283 Mon Sep 17 00:00:00 2001
From: Tony Wasserka <NeoBrainX@gmail.com>
Date: Wed, 31 Dec 2014 15:19:40 +0100
Subject: [PATCH] Pica/Rasterizer: Make orient2d a free function and rename it
to SignedArea.
---
src/video_core/rasterizer.cpp | 69 +++++++++++++++++++----------------
1 file changed, 38 insertions(+), 31 deletions(-)
diff --git a/src/video_core/rasterizer.cpp b/src/video_core/rasterizer.cpp
index 4dfc21885c..9850e517ae 100644
--- a/src/video_core/rasterizer.cpp
+++ b/src/video_core/rasterizer.cpp
@@ -55,30 +55,45 @@ static void SetDepth(int x, int y, u16 value) {
*(depth_buffer + x + y * registers.framebuffer.GetWidth()) = value;
}
-void ProcessTriangle(const VertexShader::OutputVertex& v0,
- const VertexShader::OutputVertex& v1,
- const VertexShader::OutputVertex& v2)
-{
- // NOTE: Assuming that rasterizer coordinates are 12.4 fixed-point values
- struct Fix12P4 {
- Fix12P4() {}
- Fix12P4(u16 val) : val(val) {}
+// NOTE: Assuming that rasterizer coordinates are 12.4 fixed-point values
+struct Fix12P4 {
+ Fix12P4() {}
+ Fix12P4(u16 val) : val(val) {}
- static u16 FracMask() { return 0xF; }
- static u16 IntMask() { return (u16)~0xF; }
+ static u16 FracMask() { return 0xF; }
+ static u16 IntMask() { return (u16)~0xF; }
- operator u16() const {
- return val;
- }
+ operator u16() const {
+ return val;
+ }
- bool operator < (const Fix12P4& oth) const {
- return (u16)*this < (u16)oth;
- }
+ bool operator < (const Fix12P4& oth) const {
+ return (u16)*this < (u16)oth;
+ }
- private:
- u16 val;
- };
+private:
+ u16 val;
+};
+
+/**
+ * Calculate signed area of the triangle spanned by the three argument vertices.
+ * The sign denotes an orientation.
+ *
+ * @todo define orientation concretely.
+ */
+static int SignedArea (const Math::Vec2<Fix12P4>& vtx1,
+ const Math::Vec2<Fix12P4>& vtx2,
+ const Math::Vec2<Fix12P4>& vtx3) {
+ const auto vec1 = Math::MakeVec(vtx2 - vtx1, 0);
+ const auto vec2 = Math::MakeVec(vtx3 - vtx1, 0);
+ // TODO: There is a very small chance this will overflow for sizeof(int) == 4
+ return Math::Cross(vec1, vec2).z;
+};
+void ProcessTriangle(const VertexShader::OutputVertex& v0,
+ const VertexShader::OutputVertex& v1,
+ const VertexShader::OutputVertex& v2)
+{
// vertex positions in rasterizer coordinates
auto FloatToFix = [](float24 flt) {
return Fix12P4(static_cast<unsigned short>(flt.ToFloat32() * 16.0f));
@@ -86,14 +101,6 @@ void ProcessTriangle(const VertexShader::OutputVertex& v0,
auto ScreenToRasterizerCoordinates = [FloatToFix](const Math::Vec3<float24> vec) {
return Math::Vec3<Fix12P4>{FloatToFix(vec.x), FloatToFix(vec.y), FloatToFix(vec.z)};
};
- static auto orient2d = [](const Math::Vec2<Fix12P4>& vtx1,
- const Math::Vec2<Fix12P4>& vtx2,
- const Math::Vec2<Fix12P4>& vtx3) {
- const auto vec1 = Math::MakeVec(vtx2 - vtx1, 0);
- const auto vec2 = Math::MakeVec(vtx3 - vtx1, 0);
- // TODO: There is a very small chance this will overflow for sizeof(int) == 4
- return Math::Cross(vec1, vec2).z;
- };
Math::Vec3<Fix12P4> vtxpos[3]{ ScreenToRasterizerCoordinates(v0.screenpos),
ScreenToRasterizerCoordinates(v1.screenpos),
@@ -107,7 +114,7 @@ void ProcessTriangle(const VertexShader::OutputVertex& v0,
if (registers.cull_mode != Regs::CullMode::KeepAll) {
// Cull away triangles which are wound clockwise.
// TODO: A check for degenerate triangles ("== 0") should be considered for CullMode::KeepAll
- if (orient2d(vtxpos[0].xy(), vtxpos[1].xy(), vtxpos[2].xy()) <= 0)
+ if (SignedArea(vtxpos[0].xy(), vtxpos[1].xy(), vtxpos[2].xy()) <= 0)
return;
}
@@ -153,9 +160,9 @@ void ProcessTriangle(const VertexShader::OutputVertex& v0,
for (u16 x = min_x; x < max_x; x += 0x10) {
// Calculate the barycentric coordinates w0, w1 and w2
- int w0 = bias0 + orient2d(vtxpos[1].xy(), vtxpos[2].xy(), {x, y});
- int w1 = bias1 + orient2d(vtxpos[2].xy(), vtxpos[0].xy(), {x, y});
- int w2 = bias2 + orient2d(vtxpos[0].xy(), vtxpos[1].xy(), {x, y});
+ int w0 = bias0 + SignedArea(vtxpos[1].xy(), vtxpos[2].xy(), {x, y});
+ int w1 = bias1 + SignedArea(vtxpos[2].xy(), vtxpos[0].xy(), {x, y});
+ int w2 = bias2 + SignedArea(vtxpos[0].xy(), vtxpos[1].xy(), {x, y});
int wsum = w0 + w1 + w2;
// If current pixel is not covered by the current primitive
--
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