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Pica: Add triangle clipper.

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This commit is contained in:
Tony Wasserka 2014-07-27 17:34:11 +02:00
parent 9a76a2d061
commit 94aa9da562
7 changed files with 230 additions and 8 deletions
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6
src/video_core/CMakeLists.txt
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@ -1,11 +1,13 @@
set(SRCS command_processor.cpp
set(SRCS clipper.cpp
command_processor.cpp
primitive_assembly.cpp
utils.cpp
vertex_shader.cpp
video_core.cpp
renderer_opengl/renderer_opengl.cpp)
set(HEADERS command_processor.h
set(HEADERS clipper.h
command_processor.h
math.h
primitive_assembly.h
utils.h

178
src/video_core/clipper.cpp Normal file
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@ -0,0 +1,178 @@
// Copyright 2014 Citra Emulator Project
// Licensed under GPLv2
// Refer to the license.txt file included.
#include <vector>
#include "clipper.h"
#include "pica.h"
#include "vertex_shader.h"
namespace Pica {
namespace Clipper {
struct ClippingEdge {
public:
enum Type {
POS_X = 0,
NEG_X = 1,
POS_Y = 2,
NEG_Y = 3,
POS_Z = 4,
NEG_Z = 5,
};
ClippingEdge(Type type, float24 position) : type(type), pos(position) {}
bool IsInside(const OutputVertex& vertex) const {
switch (type) {
case POS_X: return vertex.pos.x <= pos * vertex.pos.w;
case NEG_X: return vertex.pos.x >= pos * vertex.pos.w;
case POS_Y: return vertex.pos.y <= pos * vertex.pos.w;
case NEG_Y: return vertex.pos.y >= pos * vertex.pos.w;
// TODO: Check z compares ... should be 0..1 instead?
case POS_Z: return vertex.pos.z <= pos * vertex.pos.w;
default:
case NEG_Z: return vertex.pos.z >= pos * vertex.pos.w;
}
}
bool IsOutSide(const OutputVertex& vertex) const {
return !IsInside(vertex);
}
OutputVertex GetIntersection(const OutputVertex& v0, const OutputVertex& v1) const {
auto dotpr = [this](const OutputVertex& vtx) {
switch (type) {
case POS_X: return vtx.pos.x - vtx.pos.w;
case NEG_X: return -vtx.pos.x - vtx.pos.w;
case POS_Y: return vtx.pos.y - vtx.pos.w;
case NEG_Y: return -vtx.pos.y - vtx.pos.w;
// TODO: Verify z clipping
case POS_Z: return vtx.pos.z - vtx.pos.w;
default:
case NEG_Z: return -vtx.pos.w;
}
};
float24 dp = dotpr(v0);
float24 dp_prev = dotpr(v1);
float24 factor = dp_prev / (dp_prev - dp);
return OutputVertex::Lerp(factor, v0, v1);
}
private:
Type type;
float24 pos;
};
static void InitScreenCoordinates(OutputVertex& vtx)
{
struct {
float24 halfsize_x;
float24 offset_x;
float24 halfsize_y;
float24 offset_y;
float24 zscale;
float24 offset_z;
} viewport;
viewport.halfsize_x = float24::FromRawFloat24(registers.viewport_size_x);
viewport.halfsize_y = float24::FromRawFloat24(registers.viewport_size_y);
viewport.offset_x = float24::FromFloat32(registers.viewport_corner.x);
viewport.offset_y = float24::FromFloat32(registers.viewport_corner.y);
viewport.zscale = float24::FromRawFloat24(registers.viewport_depth_range);
viewport.offset_z = float24::FromRawFloat24(registers.viewport_depth_far_plane);
// TODO: Not sure why the viewport width needs to be divided by 2 but the viewport height does not
vtx.screenpos[0] = (vtx.pos.x / vtx.pos.w + float24::FromFloat32(1.0)) * viewport.halfsize_x / float24::FromFloat32(2.0) + viewport.offset_x;
vtx.screenpos[1] = (vtx.pos.y / vtx.pos.w + float24::FromFloat32(1.0)) * viewport.halfsize_y + viewport.offset_y;
vtx.screenpos[2] = viewport.offset_z - vtx.pos.z / vtx.pos.w * viewport.zscale;
}
void ProcessTriangle(OutputVertex &v0, OutputVertex &v1, OutputVertex &v2) {
// TODO (neobrain):
// The list of output vertices has some fixed maximum size,
// however I haven't taken the time to figure out what it is exactly.
// For now, we hence just assume a maximal size of 1000 vertices.
const size_t max_vertices = 1000;
std::vector<OutputVertex> buffer_vertices;
std::vector<OutputVertex*> output_list{ &v0, &v1, &v2 };
// Make sure to reserve space for all vertices.
// Without this, buffer reallocation would invalidate references.
buffer_vertices.reserve(max_vertices);
// Simple implementation of the Sutherland-Hodgman clipping algorithm.
// TODO: Make this less inefficient (currently lots of useless buffering overhead happens here)
for (auto edge : { ClippingEdge(ClippingEdge::POS_X, float24::FromFloat32(+1.0)),
ClippingEdge(ClippingEdge::NEG_X, float24::FromFloat32(-1.0)),
ClippingEdge(ClippingEdge::POS_Y, float24::FromFloat32(+1.0)),
ClippingEdge(ClippingEdge::NEG_Y, float24::FromFloat32(-1.0)),
ClippingEdge(ClippingEdge::POS_Z, float24::FromFloat32(+1.0)),
ClippingEdge(ClippingEdge::NEG_Z, float24::FromFloat32(-1.0)) }) {
const std::vector<OutputVertex*> input_list = output_list;
output_list.clear();
const OutputVertex* reference_vertex = input_list.back();
for (const auto& vertex : input_list) {
// NOTE: This algorithm changes vertex order in some cases!
if (edge.IsInside(*vertex)) {
if (edge.IsOutSide(*reference_vertex)) {
buffer_vertices.push_back(edge.GetIntersection(*vertex, *reference_vertex));
output_list.push_back(&(buffer_vertices.back()));
}
output_list.push_back(vertex);
} else if (edge.IsInside(*reference_vertex)) {
buffer_vertices.push_back(edge.GetIntersection(*vertex, *reference_vertex));
output_list.push_back(&(buffer_vertices.back()));
}
reference_vertex = vertex;
}
// Need to have at least a full triangle to continue...
if (output_list.size() < 3)
return;
}
InitScreenCoordinates(*(output_list[0]));
InitScreenCoordinates(*(output_list[1]));
for (int i = 0; i < output_list.size() - 2; i ++) {
OutputVertex& vtx0 = *(output_list[0]);
OutputVertex& vtx1 = *(output_list[i+1]);
OutputVertex& vtx2 = *(output_list[i+2]);
InitScreenCoordinates(vtx2);
DEBUG_LOG(GPU,
"Triangle %d/%d (%d buffer vertices) at position (%.3f, %.3f, %.3f, %.3f), "
"(%.3f, %.3f, %.3f, %.3f), (%.3f, %.3f, %.3f, %.3f) and "
"screen position (%.2f, %.2f, %.2f), (%.2f, %.2f, %.2f), (%.2f, %.2f, %.2f)",
i,output_list.size(), buffer_vertices.size(),
vtx0.pos.x.ToFloat32(), vtx0.pos.y.ToFloat32(), vtx0.pos.z.ToFloat32(), vtx0.pos.w.ToFloat32(),output_list.size(),
vtx1.pos.x.ToFloat32(), vtx1.pos.y.ToFloat32(), vtx1.pos.z.ToFloat32(), vtx1.pos.w.ToFloat32(),
vtx2.pos.x.ToFloat32(), vtx2.pos.y.ToFloat32(), vtx2.pos.z.ToFloat32(), vtx2.pos.w.ToFloat32(),
vtx0.screenpos.x.ToFloat32(), vtx0.screenpos.y.ToFloat32(), vtx0.screenpos.z.ToFloat32(),
vtx1.screenpos.x.ToFloat32(), vtx1.screenpos.y.ToFloat32(), vtx1.screenpos.z.ToFloat32(),
vtx2.screenpos.x.ToFloat32(), vtx2.screenpos.y.ToFloat32(), vtx2.screenpos.z.ToFloat32());
// TODO: Send triangle to rasterizer
}
}
} // namespace
} // namespace

21
src/video_core/clipper.h Normal file
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@ -0,0 +1,21 @@
// Copyright 2014 Citra Emulator Project
// Licensed under GPLv2
// Refer to the license.txt file included.
#pragma once
namespace Pica {
namespace VertexShader {
struct OutputVertex;
}
namespace Clipper {
using VertexShader::OutputVertex;
void ProcessTriangle(OutputVertex& v0, OutputVertex& v1, OutputVertex& v2);
} // namespace
} // namespace

22
src/video_core/pica.h
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@ -50,7 +50,12 @@ struct Regs {
INSERT_PADDING_WORDS(0x1);
BitField<0, 24, u32> viewport_size_y;
INSERT_PADDING_WORDS(0xc);
INSERT_PADDING_WORDS(0x9);
BitField<0, 24, u32> viewport_depth_range; // float24
BitField<0, 24, u32> viewport_depth_far_plane; // float24
INSERT_PADDING_WORDS(0x1);
union {
// Maps components of output vertex attributes to semantics
@ -82,7 +87,14 @@ struct Regs {
BitField<24, 5, Semantic> map_w;
} vs_output_attributes[7];
INSERT_PADDING_WORDS(0x1a9);
INSERT_PADDING_WORDS(0x11);
union {
BitField< 0, 16, u32> x;
BitField<16, 16, u32> y;
} viewport_corner;
INSERT_PADDING_WORDS(0x197);
struct {
enum class Format : u64 {
@ -340,6 +352,9 @@ struct Regs {
ADD_FIELD(viewport_size_x);
ADD_FIELD(viewport_size_y);
ADD_FIELD(viewport_depth_range);
ADD_FIELD(viewport_depth_far_plane);
ADD_FIELD(viewport_corner);
ADD_FIELD(vertex_attributes);
ADD_FIELD(index_array);
ADD_FIELD(num_vertices);
@ -391,8 +406,11 @@ private:
ASSERT_REG_POSITION(viewport_size_x, 0x41);
ASSERT_REG_POSITION(viewport_size_y, 0x43);
ASSERT_REG_POSITION(viewport_depth_range, 0x4d);
ASSERT_REG_POSITION(viewport_depth_far_plane, 0x4e);
ASSERT_REG_POSITION(vs_output_attributes[0], 0x50);
ASSERT_REG_POSITION(vs_output_attributes[1], 0x51);
ASSERT_REG_POSITION(viewport_corner, 0x68);
ASSERT_REG_POSITION(vertex_attributes, 0x200);
ASSERT_REG_POSITION(index_array, 0x227);
ASSERT_REG_POSITION(num_vertices, 0x228);

7
src/video_core/primitive_assembly.cpp
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@ -2,6 +2,7 @@
// Licensed under GPLv2
// Refer to the license.txt file included.
#include "clipper.h"
#include "pica.h"
#include "primitive_assembly.h"
#include "vertex_shader.h"
@ -23,8 +24,7 @@ void SubmitVertex(OutputVertex& vtx)
} else {
buffer_index = 0;
// TODO
// Clipper::ProcessTriangle(buffer[0], buffer[1], vtx);
Clipper::ProcessTriangle(buffer[0], buffer[1], vtx);
}
break;
@ -32,8 +32,7 @@ void SubmitVertex(OutputVertex& vtx)
if (buffer_index == 2) {
buffer_index = 0;
// TODO
// Clipper::ProcessTriangle(buffer[0], buffer[1], vtx);
Clipper::ProcessTriangle(buffer[0], buffer[1], vtx);
buffer[1] = vtx;
} else {

2
src/video_core/video_core.vcxproj
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@ -20,6 +20,7 @@
</ItemGroup>
<ItemGroup>
<ClCompile Include="renderer_opengl\renderer_opengl.cpp" />
<ClCompile Include="clipper.cpp" />
<ClCompile Include="command_processor.cpp" />
<ClCompile Include="primitive_assembly.cpp" />
<ClCompile Include="utils.cpp" />
@ -27,6 +28,7 @@
<ClCompile Include="video_core.cpp" />
</ItemGroup>
<ItemGroup>
<ClInclude Include="clipper.h" />
<ClInclude Include="command_processor.h" />
<ClInclude Include="gpu_debugger.h" />
<ClInclude Include="math.h" />

2
src/video_core/video_core.vcxproj.filters
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@ -9,6 +9,7 @@
<ClCompile Include="renderer_opengl\renderer_opengl.cpp">
<Filter>renderer_opengl</Filter>
</ClCompile>
<ClCompile Include="clipper.cpp" />
<ClCompile Include="command_processor.cpp" />
<ClCompile Include="primitive_assembly.cpp" />
<ClCompile Include="utils.cpp" />
@ -19,6 +20,7 @@
<ClInclude Include="renderer_opengl\renderer_opengl.h">
<Filter>renderer_opengl</Filter>
</ClInclude>
<ClInclude Include="clipper.h" />
<ClInclude Include="command_processor.h" />
<ClInclude Include="gpu_debugger.h" />
<ClInclude Include="math.h" />