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// Copyright 2016 The SwiftShader Authors. All Rights Reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#include "Clipper.hpp"
#include "Polygon.hpp"
#include "Renderer.hpp"
namespace {
inline void clipEdge(sw::float4 &Vo, const sw::float4 &Vi, const sw::float4 &Vj, float di, float dj)
{
float D = 1.0f / (dj - di);
Vo.x = (dj * Vi.x - di * Vj.x) * D;
Vo.y = (dj * Vi.y - di * Vj.y) * D;
Vo.z = (dj * Vi.z - di * Vj.z) * D;
Vo.w = (dj * Vi.w - di * Vj.w) * D;
}
void clipNear(sw::Polygon &polygon)
{
const sw::float4 **V = polygon.P[polygon.i];
const sw::float4 **T = polygon.P[polygon.i + 1];
int t = 0;
for(int i = 0; i < polygon.n; i++)
{
int j = i == polygon.n - 1 ? 0 : i + 1;
float di = V[i]->z;
float dj = V[j]->z;
if(di >= 0)
{
T[t++] = V[i];
if(dj < 0)
{
clipEdge(polygon.B[polygon.b], *V[i], *V[j], di, dj);
T[t++] = &polygon.B[polygon.b++];
}
}
else
{
if(dj > 0)
{
clipEdge(polygon.B[polygon.b], *V[j], *V[i], dj, di);
T[t++] = &polygon.B[polygon.b++];
}
}
}
polygon.n = t;
polygon.i += 1;
}
void clipFar(sw::Polygon &polygon)
{
const sw::float4 **V = polygon.P[polygon.i];
const sw::float4 **T = polygon.P[polygon.i + 1];
int t = 0;
for(int i = 0; i < polygon.n; i++)
{
int j = i == polygon.n - 1 ? 0 : i + 1;
float di = V[i]->w - V[i]->z;
float dj = V[j]->w - V[j]->z;
if(di >= 0)
{
T[t++] = V[i];
if(dj < 0)
{
clipEdge(polygon.B[polygon.b], *V[i], *V[j], di, dj);
T[t++] = &polygon.B[polygon.b++];
}
}
else
{
if(dj > 0)
{
clipEdge(polygon.B[polygon.b], *V[j], *V[i], dj, di);
T[t++] = &polygon.B[polygon.b++];
}
}
}
polygon.n = t;
polygon.i += 1;
}
void clipLeft(sw::Polygon &polygon)
{
const sw::float4 **V = polygon.P[polygon.i];
const sw::float4 **T = polygon.P[polygon.i + 1];
int t = 0;
for(int i = 0; i < polygon.n; i++)
{
int j = i == polygon.n - 1 ? 0 : i + 1;
float di = V[i]->w + V[i]->x;
float dj = V[j]->w + V[j]->x;
if(di >= 0)
{
T[t++] = V[i];
if(dj < 0)
{
clipEdge(polygon.B[polygon.b], *V[i], *V[j], di, dj);
T[t++] = &polygon.B[polygon.b++];
}
}
else
{
if(dj > 0)
{
clipEdge(polygon.B[polygon.b], *V[j], *V[i], dj, di);
T[t++] = &polygon.B[polygon.b++];
}
}
}
polygon.n = t;
polygon.i += 1;
}
void clipRight(sw::Polygon &polygon)
{
const sw::float4 **V = polygon.P[polygon.i];
const sw::float4 **T = polygon.P[polygon.i + 1];
int t = 0;
for(int i = 0; i < polygon.n; i++)
{
int j = i == polygon.n - 1 ? 0 : i + 1;
float di = V[i]->w - V[i]->x;
float dj = V[j]->w - V[j]->x;
if(di >= 0)
{
T[t++] = V[i];
if(dj < 0)
{
clipEdge(polygon.B[polygon.b], *V[i], *V[j], di, dj);
T[t++] = &polygon.B[polygon.b++];
}
}
else
{
if(dj > 0)
{
clipEdge(polygon.B[polygon.b], *V[j], *V[i], dj, di);
T[t++] = &polygon.B[polygon.b++];
}
}
}
polygon.n = t;
polygon.i += 1;
}
void clipTop(sw::Polygon &polygon)
{
const sw::float4 **V = polygon.P[polygon.i];
const sw::float4 **T = polygon.P[polygon.i + 1];
int t = 0;
for(int i = 0; i < polygon.n; i++)
{
int j = i == polygon.n - 1 ? 0 : i + 1;
float di = V[i]->w - V[i]->y;
float dj = V[j]->w - V[j]->y;
if(di >= 0)
{
T[t++] = V[i];
if(dj < 0)
{
clipEdge(polygon.B[polygon.b], *V[i], *V[j], di, dj);
T[t++] = &polygon.B[polygon.b++];
}
}
else
{
if(dj > 0)
{
clipEdge(polygon.B[polygon.b], *V[j], *V[i], dj, di);
T[t++] = &polygon.B[polygon.b++];
}
}
}
polygon.n = t;
polygon.i += 1;
}
void clipBottom(sw::Polygon &polygon)
{
const sw::float4 **V = polygon.P[polygon.i];
const sw::float4 **T = polygon.P[polygon.i + 1];
int t = 0;
for(int i = 0; i < polygon.n; i++)
{
int j = i == polygon.n - 1 ? 0 : i + 1;
float di = V[i]->w + V[i]->y;
float dj = V[j]->w + V[j]->y;
if(di >= 0)
{
T[t++] = V[i];
if(dj < 0)
{
clipEdge(polygon.B[polygon.b], *V[i], *V[j], di, dj);
T[t++] = &polygon.B[polygon.b++];
}
}
else
{
if(dj > 0)
{
clipEdge(polygon.B[polygon.b], *V[j], *V[i], dj, di);
T[t++] = &polygon.B[polygon.b++];
}
}
}
polygon.n = t;
polygon.i += 1;
}
} // anonymous namespace
namespace sw {
unsigned int Clipper::ComputeClipFlags(const float4 &v)
{
return ((v.x > v.w) ? CLIP_RIGHT : 0) |
((v.y > v.w) ? CLIP_TOP : 0) |
((v.z > v.w) ? CLIP_FAR : 0) |
((v.x < -v.w) ? CLIP_LEFT : 0) |
((v.y < -v.w) ? CLIP_BOTTOM : 0) |
((v.z < 0) ? CLIP_NEAR : 0) |
Clipper::CLIP_FINITE; // FIXME: xyz finite
}
bool Clipper::Clip(Polygon &polygon, int clipFlagsOr, const DrawCall &draw)
{
if(clipFlagsOr & CLIP_FRUSTUM)
{
if(clipFlagsOr & CLIP_NEAR) clipNear(polygon);
if(polygon.n >= 3) {
if(clipFlagsOr & CLIP_FAR) clipFar(polygon);
if(polygon.n >= 3) {
if(clipFlagsOr & CLIP_LEFT) clipLeft(polygon);
if(polygon.n >= 3) {
if(clipFlagsOr & CLIP_RIGHT) clipRight(polygon);
if(polygon.n >= 3) {
if(clipFlagsOr & CLIP_TOP) clipTop(polygon);
if(polygon.n >= 3) {
if(clipFlagsOr & CLIP_BOTTOM) clipBottom(polygon);
}}}}}
}
return polygon.n >= 3;
}
} // namespace sw