mirror of https://github.com/axmolengine/axmol.git
104 lines
3.4 KiB
C
104 lines
3.4 KiB
C
/* Copyright (c) 2007 Scott Lembcke
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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* SOFTWARE.
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*/
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// Axis structure used by cpPolyShape.
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typedef struct cpPolyShapeAxis{
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// normal
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cpVect n;
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// distance from origin
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cpFloat d;
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} cpPolyShapeAxis;
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// Convex polygon shape structure.
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typedef struct cpPolyShape{
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cpShape shape;
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// Vertex and axis lists.
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CP_PRIVATE(int numVerts);
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CP_PRIVATE(cpVect *verts);
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CP_PRIVATE(cpPolyShapeAxis *axes);
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// Transformed vertex and axis lists.
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CP_PRIVATE(cpVect *tVerts);
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CP_PRIVATE(cpPolyShapeAxis *tAxes);
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} cpPolyShape;
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// Basic allocation functions.
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cpPolyShape *cpPolyShapeAlloc(void);
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cpPolyShape *cpPolyShapeInit(cpPolyShape *poly, cpBody *body, int numVerts, cpVect *verts, cpVect offset);
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cpShape *cpPolyShapeNew(cpBody *body, int numVerts, cpVect *verts, cpVect offset);
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cpPolyShape *cpBoxShapeInit(cpPolyShape *poly, cpBody *body, cpFloat width, cpFloat height);
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cpShape *cpBoxShapeNew(cpBody *body, cpFloat width, cpFloat height);
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// Check that a set of vertexes has a correct winding and that they are convex
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cpBool cpPolyValidate(const cpVect *verts, const int numVerts);
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int cpPolyShapeGetNumVerts(cpShape *shape);
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cpVect cpPolyShapeGetVert(cpShape *shape, int idx);
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// *** inlined utility functions
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// Returns the minimum distance of the polygon to the axis.
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static inline cpFloat
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cpPolyShapeValueOnAxis(const cpPolyShape *poly, const cpVect n, const cpFloat d)
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{
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cpVect *verts = poly->CP_PRIVATE(tVerts);
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cpFloat min = cpvdot(n, verts[0]);
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int i;
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for(i=1; i<poly->CP_PRIVATE(numVerts); i++)
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min = cpfmin(min, cpvdot(n, verts[i]));
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return min - d;
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}
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// Returns true if the polygon contains the vertex.
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static inline cpBool
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cpPolyShapeContainsVert(const cpPolyShape *poly, const cpVect v)
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{
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cpPolyShapeAxis *axes = poly->CP_PRIVATE(tAxes);
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int i;
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for(i=0; i<poly->CP_PRIVATE(numVerts); i++){
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cpFloat dist = cpvdot(axes[i].n, v) - axes[i].d;
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if(dist > 0.0f) return cpFalse;
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}
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return cpTrue;
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}
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// Same as cpPolyShapeContainsVert() but ignores faces pointing away from the normal.
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static inline cpBool
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cpPolyShapeContainsVertPartial(const cpPolyShape *poly, const cpVect v, const cpVect n)
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{
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cpPolyShapeAxis *axes = poly->CP_PRIVATE(tAxes);
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int i;
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for(i=0; i<poly->CP_PRIVATE(numVerts); i++){
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if(cpvdot(axes[i].n, n) < 0.0f) continue;
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cpFloat dist = cpvdot(axes[i].n, v) - axes[i].d;
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if(dist > 0.0f) return cpFalse;
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}
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return cpTrue;
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}
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