/* glm.h Nate Robins, 1997 ndr@pobox.com, http://www.pobox.com/~ndr/ Wavefront OBJ model file format reader/writer/manipulator. Includes routines for generating smooth normals with preservation of edges, welding redundant vertices & texture coordinate generation (spheremap and planar projections) + more. */ #include #ifndef M_PI #define M_PI 3.14159265 #endif #define GLM_NONE (0) /* render with only vertices */ #define GLM_FLAT (1 << 0) /* render with facet normals */ #define GLM_SMOOTH (1 << 1) /* render with vertex normals */ #define GLM_TEXTURE (1 << 2) /* render with texture coords */ #define GLM_COLOR (1 << 3) /* render with colors */ #define GLM_MATERIAL (1 << 4) /* render with materials */ /* GLMmaterial: Structure that defines a material in a model. */ typedef struct _GLMmaterial { char* name; /* name of material */ GLfloat diffuse[4]; /* diffuse component */ GLfloat ambient[4]; /* ambient component */ GLfloat specular[4]; /* specular component */ GLfloat emmissive[4]; /* emmissive component */ GLfloat shininess; /* specular exponent */ } GLMmaterial; /* GLMtriangle: Structure that defines a triangle in a model. */ typedef struct _GLMtriangle { GLuint vindices[3]; /* array of triangle vertex indices */ GLuint nindices[3]; /* array of triangle normal indices */ GLuint tindices[3]; /* array of triangle texcoord indices*/ GLuint findex; /* index of triangle facet normal */ } GLMtriangle; /* GLMgroup: Structure that defines a group in a model. */ typedef struct _GLMgroup { char* name; /* name of this group */ GLuint numtriangles; /* number of triangles in this group */ GLuint* triangles; /* array of triangle indices */ GLuint material; /* index to material for group */ struct _GLMgroup* next; /* pointer to next group in model */ } GLMgroup; /* GLMmodel: Structure that defines a model. */ typedef struct _GLMmodel { char* pathname; /* path to this model */ char* mtllibname; /* name of the material library */ GLuint numvertices; /* number of vertices in model */ GLfloat* vertices; /* array of vertices */ GLuint numnormals; /* number of normals in model */ GLfloat* normals; /* array of normals */ GLuint numtexcoords; /* number of texcoords in model */ GLfloat* texcoords; /* array of texture coordinates */ GLuint numfacetnorms; /* number of facetnorms in model */ GLfloat* facetnorms; /* array of facetnorms */ GLuint numtriangles; /* number of triangles in model */ GLMtriangle* triangles; /* array of triangles */ GLuint nummaterials; /* number of materials in model */ GLMmaterial* materials; /* array of materials */ GLuint numgroups; /* number of groups in model */ GLMgroup* groups; /* linked list of groups */ GLfloat position[3]; /* position of the model */ } GLMmodel; /* glmUnitize: "unitize" a model by translating it to the origin and * scaling it to fit in a unit cube around the origin. Returns the * scalefactor used. * * model - properly initialized GLMmodel structure */ GLfloat glmUnitize(GLMmodel* model); /* glmDimensions: Calculates the dimensions (width, height, depth) of * a model. * * model - initialized GLMmodel structure * dimensions - array of 3 GLfloats (GLfloat dimensions[3]) */ GLvoid glmDimensions(GLMmodel* model, GLfloat* dimensions); /* glmScale: Scales a model by a given amount. * * model - properly initialized GLMmodel structure * scale - scalefactor (0.5 = half as large, 2.0 = twice as large) */ GLvoid glmScale(GLMmodel* model, GLfloat scale); /* glmReverseWinding: Reverse the polygon winding for all polygons in * this model. Default winding is counter-clockwise. Also changes * the direction of the normals. * * model - properly initialized GLMmodel structure */ GLvoid glmReverseWinding(GLMmodel* model); /* glmFacetNormals: Generates facet normals for a model (by taking the * cross product of the two vectors derived from the sides of each * triangle). Assumes a counter-clockwise winding. * * model - initialized GLMmodel structure */ GLvoid glmFacetNormals(GLMmodel* model); /* glmVertexNormals: Generates smooth vertex normals for a model. * First builds a list of all the triangles each vertex is in. Then * loops through each vertex in the the list averaging all the facet * normals of the triangles each vertex is in. Finally, sets the * normal index in the triangle for the vertex to the generated smooth * normal. If the dot product of a facet normal and the facet normal * associated with the first triangle in the list of triangles the * current vertex is in is greater than the cosine of the angle * parameter to the function, that facet normal is not added into the * average normal calculation and the corresponding vertex is given * the facet normal. This tends to preserve hard edges. The angle to * use depends on the model, but 90 degrees is usually a good start. * * model - initialized GLMmodel structure * angle - maximum angle (in degrees) to smooth across */ GLvoid glmVertexNormals(GLMmodel* model, GLfloat angle); /* glmLinearTexture: Generates texture coordinates according to a * linear projection of the texture map. It generates these by * linearly mapping the vertices onto a square. * * model - pointer to initialized GLMmodel structure */ GLvoid glmLinearTexture(GLMmodel* model); /* glmSpheremapTexture: Generates texture coordinates according to a * spherical projection of the texture map. Sometimes referred to as * spheremap, or reflection map texture coordinates. It generates * these by using the normal to calculate where that vertex would map * onto a sphere. Since it is impossible to map something flat * perfectly onto something spherical, there is distortion at the * poles. This particular implementation causes the poles along the X * axis to be distorted. * * model - pointer to initialized GLMmodel structure */ GLvoid glmSpheremapTexture(GLMmodel* model); /* glmDelete: Deletes a GLMmodel structure. * * model - initialized GLMmodel structure */ GLvoid glmDelete(GLMmodel* model); /* glmReadOBJ: Reads a model description from a Wavefront .OBJ file. * Returns a pointer to the created object which should be free'd with * glmDelete(). * * filename - name of the file containing the Wavefront .OBJ format data. */ GLMmodel* glmReadOBJ(char* filename); /* glmWriteOBJ: Writes a model description in Wavefront .OBJ format to * a file. * * model - initialized GLMmodel structure * filename - name of the file to write the Wavefront .OBJ format data to * mode - a bitwise or of values describing what is written to the file * GLM_NONE - write only vertices * GLM_FLAT - write facet normals * GLM_SMOOTH - write vertex normals * GLM_TEXTURE - write texture coords * GLM_FLAT and GLM_SMOOTH should not both be specified. */ GLvoid glmWriteOBJ(GLMmodel* model, char* filename, GLuint mode); /* glmDraw: Renders the model to the current OpenGL context using the * mode specified. * * model - initialized GLMmodel structure * mode - a bitwise OR of values describing what is to be rendered. * GLM_NONE - render with only vertices * GLM_FLAT - render with facet normals * GLM_SMOOTH - render with vertex normals * GLM_TEXTURE - render with texture coords * GLM_FLAT and GLM_SMOOTH should not both be specified. */ GLvoid glmDraw(GLMmodel* model, GLuint mode); /* glmList: Generates and returns a display list for the model using * the mode specified. * * model - initialized GLMmodel structure * mode - a bitwise OR of values describing what is to be rendered. * GLM_NONE - render with only vertices * GLM_FLAT - render with facet normals * GLM_SMOOTH - render with vertex normals * GLM_TEXTURE - render with texture coords * GLM_FLAT and GLM_SMOOTH should not both be specified. */ GLuint glmList(GLMmodel* model, GLuint mode); /* glmWeld: eliminate (weld) vectors that are within an epsilon of * each other. * * model - initialized GLMmodel structure * epsilon - maximum difference between vertices * ( 0.00001 is a good start for a unitized model) * */ GLvoid glmWeld(GLMmodel* model, GLfloat epsilon);