98 lines
2.5 KiB
C++
98 lines
2.5 KiB
C++
/*
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* DoRayMe - a quick and dirty Raytracer
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* Texture Map header
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*
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* Created by Manoël Trapier
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* Copyright (c) 2020 986-Studio.
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*
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*/
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#ifndef DORAYME_TEXTUREMAP_H
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#define DORAYME_TEXTUREMAP_H
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#include <math.h>
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#include <tuple.h>
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#include <uv_pattern.h>
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#include <colour.h>
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enum TextureMapType
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{
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SPHERICAL_MAP,
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PLANAR_MAP,
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CYLINDRICAL_MAP,
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};
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class TextureMap : public Pattern
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{
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private:
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TextureMapType type;
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UVPattern *pattern;
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public:
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TextureMap(TextureMapType type, UVPattern *pattern) : Pattern(Colour(0, 0, 0), Colour(0, 0, 0)),
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type(type), pattern(pattern) { };
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static void sphericalMap(Tuple point, double &u, double &v) {
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/* First compute the azimuthal angle
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* -π < theta <= π
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* angle increases clockwise as viewed from above,
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* which is opposite of what we want, but we'll fix it later.
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*/
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double theta = atan2(point.x, point.z);
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/* vec is the vector pointing from the sphere's origin (the world origin)
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* to the point, which will also happen to be exactly equal to the sphere's
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* radius.
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*/
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Tuple vec = Vector(point.x, point.y, point.z);
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double radius = vec.magnitude();
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/* Let's compute the polar angle
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* 0 <= phi <= π
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*/
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double phi = acos(point.y / radius);
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/* -0.5 < raw_u <= 0.5 */
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double raw_u = theta / (2 * M_PI);
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/* 0 <= u < 1
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* here's also where we fix the direction of u. Subtract it from 1,
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* so that it increases counterclockwise as viewed from above.
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*/
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u = 1 - (raw_u + 0.5);
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/* We want v to be 0 at the south pole of the sphere,
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* and 1 at the north pole, so we have to "flip it over"
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* by subtracting it from 1.
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*/
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v = 1 - phi / M_PI;
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}
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static void planarMap(Tuple point, double &u, double &v) {
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u = fmod(point.x, 1);
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v = fmod(point.z, 1);
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}
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Colour patternAt(Tuple point)
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{
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double u,v;
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switch(this->type)
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{
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default:
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case SPHERICAL_MAP:
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this->sphericalMap(point, u, v);
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break;
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case PLANAR_MAP:
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this->planarMap(point, u, v);
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break;
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}
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return this->pattern->uvPatternAt(u, v);
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}
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void dumpMe(FILE *fp) {
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fprintf(fp, "\"Type\": \"TextureMap\",\n");
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Pattern::dumpMe(fp);
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}
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};
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#endif /* DORAYME_TEXTUREMAP_H */
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