92 lines
No EOL
3.2 KiB
C++
92 lines
No EOL
3.2 KiB
C++
#include "torus.h"
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#include <cmath>
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#include <GL/glew.h>
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#define PI 3.1415926535f
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struct vec { float x; float y; float z; };
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unsigned int torusVAO, torusVBO;
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int lastSize = 0;
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void initTorus(int tubeSides, int ringSides) {
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// Free existing buffer
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if (torusVAO != 0)
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glDeleteVertexArrays(1, &torusVAO);
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if (torusVBO != 0)
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glDeleteBuffers(1, &torusVBO);
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lastSize = tubeSides * ringSides;
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// Set up buffer
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glGenVertexArrays(1, &torusVAO);
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glBindVertexArray(torusVAO);
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glGenBuffers(1, &torusVBO);
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glBindBuffer(GL_ARRAY_BUFFER, torusVBO);
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// Dynamic, because we update the vertices often V~~~~~~~~~~~~~~
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glBufferData(GL_ARRAY_BUFFER, sizeof(float) * 8 * 6 * tubeSides * ringSides, NULL, GL_DYNAMIC_DRAW);
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glEnableVertexAttribArray(0);
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glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(float), (void*)(0 * sizeof(float)));
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glEnableVertexAttribArray(0);
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glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(float), (void*)(3 * sizeof(float)));
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glEnableVertexAttribArray(1);
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glVertexAttribPointer(2, 2, GL_FLOAT, GL_FALSE, 8 * sizeof(float), (void*)(6 * sizeof(float)));
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glEnableVertexAttribArray(2);
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glBindBuffer(GL_ARRAY_BUFFER, 0);
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glBindVertexArray(0);
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}
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void genTorusPoint(float* vertex, float outerRadius, float innerRadius, float tubeSides, float ringSides, int tube, int ring) {
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float angle = float(tube) / tubeSides * 2 * PI;
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float xL = innerRadius * cos(angle);
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float yL = innerRadius * sin(angle);
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float outerAngle = float(ring) / ringSides * 2 * PI;
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float x = (outerRadius + xL) * cos(outerAngle);
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float y = (outerRadius + xL) * sin(outerAngle);
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float z = yL;
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vertex[0] = x; vertex[1] = y; vertex[2] = z;
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// TODO: Add normals and tex coords
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}
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// made by yours truly
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void genTorus(float outerRadius, float innerRadius, int tubeSides, int ringSides) {
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// Automatically generate VBO ad-hoc
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if (lastSize != tubeSides * ringSides)
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initTorus(tubeSides, ringSides);
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float* vertices = new float[(tubeSides * ringSides * 6) * 8];
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int vi = 0;
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for (int i = 0; i < tubeSides; i++) {
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for (int j = 0; j < ringSides; j++) {
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int in = (i+1) % tubeSides;
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int jn = (j+1) % tubeSides;
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genTorusPoint(&vertices[8*vi++], outerRadius, innerRadius, tubeSides, ringSides, i, j);
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genTorusPoint(&vertices[8*vi++], outerRadius, innerRadius, tubeSides, ringSides, in, j);
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genTorusPoint(&vertices[8*vi++], outerRadius, innerRadius, tubeSides, ringSides, in, jn);
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genTorusPoint(&vertices[8*vi++], outerRadius, innerRadius, tubeSides, ringSides, in, jn);
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genTorusPoint(&vertices[8*vi++], outerRadius, innerRadius, tubeSides, ringSides, i, jn);
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genTorusPoint(&vertices[8*vi++], outerRadius, innerRadius, tubeSides, ringSides, i, j);
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}
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}
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// Bind new data
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glBindBuffer(GL_ARRAY_BUFFER, torusVBO);
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glBufferSubData(GL_ARRAY_BUFFER, 0, sizeof(float) * 8 * 6 * tubeSides * ringSides, vertices);
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glBindBuffer(GL_ARRAY_BUFFER, 0);
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// Draw
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glBindVertexArray(torusVAO);
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glDrawArrays(GL_TRIANGLES, 0, tubeSides * ringSides * 6);
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} |