56 lines
1.5 KiB
C++
56 lines
1.5 KiB
C++
#include "rt_weekend.h"
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#include "ray.h"
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bool hit_sphere(const vec3 ¢er, float radius, const ray &r)
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{
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vec3 oc = r.origin() - center;
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float a = dot(r.direction(), r.direction());
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float b = 2.0 * dot(oc, r.direction());
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float c = dot(oc, oc) - radius * radius;
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float discriminant = b * b - 4 * a * c;
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return (discriminant > 0);
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}
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vec3 color (const ray &r)
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{
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if (hit_sphere(vec3(0, 0, -1), 0.5, r))
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return vec3(1, 0, 0);
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vec3 unit_direction = unit_vector(r.direction());
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float t = 0.5 * (unit_direction.y() + 1.0);
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return (1.0 - t) * vec3(1.0, 1.0, 1.0) + t * vec3(0.5, 0.7, 1.0);
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}
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extern "C"
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void
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PluginUpdateAndRender(plugin_offscreen_buffer *Buffer)
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{
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int Pitch = Buffer->Pitch;
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uint8_t *Row = (uint8_t *)Buffer->Memory;
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vec3 lower_left_corner(-2.0, -1.0, -1.0);
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vec3 horizontal(4.0, 0.0, 0.0);
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vec3 vertical(0.0, 2.0, 0.0);
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vec3 origin(0.0, 0.0, 0.0);
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for(int j = Buffer->Height - 1; j >= 0; j--)
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{
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uint32_t *Pixel = (uint32_t *)Row;
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for(int i = 0; i < Buffer->Width; i++)
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{
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float u = float(i) / float(Buffer->Width);
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float v = float(j) / float(Buffer->Height);
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ray r(origin, lower_left_corner + u * horizontal + v * vertical);
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vec3 col = color(r);
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int ir = int(255.99 * col[0]);
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int ig = int(255.99 * col[1]);
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int ib = int(255.99 * col[2]);
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*Pixel++ = (ir << 24) + (ig << 16) + (ib << 8) + 0xFF;
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}
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Row += Pitch;
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}
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}
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