51 lines
1.3 KiB
C++
51 lines
1.3 KiB
C++
#include "rt_weekend.h"
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#include "ray.h"
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bool hit_sphere(const vec3& center, 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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for(int Y = 0;
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Y < Buffer->Height;
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++Y)
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{
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uint32_t *Pixel = (uint32_t *)Row;
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for(int X = 0;
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X < Buffer->Width;
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++X)
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{
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float r = float(X) / float(Buffer->Width);
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float g = float(Y) / float(Buffer->Height);
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float b = 0.2;
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int ig = int(255.99 * r);
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int ir = int(255.99 * g);
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int ib = int(255.99 * b);
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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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