124 lines
3.4 KiB
C++
124 lines
3.4 KiB
C++
#include "RenderTarget.hpp"
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#include <cmath>
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namespace frame::render
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{
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RenderTarget::RenderTarget(Size size)
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: image(size)
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{
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}
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void RenderTarget::DrawPixel(Vector const& position, Color color)
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{
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if(position.x < 0 || position.y < 0 || position.x >= image.getWidth() || position.y > image.getHeight())
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return;
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image.at(position.x, position.y) = color;
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}
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void RenderTarget::DrawLine(Vector const& start,
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Vector const& end,
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Color color)
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{
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auto deltaX = std::abs(start.x - end.x);
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auto deltaY = std::abs(start.y - end.y);
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auto rX = start.x < end.x ? 1 : -1;
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auto rY = start.y < end.y ? 1 : -1;
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bool swap = false;
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if(deltaX < deltaY)
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{
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swap = true;
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std::swap(deltaX, deltaY);
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std::swap(rX, rY);
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}
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auto pos = start;
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auto E = 2 * deltaY - deltaX;
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DrawPixel(pos, color);
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while(pos != end)
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{
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if(E <= 0)
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{
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if(!swap)
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pos.x += rX;
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else
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pos.y += rX;
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E += 2 * deltaY;
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} else
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{
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if(!swap)
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{
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pos.x += rX;
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pos.y += rY;
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} else
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{
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pos.y += rX;
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pos.x += rY;
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}
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E += 2 * deltaY - 2 * deltaX;
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}
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if(pos.x < 0 || pos.y < 0 || pos.x >= image.getWidth()
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|| pos.y >= image.getHeight())
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break;
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DrawPixel(pos, color);
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}
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}
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void RenderTarget::DrawCircle(Vector const& center,
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int32_t radius,
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Color color)
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{
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int32_t const r_2 = radius * radius;
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Vector pos{0, -radius};
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DrawPixel(center + pos, color);
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DrawPixel(center + Vector{pos.x, pos.y * -1}, color);
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DrawPixel(center + Vector{pos.x * -1, pos.y * -1}, color);
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DrawPixel(center + Vector{pos.x * -1, pos.y}, color);
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DrawPixel(center + Vector{pos.y, pos.x}, color);
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DrawPixel(center + Vector{pos.y, pos.x * -1}, color);
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DrawPixel(center + Vector{pos.y * -1, pos.x * -1}, color);
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DrawPixel(center + Vector{pos.y * -1, pos.x}, color);
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while(pos.x <= radius / std::sqrt(2.f))
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{
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float E = pos.x * pos.x + ((float)pos.y + 0.5f) * ((float)pos.y + 0.5f) - r_2;
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if(E <= 0)
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{
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pos.x += 1;
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E += 2 * pos.x + 3;
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} else
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{
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pos.x += 1;
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pos.y += 1;
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E += 2 * pos.x - 2 * pos.y + 5;
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}
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DrawPixel(center + pos, color);
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DrawPixel(center + Vector{pos.x, pos.y * -1}, color);
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DrawPixel(center + Vector{pos.x * -1, pos.y * -1}, color);
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DrawPixel(center + Vector{pos.x * -1, pos.y}, color);
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DrawPixel(center + Vector{pos.y, pos.x}, color);
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DrawPixel(center + Vector{pos.y, pos.x * -1}, color);
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DrawPixel(center + Vector{pos.y * -1, pos.x * -1}, color);
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DrawPixel(center + Vector{pos.y * -1, pos.x}, color);
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}
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}
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} // namespace frame::render
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