118 lines
3.2 KiB
C++
118 lines
3.2 KiB
C++
#pragma once
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#include <stdint.h>
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#include <algorithm>
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#include "../datatypes.cpp"
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#include "../helpers.cpp"
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#include "../buffer.cpp"
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#include "../shaders/shaders.h"
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#include "../mappers/mappers.h"
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namespace UwU {
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class Triangle {
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private:
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public:
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Triangle(uint16_t x0, uint16_t y0, uint16_t x1, uint16_t y1, uint16_t x2, uint16_t y2) {
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this->x0 = x0;
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this->y0 = y0;
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this->x1 = x1;
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this->y1 = y1;
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this->x2 = x2;
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this->y2 = y2;
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}
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Triangle() {}
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uint16_t x0;
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uint16_t y0;
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uint16_t x1;
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uint16_t y1;
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uint16_t x2;
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uint16_t y2;
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// Draw a triangle
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template <class MapperT, class ShaderT>
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void draw (Buffer buffer, MapperBase<MapperT>& mapper, ShaderBase<ShaderT>& shader) {
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uint16_t topX, topY, midX, midY, btmX, btmY;
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// Find top, middle and bottom points of triangle
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if (y0 <= y1 && y0 <= y2) {
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topX = x0;
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topY = y0;
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if (y1 < y2) {
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midX = x1;
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midY = y1;
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btmX = x2;
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btmY = y2;
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} else {
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midX = x2;
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midY = y2;
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btmX = x1;
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btmY = y1;
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}
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} else if (y1 <= y0 && y1 <= y2) {
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topX = x1;
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topY = y1;
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if (y0 < y2) {
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midX = x0;
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midY = y0;
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btmX = x2;
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btmY = y2;
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} else {
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midX = x2;
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midY = y2;
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btmX = x0;
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btmY = y0;
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}
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} else {
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topX = x2;
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topY = y2;
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if (y0 < y1) {
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midY = y0;
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midX = x0;
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btmX = x1;
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btmY = y1;
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} else {
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midX = x1;
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midY = y1;
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btmX = x0;
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btmY = y0;
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}
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}
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uint16_t height = 1 + btmY - topY;
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int16_t longBound[height];
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int16_t splitBound[height];
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// Calculate LUT for longest vertical line (from top to bottom)
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Helpers::bresenham(0, topX, height - 1, btmX, longBound);
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// Calculate LUT for short two lines
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Helpers::bresenham(0, topX, midY - topY, midX, splitBound);
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Helpers::bresenham(midY - topY, midX, height - 1, btmX, splitBound);
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Coord2 uv;
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uint16_t leftX = std::min(topX, std::min(midX, btmX));
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// Left-handed triangle case (midpoint is left of triangle)
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if ((int16_t)midX < longBound[midY - topY]) {
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for (uint16_t i = 0; i < height; i++) {
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for (uint16_t x = (uint16_t)splitBound[i]; x <= (uint16_t)longBound[i]; x++) {
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uv = mapper.map(leftX, topY, x, i + (uint16_t)topY);
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buffer.drawPixel(x, i + (uint16_t)topY, shader.shade(uv.x, uv.y));
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}
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}
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// Right-handed triangle case (midpoint is right of triangle)
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} else {
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for (uint16_t i = 0; i < height; i++) {
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for (uint16_t x = (uint16_t)longBound[i]; x <= (uint16_t)splitBound[i]; x++) {
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uv = mapper.map(leftX, topY, x, i + (uint16_t)topY);
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buffer.drawPixel(x, i + (uint16_t)topY, shader.shade(uv.x, uv.y));
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}
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}
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}
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return;
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}
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};
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} |